Caribbean - Central America Weather

[msbee]

hi Gusty
I don't know what's over us but it sure is a little bit of unsettled weather. We are having a pretty heavy shower right now

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
225 PM AST THU OCT 15 2009

.SYNOPSIS...WEAK TROPICAL WAVE NOW LOCATED OVER THE SOUTHERN
CARIBBEAN AT AROUND 66 WEST WILL CONTINUE TO MOVE WEST AND AWAY
FROM THE LOCAL REGION TONIGHT. ON FRIDAY...HIGH PRESSURE WILL BUILD
FROM THE NORTHEAST AND IT WILL PREVAIL OVER THE LOCAL AREA THROUGH
THE BEGINNING OF NEXT WEEK. A TROPICAL WAVE NOW LOCATED AT AROUND
54 WEST WILL MOVE ACROSS THE LOCAL CARIBBEAN WATERS BETWEEN
SATURDAY NIGH AND SUNDAY MORNING.


&&

.DISCUSSION...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
DEVELOPED OVER THE NORTHWEST PORTIONS OF PUERTO RICO...PRODUCING
RAINFALL ACCUMULATIONS OF BETWEEN 1 TO 3 INCHES. ANOTHER AREA
AFFECTED BY SHOWERS WERE THE MUNICIPALITIES BETWEEN CATANO AND
DORADO.

FRIDAY...ALTHOUGH MODELS SUGGEST A SIGNIFICANT DECREASE ON
MOISTURE...ENOUGH WILL BE AVAILABLE TO GENERATE AFTERNOON SHOWERS
ACROSS THE INTERIOR AND NORTHWEST PORTIONS OF PUERTO RICO.

HIGH PRESSURE WILL BEGIN TO BUILD OVER THE LOCAL REGION TONIGHT
THROUGH FRIDAY AND IT IS EXPECTED TO STRENGTH THROUGH THE WEEKEND.
THIS HIGH PRESSURE WILL INTERACT WITH A TROPICAL WAVE THAT IS
FORECAST TO ENTER THE LOCAL CARIBBEAN ON SATURDAY. THIS
INTERACTION TIGHTENING THE PRESSURE GRADIENT ACROSS THE REGION...
THEREFORE INCREASING THE WINDS ACROSS THE LOCAL FORECAST AREA.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED ACROSS MOST TAF SITES THE
REST OF THE AFTERNOON AND TONIGHT. HOWEVER...FROM 15/18-22Z MVFR AND
POSSIBLE IFR CONDITIONS WITH MOUNTAIN OBSCURATIONS ARE POSSIBLE
ACROSS TJBQ. VCTS ARE POSSIBLE ACROSS TJMZ ALSO DURING THIS TIME
PERIOD.

&&

.MARINE...SEAS WILL CONDITIONS WILL REMAIN BETWEEN 2 TO 4 FEET
THROUGH FRIDAY NIGHT. SEAS WILL BECOME CHOPPY ON FRIDAY AS WINDS
ARE EXPECTED TO INCREASE SIGNIFICANTLY...GENERATING SEAS OF
BETWEEN 4 TO 6 FEET ACROSS THE LOCAL WATERS.

[Gustywind]

Let's see what could happen with the twave at 54W....Seems that Barbados could experience some showers/tstorms tonight?



000
AXNT20 KNHC 152326
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU OCT 15 2009

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST
FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED
ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2245 UTC.

...TROPICAL WAVES...

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 67W/68W TO THE SOUTH OF
15N MOVING WEST 10 TO 15 KT. UPPER LEVEL CYCLONIC FLOW IS ON TOP
OF THIS WAVE. STRONG SHOWERS AND THUNDERSTORMS ARE IN NORTHERN
COASTAL VENEZUELA FROM 9N TO THE COAST BETWEEN 67W AND 68W...
AND FROM 10N TO THE COAST BETWEEN 69W AND 71W. POSSIBLE SHOWERS
REMAIN WITHIN 30 NM ON EITHER SIDE OF 15N BETWEEN 67W AND 68W.

...THE ITCZ...

FROM AFRICA NEAR 11N14W TO 9N20W TO 7N30W 8N37W 7N46W TO 10N55W.
STRONG SHOWERS AND THUNDERSTORMS ARE IN COASTAL AFRICA FROM
8N TO 11N BETWEEN 12W AND 14W. ISOLATED MODERATE SHOWERS AND
POSSIBLE THUNDERSTORMS FROM 5N TO 14N BETWEEN AFRICA AND 55W.
ONE SURFACE TROUGH IN THE ITCZ IS ALONG 37W/38W TO THE SOUTH
OF 12N. A SECOND TROUGH IS ALONG 14N55W 12N56W 8N57W. STRONG
SHOWERS AND THUNDERSTORMS WITHIN 30 NM ON EITHER SIDE OF
12N59W 11N61W 10N63W. OTHER POSSIBLE SHOWERS COVER THE AREA
FROM 8N TO 15N BETWEEN 55W AND 63W.

...DISCUSSION...

