Caribbean - Central America Weather

[cycloneye]

Good morning. Good weather in general will prevail for the next couple of days.


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
541 AM AST SUN JUL 8 2012

.SYNOPSIS...A GENERALLY FAIR WEATHER PATTERN WILL CONTINUE TO
PREVAIL DURING THE NEXT TWO DAYS OR SO AS A RIDGE ALOFT PERSISTS
OVER THE FORECAST AREA. UPPER LEVEL TROUGH IS THEN FORECAST TO
DEVELOP ACROSS THE WESTERN ATLANTIC BY MID WEEK.

&&

.DISCUSSION...SHOWERS HAVE BEEN OBSERVED OVER THE COASTAL
WATERS...WITH SOME AFFECTING BRIEFLY THE EASTERN HALF OF PUERTO
RICO AS WELL THE U.S. VIRGIN ISLANDS OVERNIGHT. PATCHES OF LOW
LEVEL MOISTURE WILL CONTINUE TO AFFECT THE LOCAL ISLANDS FROM TIME
TO TIME...WITH THE DEVELOPMENT OF SHOWERS AND POSSIBLE
THUNDERSTORMS IN THE AFTERNOON OVER THE WESTERN INTERIOR AND
SOUTHWEST SECTIONS OF PUERTO RICO. HIGH PRESSURE SYSTEM CONTINUES
DOMINATING THE LOCAL REGION...MAINTAINING RELATIVELY DRY
CONDITIONS ACROSS THE AREA. FOR TUESDAY...THE NORTHERN PART OF A
TROPICAL WAVE IS EXPECTED TO PASS OVER THE AREA...INCREASING SOMEWHAT
THE CHANCES FOR SHOWERS. MEANWHILE...AN UPPER LEVEL TROUGH IS
EXPECTED TO DEVELOP OVER THE WESTERN ATLANTIC...AND IS EXPECTED TO
BE LOCATED IN A FAVORABLE AREA FRIDAY NEXT WEEK...TO ENHANCE THE
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS OVER THE REGION.


&&

.AVIATION...VFR CONDITIONS WILL PREVAIL ACROSS ALL TAF SITES THROUGH
AT LEAST 08/18Z. BRIEF PERIODS OF MVFR CONDS WITH MOUNTAIN
OBSCURATIONS ARE POSSIBLE BETWEEN 08/18Z-08/22Z AT TJMZ AND TJBQ.
WINDS WILL CONTINUE MAINLY EAST AT 10 TO 15 KTS AT THE SURFACE.




&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 79 89 79 / 20 20 20 20
STT 89 79 89 80 / 10 30 30 20

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
247 PM AST SUN JUL 8 2012

.SYNOPSIS...RIDGE PATTERN ALOFT IS EXPECTED TO WEAKEN OVER THE NEXT
FEW DAYS AS UPPER LEVEL TROUGH DEVELOPS ACROSS THE WESTERN ATLANTIC.

&&

.DISCUSSION...RIDGE PATTERN ALOFT IS EXPECTED TO WEAKEN OVER THE NEXT
FEW DAYS AS UPPER LEVEL TROUGH DEVELOPS ACROSS THE WESTERN ATLANTIC.
THIS EVOLVING PATTERN COMBINED WITH PATCHES OF LOW LEVEL MOISTURE
EMBEDDED IN THE TRADES WILL CONTINUE TO RESULT IN PASSING SHOWERS
ACROSS THE EAST COASTAL SECTIONS OF THE ISLANDS DURING THE MORNING AND
EVENING HOURS...FOLLOWED BY AFTERNOON CONVECTION WHICH WILL BE MAINLY
FOCUSED ACROSS WESTERN PORTIONS OF PUERTO RICO. AT LOW LEVELS...SURFACE
HIGH PRESSURE ACROSS THE NORTH CENTRAL ATLANTIC WILL PROMOTE A MODERATE
TO LOCALLY FRESH EAST SOUTHEAST WIND FLOW ON MONDAY...BECOMING EAST
NORTHEAST BY THE END OF THE UPCOMING WORK WEEK. AS A RESULT...FOR
MONDAY AND TUESDAY...AFTERNOON CONVECTION WILL BE CONCENTRATED ACROSS
NORTHWEST PUERTO RICO...SHIFTING OVER THE SOUTHWEST QUADRANT OF
THE ISLAND ON WEDNESDAY AND THURSDAY. THIS SOUTHEASTERLY WIND FLOW
WILL ALSO PROMOTE WARM TEMPERATURES DURING THE FIRST PART OF THE
WEEK.

&&

.AVIATION...SHRA/TSRA HAVE FORMED OVER PR DOWNSTREAM FROM EL YUNQUE
8-10 MI S OF TJSJ AND OVER CENTRAL PR ACROSS TJMZ AS WELL AS OVER
AND WEST OF TIST. INTERMITTENT MVFR/BRIEF IFR CONDS SHOULD PERSIST
IN THESE AREA TILL AFT 08/21Z. BRIEF MVFR MAY ALSO OCCUR IN TNCM AND
TKPK THROUGH 09/18Z. EXCEPT FOR MTN OBSCURATIONS IN PR BEFORE 08/23Z
AND AFT 09/17Z PREVAILING CONDS WILL BE VFR. LLVL WINDS BELOW 15 KFT
E 5 TO 15 KT BCMG ESE-SSE AFT 09/15Z.

