Caribbean - Central America Weather

[cycloneye]

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SAN JUAN PR
1004 PM AST SAT SEP 15 2012

.SYNOPSIS...SUBTROPICAL RIDGE WILL STRENGTHEN OVER THE NEXT 12 HRS
AND BUILD TO THE NORTH OF THE AREA AND THEN HOLD THROUGH MID NEXT WEEK.
INVEST 92L EXPECTED TO BRING HEAVY RAINS TO THE PR/USVI TUE.


&&

.DISCUSSION...WATER VAPOR IMAGERY SHOWS MID LEVEL DYRING/SUBSIDENCE
BUILDING FROM THE EAST AS A CELL OF THE SUBTROPICAL RIDGE BUILDS
TOWARD THE AREA. THIS WILL PROVIDE A DECENT DAY TOMORROW WITH
SIGNIFICANT LESS CONVECTION THAN PREVIOUS FEW DAYS. LOW LEVEL
MOISTURE WILL BEGIN TO INCREASE MON AHEAD OF INVEST 92L.

INVEST 92L LOCATED AROUND 450 MILES EAST OF THE WINDWARDS WILL
MOVE WNW AROUND 15 MPH NEXT TWO DAYS AND PASS SOUTH OF THE AREA
TUE EVENING. GLOBAL MODELS SHOW MOISTURE ADVECTING IN QUICKLY MON
NIGHT WITH SHOWERS AND T-STORMS INCREASING IN CVRG MONDAY NIGHT
THROUGH TUE. REGARDLESS OF DEVELOPMENT...A RAINY DAY APPEARS IN
STORE FOR THE REGION TUE ALONG WITH SQUALLY WEATHER. HAVE BUMPED
SKY...POPS AND QPF GRIDS FOR THE MON NIGHT-TUE PERIOD. SIGNIFICANT
RAINFALL ACCUMULATIONS APPEAR LIKELY ESPECIALLY FOR THE EASTERN
HALF OF PR WHICH MAY REQUIRE A FLASH FLOOD WATCH TOMORROW. WEATHER
IMPROVES QUICKLY ON WED.

&&

.AVIATION...XPCT VFR REST OF TONIGHT BUT SHRA TO REMAIN JUST
OFFSHORE OF TJSJ FOR AWHILE. ISOLD SHRA STILL PSBL USVI BUT A REMOTE
CHC OF MVFR...SLIGHTLY BTR CHC AT TKPK/TNCM AS THE HIGHER MOISTURE
HAS ARRIVED THERE. SCT SHRA/TSRA XPCTD SAT AFT BUT WITH FEWER OBSCD
MTNS. LLVL WINDS VRBL (MSTLY E-SE) TO 12 KT THRU SAT.

&&

.MARINE...UNLESS INVEST 92L DEVELOPS FURTHER INTO A TROPICAL
CYCLONE...MAINLY SEAS OF 3-5 FT ARE EXPECTED. HEAVY RAINS AND
SQUALLS ARE EXPECTED MON NIGHT-TUE.

&&

.CLIMATE...A RECORD HIGH TEMPERATURE OF 92F DEGS WAS SET TODAY AT
THE SJU LMM INTL ARPT. THIS TIED THE OLD RECORD OF 92F SET BACK IN 2003.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 78 90 78 90 / 10 40 10 30
STT 78 89 79 89 / 10 40 20 40

[cycloneye]

Good morning. We continue to watch invest 92L,but for sure some squally weather will be with us for the next couple of days.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
558 AM AST SUN SEP 16 2012

.SYNOPSIS...HIGH PRESSURE WILL CONTINUE TO DOMINATES THE LOCAL
REGION THROUGH MONDAY. AN ACTIVE TROPICAL WAVE WILL MOVE OVER THE
AREA TUESDAY. UPPER LEVEL LOW WILL FOLLOW THE TROPICA WAVE...
MAINTAINING UNSETTLED WEATHER ACROSS THE REGION THROUGH THE END OF
THE WEEK.