THE GULF OF MEXICO...
BROAD UPPER LEVEL CYCLONIC FLOW FROM A TROUGH THAT IS MOVING
ACROSS THE SOUTHEASTERN U.S.A. AND THE NORTHEASTERN GULF COAST
COVERS THE AREA TO THE NORTH OF 25N TO THE EAST OF 90W. SHOWERS
ARE POSSIBLE ACROSS THE OPEN WATERS OF THE GULF IN THIS AREA...
INCLUDING IN FLORIDA TO THE NORTH OF 28N BETWEEN 80W AND 84W.
ISOLATED MODERATE SHOWERS TO POSSIBLE THUNDERSTORMS ARE
IN MEXICO...FROM 22N TO 28N BETWEEN 100W AND 107W...IN AN
AREA OF MIDDLE TO UPPER LEVEL CYCLONIC FLOW WITH EVEN HIGHER
LEVEL ANTICYCLONIC FLOW ON TOP OF IT. UPPER LEVEL ANTICYCLONIC
OUTFLOW FROM T.D. TWENTY-E IN THE EASTERN PACIFIC OCEAN IS
BRUSHING UP AGAINST THE COAST FROM SOUTHERN GUATEMALA TO MEXICO
NEAR 100W. ISOLATED STRONG THUNDERSTORMS ARE FROM THE COAST
INLAND WITHIN 30 NM TO 45 NM FROM SOUTHWESTERN GUATEMALA TO 95W
IN THE ISTHMUS OF TEHUANTEPEC. MIDDLE LEVEL TO UPPER LEVEL
CYCLONIC FLOW COVERS THE NORTHERN ISTHMUS OF TEHUANTEPEC. THIS
CYCLONIC FLOW APPEARS TO BE PART OF THE TROUGH THAT ORIGINATES
IN THE CARIBBEAN SEA AND THAT REACHES EL SALVADOR. ISOLATED
MODERATE SHOWERS AND POSSIBLE THUNDERSTORMS COVER THE YUCATAN
PENINSULA AND PARTS OF GUATEMALA...CAUGHT UP IN BROAD UPPER
LEVEL CYCLONIC FLOW AROUND A CARIBBEAN SEA TROUGH.

THE CARIBBEAN SEA...
AN UPPER LEVEL TROUGH EXTENDS FROM THE ATLANTIC OCEAN NEAR
18N52W TO NEAR ANTIGUA AND BARBUDA...TO A WEAK CYCLONIC
CIRCULATION CENTER NEAR 16N71W...TO 12N79W TO EL SALVADOR...
AND FINALLY POSSIBLY TO THE NORTHERN ISTHMUS OF TEHUANTEPEC
OF MEXICO. ISOLATED AND DISORGANIZED SHOWERS/POSSIBLE
THUNDERSTORMS ARE OVER THE OPEN WATERS AND ON SOME OF THE
ISLANDS TO THE NORTH OF 14N TO THE WEST OF 62W. THE MOST
NOTABLE ISLANDS FOR PRECIPITATION ARE PUERTO RICO...TO THE
WEST OF 70W IN HISPANIOLA...WESTERN JAMAICA...SOUTHEASTERN
CUBA...AND CUBA TO THE WEST OF 80W.

THE ATLANTIC OCEAN...
BROAD UPPER LEVEL CYCLONIC FLOW COVERS THE AREA TO THE NORTH
OF THE BAHAMAS TO THE WEST OF 60W. A COLD FRONT PASSES THROUGH
32N45W TO 28N55W. A STATIONARY FRONT CONTINUES FROM 28N55W TO
27N60W TO 31N69W. A WARM FRONT CONTINUES NORTHWESTWARD BEYOND
31N69W. A SECOND FRONTAL BOUNDARY PASSES THROUGH 32N75W TO
30N80W AND BEYOND SOUTHWESTERN GEORGIA. BROKEN MULTILAYERED
CLOUDS AND POSSIBLE SHOWERS ARE TO THE NORTH OF 25N BETWEEN
60W AND 80W...AND TO THE NORTH OF 25N BETWEEN 40W AND 60W.
AN UPPER LEVEL RIDGE PASSES THROUGH 33N45W TO 31N48W TO
26N57W AND 24N64W. AN UPPER LEVEL TROUGH PASSES THROUGH 32N30W
TO A CYCLONIC CENTER NEAR 27N31W TO 21N34W TO 12N37W.
WEAK TROUGHS ARE INTERCONNECTED TO A 1011 MB LOW PRESSURE CENTER
THAT IS NEAR 29N29W. ONE TROUGH PASSES THROUGH 32N20W TO
29N20W...CURVING WESTWARD TO THE LOW CENTER...AND EVENTUALLY
TO 28N35W. A SECOND TROUGH GOES FROM THE 1011 MB LOW CENTER TO
26N26W AND CURVES TO 21N35W. THESE FEATURES ARE IDENTIFIABLE ON
THE VISIBLE SATELLITE IMAGES THROUGH 15/1800 UTC. SHOWERS ARE
POSSIBLE TO THE NORTH OF 20N BETWEEN 20W AND 40W.

$$
MT

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
956 PM AST THU OCT 15 2009

.UPDATE...
LATEST SATELLITE IMAGERY AND DOPPLER WEATHER RADAR SHOWED DECREASING
CLOUDS AND SHOWERS ACROSS THE REGION...WITH SKIES BECOMING CLEAR
TO PARTLY CLOUDY ACROSS THE ISLANDS AS AFTERNOON CONVECTION DISSIPATED
JUST AFTER SUNSET. LATEST TASK UPPER AIR SOUNDING WAS FAIRLY MOIST IN
THE LOW LEVELS WITH PW AT VALUE OF 2.27 INCHES...BUT SUSPECT SOME
CONTAMINATION DUE TO AFTERNOON CONVECTION. GFS MODEL GUIDANCE AND
FORECAST SKEW-T SHOWED A DECREASING TREND ON PW AT VALUES BY FRIDAY
AFTERNOON...AS SOMEWHAT DRIER AIR IS FORECAST TO MOVE IN ACROSS
THE REGION AND THE ATLANTIC HIGH BUILDS SOUTHWARDS ACROSS THE
NORTHEAST CARIBBEAN. AS INDICATED IN THE U/A SOUNDING...A LIGHT
EAST TO SOUTHEAST LOW LEVEL WIND FLOW PREVAILED THIS EVENING. BASED
ON LATEST GFS MODEL GUIDANCE THIS SHOULD BECOME MORE EASTERLY AND
INCREASE OVER THE NEXT FEW DAYS AS THE PRESSURE GRADIENT TIGHTENS
ACROSS THE REGION. MADE SOME MINOR ADJUSTMENTS TO THE SHORT TERM
FORECAST GRIDS TO DECREASE POPS AND WEATHER ACROSS THE ISLANDS
OVERNIGHT THROUGH FRIDAY MORNING. BASED ON PRESENT WEATHER PATTERN...
SHOWERS ACTIVITY SHOULD BE LESS ACROSS THE REGION ON FRIDAY AFTERNOON.

