Re: Caribbean - Central America Weather (Watching INVEST 96L)
Posted: Tue Nov 13, 2018 9:42 am
by cycloneye
A Flash Flood Watch has been issued from Tuesday thru Thursday.
Re: Caribbean - Central America Weather (Effects of strong tropical wave in NE Caribbean)
Posted: Tue Nov 13, 2018 4:52 pm
by cycloneye
Area Forecast Discussion National Weather Service San Juan PR 548 PM AST Tue Nov 13 2018
.SYNOPSIS...An active tropical wave interacting with an upper level trough will result in scattered to numerous showers and thunderstorms across the region during the next few days. Unstable weather conditions are expected to continue through at least Friday. A mid to upper level ridge will build from the northeast during the weekend, promoting fair weather conditions through early next week.
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.SHORT TERM...Today through Thursday...
A flash flood watch is in effect through at least thursday afternoon for Puerto Rico and the U.S. Virgin Islands. Scattered convection across the USVI and eastern PR left between 1-2 inches of rain today. Minor urban flooding was reported today over portions of eastern PR. An area of strong thunderstorms persisted over the offshore Caribbean waters just to the south and east of St. Croix, some of this activity is expected to affect St. Croix through the evening hours. Breezy conditions will continue with winds ranging between 15-25 mph, with the higher winds remaining across the offshore waters.
As the wave axis continues to approach the region from the east and cross the islands on Wednesday...additional showers and thunderstorms are expected to increase overnight into Wednesday morning across the USVI and the eastern portions of PR. Based on the latest guidance, the heaviest shower activity is expected between early Wednesday morning through Wednesday evening across the islands. Rainfall accumulations in general should range between 1-4 inches with isolated higher amounts through the short term period.
Re: Caribbean - Central America Weather
Posted: Wed Nov 14, 2018 4:54 am
by cycloneye
Area Forecast Discussion National Weather Service San Juan PR 529 AM AST Wed Nov 14 2018
.SYNOPSIS...Unstable pattern associated with a surface trough and an upper level low will continue to produce periods of heavy rainfall across the local islands through Thursday. Conditions will gradually improve Friday as mid-level high pressure ridge will limit the coverage and the vertical development of the showers. A moisture surge embedded in the trade winds will bring some passing showers on Saturday.
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.SHORT TERM...Today through Friday...
The interaction of a low level trough over the area with an upper level low spread from Haiti to just west of Saint Croix and abundant moisture will cause shower and thunderstorms to continue across the area. Southeast flow of 20 to 30 knots will keep a flow of moisture over the local area with southeast Puerto Rico receiving a major portion of the rainfall, but with northwest Puerto Rico receiving some afternoon showers due to local convergence and heating. A dry slot at 700 mb will enter the area around 15/12Z, but will be followed by another band of good moisture and a ribbon of moisture that will arrive from the east southeast on Friday.
The low pressure in the upper levels appears to have disrupted the formation of a tropical system and the National Hurricane Center continues to give it a dismal chance of becoming a tropical storm in the next 5 days. Also the wave has a classic inverted vee formation, the first leg of which is over Puerto Rico and the Atlantic waters to the north. This is why Saint Thomas and Saint Croix received so little rain overnight. The second leg should arrive tonight--or a little earlier in the case of the U.S. Virgin Islands. But after this leg goes by, the southeast flow that continues will bring bands of high humidity through the area and more narrow bands of drier air and subsidence that will keep shower formation likely through the period.
A flash flood watch continues in effect for all of Puerto Rico and the U.S. Virgin Islands. Local rains of 1 to 4 inches, the exact location being difficult to ascertain, are expected today through Thursday and would produce flooding. Nevertheless, widespread flooding is not expected.
.LONG TERM...Saturday through Tuesday...
Another upper level low/TUTT will approach the region from the east. This feature is forecast to remain over the Leeward Islands keeping the local area on the stable side of the trough during the weekend. However, a moisture surge embedded in the easterly trade winds will bring showers and a couple of thunderstorms at times during the weekend.
By early next week...Mid level ridge will hold and dominate the local weather conditions. This will strengthen the trade wind cap favoring a decrease in shower and thunderstorm activity. Under this pattern, fresh trade winds will carry some showers over the USVI and eastern PR in the morning followed by the typical afternoon convection over western PR.
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.AVIATION...An upper lvl low and slowly migrating trough has produced a wide area of rain, MVFR and mtn obscurations that covered the eastern quarter of PR at 14/09Z with only isolated showers over other land areas. Sct-numr showers will persist over the Atlantic waters. SHRA over land will dvlp after 14/14Z and spread west. By 14/16Z SHRA/TSRA are expected to dvlp ovr wrn and interior PR. SHRA/TSRA will also be present around the Leeward Islands. Unsettled conds will prevail thru 16/18Z in the fcst area. Sfc winds ESE 10-20 kt with some sea breeze influences aft 14/14Z. Max winds blo FL540 are ESE-SE and are all are blo FL100 at 15 to 25 kt.
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.MARINE...Breezy conditions will likely prevail the rest of the week, resulting in choppy conditions across most of the regional waters. As a result, Small Craft Advisories are in effect for most of the local waters through at least the end of the work week. Seas should range between 6-8 feet occasional up to 10 feet offshore, and between 3-6 feet elsewhere.
Area Forecast Discussion National Weather Service San Juan PR 607 AM AST Thu Nov 15 2018
.SYNOPSIS...Drier air mass will move over the local islands today. As a result, the shower and thunderstorm coverage should be less than yesterday. Another surge of moisture will increase the potential for showers and thunderstorms again during the weekend.
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.SHORT TERM...Today through Saturday...
An intense surface low (947 mb) east of Newfoundland will push a 1024 mb high to 1000 miles northeast of Punta Cana or 900 miles from San Juan, Puerto Rico. This will keep surface and low-level flow mostly east with a weak southerly component and serve to bring bands of moisture out of the western tropical Atlantic separated by some very dry patches of air.
The MIMIC product shows the first dry band now pushing across the northern end of the Leeward Islands into the U.S. Virgin Islands. Currently the GFS has 850 mb dry pocket about 200 miles southeast of the driest air at 700 mb making exact timing more difficult. But using precipitable water as a proxy, expect drying to begin around 8 AM AST over the U.S. Virgin Islands and noon on the east coast of Puerto Rico. This drier air will take its greatest toll on convection between 8-10 kft even though the GFS suggests that convection should be able to rise unimpeded to 44 kft. The drier layer should also mean an early end to convection in the western half of Puerto Rico this afternoon as well. Before this happens though, heavy showers and isolated thunderstorms should develop over western Puerto Rico. Although the threat of flash flooding is now considered over, and the Flash Flood Watch has been cancelled, urban and small stream flooding is expected in western Puerto Rico and mudslides cannot be ruled out.
