Caribbean - Central America Weather

[cordelia667]

Thank you for your reply. I will go to the correct forum you posted. Most kind.

Cordelia

Hello All From St. Croix, US Virgin Islands. As you can imagine, I am monitoring TS Dorian closely. Although, it appears the NHC and most reliable models forecast Dorian to go N of we, here in the USVI, until I see it's forward movement change to at least 290 degrees, I am not so sure how close he will be when he approaches our area. I have read on NHC Advisory movement at 285 degrees, but then on NRL read 280 degrees.

I believe TS Dorian is being steered along below a tropical ridge N of him, is that correct? And, if that is the case, will there be a lifting or weakening in the ridge, allowing Dorian to move N of us here?

Any thoughts an explanations would be most welcomed.

Cordelia
St. Croix, US Virgin Islands

Hi my friend, be welcomed thanks for posting that . You're right in so many points. All the Leewards islands should follow Dorian. The best to do is to continue monitor it very carefully. Concerning the ridge and all your questions go on the thread who focuse on TS Dorian. Our members will try to help you and explain much more.

Go on this link cordelia667: viewtopic.php?f=59&t=115276&hilit=

[cycloneye]

Hi cordelia667. Apart from Dorian,you can come to this thread to post about the weather in St Croix when you can.

[Macrocane]

Sure Dorian bears watching for you in the islands, hopefully it will recurve.

In the eastern part of El Salvador there have been 5 to 7 days without rain, the dry pattern will reach the rest of the country this weekend but moderate rainfall can be expected before that. A dry and warm period is normal for late July and early August and we call it "canicula" (dog days).

ROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
205 PM EDT WED JUL 24 2013

AT 15UTC TROPICAL STORM DORIAN CENTERED NEAR 14.3N 29.9W...WITH
MAXIMUM SUSTAINED WINDS OF 45KT AND CENTRAL PRESSURE OF 1002 HPA.
THE STORM IS MOVING TO THE WEST-NORTHWEST AT 18KT. SEE NHC
ADVISORY FOR OFFICIAL FORECAST GUIDANCE.

DISCUSSION FROM JULY 24/00UTC: UPPER LEVEL RIDGE BECOMING DOMINANT
FEATURE ACROSS MEXICO TO THE NORTH OF 20N...WHILE CENTERING AT 250
HPA ON A CLOSED LOW ALONG THE BORDER WITH ARIZONA. SOUTH OF THIS
AXIS...A TUTT IS TO MIGRATE WEST ACROSS CENTRAL MEXICO EARLY IN
THE CYCLE...AND THROUGH 24-36 HRS CONTINUES ACROSS SOUTHERN BAJA
PENINSULA INTO THE EASTERN PACIFIC. EARLY IN THE CYCLE THIS IS TO
ENHANCE CONVECTIVE DEVELOPMENT ACROSS CENTRAL MEXICO TO FAVOR
RAINFALL AMOUNTS OF 15-20MM/DAY AND MAXIMA OF 25-50MM/DAY. BUT AS
THE TUTT PULLS AWAY...THIS DECREASES TO 10-15MM/DAY AND ISOLATED
MAXIMA OF 20-40MM/DAY. OTHER ACTIVITY TO THE NORTH IS TO BUILD
ALONG THE SIERRA MADRE OCCIDENTAL...WITH RIDGE ALOFT VENTING DEEP
DIURNAL CONVECTION. IN THIS AREA EXPECTING RAINFALL AMOUNTS OF
10-15MM/DAY AND ISOLATED MAXIMA OF 20-30MM/DAY THROUGH 36
HRS...GRADUALLY DECREASING.

A MUCH SMALLER/SECONDARY CELL OF THE SUBTROPICAL RIDGE IS
INITIALIZED ACROSS THE BAHAMAS-CUBA-FLORIDA PENINSULA. A TROUGH TO
THE NORTH CONTINUES TO PRESS AGAINST THIS AXIS. THIS IS TO FAVOR
EROSION OF THE RIDGE TO THE NORTH OF 25N/26N...WHILE FOCUSING
SHORT WAVE ENERGY ACROSS THE NORTHWEST BAHAMAS.
THIS...IN-TURN...IS TO ENHANCE DIURNAL CONVECTION. INITIALLY
EXPECT RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-20MM OVER
CUBA...WITH LESSER AMOUNTS OVER THE NORTHWEST BAHAMAS. BY 36-60
HRS AMOUNTS WILL INCREASE OVER THE BAHAMAS TO 05-10MM/DAY AND
MAXIMA OF 15-20MM/DAY.

A TUTT LOW LIES TO THE SOUTH OF THIS RIDGE...MEANDERING OVER THE
NORTHWEST CARIBBEAN. UNDER INFLUENCE OF THE RIDGE TO THE NORTH AND
WEST THIS TROUGH IS TO TRACK ACROSS BELIZE TO GUATEMALA THROUGH
48-60 HRS...INTO SOUTHERN MEXICO BY 72-84 HRS. AS IT MEANDERS OVER
THE WESTERN CARIBBEAN EARLY IN THE CYCLE...THIS WILL ENHANCE
CONVECTIVE DEVELOPMENT ACROSS NICARAGUA-HONDURAS...WHERE UPPER
TROUGH PATTERN IS TO FAVOR RAINFALL AMOUNTS OF 10-15MM/DAY AND
MAXIMA OF 20-45MM THROUGH 36-48 HRS. AS THE LOW
MIGRATES...CONVECTION WILL SPREAD ACROSS EL SALVADOR/WESTERN
HONDURAS TO BELIZE-GUATEMALA/SOUTHERN STATES OF MEXICO. IN THIS
AREA WE EXPECT RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF
15-20MM BY 48-72 HRS.