&&

.AVIATION...MAIN CONCERN WILL BE VOLCANIC ASH COMING FROM MONTSERRAT.
LATEST ADVISORIES AND MODEL RUNS PLACE THE PLUM OVER THE ST CROIX
(TISX) SITE AND JUST A FEW MILES FROM THE SOUTHERN DONUT OF ST THOMAS
(TIST). WENT WITH VA IN TISX TAF UNTIL 6Z...RECEIVED PIREP CONFIRMING
ASH 50 MI SOUTH OF TISX. ASH NOT LIKELY TO REACH OTHER SITES AT THIS
TIME. OTHERWISE VFR ALL NIGHT WITH MORE SUB-VFR AND TSRA EXPECTED
FRIDAY OVER TJBQ AND TJMZ 17-21Z.

[cycloneye]

Good morning to all.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
428 AM AST FRI OCT 16 2009

.SYNOPSIS...MID-UPPER LEVEL RIDGE TO BUILD ACROSS THE REGION OVER
THE NEXT FEW DAYS AS POLAR TROUGH AMPLIFIES ACROSS THE EASTERN
U.S.

&&

.DISCUSSION...MODEL GUIDANCE SHOWS A SIGNIFICANT DRYING TREND
STARTING LATER TODAY THAT LASTS WELL INTO NEXT WEEK AS SUBSIDENCE
CAP STRENGHTENS/LOWERS AS MID-UPPER LEVEL RIDGE BUILDS ACROSS THE
REGION AS A POLAR TROUGH AMPLIFIES ACROSS THE EASTERN UNITED
STATES. LATEST LOCAL WRF-NMM MODEL SHOWS A MARKED DECREASE IN
CONVECTIVE COVERAGE FOR TODAY WHEN COMPARED TO YESTERDAY WITH SCT
TSTMS CONFINED TO NORTHWEST PR. ATMOSPHERE DRIES OUT FURTHER OVER
THE WEEKEND WITH PWAT VALUES DROPPING TO ABOUT 1.5 INCHES OR ABOUT
80% OF NORMAL FOR THIS TIME OF THE YEAR. ANTICIPATE MAINLY ISOLD
TSTMS ACROSS WRN PR DURING THE AFTERNOON OVER THE WEEKEND AND INTO
NEXT WEEK.

OF MORE CONCERN TODAY WOULD BE THE POTENTIAL FOR SOME VOLCANIC
ASH FROM THE SOUFRIERE HILLS VOLCANO TO MAKE IT TO THE U.S. VIRGIN
ISLANDS ESPECIALLY ST. CROIX GIVEN SOUTHEAST STEERING WIND FLOW
AS SEEN ON A RECENT 0730Z ACARS SOUNDING FROM SAN JUAN AND TJUA
VWP PROFILE. LATEST GRAPHICS/MESSAGES FROM VAAC INDICATE AN ASH
PLUME EXTENDING 120 NMI TO THE WEST OF MONSERRAT. ANY ERUPTION OR
GAS EMISSION WOULD BRING VOLCANIC ASH THIS WAY GIVEN FVRBL
STEERING FLOW. WILL HAVE TO WAIT FOR HIGH RESOLUTION VISIBLE AND
MODIS IMAGERY LATER TODAY TO SEE IF THERE IS ANY ASH AND/OR THE
EXTENT OF THE PLUME.

ALSO...ANTICIPATE TEMPERATURES TO EXCEED 90F TODAY GIVEN
DOWNSLOPE COMPONENT AND A DRIER AIR MASS.

&&

.AVIATION...MVFR CONDITIONS AT JMZ/JBQ WITH TSRA THIS AFTERNOON.
ALSO...ANY ERUPTION OR GAS EMISSION FROM THE SOUFRIERE HILLS
VOLCANO COULD BRING VA TO ST. CROIX. WILL WAIT FOR VISIBLE IMAGERY
LATER TODAY TO SEE IF THERE IS ANY ASH


&&

.MARINE...5 FT SEAS IN NRLY SWELLS OF ABOUT 11 SECS WILL BUILD
ACROSS THE ATLC WATERS OVR THE NEXT 48 HRS.

[cycloneye]

CARIBBEAN SEA
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1130 AM EDT FRI OCT 16 2009

OFFSHORE WATERS FORECAST FOR THE SW AND TROPICAL N ATLC FROM 07N
TO 22N BETWEEN 55W AND 65W

SEAS GIVEN AS SIGNIFICANT WAVE HEIGHT...WHICH IS THE AVERAGE
HEIGHT OF THE HIGHEST 1/3 OF THE WAVES. INDIVIDUAL WAVES MAY BE
MORE THAN TWICE THE SIGNIFICANT WAVE HEIGHT.

AMZ086-162130-
E CARIBBEAN E OF 75W TO THE LEEWARD AND WINDWARD ISLANDS
1130 AM EDT FRI OCT 16 2009

...VOLCANIC ASHFALL ADVISORY WITHIN 90 NM W QUADRANT OF
SOUFRIERE HILLS VOLCANO MONTSERRAT AT 16.7N 62.2W...

.THIS AFTERNOON...S OF 14N W OF 70W E WINDS 15 KT. ELSEWHERE E
WINDS 10 TO 15 KT. SEAS 5 FT ENTIRE AREA. VISIBILITY LESS THAN 5
NM IN VOLCANIC ASH.
.TONIGHT AND SAT...NE TO E WINDS 10 TO 15 KT INCREASING TO 20 KT
E OF 70W AND S OF 15N W OF 70W. SEAS 5 FT BUILD TO 7 FT E OF 70W.
.SAT NIGHT AND SUN...NE TO E WINDS 15 TO 20 KT. SEAS 8 FT.
.MON...NE TO E WINDS 15 KT...OCCASIONALLY 20 KT. SEAS 7 FT.
.TUE...W OF 70W E WINDS 15 TO 20 KT. SEAS 7 FT. E OF 70W E WINDS
10 TO 15 KT. SEAS 5 FT.