&&

.MARINE...MARINERS SHOULD EXPECT MODERATE TO LOCALLY FRESH TRADE WINDS
AND SEAS OF UP TO 5 FEET THROUGH AT LEAST WEDNESDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 79 90 79 89 / 20 20 20 20
STT 79 89 80 89 / 30 30 20 20

[cycloneye]

A little bit more rain on Monday for Puerto Rico.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1038 PM AST SUN JUL 8 2012

.UPDATE...CONSISTENT WITH THE FORECAST...SHOWERS AND THUNDERSTORMS
LINGERED OVER PUERTO RICO UNTIL THIS EVENING. ISOLATED PASSING
SHOWERS ARE OBSERVED ACROSS THE LOCAL AREA...MOSTLY ACROSS THE
LOCAL WATERS...THE USVI...AND EASTERN AND NORTHERN PUERTO RICO.
THESE PASSING SHOWERS ARE EXPECTED TO CONTINUE THROUGH THE NIGHT.

THE WIND IS EXPECTED TO TURN MORE EASTERLY AND THEN EAST
SOUTHEASTERLY BY TOMORROW MORNING WITH AN AREA OF HIGHER MOISTURE
APPROACHING THE LOCAL ISLANDS LATE MONDAY MORNING AND INTO THE
AFTERNOON HOURS. THIS WILL CAUSE SHOWERS AND THUNDERSTORMS TO
DEVELOP EARLY IN THE AFTERNOON...AFFECTING MOST OF PUERTO RICO.
HOWEVER...THE AREA WITH THE MORE NUMEROUS SHOWERS AND PERSISTENT
THUNDERSTORMS IS EXPECTED TO BE THE NORTHWESTERN SECTIONS OF PUERTO
RICO AS THE SEA BREEZE CONVERGENCE WILL ALSO PLAY A ROLE IN THE
DEVELOPMENT OF THESE SHOWERS AND THUNDERSTORMS OVER THAT AREA. SIMILAR
TO TODAY...THE SHOWERS AND THUNDERSTORMS ARE EXPECTED TO LINGER
TOMORROW INTO THE EVENING HOURS.

[cycloneye]

Good morning. A few showers for today as a weak wave moves thru.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
555 AM AST MON JUL 9 2012

.SYNOPSIS...A WEAK UPPER TROUGH NORTH OF THE FORECAST AREA WILL
MERGE WITH AN UPPER LOW THAT IS CENTERED NEAR 30N48W. THE RESULTANT
UPPER LOW WILL DIG SOUTHWESTWARD AND RE-ESTABLISH NORTHWEST OF THE
LOCAL REGION ON THURSDAY. AS THIS PATTERN EVOLVES...A TROPICAL WAVE
WILL MOVE MAINLY NORTHEAST OF THE AREA TODAY. HOWEVER...A TONGUE
OF MOISTURE ASSOCIATED WITH THE SOUTHERN PORTION OF THE WAVE WILL
BRUSH THE NORTHEAST CARIBBEAN BRINGING SCATTERED SHOWERS AND A FEW
THUNDERSTORMS ACROSS THE FORECAST AREA THROUGH TONIGHT.

&&

.DISCUSSION...LATEST SURFACE ANALYSIS SHOWS A TROPICAL WAVE
EXTENDING FROM THE SW NORTH ATLANTIC INTO THE NORTHERN LEEWARD
ISLANDS. THIS WAVE WILL CONTINUE TO MOVE ACROSS THE SW NORTH
ATLANTIC PASSING MAINLY NORTHEAST OF THE LOCAL AREA. ALTHOUGH
THE BRUNT OF THE MOISTURE SHOULD REMAINS NORTHEAST OF PR AND USVI
TODAY...ITS SOUTHERN FRINGES WILL AFFECT THE AREA RESULTING IN AN
INCREASE IN CLOUDINESS...SHOWERS AND THUNDERSTORMS THROUGH LATE
TONIGHT.

AFTERWARDS...AN AREA OF DRIER AIR WITH SAHARAN DUST WILL MOVE
ACROSS THE LOCAL AREA TUESDAY AND WEDNESDAY...CREATING HAZY SKIES
AND LIMITING THE SHOWER ACTIVITY OVER THE ISLANDS. ALL OPERATIONAL
MODEL SUGGESTS A DEEP TROUGH PATTERN ALOFT THAT WILL SUPPORT AN
INDUCED TROUGH NEAR THE LOCAL ISLANDS BY THE END OF THE WORK WEEK.
THIS WILL INCREASE AGAIN THE CHANCES OF SHOWER AND THUNDERSTORMS
WITH HIGH PROBABILITY OF LOCALLY HEAVY RAINFALL ACROSS PARTS OF THE
ISLANDS.

&&

.AVIATION...VFR CONDITIONS WILL CONTINUE TO PREVAIL ACROSS ALL TAF
SITES THROUGH AT LEAST 09/18Z. BRIEF PERIODS OF MVFR CONDITIONS WITH
MOUNTAIN OBSCURATIONS ARE EXPECTED ACROSS TJMZ...AND TJBQ FROM
09/18Z-09/22Z. WINDS WILL BE MAINLY EAST TO SOUTHEAST AT 10 TO 15
KNOTS EXCEPT FOR SEA BREEZE VARIATIONS IN COASTAL AREAS.

&&

.MARINE...MODERATE TRADES WITH SEAS OF 2 TO 5 FEET ARE EXPECTED
ACROSS THE REGIONAL WATERS THROUGH THE NEXT FEW DAYS.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 79 91 80 / 40 40 20 20
STT 89 80 90 80 / 40 20 20 20

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
245 PM AST MON JUL 9 2012

.SYNOPSIS...AT UPPER LEVELS...A TROUGH CONTINUES NORTH OF THE AREA
IN THE SUB TROPICS. A LOW IN THAT TROUGH WILL APPROACH PUERTO RICO
AND THE U.S. VIRGIN ISLANDS FROM THE NORTHEAST TONIGHT THROUGH
WEDNESDAY...BUT WEAKEN CONSIDERABLY BEFORE IT PASSES TO THE NORTH
ON FRIDAY. HIGH PRESSURE WILL CONSOLIDATE OVER THE AREA OVER THE
WEEKEND.