A DEEPER TUTT LIES TO THE EAST...WITH AXIS ALONG A CLOSED LOW NEAR
26N 64W. AS IT MEANDERS NORTH OF THE ISLANDS...THE TUTT IS
PRESSING AGAINST A CELL OF THE SUBEQUATORIAL RIDGE TO THE SOUTH.
THE RIDGE EXTENDS ACROSS THE ISLAND CHAIN-NORTHERN SOUTH AMERICA/
EASTERN CARIBBEAN. THROUGH 36-42 HRS TROUGH PATTERN IS TO DEEPEN
ACROSS EASTERN HISPANIOLA/PUERTO RICO-VIRGIN ISLES. THIS WILL
FAVOR EROSION OF RIDGE PATTERN ACROSS THE EASTERN CARIBBEAN
THROUGH 48-60 HRS. AFTERWARDS...TUTT BECOMES NARROW AND ELONGATED
AS IT IS TO MEANDER BETWEEN 68W-60W TO THE NORTHEAST CARIBBEAN
ISLES. UNDER INFLUENCE OF THIS TROUGH...TRADE WIND CAP ENVELOPING
THE NORTHEAST CARIBBEAN IS EXPECTED TO RAPIDLY WEAKEN. AS
CONVECTIVE INSTABILITY INCREASES...EXPECTING ISOLATED TO SCATTERED
CONVECTION TO DEVELOP ACROSS WESTERN PUERTO RICO AND CENTRAL
PORTIONS OF HISPANIOLA. FURTHERMORE...DEEP TUTT PATTERN TO THE
NORTH SUSTAINS AN INDUCED TROUGH IN THE EASTERLY TRADES ALONG 56W
TO 30N. THIS MIGRATES TO THE LEEWARD ISLES BY 30-36 HRS...TO
PUERTO RICO BY 42-48 HRS. THROUGH 60-72 HRS IT THEN CONTINUES
ACROSS THE DOMINICAN REPUBLIC. THE INDUCED TROUGH WILL FAVOR AN
INCREASE IN AVAILABLE PRECIPITABLE WATER ACROSS THE NORTHEAST
CARIBBEAN ISLES...PEAKING AT 40-45MM. ACROSS THE LEEWARD-VIRGIN
ISLES THIS IS TO THEN RESULT IN RAINFALL AMOUNTS OF 05-10MM/DAY
AND MAXIMA OF 15MM THROUGH 60 HRS...WHILE OVER PUERTO RICO
EXPECTING ACCUMULATION OF 05-10MM/DAY AND MAXIMA OF 15-20MM. AS
THE PERTURBATION ENTERS HISPANIOLA IT IS TO THEN FAVOR RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM.

AS THE SUBEQUATORIAL RIDGE MEANDERS OVER NORTHERN SOUTH AMERICA...
IT IS TO VENT DEEP CONVECTION ALONG THE NEAR EQUATORIAL TROUGH.
ACROSS VENEZUELA IT IS TO FAVOR RAINFALL AMOUNTS OF 05-10MM/DAY
AND MAXIMA OF 15-20MM. THROUGH 48-60 HRS...AS TUTT PATTERN TO THE
NORTH DEEPENS INTO THE NORTHEAST CARIBBEAN...CONVECTION ACROSS
WESTERN VENEZUELA-AMAZONIA/EASTERN COLOMBIA WILL INCREASE TO
15-20MM/DAY AND MAXIMA OF 25-50MM. BUT THIS IS TO QUICKLY WANE
THROUGH 84-96 HRS. OVER NORTHERN AND WESTERN COLOMBIA...UNDER
INFLUENCE OF THE NEAR EQUATORIAL TROUGH AND WEAK CELL OF THE
PANAMANIAN LOW...WE NOW EXPECT RAINFALL AMOUNTS OF 10-15MM/DAY AND
MAXIMA OF 20-30MM/DAY THROUGH 60 HRS.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC
INITIAL 24 36 48 60 72 84 96 TYPE
46W 49W 52W 56W 59W 62W 65W 68W TW
80W 84W 88W 92W 96W 99W 102W 105W TW
103W 105W 108W 112W 115W MOVES OUT EW

TROPICAL WAVE ALONG 46W ENTERS FRENCH GUIANA BY 24-30 HRS...WHERE
IT IS TO SUSTAIN RAINFALL AMOUNTS OF 00-05MM/DAY AND MAXIMA OF
10MM. ACROSS SURINAME TO NORTHERN GUYANA...AS IT INTERACTS WITH
THE ITCZ...IT WILL RESULT IN RAINFALL AMOUNTS OF 10-15MM/DAY AND
MAXIMA OF 20-35MM BY 48-54 HRS. AS IT PROPAGATES ACROSS
EASTERN-CENTRAL VENEZUELA EXPECTING RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-40MM/DAY BY 66-96 HRS. OVER THE
FRENCH/WINDWARD ISLES TO VIRGIN ISLES IT IS TO THEN FAVOR RAINFALL
AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-25MM BY 60-72 HRS...WITH
SIMILAR AMOUNTS OVER PUERTO RICO BY 84 HRS.

TROPICAL WAVE ALONG 80W MOVES ACROSS WESTERN PANAMA-COSTA RICA TO
NICARAGUA BY 24-30 HRS...MEANWHILE TRIGGERING RAINFALL AMOUNTS OF
10-15MM/DAY AND MAXIMA OF 20-45MM. THIS QUICKLY SPREADS ACROSS
HONDURAS TO EL SALVADOR THROUGH 60 HRS...WHILE OVER BELIZE TO
GUATEMALA/SOUTHERN MEXICO IT WILL THEN RESULT IN ACCUMULATION OF
05-10MM/DAY AND MAXIMA OF 15-20MM BY 48-72 HRS. OVER
SOUTHERN-CENTRAL MEXICO IT IS TO THEN FAVOR ISOLATED RAINFALL
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-40MM BY 72-84 HRS.

EASTERLY WAVE ALONG 103W...IN INTERACTION WITH TUTT OVER
MEXICO...IS TO FAVOR SCATTERED DEEP CONVECTION OVER SOUTHERN
SINALOA-COLIMA-NAYARIT EARLY THIS CYCLE WITH RAINFALL AMOUNTS OF
15-20MM/DAY AND MAXIMA OF 25-50MM/DAY.

MCKENZIE...BDM (BAHAMAS)
ROBINSON...MSJ (JAMAICA)
DAVISON...WPC (USA)

[cycloneye]

Good morning. Some scattered showers will develop in the afternoon hours in PR. We keep watching the progress of TS Dorian to see how much effects will be felt so stay tuned.



AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
418 AM AST THU JUL 25 2013

.SYNOPSIS...DEEP TUTT LOW NORTH OF THE AREA WILL GRADUALLY FILL
OVR THE NEXT FEW DAYS. STRONG MID-UPPER LEVEL RIDGE WILL BUILD
OVR THE AREA EARLY NEXT WEEK. TS DORIAN EXPECTED TO PASS NORTH OF
THE AREA MON NIGHT.

&&

.DISCUSSION...WHILE GUIDANCE SHOWS PW VALUES DROPPING SHARPLY
THROUGH TODAY...LATEST BLENDED TPW IMAGERY DOES NOT SUPPORT THIS
WITH CURRENT VALUES AROUND 2.0 INCHES. SO UNDER THE INFLUENCE OF
TUTT AND DEEP MOISTURE AROUND...EXPECT SCT AFTERNOON SHOWERS AND
THUNDERSTORMS TO DEVELOP HOWEVER EXPECT THIS TO BE CONCENTRATED ON
THE SOUTH SLOPES AND TRACK SWD TOWARD CARIBBEAN SEA. ON FRI AND
SAT...STEERING WINDS BECOME MORE FROM THE SE SO CONVECTION SHOULD
CONCENTRATE OVR NW PR.

