Caribbean - Central America Weather

[cycloneye]

Updated discussion by NWS San Juan


AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SAN JUAN PR
1010 PM AST SAT APR 24 2010

.UPDATE...ALL BUT THE VERY LIGHTEST OF SHOWERS HAVE FADED FROM THE
RADAR OVER LOCAL LAND AREAS AND THE ONCE POWERFUL BAND OF
CONVERGENCE APPEARS TO HAVE DISSOLVED UNDER THE INFLUENCE OF A
STRONG NORTHWESTERLY JET BEHIND AN UPPER LEVEL SHORT WAVE
MENTIONED IN THE PREVIOUS DISCUSSION. THIS IS ALSO ACCOMPANIED BY
A DROP IN THE PRECIPITABLE WATER OF ABOUT ONE THIRD OF AN INCH.


&&

.DISCUSSION...MODELS SHOW HIGH PRESSURE AT THE SURFACE MOVING PAST
PUERTO RICO ABOUT 18Z SUNDAY. ALTHOUGH THEY ARE NOT IN AGREEMENT
AS TO MOISTURE...THE GFS MOVES THE BAND BACK THROUGH THE AREA
SUNDAY WHILE THE NAM DOES SO ON MONDAY...THEY BOTH AGREE THAT LOW
LEVEL FLOW WILL CHANGE TO THE SOUTHEAST BY TUESDAY. NEVERTHELESS
BOTH MODELS ALSO SUGGEST THAT THERE WILL BE LESS MOISTURE AT 06Z
TONIGHT THAN 12Z TOMORROW MORNING AND EACH SUGGESTS THAT SHOWERS
COULD RE-FORM IN THE AREA SUNDAY MORNING. ON MONDAY BOTH MODELS
BRING A GOOD CHANCE OF SHOWERS TO THE CARIBBEAN JUST SOUTHEAST OF
PUERTO RICO BETWEEN THE MAINLAND AND SAINT CROIX. HAVE GONE WITH
BOTH SCENARIOS AS THE BACK EDGE OF THE MOISTURE IN THE MIMIC
PRODUCT IS STILL JUST NORTH OF US.

IN THE LONGER RANGE...A BAND OF MOISTURE IS NOW BEING BROUGHT IN ON
WEDNESDAY AND THIS COULD INCREASE THE SHOWER ACTIVITY...BUT
THURSDAY AND FRIDAY STILL LOOK DRIER.

&&

.AVIATION...
PREVAILING VFR CONDS EXPECTED TO CONTINUE ACROSS ALL
THE LOCAL TAF SITES THROUGH AT LEAST 25/16Z. AFT 25/16Z...SHRA
FORMATION ACROSS THE CORDILLERA CENTRAL OF PR WILL RESULT IN
MOUNTAIN OBSCURATIONS AND THE POSSIBILITY OF MVFR CIGS AND VSBY
ACROSS TJPS AND TJMZ FROM 25/17Z THROUGH 25/23Z. NE WINDS OF 10 TO
15 KTS ARE EXPECTED IN THE LLVLS FOR THE NEXT 24 HOURS.

.CLIMATE...IF THE TEMPERATURE DOES NOT FALL BELOW 77 DEGREES BY
MIDNIGHT...APRIL 24TH WILL MARK THE THIRD DAY IN A ROW IN WHICH A
NEW RECORD WARM MINIMUM TEMPERATURE HAS BEEN SET IN SAN JUAN. THE
MORNING LOW OF 80 ON APRIL 23 MARKS THE EARLIEST DATE ON RECORD
WHERE THE TEMPERATURE DID NOT FALL BELOW 80 DEGREES IN SAN JUAN.
MORE INFORMATION ABOUT THIS AND OTHER RECORDS CAN BE FOUND AT
http://WWW.WEATHER.GOV/SANJUAN IN THE NEWS ARCHIVE.

&&

[jasons2k]

Interesting - that's some warm weather for sure. One factor is probably the very warm SSTs as well.

[Gustywind]

Good morning to all

000
FXCA62 TJSJ 250934
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
534 AM AST SUN APR 25 2010

.SYNOPSIS...MID TO UPPER LEVEL TROUGH AND ASSOCIATED JET STREAK...
WILL CONTINUE CLOSE TO THE LOCAL ISLANDS TODAY. THIS FEATURE WILL
MOVE TO THE EAST...AWAY FROM THE REGION...TODAY AND MONDAY. A MID TO
UPPER LEVEL RIDGE WILL THEN BUILD ACROSS THE LOCAL ISLANDS FROM THE
SOUTHWEST EARLY DURING THE UPCOMING WEEK.