AT MID LEVELS...HIGH PRESSURE REMAINS TO THE NORTHEAST...BUT A LOW
NEAR 20 NORTH 38 WEST WILL MOVE WEST AND PASS BETWEEN THE LOCAL
AREA AND THE HIGH THURSDAY NIGHT AND FRIDAY PUSHING MOISTURE AHEAD
OF IT ON THURSDAY. HIGH PRESSURE THEN RIDGES IN OVER THE WEEKEND.

AT LOWER LEVELS...HIGH PRESSURE CONTINUES IN THE NORTHEAST CENTRAL
ATLANTIC PRODUCING MODERATE TO FRESH TRADE WINDS FROM THE EAST AND
EAST SOUTHEAST THROUGHOUT THE NEXT 10 DAYS. A WEAK TROUGH WILL
MOVE THROUGH THE AREA TONIGHT OR EARLY TOMORROW FOLLOWED BY DRIER
AIR AND SOME SAHARAN DUST. MOISTURE FROM A MID LEVEL LOW WILL
ENTER THE AREA FROM THE NORTHEAST ON THURSDAY AND REDUCE THE DUST.


&&

.DISCUSSION...SHOWERS HAVE LINGERED OVER THE ATLANTIC AND
CARIBBEAN WATERS IN RESPONSE TO THE MOISTURE MAXIMUM MOVING
THROUGH THE AREA TODAY. SHOWERS AND THUNDERSTORMS HAVE GROWN A FEW
MILES INLAND FROM THE COASTAL AREAS AND WERE LEAVING FROM 1 TO 2.5
INCHES OF RAIN FROM CIALES...MOROVIS AND JAYUYA TO RINCON AND
AGUADILLA. SHOWERS WERE ALSO MOVING ONSHORE NEAR NAGUABO AND CEIBA
AND ACROSS THE ISLAND TO SAN JUAN AND TOA BAJA. TEMPERATURES AT
SAN JUAN REACHED 89 DEGREES...BUT SHOWERS AND CLOUDS PREVENTED IT
FROM HEATING ENOUGH TO REACH 90. MOISTURE PRODUCTS WERE SHOWING
SOME UPSTREAM MOISTURE THAT WILL LIKELY KEEP SHOWERS OVER THE
ISLANDS THROUGH LATE THIS EVENING. DRIER AIR IS EXPECTED AND
SHOWERS WILL BE MORE SCATTERED...THOUGH STILL ACROSS NORTH THROUGH
NORTHEAST PUERTO RICO...ON TUESDAY. DUST INCREASES ON TUESDAY AND
WEDNESDAY. MOISTURE FROM THE NORTHEAST ON THURSDAY WILL BRING SOME
SHOWERS ONSHORE THURSDAY MORNING AND SEND THE CONVECTION TO THE
SOUTHWEST...ALTHOUGH THE LATEST 12Z RUN...IS NOT SHOWING AS MUCH
MOISTURE AT 850 MB AS WAS HAD TODAY. MOISTURE RUNS AHEAD OF A MID
LEVEL LOW DUE TO PASS ON FRIDAY AND WINDS ALSO TURN WITH ITS
PASSAGE. THIS WILL BRING SLIGHTLY WARMER WEATHER TO THE NORTH COAST
AND ONLY REGULAR CONVECTION. THE GFS THEN BRINGS AN ARC OF
MOISTURE FROM THE EAST ACROSS THE AREA SATURDAY NIGHT THAT
INCREASE LOW LEVEL MOISTURE THROUGH SUNDAY NIGHT AND MONDAY.
NEVERTHELESS MID LEVELS ARE DRY THROUGH TUESDAY EXCEPT FOR SOME
WEAK MOISTURE BETWEEN THURSDAY AFTERNOON AND FRIDAY NIGHT AND THIS
WILL LIMIT CONVECTION OVER THE AREA DUE TO THE PASSAGE OF THE
TROUGH.

&&

.AVIATION...
VFR CONDITIONS WILL CONTINUE TO PREVAIL AT ALL TAF SITES
FOR THE NEXT 24 HOURS. HOWEVER...BRIEF PERIODS OF MVFR CONDITIONS
WILL REMAIN POSSIBLE IN AND AROUND TJBQ AND TJSJ THROUGH ABOUT
09/22Z IN SHRA/TSRA. HAZY SKIES WILL PREVAIL TOMORROW THROUGH
WEDNESDAY AS A DRIER AIR MASS WITH SAHARAN DUST INVADES THE LOCAL
AREA. WINDS WILL BE MAINLY EAST TO SOUTHEAST AT 10 TO 15 KNOTS.

&&

.MARINE...WINDS AND SEAS WILL CONTINUE TO BE RELATIVELY TRANQUIL
WITH SEAS REMAINING AT OR BELOW 5 FEET FOR THE NEXT 5 TO 6 DAYS AT
LEAST. EXPECT TRADE WINDS TO REMAIN CONSISTENT FROM THE EAST
SOUTHEAST OR EAST DUE TO THE PERSISTENCE OF THE STRONG HIGH
PRESSURE OVER THE NORTHEAST CENTRAL ATLANTIC.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 78 90 79 89 / 20 20 20 20
STT 80 90 81 90 / 30 30 20 20

[cycloneye]

The Saharan dust arrives to the Eastern Caribbean on Tuesday.