LARGE SCALE SUBSIDENCE THEN BUILDS OVR THE AREA SAT NIGHT AND SUN
UNDER UPPER LEVEL RIDGE. DORIAN WILL THEN START MAKING ITS
PRESENCE WITH SOME OUTER RAIN BANDS POSSIBLY REACHING THE AREA
MON AFTERNOON. HOWEVER...DORIAN IS A SMALL TROPICAL CYCLONE AND
LATEST GUIDANCE IS STARTING TO SHIFT TO THE NORTH WITH NO TS FORCE
WINDS ON ITS SOUTH SIDE BASED ON 03Z NHC ADVISORY AND LATEST GFS
GUIDANCE. NOTE THAT DORIAN IS EXPECTED TO ENCOUNTER STRONG SHEAR
AND MID LEVEL DRY AIR AROUND DY5 AND SINCE IT IS A SMALL TROPICAL
CYCLONE IT COULD BE SUBJECT TO LARGE VARIATIONS IN INTENSITY UP OR
DOWN. ALSO...DORIAN IS EXPECTED TO SLOW DOWN SOME BY THE TIME IT
GETS CLOSER TO THE LEEWARD ISLANDS. DORIAN WILL PULL OUT OF THE
PICTURE WED WITH SUBSIDENCE AND DRYING UNDER BUILDING STRONG MID-
UPPER RIDGE. RIGHT NOW...THE BEST CHANCE TO GET SOME WX OUT OF
DORIAN IS MON AFTERNOON AND MON EVENING ALTHOUGH THE TIMING OF
THIS COULD CHANGE GIVEN DIFFERENCES WITH THE FORWARD MOTION OF DORIAN.

&&

.AVIATION...VFR CONDITIONS EXPECTED AT ALL PR AND USVI TAF SITES
THROUGH THE FORECAST PERIOD. HOWEVER...BRIEF MVFR AND MTN
OBSCURATIONS POSSIBLE AFT 26/16Z IN OR NEAR TJMZ AND TJBQ. LLVL
WINDS EASTERLY 10 TO 20 KT.


&&

.MARINE...SCT TSTMS EXPECTED TODAY THRU SAT. TS DORIAN IS EXPECTED
TO PASS NORTH OF THE AREA MON WITH SOME OUTER RAIN BANDS POSSIBLY
REACHING AMZ710. RIGHT NOW WILL KEEP WINDS AND SEAS BELOW SCA
GIVEN SMALL SIZE OF DORIAN AND WEAK WINDS ON ITS SOUTH SIDE.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 78 89 78 / 20 40 40 30
STT 89 79 89 79 / 10 40 40 40

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
259 PM AST THU JUL 25 2013

.SYNOPSIS...TUTT LOW NORTH OF THE FORECAST AREA WILL REMAIN THE
DOMINANT FEATURE THROUGH AT LEAST THE UPCOMING WEEKEND. SURFACE
HIGH ACROSS THE CENTRAL ATLANTIC WILL CONTINUE TO PROMOTE A
MODERATE TO FRESH TRADE WIND FLOW ACROSS THE LOCAL AREA. DORIAN
IS EXPECTED TO PASS NORTH OF THE LOCAL AREA MONDAY NIGHT.

&&

.DISCUSSION...SKIES WERE MOSTLY SUNNY OVER THE LOCAL ISLANDS
DURING THE DAY TODAY. WINDS WERE FROM THE EAST TO EAST NORTHEAST
AT 5 TO 15 MPH WITH SOME HIGHER GUSTS AND SEA BREEZE VARIATIONS.
TEMPERATURES WERE IN THE UPPER 80S TO THE LOWER 90S IN COASTAL
AREAS.

TUTT LOW NORTH OF THE FORECAST AREA WILL REMAIN THE DOMINANT
FEATURE THROUGH AT LEAST THE UPCOMING WEEKEND. ALTHOUGH WRF AND
GFS MODELS INDICATED PWAT VALUES BELOW 2 INCHES FRIDAY THROUGH
SUNDAY MORNING...THERE IS ENOUGH LOW LEVEL MOISTURE TO COMBINE
WITH LOCAL EFFECT AND UPPER LEVEL DYNAMICS PROVIDED BY THE
PROXIMITY OF AFOREMENTIONED TUTT...TO RESULT IN PERIODS OF
CLOUDINESS AND SHOWERS WITH THUNDERSTORMS EACH DAY. THEREFORE...
EXPECT PASSING SHOWERS ACROSS THE EAST COASTAL SECTIONS OF THE
ISLANDS DURING THE MORNING HOURS...FOLLOWED BY AFTERNOON
CONVECTION WHICH WILL BE MAINLY FOCUSED ACROSS THE CORDILLERA
CENTRAL AND NORTHERN SLOPES OF PUERTO RICO...INCLUDING PORTIONS
OF THE SAN JUAN METRO AREA FRIDAY AND SATURDAY.

TUTT WILL WEAKEN SUNDAY INTO EARLY NEXT WORK WEEK AS UPPER LEVEL
RIDGE BUILDS FROM THE EAST. IN ADDITION...A DRIER AIR MASS IS
EXPECTED TO MOVE OVER THE LOCAL AREA ON SUNDAY...AHEAD OF TROPICAL
STORM DORIAN. THIS WILL RESULT IN A GENERALLY FAIR AND MAINLY
STABLE WEATHER PATTERN SUNDAY AFTERNOON AND SUNDAY NIGHT. WEATHER
CONDITIONS MAY CHANGE EARLY NEXT WORK WEEK AS TROPICAL STORM
DORIAN REACHES THE EASTERN CARIBBEAN.

AT THIS TIME...NHC TRACK DORIAN NORTH OF THE FORECAST AREA MONDAY
AFTERNOON INTO EARLY TUESDAY MORNING. THE BEST CHANCE TO GET SOME
WEATHER IS DURING THIS TIME FRAME AS ASSOCIATED BANDS MOVE NEAR
THE LOCAL AREA. WEATHER CONDITIONS ARE EXPECTED TO QUICKLY IMPROVE
BY MID WEEK AS A MID TO UPPER LEVEL RIDGE ESTABLISHES ACROSS THE
AREA. HOWEVER...AFTERNOON SHOWERS WITH THUNDERSTORMS CANT BE RULED
OUT WEDNESDAY THROUGH AT LEAST FRIDAY.

CONSULT THE LATEST GUIDANCE AND INFORMATION FROM THE NATIONAL
HURRICANE CENTER CONCERNING THE POSSIBLE EFFECTS OF TROPICAL
STORM DORIAN.

&&

.AVIATION...VFR ALL TAF SITES XCP TJMZ IN AFT TDY/FRI AND THEN ONLY
CHC MVFR/VSBYS WI SCT OBSCD MTNS. OTW ISOLD SHRA TONITE MAINLY
OFFSHORE. WINDS BLO FL150 E 10-15 KT BCMG ESE 12-18 KT TONIGHT/FRI.