&&

.DISCUSSION...A WEAK FRONTAL TROUGH EXTENDING FROM HISPANIOLA
EASTWARD ACROSS PUERTO RICO AND CONTINUING EAST NORTHEASTWARD ACROSS
THE ATLANTIC...WILL CONTINUE NEARLY STATIONARY ACROSS THE REGION
UNTIL AT LEAST TONIGHT...WHILE DISSIPATES. THE MOISTURE PROVIDED BY
THIS FEATURE...IN COMBINATION WITH MARGINAL UPPER LEVEL DYNAMIC IS
EXPECTED TO PROMOTE THE DEVELOPMENT OF SCATTERED SHOWERS AND
THUNDERSTORMS THIS AFTERNOON...ESPECIALLY ACROSS INTERIOR...
NORTHEAST AND SOUTH SECTIONS OF PUERTO RICO. THE TROUGH IS EXPECTED
TO DISSIPATES BY MONDAY...WITH A DRY TREND THEREAFTER. SHOWER AND
THUNDERSTORMS WILL DIMINISH IN COVERAGE TODAY IN COMPARISON WITH
PREVIOUS DAYS ACTIVITY. HOWEVER...DUE TO ALREADY SATURATED SOILS
ACROSS CENTRAL PUERTO RICO...LESS RAINFALL AMOUNTS WILL INDUCE RAPID
RISES AND FLASH FLOODING ACROSS SOME LOCAL RIVERS.

TJSJ 25/00Z SOUNDING...INDICATED A PWAT VALUE OF 1.86 INCHES...A
SIGNIFICANT DECREASE FROM MORE THAN 2.0 INCHES FROM PREVIOUS THREE
RUNS. THE GFS GUIDANCE ALSO INDICATES...AN STEADY DECREASE IN PWAT
VALUES DURING THE NEXT FEW DAYS...INDICATING THAT THE NEXT DAYS WILL
BE LESS HUMID THAT PREVIOUS DAYS. HOWEVER...THE COMBINATION OF
DIURNAL HEATING WITH LOCAL EFFECTS...WILL CONTINUE TO INDUCE THE
DEVELOPMENT OF CONVECTION DURING THE AFTERNOONS. SURFACE HIGH PRESSURE
JUST OFF THE EAST COAST OF THE UNITED STATES WILL SPREAD EAST
INTO THE CENTRAL ATLANTIC TODAY THROUGH MONDAY. THIS WILL RESULT IN
A TIGHTENING OF THE LOCAL PRESSURE GRADIENT...AND THEREFORE AN
INCREASE IN THE TRADE WIND FLOW ACROSS THE REGION TONIGHT AND
MONDAY. THIS FEATURE WILL ALSO TURN THE LOW LEVEL WINDS FROM THE
SOUTHEAST EARLY IN THE WEEK...FOCUSING THE CONVECTION ACROSS
WESTERN AND NORTHWESTERN PUERTO RICO AND INDUCING ABOVE NORMAL
TEMPERATURES ACROSS NORTHERN COASTAL MUNICIPALITIES.

&&

.AVIATION...PREVAILING VFR CONDS EXPECTED ACROSS ALL LOCAL TAF SITES
THROUGH 25/15Z. HOWEVER...PASSING LOW LEVEL CLOUDS WITH A FEW LGT TO
MOD SHOWERS WILL MOVE ACROSS PICO DEL ESTE DURG THE EARLY MORNING
AND MAY BRIEFLY OBSCURE MTN TOPS VCNTY OF EL YUNQUE RAIN FOREST. AFT
25/16Z... SHRA FORMATION ACROSS THE CORDILLERA CENTRAL OF PR WILL
RESULT IN INCR CLOUDINESS WITH MTN TOP OBSCURATIONS AND PSBL MVFR
CIGS AND VSBY EN ROUTE AND VCNTY OF TJPS AND TJMZ FM 25/17Z-25/23Z.
ENE WINDS OF 5 TO 15 KTS ARE EXPECTED...SFC-050 KFT...THEN VEERING
WITH HEIGHT AND BCMG NORTHWESTERLY ABV 100 KFT.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 76 90 77 / 30 40 40 10
STT 85 76 86 79 / 40 50 50 20

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
&&

$$

09/72

[cycloneye]

Good morning to all the fellow Caribbean and Centralamerican friends. A calmer day in terms of much less rains but with the grounds oversaturated,any shower can cause flooding so lets see what happens.

[cycloneye]

Here is the complete information about what the new earliest low temperature ever recorded in San Juan.

http://www.srh.noaa.gov/sju/?n=record100423

Earliest 80 Degree Low Temperature Ever Recorded in San Juan, PR


The low temperature at the Luis Muñoz Marin Airport in San Juan fell to 80 degrees early Friday morning April 23rd, 2010, which surpassed the previous record warm minimum temperature of 78 degrees set on April 23rd, 1987. While it took till June 23rd of last year to record a low temperature of 80 degrees or warmer in San Juan, a record 59 days where the temperature did not fall below 80 degrees were still recorded in 2009.

April 23rd now marks the earliest date on record that the temperature has not fallen below 80 degrees in San Juan, with the previous record falling on May 9th, 1981. After a very warm start to the year, the average temperature through April 23rd now stands at 79.7 degrees, ranking as the 3rd warmest start to a year on record at the Luis Muñoz Marin International Airport (just behind 1983 and 1981 respectively).