&&

.DISCUSSION...LATEST SATELITE IMAGES DEPICTED A SLOT OF DRY AIR
MOVING IN OVER THE REGION. THIS AREA OF DRY AIR WILL LIMIT
SOMEWHAT THE SHOWER ACTIVITY FOR THIS AFTERNOON OVER PUERTO RICO
AND THE U.S VIRGIN ISLANDS . IN FACT...PW VALUES ARE FORECAST TO
DROP TO NEAR 1.4 INCHES BY THIS AFTERNOON. HOWEVER...DAYTIME
HEATING AND LOCAL EFFECTS...COMBINE WITH AVAILABLE MOISTURE...WILL
AID IN THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS ONCE
AGAIN...OVER THE INTERIOR AND NORTHWEST SECTIONS OF PUERTO RICO.

AN ACTIVE TROPICAL WAVE...LOCATED AROUND 600 MILES SOUTHEAST OF
PUERTO RICO EARLY THIS MORNING...WILL CONTINUE TO MOVE WEST TO
WEST-NORTHWEST DURING THE NEXT 24 TO 48 HOURS. THIS WAVE IS
ACCOMPANY BY A GOOD SURGE IN TROPICAL MOISTURE...WHICH WILL
ENCOMPASS THE REGION BEGINNING ON TUESDAY MORNING AND LASTING
THROUGH AT LEAST THURSDAY. PERIODS OF MODERATE TO HEAVY RAINFALL
CAN BE EXPECTED WITH THIS WAVE...WITH THE POTENTIAL FOR URBAN
FLOODING OVER SOME AREAS. AFTER THE PASSAGE OF THIS WAVE...AN
UPPER LEVEL LOW WILL PASS MAINLY SOUTH OF THE AREA...BRINGING
ANOTHER ROUND OF MOISTURE WHICH WILL AID IN THE DEVELOPMENT OF
SHOWERS AND THUNDERSTORMS. THROUGH THE END OF THE WEEK

&&

.AVIATION...XPCT VFR AT ALL TAF SITES THROUGHOUT THE PERIOD. SCT
SHRA/TSRA XPCTD SUN AFT...SO SOME BRIEF PDS OF MVFR POSSIBLE IN THE
AFT AT TJMZ AND TJSJ. LLVL WINDS VRBL (MSTLY E-SE) TO 15 KT THRU SUN.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 90 78 / 40 10 30 50
STT 88 78 89 79 / 40 20 40 50

[cycloneye]

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 AM EDT SUN SEP 16 2012

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

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON HURRICANE
NADINE...LOCATED ABOUT 1135 MILES WEST-SOUTHWEST OF THE AZORES.

AN ELONGATED AREA OF LOW PRESSURE LOCATED ABOUT 400 MILES EAST OF
THE LESSER ANTILLES IS PRODUCING DISORGANIZED SHOWERS AND A FEW
THUNDERSTORMS. ALTHOUGH UPPER-LEVEL WINDS ARE CURRENTLY UNFAVORABLE
FOR DEVELOPMENT TO OCCUR...THEY COULD BECOME MORE CONDUCIVE IN A
FEW DAYS. THIS SYSTEM HAS A LOW CHANCE...20 PERCENT...OF BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES WESTWARD AT
AROUND 15 MPH. REGARDLESS OF DEVELOPMENT...LOCALLY HEAVY RAINS AND
SQUALLS COULD AFFECT PORTIONS OF THE LESSER ANTILLES TODAY THROUGH
AND MONDAY.

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

$$
FORECASTER STEWART

[cycloneye]

We are in the most active period for the islands in terms of storms and hurricanes moving thru the area and on the 16th of September of 1995, one of those moved thru and that was Hurricane Marilyn that passed over St Thomas and brushed the NE corner of PR.