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1032 PM AST MON JUL 9 2012

.UPDATE...CONSISTENT WITH THE PREVIOUS FORECAST...SHOWERS AND
THUNDERSTORMS LINGERED ACROSS WESTERN PUERTO RICO UNTIL THIS
EVENING. ISOLATED PASSING SHOWERS HAVE PREVAILED OVER THE WATERS
AND ARE EXPECTED TO CONTINUE UNTIL EARLY TOMORROW MORNING.

WE HAVE SAHARAN DUST MOVING IN TOMORROW MORNING...WHICH ACCORDING
TO THE NAAPS MODEL...IT COULD HAVE A DECENT CONCENTRATION AT THE
SURFACE...ESPECIALLY TOMORROW AFTERNOON. THIS SHOULD DRY THINGS UP
CONSIDERABLY AS IT MAKES ITS WAY INTO THE LOCAL ISLANDS.
HOWEVER...GUIDANCE SUGGESTS A CHANCE OF SHOWERS AND THUNDERSTORMS
IN THE AFTERNOON ACROSS SECTIONS OF WESTERN PUERTO RICO...MOSTLY
IN AREAS WHERE SEA BREEZE CONVERGENCE OCCURS. IT IS ALSO WORTH
MENTIONING THAT GUIDANCE SUGGESTS THAT THE CONVECTION WILL OCCUR
LATER THAN IT HAS BEEN FOR THE PAST FEW DAYS...SHOWING RAIN
ACCUMULATIONS AFTER 18Z AND LINGERING UNTIL AROUND MIDNIGHT
DEPENDING ON THE NUMERICAL MODEL.

THE SHORT TERM FORECAST WAS TWEAKED TO INCLUDE HAZE DUE TO SAHARAN
DUST AND ALSO TO ACCOUNT FOR THE TIMING OF THE DUST. CONFIDENCE
IS ON THE LOW SIDE WHEN IT COMES TO THE THUNDERSTORM DEVELOPMENT
TOMORROW AFTERNOON. THE AMOUNT OF SAHARAN DUST THAT NAAPS MODEL
SHOWS IS CONSIDERABLE...AND IT MAY SIGNIFICANTLY LIMIT OR INHIBIT
CONVECTION. EVEN THOUGH SHOWERS AND THUNDERSTORMS ARE IN THE
FORECAST...PROBABILITY OF PRECIPITATION IS ON THE LOW SIDE AT 30
PERCENT OR LESS.

[cycloneye]

Good morning. A variable next few days with a mix of sun and clouds with some scattered showers.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
524 AM AST TUE JUL 10 2012

.SYNOPSIS...TUTT LOWS NORTH OF THE FORECAST AREA WILL MERGE AND
RE-ESTABLISH NORTHWEST OF THE REGION BY THE END OF THE WORK WEEK.
AT MID LEVELS...HIGH PRESSURE RIDGE REMAINS TO THE NORTHEAST...
BUT A MID-LEVEL LOW IS EXPECTED TO APPROACH THE NORTHEASTERN
CARIBBEAN ON THURSDAY...INDUCING A TROUGH AT THE SURFACE. STRONG
SURFACE HIGH PRESSURE OVER THE NORTH CENTRAL ATLANTIC IS MAINTAINING
A MODERATE SOUTHERLY FLOW ACROSS THE NORTHEAST CARIBBEAN.

&&

.DISCUSSION...SATELLITE DERIVED PWAT ANALYSIS INDICATED AN AREA
OF 10-15 PERCENT BELOW NORMAL MOISTURE AMOUNTS UPSTREAM OF THE
VIRGIN ISLANDS. THIS AREA OF DRIER AIR WILL REACH THE FORECAST
AREA BY MIDDAY TODAY AND WILL BE ACCOMPANIED WITH SAHARAN DUST...
WHICH MAY LIMIT SOMEWHAT THE SHOWER ACTIVITY ACROSS THE ISLANDS.
IN THIS PATTERN...OPERATIONAL MODELS GENERALLY SHOW A RELATIVELY
FAIR WEATHER CONDITIONS AS PWAT IS TO REMAIN LESS THAN 1.5 INCHES
THROUGH EARLY THURSDAY MORNING. HOWEVER...GOES SATELLITE IMAGERY
ALSO INDICATED PATCHES OF LOW LEVEL CLOUDS AND A FEW SHOWERS EMBEDDED
IN THIS DRIER AIR UPSTREAM OF THE ISLANDS. AS A RESULT...LIGHT
MORNING SHOWERS ARE POSSIBLE ALONG THE EAST AND SOUTHEAST COASTAL
SECTIONS OF PUERTO RICO...FOLLOWED BY ISOLATED TO SCATTERED
CONVECTION ACROSS THE NORTH CENTRAL AND NORTHWESTERN PUERTO RICO
IN THE AFTERNOON. FOR THURSDAY THROUGH FRIDAY...GFS BRINGS A
MOISTURE SURGE FROM THE EAST AND SOMEWHAT BETTER MID TO UPPER
LEVEL DYNAMICS FOR SHOWERS AND THUNDERSTORMS ACROSS THE FORECAST
AREA WITH THE ARRIVAL OF THE INDUCED TROUGH. WEATHER CONDITIONS
GRADUALLY IMPROVE DURING THE WEEKEND AS MID TO UPPER RIDGE BUILDS
NORTH OF THE FORECAST AREA.

&&

.AVIATION...EXPECT PREVAILING VFR CONDITIONS TO CONTINUE ACROSS THE
LOCAL ISLANDS AND AT ALL TAF SITES THROUGH THE FORECAST PERIOD.
HOWEVER...BRIEF MVFR CONDITIONS AND LOCAL MOUNTAIN OBSCURATIONS ARE
EXPECTED IN ISOLATED TO SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS...MAINLY IN AND AROUND TJBQ AND TJMZ FROM 10/17Z
THROUGH ABOUT 10/22Z. IN ADDITION...SAHARAN DUST WILL BE INCREASING
ACROSS THE LOCAL AREA THROUGH TODAY...RESULTING IN HAZY SKIES BUT
MOST VISIBILITIES SHOULD REMAIN P6SM.