A second band of moisture moves through the area between 16/00-12Z and another round of showers will cross mainly eastern Puerto Rico in the morning hours on Friday. Friday afternoon also looks very wet with rainfall totals exceeding two inches in some areas. The moisture that continues to flow northwest into Puerto Rico will peak again just after noon on Saturday for yet another round of heavy rainfall for Puerto Rico. Drying begins immediately afterwards.
Influence from the upper level trough and instability over the area will gradually wane through the period, but convection Thursday night (where it forms), Friday night and Saturday could gain a weak boost due to upper level divergence.
.LONG TERM...Sunday through Wednesday...
Mid level ridge will build and dominate the local weather conditions Sunday into early next week. At upper levels, a TUTT low will establish just northeast of the Leeward Islands. Both features favors the erosion of mid-upper level moisture across the local region. This will likely result in fair weather conditions across Puerto Rico and the U.S. Virgin Islands. However, trade wind showers will continue to reach portions of the U.S. Virgin Islands and eastern Puerto Rico at times but the frequency will be low. With mid level temperatures rising due to the presence of the ridge, only a couple of thunderstorms will form over western Puerto Rico each afternoon. This typical pattern will likely persist through most of next week.
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.AVIATION...Bands of moisture will pass through the area, but drier air is expected to improve flying conditions today compared to the last several days. VFR conditions are expected to prevail until SHRA/isold TSRA dvlp over wrn and interior PR aft 15/16Z with mtn obscurations. SHRA will dissipate over these area aft 15/22Z but some SHRA will return to the USVI/ern PR and the Leeward Islands aft 16/00Z. Sfc winds will be ESE at 12 to 18 knots with some sea breeze influences. Max winds WNW 30 kt at FL410 by 16/06Z otherwise maximum winds ESE 20-25 kt btwn FL030-090.
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.MARINE...Breezy conditions have resulted in choppy conditions across most of the regional waters. As a result, Small Craft Advisories are in effect for most of the local waters through at least Saturday. Mariners can expected seas of 6-8 feet with occasional up to 10 feet across the offshore waters and between 3-6 feet elsewhere. Also, a high risk of rip currents continue for the north facing beaches of Puerto Rico and Culebra as well as the east coast beaches of St. Croix.
Area Forecast Discussion National Weather Service San Juan PR 532 AM AST Fri Nov 16 2018
.SYNOPSIS...Low level moisture will increase somewhat across the local islands today and Saturday as a wind surge propagates across the Northeast Caribbean region. This feature will likely increase showers activity across the U.S. Virgin Islands and Puerto Rico from time to time. A drying trend is forecast next week as a mid-upper level ridge will bring drier and more stable air aloft.
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.SHORT TERM...Today through Sunday...
High pressure weakens and settles into the central Atlantic Ocean from out of Maine yesterday. This will maintain easterly trade wind flow that will be enhanced by a wind surge and pulse of moisture. That moisture is visible as an arc of precipitable water of greater than 2 inches that developed and moved into the Leeward Islands overnight. The GFS is in agreement with model runs from yesterday-- at least qualitatively. It brings that higher moisture through Puerto Rico today and tonight, with the best moisture over San Juan by 17/00Z. The pulse of moisture and the low-level convergence the wind surge will bring bodes well for showers to increase during the day. Working against this, the GFS sounding does show a layer of relatively dry air (less than 15 percent between 14-15 kft) at 16/18Z with precipitable water still at a hefty 1.88 inches. This is an increase from the 1.77 inches measured in the 16/00Z sounding, but the layer cuts the convective potential and limits instability where the lapse rate becomes more stable, which will limit the amounts of rain that fall when they fall. By 17/00Z, however the model is showing 1.97 inches of precipitable water and no less than 35 percent in the previously dry layer. Hence, most windward slopes on the eastern part of Puerto Rico should get some rain before the evening ends and nearly all of Puerto Rico is expected to get at least a little rain before then. Western Puerto Rico will also see very good chances of showers and isolated thunderstorms with the heating allowed during the morning hours. Expect shower formation there by 16/16Z. Afternoon and evening rains across the U.S. Virgin Islands and Puerto Rico respectively, should end rather abruptly as the model shows precipitable water dropping rapidly overnight to only 1.2 inches.
Some showers are still possible over the eastern mountains of Puerto Rico, but the rest of of the island should see a dry Saturday morning. Then showers and a few thunderstorms become likely in west northwest Puerto Rico with only isolated to scattered showers elsewhere under a pulse of moisture more evident at 700 mb. The drying trend continues into Sunday. Although some moisture is around during the day, mid levels become quite dry. Most areas outside of the general area just east of the Rincon peninsula will see only isolated showers Sunday afternoon. Then later in the afternoon the GFS shows more moisture moving in from the southeast as fragmented patches of low level moisture move through the area in rapid succession. This will generate a few showers, but coverage should be relatively sparse.
Upper level divergence aloft is very limited during the entire period and most of the action that occurs will be dependent on conditions in the lowest levels.
.LONG TERM...Monday through Thursday...
Mid to upper level ridge will hold most of the next week, under generally fair weather conditions. The drier and more stable air mass at mid-levels will reduce the coverage of the showers and the probability of thunderstorms. However, weak easterly perturbation embedded in the trade winds will briefly enhance the diurnal shower activity Monday and Wednesday when these pertubations are forecast to move across the eastern Caribbean. The rest of the week expect typical weather conditions with brief passing showers over eastern Puerto Rico and the U.S. Virgin Islands during the morning hours, followed by some afternoon showers over western Puerto Rico. Winds will gradually diminish as the week progresses due a weakening of the surface high pressure over the north central Atlantic. All in all, a drying trend and a decrease in shower activity is forecast next week under the influence of a mid-upper level ridge.
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.AVIATION...In the Leeward Islands a band of moisture is moving through bringing brief MVFR CIGS and light showers. VFR is expected there aft arnd 16/18Z till 17/06Z. A band of moisture is moving into the USVI, but MVFR conds are expected to be brief--if any-- with sct SHRA till arnd 16/18Z. SHRA/TSRA will dvlp wrn and interior PR aft arnd 16/16Z with mtn obscurations and areas of MVFR/IFR til arnd 16/22Z. Periods of SHRA are expected in most areas of PR till arnd 17/00Z. Sfc winds E- ESE 10-18 knots with gusts to 26 kt psbl. Max winds blo FL540 will be 20-26 kt blo FL120 as a low level wind surge pushes through the area.