[cycloneye]

2 PM Tropical Weather Outlook

AN ELONGATED AREA OF LOW PRESSURE LOCATED ABOUT 325 MILES EAST OF
THE LESSER ANTILLES IS PRODUCING DISORGANIZED SHOWERS AND A FEW
THUNDERSTORMS. ALTHOUGH UPPER-LEVEL WINDS ARE CURRENTLY UNFAVORABLE
FOR DEVELOPMENT TO OCCUR...THEY COULD BECOME MORE CONDUCIVE IN A
FEW DAYS. THIS SYSTEM HAS A LOW CHANCE...20 PERCENT...OF BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES WESTWARD AT
AROUND 15 MPH. REGARDLESS OF DEVELOPMENT...LOCALLY HEAVY RAINS AND
SQUALLS COULD AFFECT PORTIONS OF THE LESSER ANTILLES TODAY THROUGH
MONDAY.

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
307 PM AST SUN SEP 16 2012

.SYNOPSIS...AT UPPER LEVELS...HIGH PRESSURE WILL NOSE INTO THE
AREA FROM THE EAST AND DOMINATE THE LOCAL AREA UNTIL TUESDAY. A
WEAK LOW WILL DIVE SOUTH OVER THE LEEWARD ISLANDS WEDNESDAY WITH A
TROUGH MOVING SOUTH THROUGH THE AREA IN THE PROCESS. LOW PRESSURE
THEN REMAINS SOUTH OF THE AREA THROUGH THE NEXT WEEKEND.

AT MID LEVELS...AN EAST-WEST RIDGE JUST NORTH OF THE AREA
WILL MOVE TO THE NORTHWEST DURING THE WEEK. A WEAK TROUGH FROM A
LOW TO THE NORTHEAST WILL EDGE WESTWARD OVER THE AREA LATER NEXT
WEEK...CROSSING THROUGH THE AREA ON MONDAY OF NEXT WEEK.

AT LOWER LEVELS...A TROPICAL WAVE WITH LOW CHANCES OF BECOMING A
TROPICAL CYCLONE IN THE NEXT 48 HOURS WILL MOVE SOUTH OF THE AREA
DURING THE EARLY PART OF THE WEEK SPREADING SHOWERS AND
THUNDERSTORMS OVER THE AREA. MOISTURE BEHIND IT WILL CONTINUE THE
WETTER TREND THROUGH AT LEAST THURSDAY. LOWER LEVEL FLOW WILL BE
MOSTLY EAST SOUTHEAST THROUGH THE FOLLOWING WEEKEND.

&&

.DISCUSSION...A DRY SLOT AHEAD OF A TROPICAL WAVE...NOW MOVING INTO
THE LEEWARD ISLANDS...HAS IMPEDED MOST OF THE CONVECTION THAT WOULD
HAVE OCCURRED WITH STRONG SOLAR HEATING...NEVERTHELESS SHOWERS AND
THUNDERSTORMS DID DEVELOP OVER THE CORDILLERA CENTRAL AND IN THE
INTERIOR OF PUERTO RICO FROM OROCOVIS WEST. SHOWERS WILL
CONTINUE TO DEVELOP INTO THE EVENING DUE TO INCREASING MOISTURE.
SOUNDER DATA FROM SAINT CROIX SHOWS MOISTURE REBOUNDING SEVERAL
TENTHS OF AN INCH FROM A LOW OF 1.4 INCHES. A TROPICAL WAVE NEAR
60-61 WEST LONGITUDE WAS MOVING 20 TO 25 KNOTS TO THE WEST
NORTHWEST AND IS EXPECTED TO BEGIN AFFECTING PUERTO RICO BY MONDAY
AFTERNOON. THE NAM IS DEVELOPING THE WAVE INTO A TROPICAL
DEPRESSION BY TUESDAY AND IS A LITTLE FASTER...BUT THE GFS KEEPS IT AS
A WAVE THROUGH THE END OF THE WEEK. CURRENT FORECAST IS NEAR THE
MIDWAY POINT BUT FAVORING THE GFS SOLUTION. THIS WILL BRING
SHOWERS AND SCATTERED THUNDERSTORMS TO THE AREA THROUGH THURSDAY
AT A MINIMUM. THE MIMIC PRODUCT ALSO SHOWS CONSIDERABLE MOISTURE
BEHIND THE WAVE THAT IS ON TRACK TO CROSS PUERTO RICO. THIS
MIDWEEK ACTIVITY WILL ALSO BE ENHANCED BY THE PASSING UPPER LEVEL
TROUGH MENTIONED ABOVE. AFTER THE MAJORITY OF THE WEEK...THE LOCAL
AREA IS EXPECTED TO RETURN TO MORE SEASONABLE SHOWERS WITH EAST
SOUTHEAST FLOW THAT WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS
TO NORTHWEST PUERTO RICO AND GENERALLY DRY WEATHER TO THE
NORTHEAST AND NORTH CENTRAL COASTS. WOULD EXPECT THE SLIGHTLY
ABOVE NORMAL TEMPERATURES TO CONTINUE MONDAY...BUT RAIN MAY TEMPER
THE HEAT TUESDAY THROUGH THURSDAY.