[cycloneye]

000
FXCA62 TJSJ 161909
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
309 PM AST FRI OCT 16 2009

.SYNOPSIS...MID TO UPPER LEVEL RIDGE TO BUILD ACROSS THE REGION
OVER THE NEXT FEW DAYS. WINDS WILL SHIFT MORE EASTERLY THROUGH THE
WEEKEND. AFTERNOON CONVECTION EXPECTED EVERY AFTERNOON ACROSS THE
CORDILLERA CENTRAL.

&&

.DISCUSSION...12Z MODEL GUIDANCE STILL SHOWS A DRYING TREND...BUT
NOT AS SIGNIFICANT AS BEFORE. A DRY SLOT OF AIR WAS MOVING JUST
OVER THE U.S. VIRGIN ISLANDS...AND THROUGH THE EASTERN HALF OF
PUERTO RICO LATE THIS AFTERNOON. THIS AREA OF DRY AIR...PRODUCED
MOSTLY SUNNY SKIES ACROSS THESE AREAS THIS AFTERNOON...WITH ONLY
ISOLATED SHOWERS DEVELOPING ACROSS EL YUNQUE RAIN FOREST...MOVING
NORTHWEST ACROSS THE SAN JUAN METROPOLITAN AREA. ACROSS THE NORTH
CENTRAL...AND NORTHWEST SECTIONS OF PUERTO RICO....SOME HEAVY
SHOWERS DEVELOPED...PRODUCING BETWEEN ONE TO TWO INCHES OF
RAINFALL IN LOCALIZED AREAS. ALTHOUGH THIS DRY SLOT OF AIR WILL
LIMIT THE SHOWER ACTIVITY ACROSS THE LOCAL AREA...MAINLY OVERNIGHT
AND SATURDAY...ENOUGH MOISTURE AT THE SURFACE...WILL BE ENOUGH TO
PRODUCE THE NORMAL AFTERNOON CONVECTION ACROSS THE CORDILLERA
CENTRAL...AFFECTING MAINLY THE WESTERN HALF OF PUERTO RICO...AN
THE WESTERN PART OF THE U.S. VIRGIN ISLANDS. IN THE LONG
TERM...ALTHOUGH AN UPPER LEVEL TROUGH IS FORECAST BY COMPUTER
MODELS TO DEVELOP ACROSS THE WESTERN CARIBBEAN NEXT WEEK...MID TO
UPPER LEVEL RIDGING IS FORECAST TO REMAIN WELL ESTABLISH OVER THE
NORTHEAST CARIBBEAN...KEEPING THE TROUGH AWAY FROM THE LOCAL
AREA...WITH LITTLE OR NO EFFECTS OVER THE REGION. NO SIGNIFICANT
WEATHER EVENTS ARE FORECAST BY COMPUTER MODELS TO AFFECT THE LOCAL
AREA AT LEAST THE NEXT FIVE DAYS.


&&

.AVIATION...TEMPORARY MVFR CONDITIONS WILL CONTINUE ACROSS TJBQ
THROUGH 16/22Z...WITH VFR CONDITIONS EXPECTED ACROSS THE REMAINDER
OF THE TAF SITES. MAIN CONCERN WILL BE VOLCANIC ASH COMING FROM
MONTSERRAT WHICH IS CURRENTLY AFFECTING TKPK...TIST...TISX AND
TJPS...AND EXPECTED TO PERSIST THROUGH AT LEAST 27/00Z.

[Gustywind]

Showers are just falling here, with some gusts.

[Gustywind]

Again looks like all is quiet in the tropics, let's continue to enjoy this situation

000
ABNT20 KNHC 162338
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT FRI OCT 16 2009

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS.

$$
FORECASTER BERG

[Gustywind]

Quiet...but let's be as usual, prudent, don't let our guard down islanders as the season is not over!
000
AXNT20 KNHC 161754
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI OCT 16 2009

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST
FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED
ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 73W S OF 17N MOVING W NEAR 15 KT. THE
WAVE REMAINS EMBEDDED WITHIN AN AREA OF DEEP LAYERED MOISTURE AS
INDICATED IN THE TOTAL PRECIPITABLE WATER IMAGERY ACROSS THE
CENTRAL CARIBBEAN. VISIBLE SATELLITE IMAGERY SHOWS CYCLONIC
CURVATURE IN THE LOW-LEVEL CLOUD FIELD IN THE VICINITY OF THE
WAVE AXIS WITH SCATTERED SHOWERS AND ISOLATED TSTMS FROM 13N-17N
BETWEEN 71W-75W.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 9N13W 7N27W 8N41W 7N45W 11N59W.
A SURFACE TROUGH IS EMBEDDED WITHIN THE ITCZ ALONG 43W FROM
5N-11N. SCATTERED TO NUMEROUS MODERATE/ISOLATED STRONG
CONVECTION IS FROM 5N-11N BETWEEN 39W-47W. A SECOND SURFACE
TROUGH IS ALONG 60W APPROACHING THE LESSER ANTILLES FROM
10N-16N. SCATTERED MODERATE CONVECTION IS FROM 9N-15N BETWEEN
55W-62W. ELSEWHERE...CLUSTERS OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION ARE FROM 4N-11N BETWEEN 20W-39W. A SIMILAR
AREA OF CONVECTION IS ALONG THE W AFRICA COAST FROM 5N-9N
BETWEEN 11W-16W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL RIDGE IS ANCHORED OVER CENTRAL MEXICO COVERING
THE SW GULF AND BAY OF CAMPECHE WHILE BROAD UPPER LEVEL
TROUGHING DIPS OVER THE N/CENTRAL AND NE GULF TO 25N. THIS
LONGWAVE TROUGHING SUPPORTS A COLD FRONT THAT AT 1500 UTC ENTERS
THE GULF OVER THE BIG BEND REGION OF FLORIDA NEAR 30N84W AND
EXTENDS SW ALONG 27N90W TO NEAR BROWNSVILLE TEXAS AND INTO NE
MEXICO AS A STATIONARY BOUNDARY TO 27N104W. SCATTERED SHOWERS
AND ISOLATED TSTMS ARE WITHIN 90 NM EITHER SIDE OF THE FRONT W
OF 90W WHILE SCATTERED SHOWERS AND TSTMS ARE WITHIN 150 NM
EITHER SIDE OF THE FRONT E OF 90W TO INLAND OVER INTERIOR
PORTIONS OF THE CENTRAL FLORIDA PENINSULA. BEHIND THE COLD
FRONT...NLY WINDS UP TO 25 KT ARE EXPECTED TO CONTINUE SPREADING
OVER THE NW AND N/CENTRAL GULF THIS AFTERNOON INTO THE EVENING.
ELSEWHERE ACROSS THE REMAINDER OF THE GULF S OF THE FRONT...
GENERALLY CLEAR SKIES WITH LIGHT WINDS ARE OBSERVED S OF 24N.