&&

.MARINE...SEAS UP TO 5 FEET AND WINDS 18 KNOTS OR LESS FRIDAY THROUGH
AT LEAST SUNDAY. SEAS AND WINDS EXPECTED TO INCREASE AS DORIAN MOVES
NEAR THE LOCAL AREA. HOWEVER DUE TO UNCERTAINTIES ON PROJECTED
TRACK AND INTENSITY...DECIDED TO KEEP SEAS UP TO 6 FEET AND WINDS
21 KNOTS OR LESS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 78 88 78 88 / 20 30 20 30
STT 79 89 79 89 / 20 20 30 20

[cycloneye]

Interests in Northern Leeward Islands should monitor the progress of Dorian

TROPICAL STORM DORIAN ADVISORY NUMBER 8
NWS NATIONAL HURRICANE CENTER MIAMI FL AL042013
1100 PM AST THU JUL 25 2013

...DORIAN A LITTLE WEAKER...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...16.6N 39.6W
ABOUT 1550 MI...2500 KM E OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 20 MPH...32 KM/H
MINIMUM CENTRAL PRESSURE...1001 MB...29.56 INCHES


WATCHES AND WARNINGS
--------------------
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

INTERESTS IN THE NORTHERN LEEWARD ISLANDS SHOULD MONITOR THE
PROGRESS OF DORIAN.

[cycloneye]

From the updated San Juan NWS discussion about Dorian.


THE GFS IS TAKING DORIAN ALONG THE NORTH COAST
OF PUERTO RICO ON MONDAY NIGHT. ALTHOUGH THIS IS A POSSIBILITY...
IT IS NOT THE OFFICIAL NATIONAL HURRICANE CENTER TRACK...NOR ONE
WE WOULD CONSIDER TO BE THE HIGHEST PROBABILITY AT THIS
TIME...THEREFORE THE OUTPUT FROM THE GFS FOR WINDS AND PRECIP
QUANTITIES AND PROBABILITIES CANNOT BE USED TO POPULATE THE GRIDS
FROM ABOUT SUNDAY THROUGH WEDNESDAY. PRESENTLY IT LOOKS LIKE
TYPICAL PRECIPITATION PATTERNS FOR EASTERLY OR SLIGHTLY
NORTHEASTERLY WINDS WILL APPLY AND HAVE ADDED SOME POP FOR WESTERN
PUERTO RICO ON SUNDAY. OTHERWISE NO OTHER CHANGES WERE MADE.
DORIAN SHOULD BEGIN TO AFFECT THE WEATHER IN THE U.S. VIRGIN
ISLANDS AND PUERTO RICO SUNDAY/SUNDAY NIGHT...WITH EFFECTS INCREASING
MONDAY AHEAD OF A MONDAY AFTERNOON/EVENING PASSAGE TO THE NORTH.
THE BIG UNCERTAINTY IS HOW FAR TO THE NORTH IT WILL PASS. THIS
QUESTION SHOULD BE ANSWERABLE BY SATURDAY OR SUNDAY.

[Macrocane]

Today's HPC discussion mentions the dry conditions that I've told you about:

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
207 PM EDT THU JUL 25 2013

AT 15UTC TROPICAL STORM DORIAN CENTERED NEAR 16.0N 35.9W...WITH
MAXIMUM SUSTAINED WINDS OF 50KT AND CENTRAL PRESSURE OF 999 HPA.
THE STORM IS MOVING TO THE WEST-NORTHWEST OR 285 DEGREES AT 17MPH.
SEE NHC ADVISORY FOR OFFICIAL FORECAST GUIDANCE.

DISCUSSION FROM JULY 25/00UTC: SEASONALLY TRANSIENT QUIET PATTERN
IS ESTABLISHING ACROSS MEXICO WITH DIURNAL CONVECTION CONSTRAINED
TO THE EXTREME NORTHWEST AND SOUTHERN PARTS OF THE COUNTRY. AT
UPPER LEVELS...DOMINANT FEATURE IS AN ANTICYCLONE CENTERING OVER
ARIZONA. THE HIGH WILL MEANDER SLOWLY INTO NORTHERN
SONORA/CHIHUAHUA THROUGH THE CYCLE WHILE DOMINATING MOST OF
NORTHWESTERN MEXICO. THIS WILL HELP TO VENTILATE DIURNAL
CONVECTION WHEREVER MOISTURE IS AVAILABLE. AT THE MOMENT...BEST
CONVECTIVE INSTABILITY AND AVAILABLE MOISTURE REMAINS OVER THE
SOUTHWESTERN USA. MODELS SUGGEST CONVECTIVE INSTABILITY MEANDERING
SOUTHWESTWARD INTO THE SIERRA MADRE OCCIDENTAL TOWARDS LATE
CYCLE...WHICH WILL LEAD TO A RE-ACTIVATION OF DIURNAL CONVECTION
INTO DAY 03 TO PRODUCE AMOUNTS OF 10-15MM/DAY AND ISOLATED MAXIMA
OF 20-30MM. FURTHER SOUTH ACROSS CENTRAL/SOUTHERN MEXICO...MOST
WIDESPREAD CONVECTION IS EXPECTED EARLY IN THE CYCLE AS CONVECTIVE
INSTABILITY WILL REMAIN HIGH TO THE EAST OF TROPICAL WAVE.
EXPECTING ACCUMULATIONS OF 10-15MM/DAY AND MAXIMA OF 20-40MM.
CONVECTION WILL DECREASE IN COVERAGE AFTERWARDS WITH HIGHEST
ACCUMULATIONS IN THE 15-20MM/DAY RANGE.

TO THE EAST...ACTIVE CONVECTION WILL DOMINATE THE NORTHWESTERN
BAHAMAS AS TROUGH OVER THE EASTERN US ORGANIZES AND MEANDERS
EASTWARD. PRECIPITABLE WATER WILL REMAIN HIGH IN THE AREA WITH
AMOUNTS EXCEEDING 40MM. EXPECTING ISOLATED ACCUMULATIONS OF
05-10MM/DAY AND MAXIMA OF 15-20MM THROUGH 60 HRS. MAXIMA WILL
INCREASE TO 15-30MM ON DAY 03...TO DECREASE AGAIN AFTER.

MUCH DRIER/STABLE CONDITIONS WILL PREVAIL ACROSS THE
CENTRAL/SOUTHEASTERN BAHAMAS INTO THE GREATER ANTILLES WHILE
STRONG SUBSIDENCE CAP PERSISTS. EXPECTING MOSTLY ISOLATED SHALLOW
CONVECTION...AND A FEW ISOLATED DIURNAL THUNDERSTORMS WITH LIGHT
ACCUMULATIONS. HEAVIEST AMOUNTS ARE EXPECTED OVER THE DOMINICAN
REPUBLIC AND PUERTO RICO AS TUTT-INDUCED WAVE AND THEN WEAK
TROPICAL WAVE INTERACT WITH OROGRAPHY. THIS WILL LEAD TO AMOUNTS
INCREASING TO 05-10MM/DAY AND ISOLATED MAXIMA OF 15-25MM INTO DAY
02. STRONG CAP WILL ALSO DOMINATE THE LESSER ANTILLES...WHERE MOST
CONVECTION WILL REMAIN SHALLOW. EXPECTING HEAVIEST ACCUMULATIONS
TO PEAK AT 15-25MM MAXIMA IN INTERACTION WITH OROGRAPHY. SOME
ENHANCEMENT IS POSSIBLE ACROSS THE WINDWARDS/BARBADOS...AND THE
LEEWARDS ON DAY 03 DEPENDING UPON TRACK OF TROPICAL STORM
DORIAN...AND WHETHER OR NOT FEEDER BANDS DEVELOP. SO FAR...KEEPING
AMOUNTS PEAKING AT 15-25MM. AMOUNTS SHOULD INCREASE OVER THE
LEEWARDS/PUERTO RICO ON DAY 04...UPON EVOLUTION OF DORIAN SO FAR
FORECAST TO TRACK NORTH OF THE ISLANDS (SEE NHC FOR DETAIL).