Code: Select all

Top 5 earliest 80 degree minimum temperatures on record:

 

Date Low Temperature
April 23rd, 2010 80 F
May 9th, 1981 80 F
May 15th, 1992 80 F
May 15th, 1981 80 F
May 18th, 1983 80 F



[cycloneye]

Afternoon discussion by NWS San Juan

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
322 PM AST SUN APR 25 2010

.SYNOPSIS...AN ELONGATED MID TO UPPER LEVEL RIDGE WILL GRADUALLY
BUILD ACROSS THE LOCAL AREA TONIGHT AND MONDAY AND THEN LINGER
THROUGH THE END OF THIS UPCOMING WORK WEEK.

&&

.DISCUSSION...TODAY TURNED OUT TO BE A BIT DRIER THAN ORIGINALLY
EXPECTED...AS DEEPEST MOISTURE WAS PUSHED MAINLY SOUTH OF THE
LOCAL ISLANDS...BUT SOME LIMITED CONVECTION HAS DEVELOPED OVER THE
CENTRAL AND WESTERN INTERIOR AND WEST SECTIONS OF PUERTO RICO
DURING THE PAST HOUR OR SO. DO NOT ANTICIPATE ANY SIGNIFICANT
PROBLEMS FROM THESE SHOWERS AND THEY SHOULD DWINDLE AND END BY
25/22Z OR 25/23Z. FOR TONIGHT THROUGH AT LEAST EARLY MONDAY...
LOW LEVEL STEERING FLOW WILL GRADUALLY BECOME MORE EAST AND THEN
SOUTHEAST AND LEFTOVER MOISTURE TO OUR SOUTH AND EAST WILL ADVECT
BACK ACROSS THE LOCAL ISLANDS...TO PRODUCE SOME CLOUDINESS AND A
FEW SHOWERS. MONDAY AFTERNOON/S WEATHER WILL GREATLY DEPEND ON
THIS MOISTURE. IF IT MOVES FAST ENOUGH TOWARD THE NORTHWEST...A
SUNNY TO PARTLY CLOUDY AFTERNOON WITH DIURNALLY INDUCED SHOWERS
WILL PREVAIL...WITH VERY WARM TO HOT TEMPERATURES ALONG THE NORTH
COASTAL SECTIONS OF PUERTO RICO. HOWEVER...IF A SLOWER MOTION OF
THIS AREA OF MOISTURE TAKES PLACE...THEN A VARIABLY TO MOSTLY
CLOUDY AND MORE SHOWERY SCENARIO WILL BE THE CASE. AT THIS
POINT...AM LEANING TOWARDS THE FORMER AND HAVE SHADED GRIDS AND
FORECASTS A BIT MORE OPTIMISTIC...BUT DO NOT HAVE A GREAT FEELING
ON THIS EITHER WAY. THEREAFTER...FOR TUESDAY THROUGH THURSDAY...
COMBINATION OF MID TO UPPER LEVEL RIDGE AND AN OVERALL DRIER AND
MORE STABLE AIR MASS...SHOULD ALLOW FOR A GENERALLY FAIR WEATHER
PATTERN ACROSS THE FA. HOWEVER...LOCAL EFFECTS WILL STILL BE ABLE
TO PRODUCE SOME LOCALIZED CONVECTION EACH DAY...PARTICULARLY ON
WEDNESDAY AFTERNOON. STILL LOOKS LIKE SOUTHEAST SURFACE WINDS
COMMENCING MONDAY AND CONTINUING THROUGH WEDNESDAY AND PROBABLY
THURSDAY...SO IF ENOUGH SUNSHINE OCCURS AND SEA BREEZES ARE
LIMITED...NORTH COASTAL TEMPERATURES WILL ONCE AGAIN REACH THE
LOWER 90S.

&&

.AVIATION...EXPECT PREVAILING VFR CONDITIONS ACROSS ALL TAF SITES
DURING THE NEXT 12 HOURS. BRIEF PERIODS OF MVFR ARE POSSIBLE
ACROSS ALL TAF SITES...ESPECIALLY ACROSS TKPK...TNCM AND TJMZ DUE
TO SHOWERS AND VCSH. IN ADDITION...DUE TO THE SHOWER ACTIVITY
MOUNTAIN OBSCURATIONS WILL ALSO BE LIKELY. LATEST 25/12Z TJSJ
SOUNDING SHOWED EAST NORTHEAST WINDS BETWEEN 5 AND 10 KNOTS FROM
THE SURFACE UP TO 5K FEET.