CARIBBEAN SEA...
UPPER LEVEL TROUGHING IS ANCHORED OVER PORTIONS OF CENTRAL
AMERICA AND THE NW CARIBBEAN WITH MODERATE TO STRONG SUBSIDENCE
AND DRY AIR NOTED ON WATER VAPOR IMAGERY W OF 80W. THIS UPPER
LEVEL TROUGH EXTENDS AN AXIS FROM NICARAGUA NE ALONG 15N80W TO
NEAR PUERTO RICO WITH POSSIBLE ISOLATED SHOWERS OVER JAMAICA...
HISPANIOLA...PUERTO RICO AND ADJACENT COASTAL WATERS N OF 17N
BETWEEN 66W-80W. THE REMAINDER OF THE CARIBBEAN BASIN E OF THE
TROPICAL WAVE ALONG 73W...IS UNDER THE INFLUENCE OF AN UPPER
LEVEL RIDGE S OF 17N. MOIST SWLY UPPER LEVEL FLOW E OF 70W IS
DRAWING MIDDLE TO UPPER LEVEL TROPICAL MOISTURE OVER THE SE
CARIBBEAN. THIS MOISTURE AND INSTABILITY COUPLED WITH A SURFACE
TROUGH ALONG 60W E OF THE LESSER ANTILLES...IS GENERATING
SCATTERED SHOWERS AND ISOLATED TSTMS S OF 15N E OF 67W.

ATLANTIC OCEAN...
A BROAD UPPER LEVEL LONGWAVE TROUGH IS OVER THE ERN CONUS AND
DIPS OVER THE FLORIDA PENINSULA AS WELL AS PORTIONS OF THE FAR W
ATLC. THE ASSOCIATED SURFACE STATIONARY FRONT LIES ALONG 32N
FROM 70W TO A 1005 MB LOW CENTERED OVER SE GEORGIA. LOW-LEVEL
CONVERGENCE S OF THE FRONT AS WELL AS UPPER LEVEL DIFFLUENCE E
OF THE UPPER TROUGH AXIS IS GENERATING SCATTERED SHOWERS AND
TSTMS N OF 27N W OF 68W. FURTHER E...A BROAD UPPER LEVEL RIDGE
REMAINS OVER THE CENTRAL ATLC ANCHORED NEAR 24N58W EXTENDING A
RIDGE AXIS E-W ALONG 24N BETWEEN 45W TO 80W. A CENTRAL ATLC
UPPER LEVEL TROUGH REMAINS LARGELY NORTH OF THE REGION...BUT
EXTENDS A TROUGH AXIS ALONG 32N43W TO 30N50W. THIS UPPER LEVEL
TROUGH SUPPORTS A COLD FRONT THAT ENTERS THE REGION NEAR 32N39W
CONTINUING SSW ALONG 28N42W TO 26N49W. SCATTERED SHOWERS AND
POSSIBLE ISOLATED TSTMS ARE WITHIN 90 NM EITHER SIDE OF THE
FRONT. THE ERN ATLC IS DOMINATED BY UPPER LEVEL TROUGHING
ANCHORED ON AN UPPER LOW CENTERED NEAR 26N27W. A 1014 MB LOW IS
NEAR 27N30W WITH A SURFACE TROUGH ANALYZED FROM 28N26W TO 22N28W
WELL E OF THE SURFACE LOW. ISOLATED SHOWERS ARE WITHIN 30 NM OF
THE SURFACE TROUGH AND FROM 25N-29N BETWEEN 22W-26W.

$$
HUFFMAN

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1021 PM AST FRI OCT 16 2009

.UPDATE...
SKIES BECAME CLEAR TO PARTLY CLOUDY ACROSS THE LOCAL ISLANDS
DURING THE EVENING HOURS. A FEW SHOWERS MOVED INLAND ACROSS THE
EAST COASTAL AREAS LATE IN THE EVENING AND PRODUCED MOSTLY LIGHT
TO MODERATE SHOWERS IN ISOLATED SPOTS. THE MAIN CONCERN THIS
EVENING WAS THE PRESENCE OF SUSPENDED VOLCANIC ASH WHICH WAS
BEING SPREAD ACROSS THE REGION IN THE PREVAILING SOUTHEAST WIND
FLOW. LATEST PILOT REPORTS HOWEVER NOW SUGGESTED THAT THE ASH
HAS BECOME MORE DISPERSED ACROSS THE AREA AS NO VA WAS DETECTED.
ANOTHER PLUME OF HIGHER CONCENTRATION IS EXPECTED LATER ON AS
MENTIONED IN AVIATION DISCUSSION. WEATHERWISE...PATCHES CLOUDS
AND TRADE WIND SHOWERS WILL CONTINUE TO MAKE THEIR WAY ACROSS THE
REGION OVERNIGHT AND REACH THE EAST COASTAL SECTIONS OF PUERTO
RICO AND THE VIRGIN ISLANDS ESPECIALLY DURING THE EARLY MORNING
HOURS. OTHERWISE...NO MAJOR CHANGES MADE TO THE OVERALL FORECAST
PACKAGE WHICH HAD GOOD HANDLE ON EXPECTED WEATHER CONDITIONS FOR
THE NEXT FEW DAYS.