&&

.AVIATION...
SHRA STREAMING OFF THE USVI AND SHRA/TSRA AND DEVELOPING ACROSS
PUERTO RICO...ARE CAUSING MTN OBSCURATIONS AND MVFR/IFR
CONDITIONS. VCTS IS LIKELY AT TJSJ...TJBQ...AND TJMZ...WITH TEMPO
TSRA UNTIL AT LEAST 16/22Z FOR TJMZ AND POSSIBLY FOR TJSJ BUT
LEFT OUT OF TAF DUE TO SOME UNCERTAINTY. TROPICAL WAVE AND
ASSOCIATED SHRA/TSRA WILL APPROACH TKPK AND TNCM AT AROUND
17/00Z...CAUSING MVFR/IFR CONDITIONS OVERNIGHT. PR AND USVI
TERMINALS WILL OBSERVE IMPROVING CONDITIONS...BECOMING VFR AFTER
17/00Z.

&&

.MARINE...SEAS WILL GENERALLY SUBSIDE AFTER THE WAVE PASSAGE AND
REMAIN RELATIVELY TRANQUIL AND BELOW SIX FEET THROUGH THE NEXT
SEVEN DAYS.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 78 90 78 88 / 10 20 50 70
STT 79 89 80 90 / 20 20 50 80

[HurricaneFan]

Where is the upper level low that is suppose to cause moisture over the NE Caribbean after the passage of the Tropical Wave located now?

[cycloneye]

Where is the upper level low that is suppose to cause moisture over the NE Caribbean after the passage of the Tropical Wave located now?

That upper trough/low is east of 92L as seen at water vapor image.

http://www.ssd.noaa.gov/goes/east/catl/flash-wv.html

[cycloneye]

8 PM Tropical Weather Outlook


A WEAK LOW PRESSURE AREA LOCATED ABOUT 300 MILES EAST OF THE
LESSER ANTILLES IS PRODUCING MINIMAL SHOWER ACTIVITY. ENVIRONMENTAL
CONDITIONS ARE EXPECTED TO REMAIN UNFAVORABLE FOR DEVELOPMENT
DURING THE NEXT DAY OR TWO. THIS SYSTEM HAS A LOW CHANCE...10
PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS
AS IT MOVES WESTWARD AT AROUND 15 MPH.

[cycloneye]

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE SAN JUAN PR
958 PM AST SUN SEP 16 2012

.SYNOPSIS...SUBTROPICAL RIDGE WILL BUILD OVER THE AREA MON AND
HOLD THROUGH MID WEEK. UPPER LEVEL PATTERN WILL THEN AMPLIFY WITH
A LARGE UPPER LOW FCST TO EVOLVE ACROSS THE CNTRL ATLC WITH TROUGH
FCST TO EXTEND TO SOUTH AMERICA. TROPICAL WAVE WILL MOVE ACROSS
THE LOCAL AREA TUE NIGHT.