&&

.MARINE...GENERALLY EXPECT WINDS OF 19 KNOTS OR LESS AND SEAS OF
8 FEET OR LESS ACROSS THE REGIONAL WATERS THROUGH TUESDAY. LONG
PERIOD...NORTH NORTHEAST SWELLS WILL BEGIN TO AFFECT THE LOCAL
ATLANTIC WATERS AND THE CARIBBEAN PASSAGES LATE TONIGHT AND WILL
LINGER THROUGH AT LEAST THE FIRST PART OF TUESDAY. THERE IS A
PRECAUTIONARY STATEMENT FOR MOST OF THE LOCAL COASTAL WATERS
TONIGHT...EXCEPT A SMALL CRAFT ADVISORY WILL GO INTO EFFECT FOR
THE ATLANTIC OFF SHORE WATERS AT MIDNIGHT TONIGHT.

[cycloneye]

Small Craft Advisory in effect

URGENT - MARINE WEATHER MESSAGE
NATIONAL WEATHER SERVICE SAN JUAN PR
816 PM AST SUN APR 25 2010

...INCREASING SEAS EXPECTED TONIGHT ACROSS THE LOCAL ATLANTIC WATERS...

.LONG PERIOD...NORTH NORTHEAST SWELLS WILL BEGIN TO AFFECT THE
LOCAL ATLANTIC WATERS AND THE CARIBBEAN PASSAGES OVERNIGHT TONIGHT AND
LINGER THROUGH TUESDAY...RESULTING IN LOCALLY ROUGH AND HAZARDOUS
MARINE CONDITIONS.

AMZ710-260430-
/O.CON.TJSJ.SC.Y.0032.100426T0400Z-100427T1600Z/
ATLC WATERS OF PUERTO RICO AND USVI FROM 10NM TO 19.5N-
816 PM AST SUN APR 25 2010

...SMALL CRAFT ADVISORY REMAINS IN EFFECT FROM MIDNIGHT TONIGHT
TO NOON AST TUESDAY...

A SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS REMAINS IN EFFECT FROM
MIDNIGHT TONIGHT TO NOON AST TUESDAY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A SMALL CRAFT ADVISORY MEANS THAT WINDS OF 22 TO 33 KNOTS AND
SEAS OF 7 FEET AND GREATER ARE EXPECTED TO PRODUCE HAZARDOUS
MARINE CONDITIONS FOR SMALL CRAFT. INEXPERIENCED MARINERS...
ESPECIALLY THOSE OPERATING SMALLER VESSELS...SHOULD AVOID
NAVIGATING IN THESE CONDITIONS.

[cycloneye]

Good morning to all. Warm temperatures and afternoon diurnal showers will be the rule today.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
316 AM AST MON APR 26 2010

.SYNOPSIS...WINDS WILL BECOME SOUTHEASTERLY TODAY IN RESPONSE TO
AN AREA OF SURFACE HIGH PRESSURE ENTERING INTO THE CENTRAL
ATLANTIC. THIS WILL ALLOW THE REMNANTS OF AN OLD BOUNDARY TO MOVE
ACROSS PUERTO RICO AND THE U.S. VIRGIN ISLANDS THIS
AFTERNOON...WITH SCATTERED TO LOCALLY NUMEROUS SHOWERS EXPECTED TO
DEVELOP LATE IN THE MORNING OR BY EARLY AFTERNOON. AFTER THIS
BOUNDARY PASSES LATER TODAY...SOUTHEASTERLY WINDS AND UNSEASONABLY WARM
TEMPERATURES ARE EXPECTED TO PREVAIL THROUGH THE END OF THE WEEK.


&&

.DISCUSSION...STARTING TO SEE SOME SHOWERS FORM ACROSS THE LOCAL
CARIBBEAN WATERS AND JUST SOUTH OF SAINT CROIX THIS MORNING.
EXPECT THE ASSOCIATED BAND OF MOISTURE TO GET CARRIED NORTHWARD
ACROSS PUERTO RICO THIS AFTERNOON...AND THIS MOISTURE COMBINED
WITH DAYTIME HEATING...WITH RESULT IN SCATTERED TO LOCALLY
NUMEROUS SHOWERS THIS AFTERNOON. HOWEVER...WITH HIGH PRESSURE
STRENGTHENING IN THE MID TO UPPER LEVELS OF THE
ATMOSPHERE...EXPECT MUCH LESS ACTIVE WEATHER THAN WE SAW WITH THIS
BOUNDARY AS IT MOVED ACROSS PUERTO RICO LAST FRIDAY AND SATURDAY.

ONCE THE REMNANTS OF THIS BOUNDARY LIFT NORTH OF THE LOCAL
ISLANDS...A GENERALLY SOUTHEASTERLY FLOW...LIMITED MOISTURE...AND
STABLE MID TO UPPER LEVEL ATMOSPHERIC CONDITIONS SHOULD HELP
SUPPRESS SIGNIFICANT SHOWER ACTIVITY ACROSS THE LOCAL ISLANDS
THROUGH THE END OF THE WEEK...WITH ABOVE NORMAL TEMPERATURES
EXPECTED ACROSS THE NORTHERN HALF OF PUERTO RICO ALL WEEK. DO NOT
EXPECT A MAJOR CHANGE IN THIS OVERALL "DRIER" WEATHER PATTERN TILL
LATE NEXT WEEKEND...WHEN MODELS ARE INDICATING A TUTT LOW FORMING
NORTH EAST OF THE LOCAL ISLANDS...WHICH MAY HELP TO INCREASE
SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE LOCAL ISLANDS.