&&

.AVIATION UPDATE... MAJOR CONCERN TONIGHT IS VOLCANIC ASH FLOWS
COMING FROM MONTSERRAT. LOW LEVEL SOUTHEASTERLY WIND FLOW IS
CARRYING ASH PLUME AT THE 050-100 FT FL TOWARDS TISX...TIST AND
TJSJ. BEST GUESS FROM SATELLITE ANALYSIS AND TRACKING TOOLS PLACE
THE MOST DENSE PORTION OF ASH CLOUD AT TISX 0145Z...AND SHOULD BE
REACHING TJSJ BY 0300-0400Z. CONSIDERABLE DIFFICULTY IN
DETERMINING THE EXACT LOCATION OF THE ASH CLOUD CONSIDERING LACK
OF VISIBLE IMAGERY SINCE LAST SIGNIFICANT ERUPTION OCCURRED AROUND
22-23Z. BUT...BACK EDGE OF ASH CLOUD SHOULD CLEAR TIST/TISX BY
0800Z...AND CLEAR TJSJ NO LATER THAN 1300Z. WILL KEEP VA IN TAFS
FOR THOSE SITES...AS WELL AS TJPS (ALTHOUGH ITS MARGINAL THERE)
UNTIL THE ABOVE MENTIONED TIMES. OTHERWISE...VFR AND NO SIG
WEATHER THREATS APART FROM THE ASH.

[cycloneye]

Good morning to all.

FXCA62 TJSJ 170830
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
430 AM AST SAT OCT 17 2009

.SYNOPSIS...MID-UPPER LEVEL RIDGE TO MAINTAIN ITS GRIP OVER THE
REGION THROUGH NEXT TUE. RIDGE THEN EXPECTED TO BREAK DOWN MIDDLE
OF THE NEXT WEEK AS WESTERLIES ESTABLISH ACROSS THE SUBTROPICAL
ATLC TOWARD THE END OF NEW WORK WEEK.

&&

.DISCUSSION...SHOWER/TSRA ACTIVITY ACROSS THE ERN THIRD OF PR AND
THE USVI EARLY THIS MORNING APPEARS TO BE ENHANCED BY A SURFACE
TROUGH ALONG 63/64W. HOWEVER...LATEST RADAR IMAGERY SHOWS ACTIVITY
ON THE DOWNWARD TREND WITH CLOUD TOPS WARMING AND HARDLY ANY CG
LIGHTNING ACTIVITY.

FOR TODAY...GFS SHOWS A SURGE IN THE TRADE EASTERLIES WITH 25-KT
WINDS AT THE H85 LEVEL WITH SIG MID LEVEL DRYING. LATEST WRF-NMM
MODEL DEVELOPS HARDLY ANY CONVECTION FOR THIS AFTERNOON. THIS
SEEMS REASONABLE GIVEN RAPID WEAKENING SEEN WITH CURRENT
CONVECTION. PERHAPS JUST A BRIEF OVER THE AGUADILLA AREA.

AS MID-UPPER LEVEL RIDGE BUILDS ACROSS THE NORTHEAST CARIBBEAN
OVER THE NEXT FEW DAYS...MODELS SHOW A SUBSIDENCE CAP THAT
MEANDERS BETWEEN 700-500 MB WITH PWAT VALUES REMAINING CLOSE TO
NORMAL FOR THIS TIME OF THE YEAR. RH TIME HEIGHTS AND FCST MODEL
SOUNDINGS SHOW MOISTURE DEEP ENOUGH TO GENERATE SHALLOW AFTERNOON
CONVECTION OVER LAND AS OPPOSED TO DEEP CONVECTION.

BY THE END OF NEXT WEEK...MODELS SHOW RIDGE BREAKING DOWN AS
WESTERLIES BECOME ESTABLISHED JUST NORTH OF PR/USVI. LATEST
GFS/ECMWF INDICATE MOISTURE SURGING ACROSS THE ISLANDS AS WINDS
TURN MORE SRLY. THIS ALSO SEEMS TO COINCIDE WITH A FAVORABLE PHASE
OF THE MJO AND NEGATIVE H25 VELOCITY ANOMALIES. IT THUS APPEAR THAT A
WETTER SCENARIO IS ON TAP FOR NEXT WEEKEND.

&&

.AVIATION...WINDS EXPECTED TO TURN MORE EASTERLY TODAY WHICH
SHOULD KEEP ANY VOLCANIC ASH SOUTH OF PR AND THE USVI. VFR
CONDITIONS EXPECTED EVERYWHERE WITH ONLY VCSH OR VCTS FOR TJBQ.

&&

.MARINE...SURGE IN THE TRADE EASTERLIES TODAY WILL BRING WINDS
CLOSE TO 20 KTS ACROSS THE WATERS. EXERCISE CAUTION STATEMENTS IN
EFFECT.