&&

.DISCUSSION...TROPICAL WAVE EAST OF THE WINDWARD ISLANDS WILL
CONITNUE TO MOVE WESTWARD NEXT 48 HRS MOVING ACROSS THE AREA TUE
NIGHT. MOISTURE WILL INCREASE OVERNIGHT WITH SCT SHOWERS/TSTORMS
EXPECTED ACROSS THE WATERS SOUTHEAST OF ST CROIX. THEN MOISTURE
SPREADS WWD ACROSS PR WITH SHOWERS AND STORMS EXPECTED ACROSS SW
PR UNDER A ENE LOW LEVEL FLOW. MOISTURE THEN BECOMES MUCH DEEPER
LATE MON NIGHT AND TUE WITH TSTMS INCREASING IN CVRG ACROSS ERN
PR AND USVI AS TROPICAL WAVE MOVES ACROSS THE ERN CARIB SEA S OF
PR MON NIGHT. IT APPEARS ERN PR WILL HAVE THE GREATEST RISK OF
EXPERIENCING FLASH FLOODING DUE TO THE FAST RESPONSE OF RIVERS IN
THAT AREA. WEATHER IS EXPECTED TO IMPROVE RAPIDLY WED AFTERNOON.

&&

.AVIATION...OCCASIONAL MVFR CONDITIONS ARE EXPECTED OVER TKPK AND
TNCM AS SHOWERS AND THUNDERSTORMS MOVE ACROSS THE VICINITY OF
THESE TERMINALS THROUGH EARLY MONDAY. EXPECT VFR CONDITIONS ACROSS
THE REST OF THE TERMINALS. AFTER MIDNIGHT SOME OF THESE SHOWERS
AND THUNDERSTORMS COULD MOVE OVER THE TISX TERMINAL. ONCE AGAIN
SCT SHRA/TSRA XPCTD MON AFT...SOME BRIEF PDS OF MVFR POSSIBLE IN
THE AFTERNOON AT TJMZ AND TJPS. TONIGHT LLVL WINDS VRBL...MONDAY A
MORE NE COMPONENT.

&&

.MARINE...SEAS 2-4 FT INCREASING UP TO 5 FT TUE WITH PASSAGE OF
TROPICAL WAVE. WINDS GENERALLY BELOW SCEC BUT LOCALLY HIGHER
WINDS AND WAVES CAN BE EXPECTED NEAR TSTMS. CLOUD TO WATER
LIGHTNING THE MAIN HAZARD.

&&

.CLIMATE... A RECORD HIGH TEMPERATURE OF 92 DEGREES WAS SET TODAY
AT THE CHRISTIANSTED AIRPORT/USVI. THIS TIED THE OLD RECORD OF 92
SET BACK IN 1993.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 91 79 90 79 / 20 10 30 60
STT 90 79 83 79 / 30 20 30 60

[cycloneye]

Good morning. The rain will increase starting today as the wave moves thru the islands.


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
538 AM AST MON SEP 17 2012

.SYNOPSIS...AN UPPER RIDGE WILL BUILD AND PERSIST OVER THE EASTERN
CARIBBEAN THROUGH AT LEAST MID-WEEK. A TROPICAL WAVE WILL MOVE
ACROSS THE EASTERN CARIBBEAN LATE TONIGHT...PROMOTING AN UNSTABLE
WEATHER PATTERN ACROSS THE LOCAL REGION. CONDITIONS WILL REMAIN
RELATIVELY UNSTABLE THROUGH AT LEAST THURSDAY AS THE ITCZ MOISTURE
WILL GRADUALLY LIFT ACROSS THE AREA IN THE WAKE OF THE TROPICAL WAVE.