&&

.AVIATION...PREVAILING VFR CONDS EXPECTED ACROSS ALL LOCAL TAF SITES.
EXPECTED BRIEF PERIODS OF MVFR ARE POSSIBLE...ESPECIALLY ACROSS TJBQ
AND TJMZ BETWEEN 26/18Z-26/22Z. THE AFTERNOON SHOWER ACTIVITY COULD
PRODUCE MOUNTAIN OBSCURATIONS ALONG THE CENTRAL AND WESTERN INTERIOR OF
PR. NO OTHER OPERATIONAL IMPACTS ARE EXPECTED FOR THE NEXT 24 HOURS
ACROSS FLIGHT AREA.

[Gustywind]

[cycloneye]

Afternoon discussion by NWS San Juan

I highlighted the long term paragraph as it mentions the ITCZ to lift northward. Hmmm,maybe the first tropical waves of the year?

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
228 PM AST MON APR 26 2010

.SYNOPSIS...SURFACE HIGH PRESSURE ACROSS THE CENTRAL ATLANTIC WILL
SHIFT EAST. AN AREA OF LOW PRESSURE WILL MOVE ACROSS THE WESTERN
ATLANTIC THE NEXT TWO DAYS. ANOTHER SURFACE HIGH PRESSURE WILL
BUILD ACROSS THE LOCAL AREA BY THE END OF THE WEEK. THIS SECOND
HIGH PRESSURE SYSTEM WILL PUSH A COLD FRONT OR ITS REMNANTS ACROSS
THE LOCAL AREA DURING THE WEEKEND.

&&

.DISCUSSION...SOME SHOWERS WERE NOTED ACROSS THE CARIBBEAN COASTAL
WATERS LATE THIS AFTERNOON...APPROACHING THE SOUTHERN COAST OF
PUERTO RICO. OTHER SHOWERS STARTED TO DEVELOPED ACROSS NORTH
CENTRAL PUERTO RICO...AND ACROSS THE NORTHWEST SECTION OF PUERTO
RICO. MEANWHILE...IN THE U.S. VIRGIN ISLANDS...SOME STREAMERS
DEVELOPED...BUT LITTLE RAINFALL WAS OBSERVED OVER THE ISLANDS.
WINDS HAVE BECOME MORE SOUTHERLY DURING THE LAST 24 HOURS. SURFACE
HIGH PRESSURE LOCATED ACROSS THE CENTRAL ATLANTIC...WILL SHIFT
EAST DURING THE NEXT DAY...AND WINDS ARE EXPECTED TO TURN MORE
SOUTHERLY BY MID WEEK. THIS CHANGE IN WIND DIRECTION...WILL COMBINE
WITH AVAILABLE MOISTURE...PROMOTING THE DEVELOPMENT OF SHOWERS
ACROSS THE NORTHWEST PART OF PUERTO RICO EACH AFTERNOON. ALSO...AS
THE HIGH PRESSURE SHIFT EAST...A LOW PRESSURE SYSTEM WILL PASS
WELL NORTH OF THE LOCAL AREA...BUT WILL BRING WITH IT DEEP
TROPICAL MOISTURE FROM THE SOUTHWEST BY MID WEEK. THEREFORE...AT
LEAST THROUGH WEDNESDAY...EXPECT THIS WEATHER SCENARIO...WITH
AFTERNOON SHOWERS DEVELOPING ACROSS THE CORDILLERA CENTRAL OF
PUERTO RICO DEVELOPING EACH AFTERNOON TO OCCUR. HOWEVER...AS THE
WEEK PROGRESS...A DRYING TREND IS EXPECTED TO OCCUR. ANOTHER
SURFACE HIGH PRESSURE IS FORECAST TO BUILD ACROSS THE WESTERN
ATLANTIC. LATEST SJU-GFS PROG SOUNDINGS INDICATED PW VALUES WILL
DROP SIGNIFICANTLY AT THE END OF THE WEEK...DROPPING TO NEAR 1.2
INCHES BY THE WEEKEND. THEREFORE...THE CHANCES OF RAINFALL WILL
DIMINISH SOMEWHAT ACROSS THE LOCAL AREA BY THAT TIME.