[Gustywind]

000
AWCA82 TJSJ 170929
RWSVI

WEATHER SUMMARY FOR THE U.S. VIRGIN ISLANDS
NATIONAL WEATHER SERVICE SAN JUAN PR
529 AM AST SAT OCT 17 2009

VARIABLY CLOUDY SKIES WERE OBSERVED ACROSS THE U.S. VIRGIN ISLANDS
OVERNIGHT AS SHOWERS AND THUNDERSTORMS MOVED ACROSS THE ISLANDS
AND SURROUNDING COASTAL WATERS AROUND MIDNIGHT. AFTERWARD...RAIN
ACTIVITY HAS SIGNIFICANTLY DECREASE OVER THE AREA. WINDS HAVE BEEN
FROM THE EAST SOUTHEAST AT 10 MPH OR LESS.

RELATIVELY DRY AND HAZY LOOKING SKIES AND FAIR WEATHER CONDITIONS
ARE EXPECTED FOR TODAY ACROSS THE LOCAL ISLANDS. FOR THE REMAINDER
OF THE WEEKEND INTO THE FIRST HALF OF NEXT WEEK...FAIR WEATHER
CONDITIONS ARE EXPECTED TO PREVAIL WITH SLIGHT CHANGES OF RAIN.

ACROSS THE LOCAL WATERS...SEAS WILL BE 6 FEET OR LESS AND WINDS
ARE EXPECTED TO BE 20 KNOTS OR LESS THROUGH SUNDAY. SMALL CRAFT
SHOULD EXERCISE CAUTION ACROSS THE OFF SHORE ATLANTIC AND LOCAL PASSAGES.

$$

[cycloneye]

After a few days with some cooler temps,today is very warm here (91F as I post this) How are the temperatures in the islands?

http://www.weather.gov/view/prodsByStat ... ype=hourly

[Gustywind]

Maybe some ITCZ action?

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
236 PM AST SAT OCT 17 2009

.SYNOPSIS...SURFACE HIGH PRESSURE WILL CONTINUE TO EXTEND FROM
THE CENTRAL ATLANTIC SOUTHWEST TO THE NORTHEAST CARIBBEAN THROUGH
AT LEAST MONDAY. MID TO UPPER LEVEL RIDGE EXPECTED TO WEAKEN AS A
MID TO UPPER LEVEL TROUGH DEVELOPS ACROSS THE CENTRAL ATLANTIC.

&&

.DISCUSSION...MAIN FEATURE TODAY WAS VOLCANIC ASH WHICH WAS OBSERVED
ACROSS PUERTO RICO LATE THIS MORNING AND EARLY THIS AFTERNOON.
MOST OF IT HAS MOVED WEST...LEAVING ONLY SOME RESIDUAL ASH ACROSS
THE LOCAL AREA. REFER TO AVIATION SECTION FOR MORE DETAILS. IN THE
MEANTIME...A DRIER AIR MASS HAS MOVED ACROSS THE LOCAL REGION THIS
AFTERNOON...LIMITING SIGNIFICANTLY THE CHANCES FOR RAINFALL AND
CLOUDS COVERAGE. THIS WEATHER PATTERN IS EXPECTED TO CONTINUE AT
LEAST TROUGH MONDAY...WHEN MOISTURE IS FORECAST TO MOVES ACROSS
THE LOCAL AREA DURING THE AFTERNOON. GFS/NAM MODELS AGREED WITH
THIS...INCREASING THE POPS AND RH VALUES FOR THIS DAY. IN THE LONG
TERM...MID TO UPPER LEVEL RIDGE IS EXPECTED TO WEAKEN...AS A MID
TO UPPER LEVEL TROUGH DEVELOPS ACROSS THE CENTRAL ATLANTIC...AND
MOVES WESTWARD CLOSER TO THE LESSER ANTILLES. THIS WILL INDUCE A
MORE SOUTHERLY WIND FLOW ACROSS THE NORTHEAST CARIBBEAN. NO
SIGNIFICANT WEATHER EVENTS ARE FORECAST BY COMPUTER MODELS TO
AFFECT THE LOCAL AREA AT LEAST THE NEXT 5 DAYS.

&&

.AVIATION...EXPECT PREVAILING VFR CONDITIONS ACROSS THE LOCAL ISLANDS
AND AT ALL LOCAL TAF SITES TONIGHT. HOWEVER...BRIEF MVFR CONDITIONS
AND LOCAL MOUNTAIN OBSCURATIONS ARE EXPECTED...MAINLY OVER THE
NORTHWEST QUARTER OF PUERTO RICO...INCLUDING TJMZ AND TJBQ THROUGH
17/21Z...IN SCATTERED SHOWERS AND POSSIBLY AN ISOLATED THUNDERSTORM
OR TWO.

IN ADDITION...SMALL AREA/PATCH OF VOLCANIC ASH CURRENTLY EXTENDING
FROM WELL NORTHWEST OF AGUADILLA SOUTH SOUTHEAST ACROSS THE MONA
PASSAGE AND JUST CLIPPING THE WEST COAST OF PUERTO RICO...INCLUDING
TJMZ AND TJBQ AND STILL MOVING WEST NORTHWEST AT 20 TO 25 KNOTS.
EXPECT VA TO GENERALLY BE GONE FROM THESE TWO SITES BY 17/19Z.
PLEASE REFER TO SIGMET FOXTROT 2. REMAINING ASH PLUME AND ANY
ADDITIONAL "NEW" VA THROUGH TONIGHT...SHOULD REMAIN MAINLY SOUTH OF
THE LOCAL ISLANDS. PLEASE REFER TO SIGMET LIMA 13.