CENTRAL AMERICA IS UNDER THE INFLUENCE OF THE MID-SUMMER DROUGHT
WITH ACTIVE CONVECTION CONSTRAINED TO AREAS NEAR AND TO THE SOUTH
OF NICARAGUA. A TUTT WILL CONTINUE RETROGRESSING FROM THE GULF OF
HONDURAS INTO THE TEHUANTEPEC REGION THROUGH THE CYCLE...INDUCING
A LOW-LEVEL TROUGH TO ITS SOUTHEAST. TUTT-INDUCED TROUGH WILL
ENHANCE CONVECTION ACROSS NICARAGUA AND COSTA RICA ON DAY 01
LEADING TO AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-30MM. TUTT IS
ALSO DRAWING THE ITCZ TO THE NORTH BUILDING A MOISTURE POOL OVER
THE SOUTHERN CARIBBEAN. THIS WILL SUSTAIN ACTIVE CONVECTION IN THE
REGION AIDED BY EASTERLY WAVE APPROACHING ON DAY 03. THIS WILL
LEAD TO ANOTHER PULSE OF WIDESPREAD DEEP CONVECTION TO PRODUCE
AMOUNTS OF 10-15MM/DAY AND MAXIMA OF 20-45MM OVER COSTA RICA...AND
MAXIMA OF 20-35MM OVER PANAMA.

ACROSS NORTHERN SOUTH AMERICA STRONGEST CONVECTION IS INITIALLY
ORGANIZING ALONG AND OFF THE EASTERN ANDEAN SLOPES...WHERE
SOUTHEASTERLY SURGE AND WANING SHEAR LINE ARE ENHANCING LOW LEVEL
CONVERGENCE. THIS WILL LEAD TO AMOUNTS OF 15-20MM/DAY AND MAXIMA
OF 25-50MM FROM NORTHEASTERN ECUADOR INTO WESTERN VENEZUELA
THROUGH 36 HRS. BY 36-60 HRS CONVECTION WILL REORGANIZE AHEAD OF
TROPICAL WAVE. THIS WILL LEAD TO AMOUNTS OF 15-20MM/DAY AND MAXIMA
OF 30-60MM OVER SOUTHERN AND EASTERN VENEZUELA. BY 60-84
HRS...ITCZ CONVECTION WILL PRODUCE AMOUNTS OF 05-10MM/DAY AND
MAXIMA OF 15-25MM ACROSS MOST OF SOUTHERN AND EASTERN
VENEZUELA/RORAIMA AND THE NORTHERN GUIANAS.

TROPICAL/EASTERLY WAVES INITIALIZED AT 12UTC
INITIAL 24 36 48 60 72 84 96 TYPE
52W 55W 59W 62W 66W 69W 72W 75W TW
62W 65W 69W 72W 75W 78W 81W 85W TUTT INDCD/EW
88W 92W 95W 98W 102W 106W 109W 112W TW
108W 112W 114W MOVES OUT EW

WEAK TROPICAL WAVE AT 52W WILL HAVE STRONGEST EFFECTS OVER
NORTHERN SOUTH AMERICA...ESPECIALLY ONCE IT CROSSES EASTERN
VENEZUELA ON DAY 02. OVER THE CARIBBEAN BASIN WAVE WILL ONLY LEAD
TO AN ENHANCEMENT OF SHALLOW CONVECTION LEADING TO ACCUMULATIONS
HARDLY EXCEEDING 15MM/DAY IN FLAT REGIONS...AND 15-25MM IN
INTERACTION WITH OROGRAPHY.

TUTT-INDUCED WAVE INITIALIZED AT 62W AND TO THE SOUTH OF 30W WILL
PROPAGATE WESTWARD EMBEDDED IN THE TRADES...TO EVOLVE INTO AN
EASTERLY WAVE. THIS WAVE WILL ENHANCE DIURNAL CONVECTION ACROSS
PUERTO RICO AND HISPANIOLA LEADING TO ISOLATED MAXIMA OF 15-25MM.
BEST ENHANCEMENT WILL BE ACROSS PANAMA/COSTA RICA ON DAYS 03 AND
04 WHERE...IN INTERACTION WITH DEEP MOISTURE POOL...WILL PRODUCE
AMOUNTS PEAKING AT 10-15MM/DAY AND MAXIMA OF 20-45MM.

TROPICAL WAVE AT 88W IS EXITING INTO THE EASTERN PACIFIC.
SEASONALLY DRY CONDITIONS TO THE NORTH ARE INHIBITING ITS EFFECTS
ON CONVECTION.

WAVE INITIALIZED AT 108W IS EXITING THE DOMAIN WHILE STILL
SUSTAINING ACTIVE DIURNAL CONVECTION ACROSS SOUTHWEST MEXICO EARLY
IN THE CYCLE.

MCKENZIE...BDM (BAHAMAS)
ROBINSON...MSJ (JAMAICA)
DAVISON...WPC (USA)
GALVEZ...WPC (USA)

[cycloneye]

Good morning. All eyes are on what TS Dorian will do in the next couple of days to see how the effects will be in the NE Caribbean so stay tuned.


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
529 AM AST FRI JUL 26 2013

.SYNOPSIS...STRONG SURFACE HIGH ACROSS THE CENTRAL ATLANTIC WILL
CONTINUE TO PROMOTE A MODERATE EASTERLY TRADES ACROSS THE REGION
THROUGH MUCH OF THE WEEKEND. TUTT LOW NORTH OF THE AREA WILL REMAIN
THE DOMINANT FEATURE THROUGH AT LEAST SATURDAY. THE TUTT IS FORECAST
TO SHIFT FURTHER WEST OF THE AREA AND FILL BY SUNDAY AND INTO
EARLY NEXT WEEK...IN RESPONSE TO UPPER LEVEL RIDGE WHICH WILL
MOVE IN FROM THE EAST. AT 500 AM AST...0900 UTC...THE CENTER OF
TROPICAL STORM DORIAN WAS LOCATED NEAR LATITUDE 17.1 NORTH...
LONGITUDE 41.5 WEST. DORIAN IS MOVING TOWARD THE WEST NORTHWEST
NEAR 20 MPH. A TURN TOWARD THE WEST AND AN INCREASE IN FORWARD
SPEED ARE EXPECTED DURING THE NEXT COUPLE OF DAYS. MAXIMUM
SUSTAINED WINDS ARE NEAR 50 MPH...WITH HIGHER GUSTS. TROPICAL
STORM DORIAN IS STILL EXPECTED TO PASS NORTH OF THE LOCAL AREA
LATE MONDAY. PLEASE REFER TO THE LATEST ADVISORIES ISSUED BY THE
NATIONAL HURRICANE CENTER IN MIAMI FL.