IN THE LONG TERM...THIS SECOND HIGH PRESSURE...WILL PUSH A COLD
FRONT OR ITS REMNANTS ACROSS THE LOCAL AREA...BUT NO SIGNIFICANT
RAINFALL IS EXPECTED WITH THIS SYSTEM AT THIS TIME. MODELS ALSO
SUGGEST...THE INTER TROPICAL CONVERGENCE ZONE...ITCZ...WILL SHIFT
FURTHER NORTH THE NEXT WEEK...WHICH COULD BE ANOTHER FEATURE TO
OBSERVED...AS THIS WILL HELP ALSO IN THE DEVELOPMENT OF AFTERNOON
SHOWERS...AS DEEP TROPICAL MOISTURE WILL BE TRANSPORTED IN THE
TRADE WINDS FLOW.

&&

.AVIATION...PREVAILING VFR CONDS EXPECTED ACROSS ALL LOCAL TAF SITES.
EXPECTED BRIEF PERIODS OF MVFR POSSIBLE...ESPECIALLY ACROSS TJBQ
AND TJMZ BETWEEN 26/18Z-26/22Z. THE AFTERNOON SHOWER ACTIVITY
COULD PRODUCE MOUNTAIN OBSCURATIONS ALONG THE CENTRAL AND WESTERN
INTERIOR OF PR. NO OTHER OPERATIONAL IMPACTS ARE EXPECTED FOR THE
NEXT 24 HOURS ACROSS FLIGHT AREA.

[tropicana]

Regional Weather Summary
Mon Apr 26 2010

Monday's Highs and rain (if any)

Piarco, C. Trinidad 34.5C 94F 2mm (late this afternoon)
Crown Point, Tobago 32.8C 91F

Grantley Adams, Barbados 32.2C 90F
Arnos Vale, St Vincent 31.5C 89F 3.4mm
Hewannora, St Lucia 31.5C 89F
Vigie, St Lucia 32.3C 90F trace

Melville Hall, Dominica 31.2C 88F
Canefield, Dominica 33.3C 92F trace
Le Lamentin, Martinique 32.4C 90F
Le Raizet, Guadeloupe 31.4C 88F 0.8mm

Golden Rock, St Kitts 29.8C 86F trace
West End, Anguilla 31.1C 88F 0.5mm
VC Bird, Antigua 30.4C 86F trace
San Juan, Puerto Rico 31.1C 88F 0.3mm

Norman Manley, Jamaica 31.4C 88F
Sangster, Montego Bay, Jamaica 32.5C 91F
Owen Roberts, Grand Cayman 31.4C 88F
Havana, Cuba 31.0C 88F 54.0mm

Nassau, Bahamas 29.9C 86F 21.6mm
Hamilton, Bermuda 22.9C 73F

-justin-

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1006 PM AST MON APR 26 2010

.UPDATE...ISOLATED SHOWERS REMAIN ACROSS THE LOCAL WATERS THIS
EVENING. WENT AHEAD AND REDUCED SHOWER COVERAGE OVER LAND FOR THE
REMAINDER OF THE EVENING AND OVERNIGHT HOURS...AS SE FLOW AND
LIMITED LOW LEVEL MOISTURE SHOULD KEEP MOST OF THE NORTHERN TWO
THIRDS OF PUERTO RICO DRY OVERNIGHT. STILL EXPECT SE WIND
FLOW...LIMITED MOISTURE...AND MAINLY DIURNALLY DRIVEN SHOWER
ACTIVITY ACROSS THE INTERIOR AND NORTHWESTERN SECTIONS OF PUERTO
RICO THROUGH THE END OF THE WEEK...WITH NO SIGNIFICANT CHANGES
NECESSARY TO INHERITED FORECAST THIS EVENING.

&&

.AVIATION...PREVAILING VFR CONDITIONS EXPECTED ALL TAF SITES FOR
NEXT 24 HOURS IN ESE LLVL WIND FLOW OF 10 TO 15 KTS. A VCSH OR
-SHRA WILL BE POSSIBLE ACROSS TJBQ AND TJMZ FROM 27/18-27/23Z
TOMORROW...ALONG WITH TEMPORARY MOUNTAIN OBSCURATIONS ACROSS THE
CORDILLERA CENTRAL.

[cycloneye]

Good morning to all.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
448 AM AST TUE APR 27 2010

.SYNOPSIS...SURFACE HIGH PRESSURE ACROSS THE CENTRAL ATLANTIC THIS
MORNING...WILL SHIFT EAST NORTHEASTWARD...MAINTAINING A SOUTHEAST
LOW LEVEL WIND FLOW ACROSS THE REGION UNTIL AT LEAST THURSDAY.
AN AREA OF LOW PRESSURE WILL MOVE ACROSS THE NORTHWESTERN ATLANTIC
TODAY WITH THE ASSOCIATED FRONTAL TROUGH PROGRESSING SOUTHEASTWARD.
ANOTHER SURFACE HIGH PRESSURE WILL BUILD ACROSS THE REGION BY THE
UPCOMING WEEKEND...PUSHING THE FRONTAL TROUGH NEAR OR ACROSS THE
LOCAL ISLANDS.