&&

.DISCUSSION...LATEST SURFACE ANALYSIS SHOWED A TROPICAL WAVE/WEAK
LOW PRESSURE AREA ABOUT 200 MILES EAST OF THE LESSER ANTILLES.
THIS TROPICAL WAVE IS FORECAST TO CROSS THE EASTERN CARIBBEAN
TONIGHT AND MOVES JUST SOUTH OF THE FORECAST AREA ON TUESDAY.
DEEP MOISTURE ASSOCIATED WITH THE NORTHERN FRINGES OF THE WAVE
WILL AFFECT THE LOCAL ISLANDS...BRINGING AN INCREASE IN CLOUDS AND
SHOWERS ACROSS THE AREA LATE TONIGHT THROUGH AT LEAST WEDNESDAY.
FORECAST CHARTS SUGGEST PWAT VALUES INCREASING RAPIDLY UP TO 2.3
INCHES ON TUESDAY AFTERNOON AND REMAINING OVER 2 INCHES THROUGH
EARLY WEDNESDAY. THEN...MOISTURE WILL SLOWLY DECREASE AFTER WEDNESDAY
EVENING AS WELL AS THE K-INDEX VALUES. HOWEVER...CONDITIONS WILL
REMAIN CLOUDY AND SHOWERY THURSDAY WITH SOME SLIGHT IMPROVEMENT ON
FRIDAY. FOR THE WEEKEND...A TUTT LOW WILL SETTLE OVER THE EASTERN
CARIBBEAN...DESTABILIZING THE ATMOSPHERE...WITH DEEP MOISTURE POOLING
ONCE AGAIN ACROSS THE LEEWARD/VIRGIN ISLES TO EASTERN PUERTO RICO.

&&

.AVIATION...VFR CONDITIONS WILL PREVAIL ACROSS MOST TAF SITES
THROUGH AT LEAST 17/16Z. PERIODS OF MVFR CONDITIONS ARE POSSIBLE
OVER TNCM...AND TKPK AS TROPICAL WAVE AFFECTED THESE SITES
THROUGHOUT THE DAY. PERIODS OF MVFR CONDITIONS ARE EXPECTED OVER
TJMZ...AND TJBQ FROM 17/18Z-17/22Z IN SHRA/TSRA. WINDS WILL CONTINUE
MAINLY EAST AT 10 TO 15 KTS.

&&

.MARINE...SEAS 2-4 FT THROUGH MOST OF THE WEEK. ONLY A SLIGHT INCREASE
IN THE WAVE HEIGHTS ON TUESDAY WITH PASSAGE OF TROPICAL WAVE. HOWEVER...
WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW SCA BUT LOCALLY HIGHER WINDS
AND WAVES ARE POSSIBLE NEAR TSTMS. DANGEROUS CLOUD TO WATER LIGHTNING
WILL BE THE MAIN HAZARD...ESPECIALLY ON TUESDAY.

&&

.CLIMATE...FM PREV DISCUSSION...
AT THE SJU LMM INTL ARPT...THE FIRST HALF OF SEP 2012 WAS THE
DRIEST ON RECORD WITH ONLY 0.24 INCHES OF RAIN MEASURED. IT WAS
ALSO THE SECOND WARMEST START TO SEP ON RECORD WITH AN AVG TEMP
OF 85.0F DEGS.

AT THE CHRISTIANSTED ST CROIX ARPT...THE FIRST HALF OF SEP 2012
WAS THE SECOND DRIEST ON RECORD WITH ONLY 0.21 INCHES OF RAIN
MEASURED.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 91 78 89 78 / 30 60 70 50
STT 89 78 88 80 / 30 60 80 60

[cycloneye]

8 AM Tropical Weather Outlook.

MINIMAL SHOWER ACTIVITY IS ASSOCIATED WITH A WEAK LOW PRESSURE
SYSTEM LOCATED ABOUT 150 MILES EAST OF THE NORTHERN WINDWARD
ISLANDS. ENVIRONMENTAL CONDITIONS ARE NOT CONDUCIVE FOR
DEVELOPMENT...AND THIS SYSTEM HAS A LOW CHANCE...NEAR 0 PERCENT...
OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT
MOVES WESTWARD AT AROUND 15 MPH.