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1015 PM AST SAT OCT 17 2009

.UPDATE...ISOLATED TO SCATTERED SHOWERS WILL CONTINUE TO MOVE
ACROSS SECTIONS OF THE VI AND EASTERN PUERTO RICO OVERNIGHT.
CONTINUE TO EXPECT A MAINLY FAIR WEATHER DAY ACROSS THE REGION
TOMORROW...WITH LIMITED AFTERNOON CONVECTION ACROSS PUERTO RICO
AND A SHIFT IN WINDS TO A MORE EASTERLY DIRECTION...KEEPING
ANY VOLCANIC ASH SOUTH OF THE LOCAL ISLANDS. ONLY A FEW MINOR
TWEAKS MADE TO INHERITED FORECAST THIS EVENING...AS PREVIOUS
FORECAST REMAINS IN LINE WITH LATEST COMPUTER MODEL GUIDANCE AND
SATELLITE DATA.

&&

.AVIATION...
EXPECT PREVAILING VFR CONDITIONS AT ALL LOCAL TAF SITES
THRU 18/16Z. RELATIVELY DRY...SOMEWHAT UNSTABLE CONDS WILL CONTINUE
WITH PREVAILING EASTERLY TRADE WIND FLOW. AFTERNOON THUNDERSTORMS
WILL DEVELOP IN WESTERN INTERIOR PUERTO RICO AND SPREAD INTO TJMZ
AFT 18/17Z. SIGMET LIMA 14 IN EFFECT UNTIL 18/0515Z FOR VOLCANIC ASH
SPREADING WEST OF MONTSERRAT.

[cycloneye]

Good morning to all.

000
FXCA62 TJSJ 180829
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
429 AM AST SUN OCT 18 2009

.SYNOPSIS...MID-UPPER LEVEL RIDGE WILL HOLD THROUGH MID WEEK THEN
BEGIN TO BREAK DOWN AS WESTERLIES BECOME ESTABLISHED ACROSS THE
SUBTROPICAL ATLC BY THE END OF THE NEW WORK WEEK.

&&

.DISCUSSION...A VERY DRY AIR MASS HAS SETTLED ACROSS THE REGION
THIS MORNING WITH PWAT VALUES DOWN 1.5 INCHES OR ABOUT 80% OF
NORMAL FOR THIS TIME OF THE YEAR. TYPICAL ISOLD EARLY MORNING
SHOWER ACTIVITY CONTINUES TO AFFECT THE ERN THIRD OF PR THIS
MORNING AND ADJACENT WATERS BUT XPCT ACTIVITY TO WANE AFTER
SUNRISE. FOR THIS AFTERNOON...ATMOSPHERE IS FCST TO DRY OUT
FURTHER WITH K INDEX AND PWAT VALUES PLUMMETING AND A SUBSIDENCE
CAP THAT BUILDS DOWN TO 700 MB. ANY CONVECTION TODAY WILL BE
EXTREMELY ISOLD AND VERY SHORT BRIEF AND PROBABLY NOT EVEN WORTH
MENTIONING. GREAT DAY TO HEAD OUT TO THE BEACH.

AS MID UPPER LEVEL RIDGE HOLDS ITS GRIP ACROSS THE REGION...THE
SUBSIDENCE CAP HOLDS BETWEEN 700 AND 500 MB. THERE MIGHT BE JUST ENOUGH
MOISTURE FOR ISOLD/SCT SHALLOW AFTERNOON CONVECTION BUT NOT
ANTICIPATING MUCH IN THE WAY OF LIGHTNING ACTIVITY DUE TO WARM
EQUILIBRIUM LEVELS.

AS MID-UPPER RIDGE BREAKS DOWN DURING THE MIDDLE OF THE WEEK
ANTICIPATE A SLOW INCREASE IN CONVECTION AFTER WEDNESDAY. THINGS
MOISTEN UP CONSIDERABLY FOR NEXT WEEKEND WITH GFS/ECMWF MODELS INDICATING
K INDICES INCREASING TO NEAR 35 AND PWATS APPROACHING 2.0 INCHES.
GUIDANCE ALSO INDICATES A STRONG SHORTWAVE-TROUGH WILL MOVE ACROSS
PUERTO RICO NEXT FRIDAY. IN ADDITION...MJO PROGNOSIS INDICATE THE
CARIBBEAN SEA IN A MORE FVRBL PHASE FOR ENHANCED/ORGANIZED
RAINFALL. ANTICIPATING A MUCH WETTER SCENARIO FOR NEXT WEEKEND.

FOR THOSE WHO THOUGHT THE 2009 ATLC HURRICANE SEASON WAS OVER...LAST
SVRL RUNS OF THE ECMWF MODEL HAVE BEEN INDICATING A STRONG
TROPICAL CYCLONE DEVELOPING ACROSS THE SOUTHWEST CARIBBEAN SEA
OVER THE NEXT 48 HRS. WHILE TPC DOES NOT HAVE ANYTHING MENTIONED
IN THEIR LATEST TROPICAL WX OTLK...LATEST IR IMAGERY SHOWS A
MARKED INCREASE IN DEEP CONVECTION NORTH OF PANAMA WITH EVIDENCE
OF SOME MID LEVEL TURNING. GIVEN THE CONSISTENCY OF THE ECMWF
MODEL OVER THE LAST THREE DAYS PREDICTING A STRONG AND WELL-
DEVELOPED TROPICAL CYCLONE AND THE RECENT INCREASE IN CONVECTION
ALONG WITH FVRBL CLIMATOLOGICAL AND MJO CONDITIONS AM ANTICIPATING
SOMETHING WILL DEVELOP EVENTUALLY IN THAT AREA THIS WEEK.

&&

.AVIATION...VFR EVERYWHERE WITH JUST VCSH AT BEST. ANY VOLCANIC
ASH EXPECTED TO REMAIN WELL SOUTH OF THE ISLANDS DUE TO
UNFAVORABLE STEERING FLOW.

&&

.MARINE...GUSTY WINDS UP TO 20 KTS THE ONLY CONCERN. SEAS 4-5 FT
UNPROTECTED WATERS.

[Gustywind]

Good morning
Quiet tropics...

[Gustywind]

000
ABNT20 KNHC 181132
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 AM EDT SUN OCT 18 2009

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS.

$$
FORECASTER BRENNAN