&&

.DISCUSSION...ONLY FEW ISOLATED SHOWERS WERE DETECTED OVERNIGHT
MAINLY ACROSS THE ATLANTIC OFFSHORE WATERS. NO SIGNIFICANT SHOWER
ACTIVITY WAS DETECTED ELSEWHERE ACROSS THE REGION SO FAR THIS
MORNING. THE SURFACE HIGH PRESSURE ACROSS THE CENTRAL ATLANTIC...
NORTHEAST OF PUERTO RICO...WILL MAINTAIN A LOW LEVEL SOUTHEAST
TRADE WIND FLOW ACROSS THE REGION DURING THE NEXT FEW DAYS. NO
SIGNIFICANT CONVECTION IS EXPECTED DURING THE NEXT SEVERAL DAYS.
IN AGREEMENT WITH THIS REASONING...THE GFS FORECAST SOUNDING
INDICATED PWAT VALUES WELL BELOW 2.0 INCHES UNTIL AT LEAST THE
UPCOMING WEEKEND. HOWEVER...THE COMBINATION OF DIURNAL HEATING
WITH LOCAL EFFECTS...WILL CONTINUE TO INDUCE THE DEVELOPMENT OF
CONVECTION EACH AFTERNOON MAINLY ACROSS WESTERN AND NORTHWESTERN
SECTIONS OF PUERTO RICO.

A LOW PRESSURE SYSTEM WILL MOVE ACROSS THE NORTHWESTERN ATLANTIC
TODAY...WITH THE ASSOCIATED FRONTAL BOUNDARY/SHEAR LINE PROGRESSING
ALSO SOUTHEASTWARD ACROSS THE ATLANTIC. A SECOND SURFACE HIGH
PRESSURE WILL MOVE ACROSS THE ATLANTIC...EAST OF FLORIDA...BY
FRIDAY. THIS FEATURE WILL PUSH THE REMNANTS OF THE FRONTAL
BOUNDARY ACROSS THE LOCAL COASTAL WATERS BY THE UPCOMING
WEEKEND...INCREASING THE CHANCES OF SHOWERS.

&&

.AVIATION...PREVAILING VFR CONDITIONS ARE EXPECTED ACROSS ALL LOCAL
TAF SITES TODAY. TYPICAL SEA BREEZE CONVERGENCE COULD HELP IN THE
DEVELOPMENT OF DIURNAL ISOLATED SHOWERS OVER THE WESTERN INTERIOR OF
PR...RESULTING IN BRIEF PERIODS OF MVFR CONDITIONS OVER TJBQ BETWEEN
26/18Z-26/22Z.

[Macrocane]

The GFS continue to show the possibility of some sort of tropical development with a disturbance in the EPAC, the TWD has been mentioning since yesterday that heavy rainfall is possible in Central America, this is the paragraph that discusses the system, it seems that our rainy season is about to begin:

PERSISTANT CONVECTION
ACROSS THIS ZONE HAS ALLOW FOR THE LARGE UPPER RIDGE TO
TELECONNECT WITH UPPER RIDGE ACROSS CENTRAL S AMERICA TO
MAINTAIN EXCELLENT UPPER DIFFLUENCE ACROSS THE ITCZ BETWEEN 85W
AND 108W. SEVERAL LOW TO MID LEVEL CYCLONIC SWIRLS ARE NOTED IN
IR IMAGERY FROM THE SW CARIBBEAN OFF OF COLOMBIA TO 93W WITH
GLOBAL MODELS SUGGESTING SOME POSSIBILITY OF BETTER ORGANIZATION
OF A BROAD LOW WITHIN THIS GYRE OVER THE NEXT FEW DAYS. WITH
CONTINUED LLVL NW TO W FLOW FORECAST N OF THE ITCZ OVER THE NEXT
SEVERAL DAYS...SLOW MOTION OF ANY ORGANIZED CONVECTION IS LIKELY
AND COULD LEAD TO VERY HEAVY TO COPIOUS RAINFALL IN THIS VERY
MOIST AND UNSTABLE REGION DURING THE NEXT FEW
DAYS...PARTICULARLY ACROSS THE MOUNTAINOUS TERRAIN OF CENTRAL
AMERICA FROM COSTA RICA TO GUATEMALA.

[cycloneye]

Keep us informed about this potential rainmaker or more stronger? I can see a invest for this if it starts to consolidate in the next 24-36 hours.

[JonathanBelles]

I've been watching this on the NAM/GFS for a few days now, and it looks promising.

Note: Central America is two words.

[Gustywind]

:uarrow: Keep us informed about this potential rainmaker or more stronger? I can see a invest for this if it starts to consolidate in the next 24-36 hours.

What a complex of...