[cycloneye]

12z Surface Analysis by TAFB.

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
201 PM AST MON SEP 17 2012

.SYNOPSIS...A MID TO UPPER LEVEL RIDGE PATTERN WILL CONTINUE TO PREVAIL
ACROSS THE LOCAL AREA THROUGH MID WEEK. TUTT LOW IS EXPECTED TO DEVELOP
ACROSS THE CENTRAL ATLANTIC...DIGGING SOUTHWEST TOWARDS OUR FORECAST AREA
WEDNESDAY THROUGH FRIDAY. NEXT TROPICAL WAVE WILL REACH PR AND USVI LATE
TONIGHT INTO TOMORROW.

&&

.DISCUSSION...SHOWERS AND THUNDERSTORMS STILL EXPECTED ACROSS WEST AND
SOUTHWEST PUERTO RICO THIS AFTERNOON DUE TO LOCAL EFFECTS AND DIURNAL
HEATING. THESE SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DISSIPATE
AROUND SUNSET LEAVING PARTLY CLOUDY SKIES.

LOCAL WEATHER REGIME WILL CHANGE LATE TONIGHT INTO TOMORROW MORNING AS
TROPICAL WAVE...NOW LOCATED ACROSS THE LESSER ANTILLES...REACHES PR AND
USVI. SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THIS WAVE ARE ANTICIPATED
ACROSS EASTERN PUERTO RICO AND USVI TOMORROW MORNING...SPREADING ACROSS
CENTRAL AND WEST PUERTO RICO THROUGHOUT THE DAY. AT THIS TIME...LOOKS
LIKE SAINT CROIX IS GOING TO TAKE THE BULK OF ENERGY AND MOISTURE.
THIS WET/ACTIVE WEATHER PATTERN WILL PREVAIL FOR THE NEXT TWO DAYS
OR SO.

TUTT LOW IS EXPECTED TO DEVELOP ACROSS THE CENTRAL ATLANTIC...DIGGING
TOWARDS OUR FORECAST AREA WEDNESDAY THROUGH FRIDAY. AS IT ENTERS THE
EASTERN CARIBBEAN...A MID TO UPPER LEVEL CAP WILL ESTABLISH...LEADING
TO A RAPID EROSION OF AVAILABLE MOISTURE. HOWEVER...ENVIRONMENTAL
CONDITIONS WILL QUICKLY IMPROVE DURING THE WEEKEND AS THE TUTT MOVES
FURTHER WEST...RESULTING IN ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS
ACROSS THE LOCAL ISLANDS.

&&

.AVIATION...A TROPICAL WAVE WILL SPREAD SCT SHWRS/TSTMS ACROSS THE
FCST AREA BEGINNING IN TKPK AND TNCM AND SPRDG WNW TO TISX BY 18/04Z
AND TIST...TJSJ BY 18/08Z. MTN OBSCURATIONS. SCT SHWRS/TSTMS ARE
EXPECTED AREA WIDE BY 18/15Z. LLVL WINDS 5-15 KT FROM ENE BCMG
ESE-SE AFT 18/18Z AS WAVE AXIS PASSES THROUGH AREA.

&&

.MARINE...SEAS 2-4 FT THROUGH MOST OF THE WEEK. ONLY A SLIGHT INCREASE
IN THE WAVE HEIGHTS ON TUESDAY WITH PASSAGE OF TROPICAL WAVE.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 81 90 78 89 / 50 70 50 50
STT 81 88 80 88 / 50 60 50 50

[msbee]

We got nothing from it except stifling heat and humidity

[cycloneye]

We got nothing from it except stifling heat and humidity

Wave passing south of your location Barbara. Let's see if the trailing moisture can go up to that island. Let's see how much rain falls in PR tonight and Tuesday with the wave passage mainly to our south.