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.MARINE...Choppy seas will continue through the end of the week as breezy conditions will likely prevail across the regional waters. As a result, Small Craft Advisories are in effect for most of the local waters through Saturday, except for offshore Atlantic water where choppy conditions will prevail through Sunday. Mariners can expected seas of 6-8 feet with occasional up to 10 feet across the offshore waters and between 3-6 feet elsewhere. Also, a high risk of rip currents continue for the north facing beaches of Puerto Rico as well as the north and east coast of St. Croix.
Area Forecast Discussion National Weather Service San Juan PR 507 AM AST Sat Nov 17 2018
.SYNOPSIS...Diminishing moisture will produce less shower activity today, but some showers are still indicated. Showers and possible thunderstorms will return Tuesday night and Wednesday with the next band of better moisture, although some 700 mb moisture will be present. Shower activity will persist through the end of next week as a cold front approaches late next week.
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.SHORT TERM...Today through Monday... A somewhat settled weather pattern is progged through the short-term period with scattered showers across the eastern areas of Puerto Rico during the morning, then showers over portions of the western areas during the afternoon.
A drier weather pattern is expected to prevail through Monday. This is a result of drier air in the mid to upper-levels of the atmosphere as well as the 850 mb level. This air will move in from the east later this morning and through the afternoon. The GFS shows 850 mb to 700 mb relative humidities ranging from 20 to 40 percent. These values are 2 standard deviations below November`s climatology for San Juan Puerto Rico.
Sunday afternoon low-level moisture will increase over the western areas of the islands, then another patch of drier air is progged to rapidly filter in again out of the east. This patch of drier air will drop relative humidities values to the 25th percentile. Therefore, showers will be limited again across the area.
A strong ridge of high pressure will maintain it`s hold across the central Atlantic waters and promote a moderate to fresh easterly wind flow across the area. At the upper-levels, a weak trough remains to the northeast of Puerto. This feature will not have much of an effect on the local weather. Therefore, the short-term forecast is predicated on the drier air and patches of moisture that are forecast to move in from the east.
.LONG TERM...Tuesday through Saturday... High pressure will continue in the west central sub-tropical Atlantic. Higher pressure will begin to build into the western Atlantic out of the northeastern United States Friday night and Saturday of next week. Upper level high pressure will dominate the weather pattern until Friday and Saturday when a long wave trough will approach the area. An area of low level moisture will move into Puerto Rico and the U.S. Virgin Islands from the east northeast and bring a weak wind surge. This will increase the showers across the area on Tuesday night and Wednesday. This showery pattern will continue on and off through the period as patches of moisture move through. On Friday winds in the lower levels become nearly calm as a col at the end of an approaching frontal zone moves into the area. This will increase rain chances but should keep the best rains over the interior of the island Friday and Saturday. Due to the shallow nature of the best moisture rain fall amounts will be light to moderate, though the lack of good steering winds could leave some heavy showers in one place for an extended period of time during Friday and Saturday afternoons and might provoke an episode of local urban and small stream flooding.
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.AVIATION...VFR conds are expected to prevail through the reminder of the TAF period. Iso SHRA/tsra will develop across terminals TJMZ and TJBQ by 17/15Z before clearing out by 18/00Z. Sfc winds out of the east to southeast at 10 to 15 kts with higher gust up to 25 kts. Maximum winds ESE 25 kt at FL150 and NNW-N 25 kt btwn FL350-410.
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.MARINE...Winds from a passing wind surge have kept seas riled and seas in the outer Atlantic are still running 6 to 8 feet. Elsewhere in unprotected waters seas are running 5 to 7 feet. Although seas of at least 7 feet will persist in the northeast corner of the outer Atlantic waters through Wednesday, seas in the other waters should come down overnight tonight.
Area Forecast Discussion National Weather Service San Juan PR 521 AM AST Sun Nov 18 2018
.SYNOPSIS...Moderate trade wind flow will bring scattered showers to the area under upper level high pressure. A vigorous band of moisture will increase showers on Wednesday and thunderstorms will likely return to the interior. Then a cold front will approach the area and may cross on Saturday.
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.SHORT TERM...Today through Tuesday...
A stable weather pattern will continue to prevail as a result of limited moisture, a drier air mass and a surface and mid-level ridge over the area. The drier air mass, the surface and the mid- level ridges will limit shower development during the afternoon across most of the forecast area through Tuesday. However moderate trade winds with embedded moisture will periodically move in from the east. This could lead to isolated showers--mainly over portions of the interior and western Puerto Rico during the afternoon. Tuesday, model guidance shows moisture returning from the east and to the north of Puerto as a result of a stationary frontal boundary to the north of the islands. Therefore rain chance should go up during the middle of the week.
.LONG TERM...Wednesday through Sunday... At upper levels the ridge over the area will shift to the east through Thursday. A broad upper level trough will cross through and north of the area late Friday and pass through the leeward Islands on Sunday. At the surface and at lower levels a band of moisture will move through the area on Wednesday, followed by another pulse on Thursday and Friday. On Saturday surface flow slows and 700 mb flow becomes southwesterly as a front is forecast to move into the forecast area and cross through Puerto Rico and the U.S. Virgin Islands. Confidence is somewhat low on this crossing as the GFS generally moves fronts too far southeast, so have tempered the forecast somewhat regarding shower activity. There is moisture however so POPs will be fairly good until Sunday. The low level trough also stalls over the area with some good moisture. Mid and upper level moisture values drop significantly by Sunday, so rain chances are expected to taper off then.
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.AVIATION...VFR conditions are expected to prevail across TAF sites through 18/22Z. -SHRA/SHRA are forecast to develop across the western and interior areas of Puerto Rico, or near terminal sites TJMZ and TJBQ by 18/17Z. Clearing is forecast to begin around 18/23Z. Winds will continue to prevail from the east to northeast at 15 to 20 kts with higher gusts possible--on exposed coasts. Winds back to the east- northeast at 026 to 041 kft ranging from 20 to 30 kts.
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.MARINE...Seas will come down some today and all small craft advisories up previously will come down by 2 PM AST. Small craft will need to exercise caution afterward. Conditions will deteriorate briefly in the local Atlantic outer waters Monday night, but seas are expected to subside on Tuesday.
Area Forecast Discussion National Weather Service San Juan PR 404 AM AST Mon Nov 19 2018
.SYNOPSIS...A surface high pressure located over the central Atlantic will continue to generate easterly winds across the local region. Expect increasing moisture associated to a low level disturbance that is forecast to move across the southern Caribbean waters between today through Tuesday.