&&

.DISCUSSION...ALTHOUGH PREVIOUS TJSJ 26/00Z UPPER AIR SOUNDING
ALONG WITH RECENT GROUND BASED GPS IPW AND BLENDED TPW SUGGEST
PWAT VALUES BELOW 1.60 INCHES...EXPECT THE EASTERLY TRADES TO
ADVECT SUFFICIENT LOW LEVEL MOISTURE ACROSS THE REGION TO COMBINE
WITH LOCAL EFFECTS AND THE INFLUENCE OF THE UPPER LEVEL TROUGH...
TO RESULT IN PERIODS OF CLOUDINESS WITH SHOWERS WITH ISOLATED
THUNDERSTORMS ACROSS PARTS OF THE ISLANDS AND LOCAL WATERS.
EXPECT EARLY MORNING PASSING SHOWERS ACROSS THE EAST COASTAL
SECTIONS OF THE ISLANDS...FOLLOWED BY AFTERNOON CONVECTION WHICH
WILL BE MAINLY FOCUSED ACROSS THE CORDILLERA CENTRAL AND NORTHERN
SLOPES OF PUERTO RICO...INCLUDING PORTIONS OF THE SAN JUAN METRO
AREA TODAY. SIMILAR CONDITIONS ARE EXPECTED ON SATURDAY.

SOMEWHAT DRIER AIR MASS AND INCREASING SUBSIDENCE WILL MOVE OVER THE
LOCAL AREA IN ADVANCE OF TROPICAL STORM DORIAN. THIS WILL RESULT IN
A MOSTLY FAIR AND STABLE WEATHER PATTERN ACROSS THE REGION ON SUNDAY.
HOWEVER BY LATE SUNDAY NIGHT AND INTO EARLY NEXT WEEK...WEATHER
CONDITIONS MAY CHANGE AS TROPICAL STORM DORIAN APPROACHES THE NORTHEAST
CARIBBEAN. BASED ON THE PRESENT FORECAST TRACK...TROPICAL STORM DORIAN
SHOULD BEGIN TO AFFECT THE U.S. VIRGIN ISLANDS AND PUERTO RICO LATE
SUNDAY THROUGH MONDAY. THIS WILL RESULT IN INCREASED POTENTIAL FOR
LOCALLY HEAVY RAINFALL ACROSS THE REGION. HOWEVER...THERE STILL
REMAINS UNCERTAINTY AS TO HOW FAR TO THE NORTH IT WILL PASS...AND
WILL HAVE TO CLOSELY MONITOR HOW THINGS UNFOLD DURING THE NEXT 24-36
HOURS...AND MAKE ADJUSTMENTS TO THE LOCAL FORECAST WHEN DEEMED NECESSARY.

&&

.AVIATION...VFR CONDITIONS EXPECTED ACROSS THE LOCAL TERMINALS OVERNIGHT
AND MORNING. SHRA/TSRA DEVELOPMENT MAY AFFECT THE VICINITY OF TJSJ AND
TJMZ AFTER 26/16Z. TJBQ WILL LIKELY OBSERVE TSRA AFTER 26/16Z...CAUSING
MVFR OR EVEN IFR CONDITIONS. MTN OBSCURATIONS ARE TO BE EXPECTED
AS CLOUDINESS INCREASES THROUGH THE DAY. EASTERLY WINDS WILL BE
AROUND 10-15 KNOTS AND GUSTY WITH SEA BREEZE VARIATIONS.


&&

.MARINE...SEAS UP TO 5 FEET AND WINDS 19 KNOTS OR LESS TODAY THROUGH
AT LEAST SATURDAY. AS TROPICAL STORM DORIAN APPROACHES THE NORTHEAST
CARIBBEAN AND BASED ON THE PRESENT FORECAST TRACK...EXPECT MARINE
CONDITIONS TO GRADUALLY DETERIORATE WITH INCREASING WINDS AND BUILDING
SEAS FORECAST ACROSS THE LOCAL WATERS AND ALL PASSAGES. PLEASE CONTINUE
TO MONITOR AND CONSULT THE LATEST MARINE GUIDANCE AND TROPICAL STORM
ADVISORIES ISSUED BY THE WFO SAN JUAN AND THE NATIONAL HURRICANE CENTER
CONCERNING THE POSSIBLE EFFECTS OF TROPICAL STORM DORIAN OVER THE UPCOMING
WEEKEND.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 77 87 78 / 30 20 30 10
STT 89 79 89 79 / 20 30 20 10

[cycloneye]

11 AM EDT Forecast Track

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
255 PM AST FRI JUL 26 2013

.SYNOPSIS...TUTT LOW NORTH OF THE FORECAST AREA WILL REMAIN THE
DOMINANT FEATURE THROUGH AT LEAST THE FIRST PART OF THE UPCOMING
WEEKEND. SURFACE HIGH ACROSS THE CENTRAL ATLANTIC WILL CONTINUE
TO PROMOTE A MODERATE TO FRESH TRADE WIND FLOW ACROSS THE LOCAL
AREA THROUGH MONDAY. BASED ON THE LATEST NHC FORECAST...DORIAN
IS EXPECTED TO PASS NORTH OF THE LOCAL AREA ON MONDAY.

&&

.DISCUSSION...SKIES WERE PARTLY CLOUDY OVER THE LOCAL ISLANDS
DURING THE DAY TODAY. HEAVY SHOWERS AND STRONG THUNDERSTORMS
DEVELOPED OVER NORTHWEST PUERTO RICO THIS AFTERNOON. WINDS WERE
FROM THE EAST TO EAST SOUTHEAST AT 5 TO 15 MPH WITH SOME HIGHER
GUSTS AND SEA BREEZE VARIATIONS. TEMPERATURES WERE IN THE UPPER
80S TO THE LOWER 90S IN COASTAL AREAS.

TUTT LOW NORTH OF THE FORECAST AREA WILL REMAIN THE DOMINANT FEATURE
THROUGH THE FIRST PART OF THE UPCOMING WEEKEND. ALTHOUGH GUIDANCE
CONTINUED TO INDICATE PWAT VALUES BELOW 2 INCHES THROUGH SATURDAY
EVENING...THERE IS ENOUGH LOW LEVEL MOISTURE TO COMBINE WITH
LOCAL EFFECT AND FAVORABLE UPPER LEVEL DYNAMICS PROVIDED BY THE
PROXIMITY OF AFOREMENTIONED TUTT TO RESULT IN PERIODS OF CLOUDINESS
AND SHOWERS WITH THUNDERSTORMS. THEREFORE...EXPECT PASSING SHOWERS
ACROSS THE EAST COASTAL SECTIONS OF THE ISLANDS THIS EVENING AND
SATURDAY MORNING...FOLLOWED BY AFTERNOON CONVECTION WHICH WILL BE
MAINLY FOCUSED ACROSS THE CORDILLERA CENTRAL AND NORTHERN SLOPES
OF PUERTO RICO...INCLUDING PORTIONS OF THE SAN JUAN METRO AREA
SATURDAY AFTERNOON.