[cycloneye]

It was a very warm afternoon here as the maximun temperature in San Juan reached 93F.

http://forecast.weather.gov/product.php ... glossary=1

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
215 PM AST TUE APR 27 2010

.SYNOPSIS...SURFACE HIGH PRESSURE ACROSS THE CENTRAL
ATLANTIC...WILL MAINTAIN A FRESH SOUTHEAST WIND FLOW ACROSS THE
LOCAL AREA THROUGH AT LEAST FRIDAY. ANOTHER SURFACE HIGH PRESSURE
WILL BUILD ACROSS THE WESTERN ATLANTIC SATURDAY. AN UPPER LEVEL
TROUGH WILL DEVELOP ACROSS THE NORTHEAST CARIBBEAN BY THE END OF
THE WEEKEND. WARMER THAN NORMAL MAXIMUM TEMPERATURES EXPECTED
ALONG THE NORTHERN SLOPES OF PUERTO RICO AT LEAST THROUGH FRIDAY.

&&

.DISCUSSION...LITTLE SHOWER ACTIVITY HAS DEVELOPED SO FAR ACROSS
THE LOCAL REGION. ONLY ISOLATED LIGHT SHOWERS WERE EVIDENT ACROSS
THE NORTHWEST SECTION OF PUERTO RICO. STILL EXPECT SOME SHOWER
DEVELOPMENT LATE THIS AFTERNOON ACROSS THE NORTHWEST SECTION OF
PUERTO RICO...BUT OVERALL...SHOULD REMAIN SUNNY AND HOT ACROSS
MUCH OF PUERTO RICO. THE MAIN WEATHER FEATURE WHICH IS IN TOTAL
CONTROL OF OUR LOCAL WEATHER IS A HIGH PRESSURE SYSTEM WHICH IS
LOCATED LATE THIS AFTERNOON ACROSS THE EASTERN CENTRAL ATLANTIC.
THIS HIGH PRESSURE WILL MAINTAIN A FRESH SOUTHEAST WIND FLOW
ACROSS THE REGION AT LEAST THROUGH FRIDAY. THIS WILL PROMOTE
HIGHER THAN NORMAL MAXIMUM TEMPERATURES...MAINLY ACROSS THE
NORTHERN HALF OF PUERTO RICO. FOR MORE DETAIL...REFER TO CLIMATE
SECTION BELOW.

IN THE MEANTIME...NO SIGNIFICANT WEATHER EVENTS ARE EXPECTED TO
AFFECT THE LOCAL AREA DURING THE NEXT SEVERAL DAYS. MOST OF THE
SHOWER ACTIVITY WILL OCCUR MAINLY EACH AFTERNOON...ACROSS THE
WESTERN PART OF THE ISLANDS. A SURFACE HIGH PRESSURE IS EXPECTED
TO BUILD ACROSS THE WESTERN ATLANTIC FRIDAY. THIS HIGH PRESSURE IS
EXPECTED TO PUSH THE REMNANTS OF A FRONTAL BOUNDARY ACROSS THE
LOCAL AREA BY THE BEGINNING OF NEXT WEEK. ALSO...AN UPPER LEVEL
THROUGH IS EXPECTED TO DEVELOP ACROSS THE REGION...WHICH WILL
SUPPORT MORE CHANCES FOR RAINFALL ACROSS THE LOCAL AREA NEXT
TUESDAY.

ALSO...THIS HIGH PRESSURE WILL INDUCE A MORE EASTERLY WIND FLOW
ACROSS THE NORTHEAST CARIBBEAN. WITH THIS IN MIND...MAXIMUM
TEMPERATURES ARE EXPECTED TO BE BACK TO NORMAL ACROSS THE NORTHERN
HALF OF PUERTO RICO DURING THE WEEKEND.

&&

.AVIATION...EXPECT PREVAILING VFR CONDITIONS ACROSS ALL TAF SITES
DURING THE NEXT 24 HOURS. BRIEF PERIODS OF MVFR ARE POSSIBLE ACROSS
TJBQ AFT 27/18Z...DUE TO POSSIBLE SHOWERS. LATEST 27/12Z TJSJ
SOUNDING SHOWED SOUTH TO SOUTHEAST WINDS BETWEEN 5 TO 25 KTS FROM
THE SURFACE UP TO 7KFT...THEN BCMG SOUTHWESTERLY.

&&

.CLIMATE...AT 123 PM AST...THE MERCURY REACHED 93 DEGREES AT THE
SAN JUAN LUIS MUNOZ MARIN INTERNATIONAL AIRPORT. THIS READING TIES
THE RECORD HIGH TEMPERATURE FOR THIS DATE OF 93 DEGREES SET IN
1992.

[Macrocane]

The SNET (El Salvador's weather service) issued the first special report about the disturbance in the EPAC waters. It says in summary:

Description of the event:
The ITCZ located off central american coast looks very active and is producing fluctuating cloud fields from Costa Rica to Guatemala pulling abundant moisture in from the Pacific.

Forecast

Wednesday April 28: Abundant moisture from the Pacific and the Caribbean sea will produce moderate to strong showers and thunderstorms especially in the central and eastern parts of the country and high areas.

Thursday April 29: Moisture will continue to move from the Pacific and the Caribbean producing scattered and heavy showers.

[cycloneye]