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.SHORT TERM...Today through Wednesday...
Modest high pressure at the surface continues over the central Atlantic. A ridge of high pressure at upper levels will move across the area from Haiti to arrive on Wednesday, with north to northwest flow over the area the entire period. Mid levels are exceptionally dry (less than 6%) through Wednesday night. This will limit showers and convection over the area significantly. This morning a band of moisture begins to generate around 52 west in the easterly flow. It will strengthen through Wednesday and expand in area as it approaches Puerto Rico and the U.S. Virgin Islands. It will enter the forecast area on Tuesday afternoon, spread through the area late Tuesday and Tuesday night, then leave the area just as quickly on Wednesday morning. Models show its maximum vertical extent when it passes over San Juan Tuesday night should be only about 600 mb, so thunderstorms are not expected. Low level moisture on Wednesday will probably linger long enough to support good--though shallow-- convection Wednesday afternoon in western Puerto Rico, otherwise conditions dry rapidly and few showers should be seen. One note, although models have been consistent with regard to the existence of this feature, they have steadily advanced its arrival by several hours in each run as well as weakened it during the last past several days. This trend may continue.
.LONG TERM...Thursday through Monday... High Pressure will move closer our local forecast area on Thursday generating a more stable and drier conditions across the local region through Friday. After Saturday the forecast will depend how close the frontal boundary will be to our local forecast area. On the latest GFS model suggest the highest amount of moisture will stay over the Atlantic ocean but enough moisture will reach the local area to increase the chances of showers on Sunday and Monday.
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.AVIATION...VFR conditions are expected to prevail across the forecast area thru 20/06Z. With exceptions mentioned blo. -SHRA/SHRA are fcst to dvlp across the wrn and interior areas of PR by 19/19Z, clrg aft 18/23Z. Any MVFR due to CIGS will be brief as it was earlier this morning at TIST and would be most likely at TISX and TKPK bfr 19/15Z. Brief MVFR will also be psbl at TJMZ btwn 19/18- 21Z with mtn obscurations over the Cordillera Central. Winds will continue to prevail from the east to northeast at 10 to 15 kt-- highest along the coasts with sea breeze influences. Max winds NW-N 25-25 kt btwn FL270-470.
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.MARINE...Small craft operators should exercise caution as combined seas are forecast to be between 4 to 6 feet across local Atlantic waters, Anegada Passage and the off shore Caribbean waters. A small NE ground swell will continue to reach our northern exposed coast through at least mid week. Another northern swell will reach our northmen coast on Saturday night and peak on Sunday morning. Easterlies winds throught at least mid week on the range of between 10 to 20 knots. There is a moderate risk of rip currents across many of the local northern exposed beaches today.
Area Forecast Discussion National Weather Service San Juan PR 425 AM AST Tue Nov 20 2018
.SYNOPSIS...A generally stable weather pattern to continue through the end of the week under ridge pattern. However, patches of low level moisture will assure passing showers later today through this evening.
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.SHORT TERM...Today through Thursday...
Fair weather conditions with significantly limited shower activity will prevail across the forecast area through mid morning. An area low level moisture now locate just east of the lesser antilles will enter the Anegada Passage early this morning and then over the local islands late this morning. Most of these showers are fast pace moving and no significant rainfall accumulations are expected. These showers could generate a few gusty winds as they pass by. After this Fair weather conditions will continue with significantly limited shower activity across the forecast area this evening. This is the result of drier air moving across the region and the effects of a surface to mid- level ridge of high pressure located over the north central Atlantic. The occasional patch of low- level moisture is expected once again Wednesday afternoon into Thursday. If any convection occurs, especially in the afternoon, it will be short- lived due to unfavorable environmental conditions.
.LONG TERM...Friday through Tuesday... On Friday although it will remain relatively stable, moisture content across the region will begins to increase. After Saturday the forecast will depend how close the frontal boundary will be to our local forecast area. On the latest GFS model suggest the highest amount of moisture will stay over the Atlantic ocean but enough moisture will reach the local area to increase the chances of showers from Sunday through Tuesday.
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.AVIATION...VFR conditions are expected to prevail across the forecast area through 21/06Z. As a band of moisture moves westward across the region, expect VCSH first at TKPK/TNCM around 20/08Z, then TJSJ at around 20/16Z, TJPS at around 20/22Z, and TJBQ at around 20/22Z. Afternoon convection will also bring VCSH to TJMZ/TJBQ between 20/16Z and 20/22Z. Winds will continue to prevail from the east to northeast at 10 to 15 kt--highest along the coasts with sea breeze influences and near showers and thunderstorms.
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.MARINE...Small craft operators should exercise caution as combined seas are forecast to be between 4 to 6 feet across local Atlantic waters, Anegada Passage and the off shore Caribbean waters. Easterlies winds throught at least mid week on the range of between 10 to 20 knots. There is a high risk of rip currents across many of the local northern exposed beaches today.
A A generally stable weather pattern to continue through the end of the week under ridge pattern. However, patches of low level moisture will assure passing showers particularly Tuesday night into Wednesday morning. northerly swell will reach the local Atlantic waters on Saturday night and peak on Sunday morning.
Area Forecast Discussion National Weather Service San Juan PR 437 AM AST Wed Nov 21 2018
.SYNOPSIS...A generally stable weather pattern will continue through the end of the week under ridge pattern. However, patches of low level moisture will assure passing showers during this period..
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.SHORT TERM...Today through Friday...
Although the current dominant feature is a mid level ridge, a plume of moisture associated to a short wave perturbation will continue to result in showers streaming over the local waters and possibly moving over coastal areas of southern Puerto Rico as it continues to move westward and away from the local islands. Drier air will invade once again the forecast area and a more stable weather pattern is expected through at least Friday morning. That is, mostly clear to partly cloudy skies with light passing showers streaming over the waters into windward areas of the islands during the overnight and early morning hours, followed by the development of showers over portions of the interior and western Puerto Rico in the afternoon. Then, the mid level ridge pattern is forecast to weaken on Friday as a mid level trough pulls from the northwest into the region. This feature will bring favorable upper level conditions and thus, an increase in convection across the forecast area after midday on Friday. Winds will continue from the east around 10-20 knots, but forecast to decrease on Friday.
.LONG TERM...Saturday through Wednesday...
The old frontal boundary located north of Puerto Rico will slowly dig south over the local forecast area through Saturday. This feature will help increase the moisture content over the region and therefore increase the chance of passing showers across the local islands. On Monday the Boundary is expected to move North and drag the moisture with it. High pressure will once again build over the area after Wednesday generating a more stable and dry conditions across the local forecast area.