TUTT IS EXPECTED TO SHIFT WEST SUNDAY INTO EARLY NEXT WORK WEEK AS
UPPER LEVEL RIDGE MOVE IN FROM THE EAST. IN ADDITION...A DRIER AIR
MASS IS EXPECTED TO MOVE OVER THE LOCAL AREA ON SUNDAY...AHEAD OF
TROPICAL STORM DORIAN. THIS WILL RESULT IN A GENERALLY FAIR AND
MAINLY STABLE WEATHER PATTERN ON SUNDAY. WEATHER CONDITIONS MAY
CHANGE EARLY NEXT WORK WEEK AS TROPICAL STORM DORIAN APPROACHES THE
EASTERN CARIBBEAN.

AT THIS TIME...BASED ON THE LATEST NHC FORECAST...DORIAN IS EXPECTED
TO PASS NORTH OF THE LOCAL AREA ON MONDAY. THE BEST CHANCE TO GET
SOME WEATHER IS MONDAY MORNING THROUGH EARLY TUESDAY MORNING AS
OUTER RAINBANDS MOVE NEAR THE LOCAL AREA. WEATHER CONDITIONS ARE
EXPECTED TO QUICKLY IMPROVE BY MID WEEK AS MID TO UPPER LEVEL
RIDGE ESTABLISHES ACROSS THE AREA. HOWEVER...AFTERNOON SHOWERS
WITH THUNDERSTORM CANT BE RULED OUT WEDNESDAY THROUGH AT LEAST
FRIDAY.

&&

.AVIATION...MOSTLY VFR CONDITIONS EXPECTED DURING THE FORECAST
PERIOD. HOWEVER...SOME SHOWERS WITH THUNDERSTORMS WILL REMAIN
POSSIBLE IN AND AROUND TJSJ/TJBQ TIL 26/22Z. WINDS BLO FL150 ESE
15-20 KT THRU SAT.

&&

.MARINE...CONTINUE WINDS/SEAS TO 19KT/5FT THROUGH AT LEAST SATURDAY.
BUT LOOK FOR CONDITIONS TO DETERIORATE BY SUNDAY EVENING TO EARLY
MONDAY AS DORIAN APPROACHES.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 77 87 78 89 / 20 30 10 20
STT 79 89 79 90 / 30 20 10 20

[cycloneye]

There was a small tornado in a town called Moca in NW PR in the afternoon causing some damage to some houses stripping their roofs.Also,some trees came down.

https://www.facebook.com/cmcaribe

[Gustywind]

For those who are interrested, here is a radar animation of TS Chantal moving quickly between Ste Lucia and Martinica. You can clearly see the center of Chantal swirling. These animations are from our Pro Mets of Guadeloupe posted on our website weather forecast: http://www.meteo.gp/

Enjoy it .

Gustywind

Radar animation of TS Chantal reaching Martinica :

http://www.meteo.gp/alaune/alaune_auto/ ... r_2013.gif

Sat animation of TS Chantal reaching Martinica:

http://www.meteo.gp/alaune/alaune_auto/ ... t_2013.gif

[Gustywind]

There was a small tornado in a town called Moca in NW PR in the afternoon causing some damage to some houses srtipping their roofs.Also,some trees came down.

https://www.facebook.com/cmcaribe

hopefully not too impressive damages but these kind of images are always suprising . No report of death is an excellent news Cycloneye . Thanks for posting that report.

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1003 PM AST FRI JUL 26 2013

.UPDATE...LATEST MODELS SHOW MOISTURE INCREASING DURING THE
MORNING HOURS AND THIS SHOULD BRING MORE SHOWERS AND THUNDERSTORMS
TO THE AREA WITH POPS FOR SATURDAY JUST SLIGHTLY LESS THAN TODAY`S
ACTIVITY. SOUNDING CAME IN WITH 1.74 INCHES OF PRECIPITABLE
WATER...BUT WAS MUCH MORE STABLE THAN PREVIOUS SOUNDINGS WITH A
MINUS 2.6 LIFTED INDEX. NEVERTHELESS SMALL MODERATE SHOWERS ARE
SPRINKLED ACROSS THE CARIBBEAN AND ATLANTIC WATERS EAST OF A LINE
EXTENDING NORTHEAST OF ARECIBO.

&&

.DISCUSSION...THE GFS HAS COMPLETELY CHANGED ITS INTERPRETATION OF
THE FUTURE FOR TROPICAL STORM DORIAN WHICH HAS WEAKENED
CONSIDERABLY IN THE LAST 6 HOURS. IN FACT THE MODEL EVEN
INITIALIZED THE SYSTEM WITH A CENTRAL PRESSURE OF ABOUT 6 MB MORE
THAN WAS ANALYZED BY THE HURRICANE CENTER. THEREFORE HAVE ONLY
TEMPERED THE FORECAST WITH THE GFS...TRYING TO STRIKE A BALANCE
BETWEEN A WEAKENING SYSTEM AND THE NEAR DISSIPATED STATE DESCRIBED
BY THE MODEL AS IT PASSES NORTH OF THE AREA SUNDAY NIGHT IN THE
STATE OF AN OPEN WAVE. SOME ADJUSTMENTS MAY ALSO BE NEEDED BEYOND
SUNDAY NIGHT...BUT FOR NOW THE SITUATION IS TOO UNCERTAIN TO MAKE
EDUCATED CHANGES. NEWER MODEL WILL LIKELY HAVE A BETTER HANDLE ON
THE MEDIUM RANGE SITUATION.

[cycloneye]

Good morning. Some showers will fall in PR this afternoon with the trough nearby.It looks like the PR area will escape most of the bad weather associated with Dorian or remnants but we continue to watch just in case there are changes.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
513 AM AST SAT JUL 27 2013

.SYNOPSIS...TROPICAL STORM DORIAN IS CENTERED NEAR 18.2N 50.0W AT
500 AM AST...SOME 860 MILES EAST OF THE NORTHERN LEEWARD ISLANDS.
DORIAN WAS MOVING WEST AROUND 22 MPH WITH MAXIMUM SUSTAINED WIND
SPEED NEAR 40 MPH. MINIMUM CENTRAL PRESSURE IS NOW 1011 MB. PLEASE
SEE THE LATEST FORECAST/ADVISORY ISSUED BY THE NATIONAL HURRICANE
CENTER IN MIAMI.