&&

.MARINE...STRONG HIGH PRESSURE FAR NORTHEAST OF THE REGION WILL
MAINTAIN A MODERATE TRADE WINDS ACROSS THE REGIONAL WATERS THROUGH
THE SEVERAL DAYS. SEAS WILL RANGE BETWEEN 3 AND 5 FEET THROUGH
THURSDAY...INCREASING SLIGHTLY TO 6 FEET LATER FRIDAY THROUGH SUNDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 78 90 78 / 20 20 20 30
STT 89 80 89 79 / 20 20 20 30

[Gustywind]

[Gustywind]

Loop of the Tropical Activity

[underthwx]

lookin good down there in the Caribbean atm...unlike here in SE Texas...good morning to the entire population of the Caribbean...

[Gustywind]

lookin good down there in the Caribbean atm...unlike here in SE Texas...good morning to the entire population of the Caribbean...

Hi my friend. Thanks to you we appreciate your wink towards us in the Carib . And what's up in your area? Are you in shape?
See you soon.

Regards
Gustywind

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
301 PM AST TUE JUL 10 2012

.SYNOPSIS...AT UPPER LEVELS...A LOW NORTHEAST OF THE AREA EMBEDDED
IN A TROUGH THAT EXTENDS FROM THE CENTRAL ATLANTIC TO THE
BAHAMAS...WILL PASS NORTH OF THE AREA FRIDAY WHILE DISSIPATING.
LOW PRESSURE WILL THEN RE-FORM OVER THE BAHAMA ISLANDS. A NORTH-
SOUTH RIDGE FORMS ON SATURDAY OVER THE AREA BEFORE LOW PRESSURE
DIGS IN FROM THE NORTHEAST EARLY NEXT WEEK.

AT MID LEVELS...LOW PRESSURE NEAR 17 NORTH 44 WEST WILL MOVE WEST
THROUGH WEDNESDAY THEN TURN NORTHWEST AND PASS NORTH OF THE AREA
THURSDAY NIGHT. A RIDGE WILL MOVE IN ON SATURDAY AND FADE SLOWLY
UNTIL A WEAK TROUGH APPROACHES FROM THE EAST MID WEEK NEXT WEEK.

AT LOWER LEVELS...HIGH PRESSURE DOMINATES THE CENTRAL ATLANTIC AND
TROPICAL ATLANTIC MAINTAINING MODERATE TO FRESH EAST TO EAST
SOUTHEAST TRADE WINDS. A WEAK TROUGH WILL BE INDUCED BY THE
PASSING MID LEVEL LOW...OTHERWISE BANDS OF MOISTURE WILL PASS
THROUGH IN THE TRADE WINDS THROUGH THE END OF NEXT WEEK.

&&

.DISCUSSION...DRIER AIR PREVAILED TODAY AND SIGNIFICANT SHOWERS
HAD NOT YET BEGUN AS OF 10/1845Z. RADAR SHOWED TRACES OF STREAMERS
MOVING OFF THE U.S. VIRGIN ISLANDS TOWARD THE WEST NORTHWEST
INDICATING THE DRYNESS AND THE GENERAL DIRECTION OF THE FLOW.
BETTER MOISTURE IS INDICATED FOR WEDNESDAY AND THURSDAY. A WEAK
TROUGH WILL BE INDUCED AT THE SURFACE BY THE MID-LEVEL LOW
MIGRATING FROM THE EAST AND A BAND OF MOISTURE ROTATING AROUND
IT WILL ENTER THE AREA FROM THE NORTHEAST EARLY THURSDAY
MORNING. THIS WILL BRING INCREASED CHANCES OF BRIEF PASSING
SHOWERS IN THE NORTHERN VIRGIN ISLANDS AND ON THE WINDWARD SIDE OF
PUERTO RICO THURSDAY. COOLER TEMPERATURES ARE ALSO INDICATED FOR
THE NORTHERN HALF OF PUERTO RICO. THE PASSING TROUGH WILL CAUSE A
RAPID SWITCH IN THE TRADE WIND FLOW FROM EAST NORTHEAST ON
THURSDAY TO EAST SOUTHEAST ON FRIDAY. MODEST MOISTURE WILL
CONTINUE THROUGHOUT FOLLOWED BY DRYING ON MONDAY. THE GFS
INDICATES THAT A SOMEWHAT MORE UNSTABLE ATMOSPHERE WILL PREVAIL
BETWEEN SATURDAY NIGHT AND TUESDAY THAN BETWEEN TONIGHT AND FRIDAY
NIGHT...SO WITH A LITTLE MORE MOISTURE BETTER CHANCES OF SHOWERS
AND SCATTERED THUNDERSTORMS ARE INDICATED FOR THAT PERIOD IN THE
NEXT 5 DAYS. NO MAJOR EVENTS ARE INDICATED AS ALL WAVES LEAVING
AFRICA ARE DISINTEGRATING AS THEY APPROACH THE AREA...IN PART DUE
TO THE INCREASED SHEAR ENCOUNTERED IN THE WESTERN PART OF THE
TROPICAL ATLANTIC.