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.AVIATION...VFR conditions are expected to prevail across all TAF sites during the next 24 hours. VCSH possible through at least 21/13z across all terminals, except for TJMZ. Afternoon convection will result in VCSH at TJMZ/TJBQ between 21/14z and 21/23z. Winds will continue from the E-ESE at 10-20 kt blo FL100.
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.MARINE...Small craft advisory continues in effect for the offshore Atlantic waters due to seas up to 7 feet. Elsewhere, small crafts should exercise caution due to seas up to 6 feet and/or winds up to 20 knots through at least Wednesday. A high rip current risk remains in effect for the northern beaches of Puerto Rico. Moderate risk continues across the rest of the island and across the USVI.
A series of northerly swell are forecast to affect the regional Atlantic waters. The first pulse of the northerly swell will reach our local waters on Saturday night and peaking on Sunday morning. A second pulse will reach the local waters on Tuesday morning and the third pulse will be on Wednesday afternoon.
Area Forecast Discussion National Weather Service San Juan PR 414 AM AST Thu Nov 22 2018
.SYNOPSIS...A generally stable weather pattern will continue through Saturday as drier than normal airmass dominates the local area. An increase in low-level moisture is expected late Saturday night into early next week as a surface low quickly moves northeastward into the north central Atlantic, pulling tropical moisture over the local area. However, shower activity will be limited as a mid level ridge moves in from the west and affects the local weather conditions through the rest of the forecast period.
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.SHORT TERM...Today through Saturday...
Mostly fair weather pattern is expected to continue for the next few days as drier than normal airmass dominates the local area. The available moisture is for the most part limited to the lower levels with dry air in the mid levels. There is also a mid and upper level ridge, which is keeping a stable atmosphere. A broad upper trough will move north of the local area on Saturday and moisture is also expected to start increasing late Saturday. This means that the nighttime and early morning trade wind showers will be isolated and brief, generally leaving trace amounts of rain to a few hundredths of an inch of rain in the few areas that do observe rain. Then in the afternoon, especially this afternoon, some light to moderate showers could develop across the northwestern quadrant of Puerto Rico due to local effects, but the amounts are not expected to cause hazardous conditions. A brief patch of moisture may pass through the area on Friday afternoon, which will help in the development of showers over Puerto Rico, especially in areas of sea breeze convergence, while the rest of the local islands may observe little to no rainfall. Saturday looks mostly dry during the daytime hours, but moisture will start to increase on Saturday night and will linger for a few days after that, for more details see below the long term section.
.LONG TERM...Sunday through Thursday...
Global models suggest that a surface low pressure will build and locate north of the region, pulling patches of tropical moisture into the forecast area Sunday through Monday as it moves quickly to the northeast. Then, a surface high pressure is expected to build over the Bahamas late Monday and drift eastward across the western Atlantic and north of the region through mid week. As a result, easterly low-level winds will turn from the northeast late Monday into Tuesday, but will veer to the east southeast on Wednesday. The low-level moisture that is expected to move across the local islands during the forecast period will enhance the potential for shower development. However, a mid level ridge drifting eastward across the region will limit the coverage and intensity of this activity.
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.AVIATION...VFR conditions are expected across the local terminals for the next 24 hours. Afternoon convection may result in VCSH at TJMZ/TJBQ between 22/18z and 22/22Z. Winds will be from the E to ESE with sea breeze variations at 10-15 KT.
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.MARINE...Choppy/Rough marine conditions are expected to continue across the outer Atlantic and Caribbean waters, as well as the Mona and Anegada Passage due to seas up to 6 feet. Therefore, small craft operators should exercise caution. Elsewhere, seas up to 5 feet are expected. Easterly winds up to 20 knots will continue across the regional waters. A high rip current risk remains in effect until early this morning for the north central coast of Puerto Rico. Then, a low to moderate risk will continue at least through Sunday for beaches of Puerto Rico and the U.S. Virgin Islands.
A series of northerly swell are forecast to affect the regional Atlantic waters and local passages. The first pulse of the northerly swell will reach our local waters late Saturday night, peaking on Sunday morning and continuing through Monday morning. A second pulse will reach the local waters on Wednesday afternoon, peaking late Wednesday night and continuing until Friday.
Area Forecast Discussion National Weather Service San Juan PR 501 AM AST Fri Nov 23 2018
.SYNOPSIS...The combination of a patch of low-level moisture moving across the area and an approaching upper level through will aid in the development of showers and possible thunderstorms across the local islands today. Conditions will somewhat dry out on Saturday, but a low pressure system moving over the western and into the north central Atlantic is expected to enhance moisture transport over the region by Sunday and Monday. Although the chance of shower development may increase during this period, upper level conditions are not expected to favor any significant development. A more stable weather pattern will return by Tuesday through the end of the workweek.
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.SHORT TERM...Today through Sunday...
A patch of moisture is moving in and causing light rain across the USVI into eastern PR, this shower activity is expected to dissipate by the mid morning hours. An upper trough will be over Hispaniola by the afternoon hours, causing some divergence aloft over the local area, which may combine with the available moisture and local effects to cause showers to develop in the afternoon across the northwestern quadrant of PR. Given this pattern, there is a slight chance of a brief thunderstorm this afternoon, but the mid levels are rather dry and forecast soundings show an inversion at about 650mb, which might be a bit much to overcome to cause a thunderstorm. However, the WRF model is suggesting small areas with good rainfall in the mid afternoon hours, and given the fact that there is currently more moisture and rainfall than what the models are suggesting, a brief thunderstorm this afternoon seems unlikely but a slight possibility will not be ruled out.
Saturday looks fairly dry again with the exception of some moisture across the Caribbean waters and slightly increasing moisture over the local area on Saturday afternoon. This moisture may combine with the local effects and diurnal heating to cause the development of showers across the northwestern quadrant of PR once again in the afternoon, while the rest of the local islands observe fair weather. Similar pattern is expected on Sunday as we have slightly higher moisture and showers over western PR in the afternoon could develop due to local effects.
.LONG TERM...Monday through Friday...
Global models continue to suggest that the trailing edge of a complex, non-tropical low pressure system will enhance moisture transport into the forecast area on Monday as it moves quickly eastward to east-northeastward over the western and north central Atlantic. During the same period, a surface high pressure is forecast to build over the Bahamas and drift eastward across the western Atlantic and north of the region through the middle of the week. As a result, easterly low-level winds will turn from the northeast on Monday through Wednesday, but will veer to the east southeast on Thursday. Any patch of low-level moisture that will move across the local islands will enhance the potential for shower development. However, a mid level ridge drifting east- northeastward into the northeastern Caribbean and central Atlantic will suppress the coverage and intensity of this activity.