LOCALLY...THE DOMINANT FEATURE IS A TUTT AND ASSOCIATED LOW WHICH
SAGS SOUTH ACROSS THE REGION INTO LOCATED EAST CENTRAL CARIBBEAN.
THE TUTT WILL CONTINUE TO RETROGRESS WESTWARD DURING THE NEXT FEW
DAYS AS AN UPPER RIDGE WILL MOVE IN FROM THE EAST AND SET UP ACROSS
THE NORTHEAST CARIBBEAN. STRONG SURFACE HIGH PRESSURE ACROSS THE
CENTRAL ATLANTIC WILL MAINTAIN MODERATE EASTERLY TRADES ACROSS THE
NORTHEAST THROUGH THE REST OF THE WEEKEND AND INTO EARLY NEXT WEEK.

&&

.DISCUSSION...THE PREVAILING EASTERLIES WILL CONTINUE TO TRANSPORT
FRAGMENTS OF LOW TO MID LEVEL MOISTURE ACROSS THE REGION THROUGHOUT
THE DAY. LATEST MODEL GUIDANCE SUGGEST PWAT VALUES TO AVERAGE AROUND
1.80 AT LEAST THROUGH TODAY THEN SIGNIFICANTLY DECREASE TO 1.50 OR
LESS BY SUNDAY AND MONDAY. UNTIL THEN HOWEVER...THE PROXIMITY OF
THE UPPER TROUGH WILL CONTINUE TO ENHANCE EARLY MORNING AND DIURNAL
CONVECTION WHICH WILL AFFECT PARTS OF THE NORTH AND EAST COASTAL
SECTIONS OF THE ISLANDS DURING THE MORNING...THEN LATER SPREAD
ACROSS PARTS OF THE NORTH AND WEST SECTIONS OF PUERTO RICO IN THE
AFTERNOON . SOME AFTERNOON CONVECTION MAY LEAD TO PERIODS OF LOCALLY
HEAVY RAINFALL AND BRIEF GUSTY WINDS WITH THE DEVELOPMENT OF ISOLATED
BUT STRONG THUNDERSTORMS POSSIBLE ONCE AGAIN TODAY. SHOWERS AND
ONE OR TWO ISOLATED THUNDERSTORMS WILL REMAIN POSSIBLE IN AND AROUND
SOME OF THE VIRGIN ISLANDS BUT SO FAR ACTIVITY WILL BE SHORT LIVED
WITH NO SIGNIFICANT RAINFALL AMOUNTS EXPECTED AT THIS TIME.

BASED ON LATEST TRACK...DORIAN AND MOST OF THE ASSOCIATED MOISTURE
AND CONVECTIVE CLUSTERS SHOULD MOVE NORTH AND EAST OF THE LOCAL
REGION. AT THIS TIME DORIAN IS FORECAST TO WEAKEN TO A TROPICAL
DEPRESSION EAST TO NORTHEAST OF THE LEEWARD ISLANDS LATER TODAY
THEN CONTINUE NORTH OF PUERTO RICO AND THE VIRGIN ISLANDS ON LATE
SUNDAY THROUGH MONDAY BEFORE DISSIPATING. LATEST MODEL GUIDANCE
NOW SUGGEST MOST OF ASSOCIATED MOISTURE SHOULD REMAIN NORTH OF THE
REGION. HOWEVER STILL EXPECT OCCASIONAL FRAGMENTS OF MOISTURE TO
MOVE ACROSS THE REGION THROUGH AT LEAST TUESDAY. THEREFORE PERIODS
OF EARLY MORNING AND DIURNAL CONVECTION CAN BE EXPECTED EACH DAY
THROUGH THE EARLY PART OF NEXT WEEK.

&&

.AVIATION...MOSTLY VFR CONDITIONS EXPECTED ACROSS THE LOCAL
TERMINALS THIS MORNING WITH PASSING -SHRA...ESPECIALLY AFTER
27/10Z. SHRA/TSRA MAY AFFECT THE VICINITY OF TJSJ AND TJMZ AFTER
27/16Z WHILE TJBQ WILL LIKELY OBSERVE TSRA AFTER 27/16Z...CAUSING
MVFR OR EVEN IFR CONDITIONS. WIND WILL BECOME SLIGHTLY STRONGER AT
10-15 KNOTS AND GUSTY TODAY BUT STILL FROM THE EAST TO ESE WITH SEA
BREEZE VARIATIONS AFTER 27/14Z.

&&

.MARINE...
TROPICAL STORM DORIAN CONTINUE TO SHOW SIGNS OF WEAKENING AS IT MOVED
RAPIDLY WESTWARD. LATEST MODEL GUIDANCE AND ANALYSIS NOW SUGGEST 7
FOOT SEAS ONLY BRIEFLY AFFECTING THE OFFSHORE WATERS. THEREFORE MADE
ADJUSTMENTS TO THE LOCAL WINDS AND SEAS TO NOW REFLECT WINDS OF 20
KNOTS OR LESS AND SEAS OF 7 FEET OR LESS THROUGH THE REST OF THE WEEKEND.
PLEASE REFER TO THE LATEST MARINE WEATHER STATEMENTS AND COASTAL WATERS
FORECAST ISSUED BY THE NATIONAL WEATHER SERVICE SAN JUAN.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 77 88 77 / 50 20 30 40
STT 89 78 89 78 / 50 20 20 40

[Gustywind]

INTERESTS IN THE NORTHERN LEEWARD ISLANDS SHOULD MONITOR THE PROGRESS OF DORIAN.

000
WTNT34 KNHC 270832
TCPAT4

BULLETIN
TROPICAL STORM DORIAN ADVISORY NUMBER 13
NWS NATIONAL HURRICANE CENTER MIAMI FL AL042013
500 AM AST SAT JUL 27 2013

...DORIAN CONTINUES MOVING RAPIDLY WESTWARD AS A TROPICAL STORM...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...18.2N 50.0W
ABOUT 860 MI...1385 KM E OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...W OR 275 DEGREES AT 22 MPH...35 KM/H
MINIMUM CENTRAL PRESSURE...1011 MB...29.85 INCHES


WATCHES AND WARNINGS
--------------------
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

INTERESTS IN THE NORTHERN LEEWARD ISLANDS SHOULD MONITOR THE
PROGRESS OF DORIAN.

[msbee]

good morning
watching Dorian..glad he is getting weaker....... any guesstimates on what weather we can expect in the Northern islands?
I am thinking some rain..squalls.... and high seas but not much more than that. Am I right?

[cycloneye]

good morning
watching Dorian..glad he is getting weaker....... any guesstimates on what weather we can expect in the Northern islands?
I am thinking some rain..squalls.... and high seas but not much more than that. Am I right?

Hi Barbara. Yes,those may be the kind of effects the Northern Leewards will have.Let's continue to watch the progress of Dorian in case there are changes.

[Gustywind]

good morning
watching Dorian..glad he is getting weaker....... any guesstimates on what weather we can expect in the Northern islands?
I am thinking some rain..squalls.... and high seas but not much more than that. Am I right?

Hi Barbara. Yes,those may be the kind of effects the Northern Leewards will have.Let's continue to watch the progress of Dorian in case there are changes.

You're both right . We never knows in the tropics even if we're in July.