&&

.AVIATION...
VFR CONDITIONS WILL CONTINUE TO PREVAIL AT ALL TAF SITES
FOR THE NEXT 24 HOURS. HOWEVER...BRIEF MVFR CONDITIONS WILL REMAIN
POSSIBLE IN AND AROUND TJBQ IN ISOLATED SHRA/TSRA THROUGH ABOUT
11/00Z. IN ADDITION...SAHARAN DUST WILL BE INCREASING ACROSS THE
LOCAL AREA THROUGH SUNRISE WEDNESDAY...RESULTING IN HAZY SKIES...BUT
MOST VISIBILITIES SHOULD REMAIN P6SM. LLVL WINDS BELOW 20 KFT ARE
ESE 15-25 KT BUT WILL BECOME ENE 10 TO 20 KT BY 11/18Z.

&&

.MARINE...SLIGHTLY INCREASED WINDS BROUGHT SLIGHTLY INCREASED SEAS
WHICH WILL CONTINUE THROUGH TONIGHT. WINDS AND SEAS WILL DIMINISH
WITH THE PASSAGE OF THE MID LEVEL TROUGH THURSDAY AND FRIDAY.
SKIES WILL BE HAZY WITH VISIBILITIES GENERALLY BETWEEN 7 AND 12
MILES DUE TO SAHARAN DUST.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 78 90 78 88 / 20 20 30 30
STT 80 89 79 88 / 20 20 30 30

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1030 PM AST TUE JUL 10 2012

.UPDATE...INHERITED FORECAST PACKAGE LOOKS GOOD FOR NOW BASED ON
LATEST MODEL GUIDANCE AND PRESENT CONDITIONS. THEREFORE ONLY MINOR
ADJUSTMENTS WERE MADE TO THE SHORT TERM WINDS GRIDS BASED ON LATEST
TJSJ UPPER AIR DATA...AND LOCAL SURFACE OBSERVATIONS. LOW TO MID
LEVEL INDUCED TROUGH/EASTERLY PERTURBATION NEAR 42/43 WEST STILL
EXPECTED TO ARRIVE ACROSS THE EASTERN CARIBBEAN ON THURSDAY OR
FRIDAY AND SO FAR STILL ONLY EXPECTED SLIGHT INCREASE IN SHALLOW
EASTERLY TRADE WIND MOISTURE. HOWEVER...NO MAJOR WEATHER FEATURE
IN SIGHT FOR THE NEXT SEVERAL DAYS. BASED ON LATEST NAAPS AEROSOL
PRODUCT AND SAL ANALYSIS...MODERATE TO HIGH CONCENTRATION OF SAHARAN
DUST WILL LINGER ACROSS THE REGION THROUGH AT LEAST WEDNESDAY.

[cycloneye]

Good morning. A trough and a Tropical Wave will be the dominant features for the rest of this week and next weekend.


AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE SAN JUAN PR
636 AM AST WED JUL 11 2012

.SYNOPSIS...TUTT LOW NORTHEAST OF THE ISLANDS WILL MOVE WESTWARD
JUST NORTH OF THE GREATER ANTILLES AND RELOCATE OVER THE BAHAMAS
ON SATURDAY. A MID-LEVEL LOW IS EXPECTED TO APPROACH THE NORTHEASTERN
CARIBBEAN ON THURSDAY...INDUCING A TROUGH AT THE SURFACE. STRONG
SURFACE HIGH PRESSURE OVER THE NORTH CENTRAL ATLANTIC IS MAINTAINING
A MODERATE SOUTHEASTERLY FLOW ACROSS THE NORTHEAST CARIBBEAN.
WETTER CONDITIONS ARE EXPECTED THURSDAY THROUGH SUNDAY AS AN
INDUCED TROUGH MOVES ACROSS THE AREA LATE THURSDAY AND FRIDAY...
FOLLOWED BY THE NEXT TROPICAL WAVE DURING THE UPCOMING WEEKEND.

&&

.DISCUSSION...HAZY SKIES WITH LIMITED SHOWER ACTIVITY IS EXPECTED
TODAY ACROSS THE LOCAL ISLANDS. ALTHOUGH...SATELLITE AND RADAR
IMAGERY INDICATED A FEW PASSING SHOWERS AFFECTING THE WINDWARD
SECTIONS OF THE ISLANDS EARLY THIS MORNING...THE PROBABILITY OF
PRECIPITATION SHOULD DIMINISH SIGNIFICANTLY AFTER SUNRISE.
HOWEVER...THE TYPICAL SEA BREEZE CONVERGENCE ACROSS THE WEST
SECTIONS OF PUERTO RICO WILL HELP TO DEVELOP A COUPLE OF
THUNDERSTORMS NEAR CABO ROJO AND NEARBY MUNICIPALITIES THIS
AFTERNOON.

GFS BRINGS AN INDUCED TROUGH AND ITS ASSOCIATED MOISTURE ACROSS THE
FORECAST AREA FROM LATE THURSDAY THROUGH FRIDAY. THIS TROUGH WILL
BE SUPPORTED BY A MID TO UPPER LOW...WHICH WILL HELP TO INCREASE
THE CONVECTIVE INSTABILITY OVER THE ISLANDS. THIS TRANSLATES TO
INCREASED CHANCE FOR ORGANIZED CONVECTION ACROSS THE FORECAST
AREA...WITH HI-RES MODELS SHOWING MOST ACTIVE CONVECTION DEVELOPING
ACROSS THE COASTAL WATERS AND THE INTERIOR SECTIONS OF PUERTO
RICO. OPERATIONAL MODELS DO NOT INDICATE MUCH IMPROVEMENT IN THE
WEATHER CONDITIONS UNTIL NEXT WEEK...DUE TO THE NEXT TROPICAL
WAVE THAT IS FORECAST TO MOVE NEAR THE ISLANDS DURING THE WEEKEND.