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.AVIATION...VFR conditions are expected across the local terminals for the next 24 hours. Afternoon convection may result in VCSH at TJMZ/TJBQ between 23/18z and 23/22Z. Winds will be from the E to ESE with sea breeze variations at 10-15 KT.
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.MARINE...Seas are expected to remain at or below 5 feet at least until Sunday, when seas will increase slightly with the arrival of a northerly swell. However, only precautionary states may be require at the time, particularly for the Atlantic waters and local passages. A moderate risk of rip currents will continue for most beaches along the north coast of Puerto Rico, and a few beaches of Culebra, Vieques and the U.S. Virgin Islands. The risk of rip currents may increase to high Saturday afternoon.
Area Forecast Discussion National Weather Service San Juan PR 413 AM AST Sat Nov 24 2018
.SYNOPSIS...The mid to upper level ridge will generate dry and stable conditions across the region, This feature will limit the shower development until at least Sunday. Moisture associated to a frontal boundary now located north of the region will move closer increasing the chances of rain on Sunday and Monday. On Tuesday the ridge is forecast to build over the local area returning to a more dry and stable pattern.
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.SHORT TERM...Today through Monday...
Relatively dry airmass expected to continue today across the local area, especially over Puerto Rico. There is an area of higher moisture over the USVI and the Caribbean waters, which is expected to develop into a line of moisture and continue through Monday as moisture gets pulled by a surface low pressure system over the west central Atlantic. Even though there is some higher moisture nearby, the shower activity should be limited and mostly limited to the local waters, USVI, and eastern PR in the morning hours. The mid levels are too dry to support any significant shower development in the afternoon over Puerto Rico. The forecast soundings are suggesting precipitable water values mainly between 1.0 and 1.3 inches for today, which is rather dry, with most of the dry air above 700mb, but the lower levels do not look particularly moist either. Having said that, the lower levels moisten up a bit on Sunday, which could bring scattered showers to the USVI and eastern PR in the early morning hours, then some showers could develop over PR in the afternoon hours. Then for Monday, as the line of moisture develops and brings deeper moisture, the latest guidance insists that the eastern third of PR and perhaps the islands of Vieques and Culebra could observe scattered showers in the morning hours with the southwestern quadrant of PR possibly observing more significant and persistent rainfall in the afternoon, according to the WRF model.
.LONG TERM...Tuesday through Saturday
Frontal Boundary will remain stationary North of the local region through this forecast period with a mid to upper level ridge dominating the local forecast area. Although pulses of moisture are expected to move across the region, rainfall accumulations will not be significant. As the week goes by the frontal boundary will move closer to our region increasing the chances of showers for Saturday and Sunday
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.AVIATION...VFR conditions are expected across the local terminals for the next 24 hours. There may be some -SHRA across western PR after 24/18Z but these showers if they affect any of the local terminals it would be mainly in the vicinity and should be relatively short lived. Winds will be at around 10 kts from the SE for TIST, TISX and TJPS terminals, then E to NE for TJSJ and TJBQ, with TJMZ observing westerly winds due to sea breeze variations.
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.MARINE...Tranquil marine conditions will prevail through at least Tonight with seas between 2 to 4 feet and winds at around 10 knots. Tonight a northerly swell is forecast to affect the Atlantic waters an all local passages. Swells are expected to peak at 6 feet early Sunday morning and subside on Monday.
Area Forecast Discussion National Weather Service San Juan PR 410 AM AST Sun Nov 25 2018
.SYNOPSIS...The main feature dictating our weather pattern for the next several days is a mid to upper level ridge will continue to build and reestablish across the region through Friday and therefore maintain overall dry and stable conditions.
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.SHORT TERM...Today through Tuesday...
Fair weather is expected for most of the local area in the morning hours with showers developing in the afternoon, initially across the interior sections of Puerto Rico and then possibly displacing west and north of central PR. Some of the local guidance suggests that some of the showers could be significant enough to cause ponding of water on poor drainage areas. All this is because a narrow band of moisture is expected to move over PR in the afternoon hours, which will combine with the diurnal heating and local effects to have these showers develop. The local winds are rather light, so the showers are expected to develop in the interior pf PR, then due to its own outflow, more showers could develop later in the afternoon away from the interior of PR. The forecast soundings suggest that even though moisture is to increase slightly this afternoon, the mid levels are still rather dry and the upper levels are not conducive to thunderstorm development, therefore scattered to locally numerous showers are forecast but thunderstorms were left out. The coastal sections of Puerto Rico as well as the USVI should observe mainly fair weather with only a slight chance of showers. Having said that, keep in mind that some of the showers over PR could displace outwards from the interior of PR, particularly to western PR and some sections of the north central, eastern interior and near the San Juan metro, causing brief showers in the afternoon. There is some uncertainty though since too many factors come into play.
The local winds will still be on the lighter side, around 10 mph and lower across the interior sections of PR, becoming a bit more east northeasterly while the available moisture will be mainly limited to the lower levels on Monday and Tuesday. This setup will continue to promote mainly fair weather across the local islands, isolated or brief showers, if any, across the USVI and eastern PR during the nighttime hours and some showers to develop across western PR in the afternoon. A slightly higher patch of moisture could move in on Monday night into Tuesday, causing scattered showers across the north and eastern sections of PR and the northern USVI. With regards to temperatures, seasonable temperatures are expected, highs in the mid to upper 80s across the lower elevations of PR and across the USVI.
.LONG TERM...Wednesday through Sunday...
The mid to upper level ridge will generate dry and stable conditions across the region, This feature will limit the shower development until at least Friday. Only expect patches of moisture generating passing shower across the local region and some showers across the interior and western of Puerto Rico each afternoon. The GFS model suggest that for the incoming weekend these patches of moisture will become larger and more frequent therefore increasing slightly the chance of showers for this period.
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.AVIATION...VFR conditions are expected across the local terminals for the next 24 hours. There may be some SHRA across central into western PR after 25/18Z, which could at times reach the vicinity of the terminals in PR. Winds will be generally light, heavily influenced by sea breeze variations at around 5 to 10 knots.
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.MARINE...Local buoys already are already reporting the arrival of the northerly swell across the local Atlantic waters and local passages. The Buoy 41043 at 7:50 pm on Sunday showed the peak of the episode and now is showing a slow decrease on the height of the swell. Near shore Caribbean waters should expect seas of between 1 to 3 feet. Winds will remain at around 10 kts.
Beachgoers should be aware moderate to occasional large breaking swells along the northern coast of Puerto Rico and USVI. For this reason there is a high rip current risk for the Northwest through northeast facing beaches of Puerto Rico and Northern USVI.
Area Forecast Discussion National Weather Service San Juan PR 503 AM AST Mon Nov 26 2018
.SYNOPSIS...Surface high pressures at the surface, mid levels, and upper levels will continue to promote mainly fair weather across the local islands for the next couple of days, with the exception of some areas of western Puerto Rico due to local effects and the limited available moisture. Light to moderate winds are expected for the next several days. Seasonable temperatures are also expected. No major feature is expected to have significant impacts over the local islands.
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.SHORT TERM...Today through Wednesday... Showers developed across the coastal waters of southwest Puerto Rico and the northern U.S. Virgin Islands overnight. However, showers stayed along the coastal waters and no activity was detected over land, where skies remained mostly clear. Tranquil weather conditions will persist through the morning hours. But, diurnal and local effects will aid in the development of showers across the interior and northwest sections of Puerto Rico as well as downwind from El Yunque and from the Virgin Isles.
A mid-upper level ridge will continue to build and remain the main feature over the islands. Under this pattern and with an easterly wind flow, dry and stable atmospheric conditions will prevail through the sort-term. Although, moisture will remain below November normal values, a patch of moisture is forecast to reach the islands by Tuesday morning. This band will increase shower activity, but the mid-upper level ridge should suppress its vertical development. At this time, Wednesday would be another beautiful day with little or no shower activity, mostly sunny skies and seasonal temperatures.
.LONG TERM...Thursday through Tuesday...
Rather uneventful weather pattern is in store in the long term. Latest guidance is suggesting that a surface high pressure will move into the western Atlantic and move east, north of the local islands and remain dominating the local wind flow through the long term period, while there is a frontal boundary to the north of the local islands but that will remain just north of 20N before it weakens and fragments, having no impact locally. Then in the upper levels it looks like we will be under the influence of a ridge and same could be said for the mid levels. The available moisture in the long term will vary in patches of below normal to normal and briefly above normal moisture. So we will be observing fair weather but the chances of rain will increase when one of these patches of moistures passes over the local area. Having said that, even when moisture increases in one of these patches, the moisture will be mainly in the lower levels, it is not until very late in the forecast period that the column of moisture is observed through the mid levels, but this is very late in the period and confidence is really low. So at this time we can expect fair weather with moments of scattered showers when a patch of moisture moves in.
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.AVIATION...VFR conds are expected through the morning and early afternoon hours across the local terminals. SHRA expected across western PR after 26/18Z could cause VCSH at TJMZ, TJBQ and TJPS. Light winds through 26/13Z, increasing to 10-15KT from the east with sea breeze variations thereafter. Due to the expected convection in the afternoon, mountain obscurations can be expected.
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.MARINE...Seas are now generally between 2 and 5 feet and the winds 10 to 15 knots. These fairly benign seas are expected until late this workweek when a northerly swell, due to a surface low pressure across the northwestern Atlantic, invades the local waters.
Area Forecast Discussion...CORRECTED National Weather Service San Juan PR 419 AM AST Tue Nov 27 2018
.SYNOPSIS...Surface high pressure at the surface is weakening and a surface trough north of the local islands is expected by Thursday. The mid and upper levels will have a ridge for the next few days and will continue to promote mainly fair weather across the local islands for the next couple of days. However, some areas of western Puerto Rico may observe rain in the afternoons due to local effects combining with the limited available moisture. Light to moderate winds are expected for the next several days. Seasonable and near normal temperatures are expected this week.
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.SHORT TERM...Today through Thursday...
Surface moisture associated with a pre-frontal band will move from the southeast and northeast across the U.S. Virgin Islands, east Puerto Rico and surrounding waters through the morning hours. As this moisture move inland, it is expected to increase the chance for shower activity across the Virgin Isles during the morning and across the interior and west sections of Puerto Rico during the afternoon hours. A ridge aloft will limit vertical development across the islands, for that reason no thunderstorms were included in the forecast package. But, under a weak steering wind flow, rainfall activity could produce ponding of water on roads and low lying areas. In addition, urban and small stream flooding should not be ruled out during the afternoon.
After the passage of this surface feature, the local weather will be dominated by a mid-high pressure ridge and very dry air Wednesday and Thursday. As a result, no significant rainfall event is expected and thunderstorms were not included in the forecast package. However, isolated to scattered showers should not ruled out each afternoon over the interior and western Puerto Rico.
.LONG TERM...Friday Through Wednesday...
Very little to no change in the long term forecast compared to what we discussed yesterday. It still looks like a pretty uneventful weather pattern is to be expected with perhaps the only important feature being an upper low over the local area at the very end of the forecast period on Wednesday, which is frankly too far to put too much weight on it at the moment. Having said that, the latest guidance is still suggesting that a surface high pressure will move into the western Atlantic on Friday and move east, to the north of the local islands and remain dominating the local wind flow through the first half of next week. There may be a frontal boundary to the north of the local islands on Friday, but will remain north of 20N before it dips a bit further south while it weakens and fragments on Saturday, having no impact locally other than an increase in moisture across the local area on Sunday night. In the upper levels it still looks like we will be under the influence of a ridge until at least Tuesday, with the aforementioned upper low possibly developing on Wednesday. We will have a ridge in the mid levels through the long term period. The available moisture in the long term will vary in patches except maybe on Monday where the fragmented frontal boundary may provide persistent moisture over the local area. So we will be observing fair weather but the chances of rain will increase slightly when moisture increases over the local area, but there is really no significant increase in the rainfall forecasts from the long range model solutions. So at this time we can still expect mainly fair weather with moments of scattered showers when a patch of moisture moves in.
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.AVIATION...VFR conds are expected across the local terminals. However, mountain obscuration should not ruled be out across the interior and western PR this afternoon. As a result, SHRA/-SHRA could impact TJBQ/TJMZ between 27/16-22z. Surface winds will continue calm to light-vrb through 27/13Z, increasing to 10-15KT from the east with sea breeze variations thereafter.
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.MARINE...Seas are generally between 2 and 5 feet and the winds 10 to 15 knots. These fairly benign seas are expected until late in the workweek when a northerly swell invades the local waters, causing seas to increase to at least 6 feet on Friday.
Area Forecast Discussion National Weather Service San Juan PR 504 AM AST Wed Nov 28 2018
.SYNOPSIS... Below normal dry conditions will prevail across the islands through the end of the work-week. Aloft, a mid-upper level ridge will inhibit vertical development and thus thunderstorm formation. However, overnight and early morning showers across the windward sections of Puerto Rico and the U.S. Virgin Islands followed by afternoon showers across the interior and west Puerto Rico should not be ruled out each day.