&&

.AVIATION...EXPECT PREVAILING VFR CONDITIONS TO CONTINUE ACROSS THE
LOCAL ISLANDS AND AT ALL TAF SITES THROUGH THE FORECAST PERIOD.
HOWEVER...BRIEF MVFR CONDITIONS AND LOCAL MOUNTAIN OBSCURATIONS ARE
EXPECTED IN ISOLATED TO SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS...MAINLY OVER THE CENTRAL AND WESTERN INTERIOR AND
SOUTHWEST SECTIONS OF PUERTO RICO INCLUDING AT LEAST IN THE VICINITY
OF TJMZ AND TJPS...FROM 11/17Z THROUGH ABOUT 11/22Z. IN ADDITION...
SAHARAN DUST WILL CONTINUE ACROSS THE LOCAL AREA THROUGH TODAY...
RESULTING IN HAZY SKIES BUT MOST VISIBILITIES SHOULD AGAIN REMAIN
P6SM.

&&

.MARINE...STRONG HIGH PRESSURE FAR NORTHEAST OF THE REGION WILL
MAINTAIN A MODERATE TRADE WINDS ACROSS THE REGIONAL WATERS THROUGH
THE SEVERAL DAYS. SEAS WILL RANGE BETWEEN 3 AND 5 FEET THROUGH
THURSDAY...INCREASING SLIGHTLY TO 6 FEET OVER THE WEEKEND WHEN
THE TROPICAL WAVE IS EXPECTED TO MOVE ACROSS THE ISLANDS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 78 88 77 / 20 30 30 30
STT 90 79 88 78 / 20 30 50 50

[underthwx]

Morning CE and friends...what is the ICTZ lookin like this morning...couple days ago when i last looked it was full of dry air...

[cycloneye]

Morning CE and friends...what is the ICTZ lookin like this morning...couple days ago when i last looked it was full of dry air...

The only areas that the ITCZ is active now are around the wave Midway between Africa and the Lesser Antilles,South of CV Islands and just East of Trinidad & Tobago to 55W. So far it has not been as active this year because of the Saharan Dust events that have occured many times.

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
300 PM AST WED JUL 11 2012

.DISCUSSION...12Z TJSJ RAOB SHOWED A SIGNIFICANT INVERSION/CAP TO
OVERCOME FOR ANY CONVECTION TO OCCUR THIS AFTERNOON. WELL DEVELOPED
CUMULUS AIDED BY CONVERGING OCEAN BREEZES OVER SOUTHWEST PR HAS
FINALLY BEGUN TO BREAK THROUGH THE INVERSION IN LAST 30 MINUTES...
AND EVEN ALONG LONG STREAMER INTO EASTERN PR. LIMITED PRECIPITABLE
WATER (1.3 IN.) SUGGESTS FLOODING WILL NOT BE AN ISSUE. EXTRAPOLATION
OF MIMIC/TPW LOOP AND MODELS INDICATE THAT MOISTURE ARRIVING FROM
NORTHEAST WILL INCREASE LATE TONIGHT AND REACH 1.8 INCHES THU/FRI.
THIS WILL CAUSE MORE SHOWERS/THUNDER FOR WEST PR ON THU AND FOR
NORTHERN PR FRI AS FLOW TURNS SOUTHEAST. HOWEVER...WILL NOT
INCREASE THE COVERAGE OF SHOWERS TONIGHT/EARLY THU AS THE NUMBER
OF SHOWERS NOTED ON SATELLITE CURRENTLY EMBEDDED IN THE HIGHER
MOISTURE NORTHEAST OF PR IS UNREMARKABLE.

WESTWARD MOVING TUTT ABOUT 35N/60W COVERS A LARGE AREA BUT ITS
ASSOCIATED WINDS ARE WEAK AND DON/T BELIEVE IT WILL BE AN ENHANCING
PLAYER FOR CONVECTION MUCH NEXT COUPLE OF DAYS ESPECIALLY IT
REMAINS TO FAR NORTH TO GET UNDERNEATH THE CYCLONIC FLOW. IT IS
CAUSING PERSISTENT DEEP SHEAR ACROSS THE TROPICAL ATLANTIC AND IS
SUPPRESSING TROPICAL WAVES TRYING TO DEVELOP. NAM/GFS INDICATES A
WEAK TROPICAL WAVE WILL TAKE THE PRECIPITABLE WATER NOTCH IN ITCZ
AT 10N/40W AND DRIVE IT TO USVI BY SAT AFTERNOON...WITH A LOBE OF
HIGH 700 MB THETA-E FOLLOWING THE WAVE. THE WAVE ARRIVES TOO LATE
(IF MODEL IS CORRECT) TO INCREASE AFTERNOON CONVECTION OVER
PR...BUT DID INCREASE SHOWERS TO SCATTERED AS INDICATED BY
FORECAST FOR USVI. ANOTHER WEAK/LOW AMPLITUDE TROPICAL WAVE IS
EXPECTED LATE SUNDAY.

&&

.AVIATION...CONT VFR. INCR MOISTURE MAY CAUSE MVFR CIGS IN SCT
SHRA LATE TONIGHT/EARLY THU XCP TJPS/TJMZ. LLVL WINDS NE 10-20 KT
BCMG E AND WEAKENING THU.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 78 88 77 89 / 30 30 30 40
STT 79 88 78 88 / 30 50 50 50

[cycloneye]

Night update:

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1019 PM AST WED JUL 11 2012

.UPDATE...PREVAILING EAST NORTHEAST WIND FLOW HAS BEGUN TO ADVECT
SHALLOW PATCHES OF MOISTURE INLAND ACROSS PARTS OF NORTHEAST
PUERTO RICO AS WELL AS OVER PARTS OF CULEBRA...VIEQUES AND AS FAR
SOUTH AS THE ISLAND OF SAINT CROIX. SO FAR THE SHOWERS HAVE BEEN
QUICK PASSING AND EXPECT THE BRIEF INTERVALS OF PASSING SHOWERS TO
CONTINUE THROUGH THE EARLY MORNING HOURS. OVERALL INHERITED FORECAST
PACKAGE LOOKS GOOD FOR NOW AND IN AGREEMENT WITH PREVIOUS FORECAST
REASONING. ONLY MINOR ADJUSTMENTS MADE TO THE SHORT AND LONG TERM
GRIDS AS WINDS WERE UPDATED BASED ON MODEL INITIALIZATION AND LATEST
GFS GUIDANCE WHICH SO FAR HAD GOOD HANDLE ON LOCAL WEATHER PATTERN.
DECIDED TO KEEP THE HAZE OUT OF THE OVERALL PACKAGE FOR NOW AS EXPECT
LESSER AMOUNTS OF SAHARAN DUST OVER THE NEXT FEW DAYS...AT LEAST UNTIL
ANOTHER SIGNIFICANTLY HIGHER CONCENTRATION...NOW JUST OFF THE AFRICAN
COAST... IS EXPECTED TO ARRIVE AND SPREAD ACROSS THE REGION BY LATE
SUNDAY AND INTO THE EARLY PART OF NEXT WEEK.

[cycloneye]

Good morning. Upper trough and Tropical Wave will enhance the rains for the Eastern Caribbean islands for the next few days.


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
538 AM AST THU JUL 12 2012

.SYNOPSIS...A TUTT LOW NORTHEAST OF THE LOCAL AREA THIS MORNING...
WILL CONTINUE MOVING WEST THE NEXT COUPLE OF DAYS WITH A BROAD LOW
TO MID LEVEL REFLECTION PASSING ACROSS THE FA THIS AFTERNOON
THROUGH FRIDAY. AN TUTT INDUCED PERTURBATION WILL THEN AFFECT THE
LOCAL AREA SATURDAY FOLLOWED BY A TROPICAL WAVE SUNDAY.

&&

.DISCUSSION...ALTHOUGH IT WILL NOT BE CLOUDY AND RAINY ALL THE
TIME...AN INCREASINGLY UNSETTLED SPELL OF WEATHER APPEARS ON TAP
FOR THE FA DURING THE NEXT SEVERAL DAYS. FOR TODAY THROUGH
FRIDAY...AS AFOREMENTIONED TUTT PASSES BY TO OUR NORTH AND BROAD
LOW TO MID LEVEL REFLECTION MOVES ACROSS THE FA...THESE FEATURES
AND ASSOCIATED MOISTURE WILL COMBINE WITH LOCAL EFFECTS...TO
PRODUCE AREAS OF CLOUDINESS...SCATTERED TO NUMEROUS SHOWERS AND
ISOLATED THUNDERSTORMS OVER PARTS OF THE LOCAL ISLANDS...WITH THE
BEST DYNAMICS EXPECTED FOR FRIDAY. THEREAFTER...THE FORECAST
BECOMES A BIT TRICKY...ESPECIALLY WHEN TRYING TO COMPARE LATEST
OBSERVED DATA WITH MODEL PROJECTIONS AND RESULTANT TIMING OF
FEATURES. THAT SAID...WE EXPECT A TUTT INDUCED PERTURBATION ALONG
51 DEGREES WEST EARLY THIS MORNING TO MOVE ACROSS THE LOCAL AREA
SATURDAY...FOLLOWED BY A TROPICAL WAVE CURRENTLY NEAR 43 DEGREES
PASSING ACROSS THE FA SUNDAY. THESE TWO FEATURES AND PARTICULARLY
THE TIMING OF SUBSIDENCE INDUCED DRY SLOTS VERSUS THE BEST AREAS
OF MOISTURE AND HENCE THE BEST CHANCES OF ACTIVE WEATHER...WILL
NEED TO BE FOLLOWED CLOSELY THE NEXT COUPLE OF DAYS. THUS...EXPECT
ADJUSTMENTS TO MODEL SOLUTIONS AND SUBSEQUENTLY CHANGES TO LOCAL
GRIDS AND FORECASTS TO BE FORTHCOMING DURING THE NEXT 24 TO 48
HOURS...AS THE WEEKEND FORECAST IS FINE TUNED.

&&

.AVIATION...PATCHES OF MOISTURE EMBEDDED IN A NORTHEASTERLY
TRADE WIND FLOW WILL CONTINUE TO AFFECT THE LOCAL ISLANDS FROM
TIME TO TIME THROUGH AT LEAST THE NEXT 24 HOURS. AS A RESULT...
TJSJ/TJBQ...TIST/TISX...TNCM AND TKPK WILL BE EXPERIENCING VCSH
AND -SHRA IN THE MORNING HOURS. BTWN 12/17Z AND 12/21Z TSRA WILL
BE POSSIBLE IN AND AROUND TJPS AND TJMZ...CAPABLE OF PRODUCING
MVFR/IFR CONDITIONS AND MTN OBSCURATIONS NEAR THESE TAF SITES.
WIND IS EXPECTED TO BE NORTHEAST AT 10 TO 20 KTS WITH HIGHER
GUSTS NEAR SHRA/TSRA.

&&

.MARINE...GENERALLY EXPECT WINDS OF 18 KNOTS OR LESS AND SEAS OF 6
FEET OR LESS ACROSS THE REGIONAL WATERS THROUGH AT LEAST SATURDAY.
SMALL BOAT OPERATORS SHOULD EXERCISE CAUTION ACROSS PARTS OF THE
LOCAL COASTAL WATERS TODAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 76 89 77 / 30 30 40 20
STT 90 78 89 79 / 30 40 40 30

[Gustywind]