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Short Term...Today through Friday...
A mid to upper level ridge over the central and eastern Caribbean will dominate the local weather conditions through the short term period. This will continue to promote a drying trend through at least late Thursday. An upper level trough and associated surface front are expected to approach the northeast Caribbean between Thursday and Friday, however, these two features are expected to provide little support for shower development as the upper ridge continues to hold over the region and the front lingers near 20N. Steering winds will continue at less than 10 kt through Thursday.
Diurnally induced afternoon showers are expected to develop today, mainly over portions of the interior and west/southwest PR. Lacking any upper level support only light to moderate rainfall amounts are possible. Maximum temperatures today are forecast to reach the high 80s to low 90s across coastal areas of southern and northern PR and in the mid to high 80s across the USVI. Models are indicating an even drier day on Thursday and an increase in low level moisture across the Caribbean waters on Friday. East to northeast trade winds will increase once again on Friday as a surface high pressure moves over the western Atlantic.
.LONG TERM...Saturday through Thursday... The aformentioned surface high pressure will drift from the western Atlantic into the eastern Atlantic ocean through the rest of the forecast period. Under this weather pattern, patches of low level moisture will reach the islands each day creating a seasonal weather pattern. Unfavorable upper level dynamic will continue, as the ridge aloft continues through much of the upcoming week. However, the latest model guidance suggested the remnants of a frontal boundary which may provide enough surface moisture to increase shower activity Sunday-Tuesday. In general, fair weather conditions will persist through much of the forecast period.
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.AVIATION... Mainly VFR conditions are expected to prevail during the next 24 hours across all terminals. Showers expected mainly across the regional waters and between 16z-22z over the interior and southwestern sections of PR. Light ESE winds will continue with sea breeze variations aft 15z.
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.MARINE... Tranquil marine conditions with seas below 5 feet and winds between 5 and 15 knots will continue across the local waters through at least Friday. Then a northerly swell is expected to reach the regional waters, increasing seas between 5 and 7 feet.
Area Forecast Discussion National Weather Service San Juan PR 501 AM AST Thu Nov 29 2018
.SYNOPSIS... Below normal dry conditions will prevail through at least Saturday. At upper level, a mid-upper level ridge will inhibit vertical development and thus thunderstorm formation. However, the trade winds will push patches of surface moisture at times each day.
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.SHORT TERM...Today through Saturday... Ridge aloft will continue to promote fair weather conditions and mostly sunny skies are expected across Puerto Rico today. An area of low level clouds with light showers was moving from the Leeward Islands into the local Caribbean waters. Therefore a few showers could move at times across portions of St. Croix today, however, no significant rainfall amounts are expected. Maximum temperatures will range between the high 80s to the low 90s across the lower elevations. Light winds will continue today and are expected to turn more from the northeast tonight and increase to around 15 kt through the weekend.
A surface front is forecast to stall just north of the region through the short term period. A weak shearline will increase the chances of showers on Friday afternoon, however, lacking any upper level support only light to moderate rainfall amounts are possible over portions of the southwestern quadrant of Puerto Rico. Across the USVI, passing showers should increase with the best rainfall accumulations expected over St. Croix.
.LONG TERM...Sunday through Friday... A backdoor front is expected to dig into the region increasing shower activity by early next week. However, model guidance still suggesting unfavorable upper level dynamic for the development of thunderstorm activity, as the ridge aloft is forecast to remain in place through at least Tuesday. Therefore, the best chance for showers is between late Sunday night into Tuesday.
A retrogressive TUTT is forecast to amplify near the Lesser Antilles, weakening the ridge pattern aloft, but we will have a high pressure ridge at mid levels through the long period. Having said that, a fair weather pattern is forecast for the upcoming week.
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.AVIATION... Mainly VFR conditions are expected to prevail during the next 24 hours across all terminals. Light sfc ESE winds will continue with sea breeze variations after 15z. Winds turn more ENE after 22z.
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.MARINE... Tranquil marine conditions with seas below 5 feet and winds between 5 and 15 knots will continue across the local waters through late tonight. Then a northerly swell is expected to reach the regional waters, increasing seas between 5 and 7 feet across the Atlantic Waters.
Area Forecast Discussion National Weather Service San Juan PR 503 AM AST Fri Nov 30 2018
.SYNOPSIS... A surge of moisture will bring passing showers across the windward sections of the islands through the morning hours. Thunderstorm development is not anticipated due to a mid to upper level ridge pattern. Another dry air mass is expected to reach the islands by late Saturday morning into early Sunday.
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Short Term...Today through Sunday...
A mid to upper level ridge will continue to hold through the short term period. Promoting fair weather conditions in general across the region. At lower levels, a surface front is forecast to stall north of the region while a surface high pressure builds behind the front promoting an east to northeast wind flow across the region. This will bring patches of low level clouds and light to moderate passing showers through the weekend. Although models suggest an increase in precipitable water content, it will continue below normal values. At least through Sunday, diurnally induced afternoon showers should develop each day over portions of the interior and west/southwest PR and as steering winds increase between 15-20 kt, streamers should develop off the USVI around noon each day.
.LONG TERM...Monday through Friday...
The remnants of a frontal boundary is expected to dig into the region increasing the available moisture as well as shower activity by early next week. Thunderstorm development is not anticipated at this time, as the ridge aloft is forecast to remain in place through much of the forecast period. However, model guidance suggested a good chance for moisture advection between Monday and Tuesday.
A retrogressive TUTT is forecast to amplify near the Lesser Antilles by mid-week, but should remain far enough to impact the local region. Having said that, a fair weather pattern is forecast to continue, with the arrival of patches of moisture at times.
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.AVIATION... Mainly VFR conditions are expected to prevail during the next 24 hours across all terminals. However, SHRA is expected over western PR between 16z-22z impacting mainly TJMZ. ENE winds at the sfc btw 10-15 kt, sea breeze variations expected aft 15z across southwestern PR.
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.MARINE... A north-northwest swells was detected moving across the local waters. Mariners can expect seas between 5 and 7 feet with occasional seas up to 9 feet across the Atlantic Waters. As a result, a small craft advisory is in effect for the Atlantic Offshore waters. Winds will gradually increase across the regional waters and local passages through the upcoming weekend. Small craft operators are urge to exercise caution over the expose local waters. Marine conditions are forecast to improve by mid- week of the upcoming week.
Beach goers should exercise caution from the northwest through northeast coastline of Puerto Rico, Culebra and St Thomas due to a high risk of rip currents.