[cycloneye]

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SAN JUAN PR
957 PM AST MON SEP 17 2012

.SYNOPSIS...MID-UPPER LEVEL RIDGE WILL HOLD THROUGH MID WEEK.
UPPER LEVEL PATTERN WILL THEN AMPLIFY WITH A DEEP CUTOFF LOW FCST
TO EVOLVE ACROSS THE CNTRL ATLC AND EXTEND A TROUGH INTO SAMERICA.
TROPICAL WAVE WILL MOVE ACROSS THE ERN CARIBBEAN SEA OVERNIGHT.

&&

.DISCUSSION...DEEP MOISTURE ASSOCIATED WITH TROPICAL WAVE STILL
YET TO ARRIVE INTO THE FCST AREA. GLOBAL MODELS SHOW SHOWERS AND
T-STORMS INCREASING TOWARD DAYBREAK AS WAVE AXIS MOVES ACROSS THE
AREA. TUE LOOKS PRETTY CLOUDY AND SHOWERY ALL DAY HOWEVER RAINFALL
ACCUMULATIONS WILL NOT BE EXCESSIVE AND AM NOT ANTICIPATING
MUCH IN THE WAY OF FLOODING PROBLEMS EXCEPT IN URBAN AND LOW LYING
AREAS. MID LEVEL DRYING IS INDICATED FOR WED WHICH SHOULD RESULT
IN BREAKS IN CLOUD COVER AND HELP DESTABILIZE ATMOSPHERE.
OVERALL...THERE SHOULD BE A LITTLE LESS CVRG ON WED BUT ANY
CONVECTION COULD STILL BE INTENSE. FURTHER DRYING IS EXPECTED FOR
THU AND THROUGH THE REST OF THE WEEK.

&&

.AVIATION...INCREASING CLOUDINESS EXPECTED ACROSS ALL TAF SITES
TONIGHT. SHRA TO INCREASE FOR TKPK/TNCM AND TISX OVERNIGHT.
APPROACHING TROPICAL WAVE WILL PRODUCE SHRA/TSRA OVER THE LOCAL AREA
WHICH WILL IMPACT ALL TAF SITES AFTER 18/12Z. WINDS WILL BE LIGHT
AND VARIABLE OVERNIGHT...BECOMING EASTERLY IN THE MORNING AT AROUND
10 KTS AND GUSTY...ESPECIALLY AROUND THE TSRA.

&&

.MARINE...SEAS 3-5 FT AND WINDS UP TO 17 KNOTS. HEAVY
RAINFALL...LOW VSBYS AND CG LIGHTNING THE MAIN HAZARDS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 80 85 80 83 / 80 80 40 30
STT 76 83 76 87 / 70 70 30 40

[cycloneye]

Good morning.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
459 AM AST TUE SEP 18 2012

.SYNOPSIS...MID TO UPPER RIDGE EXTENDS FROM THE TROPICAL ATLANTIC
TO THE NORTHEAST CARIBBEAN. A TROPICAL WAVE JUST SOUTH OF THE
FORECAST AREA WILL MOVE ACROSS THE EASTERN CARIBBEAN TODAY THROUGH
WEDNESDAY MORNING AND ACROSS THE CENTRAL CARIBBEAN WEDNESDAY THROUGH
FRIDAY. A DEEP UPPER LOW IS FORECAST TO AMPLIFY ACROSS THE CENTRAL
ATLANTIC BY THE UPCOMING WEEKEND. AT THE SAME TIME...ANOTHER
UPPER LOW/TUTT ESTABLISHES ACROSS THE EASTERN CARIBBEAN.

&&

.DISCUSSION...SATELLITE ANALYSIS AND LATEST SFC ANALYSIS SHOWS A
TROPICAL WAVE OVER THE EASTERN CARIBBEAN MOVING WEST AT 10-15KT.
SATELLITE BLENDED PWAT ANALYSIS INDICATES A LARGE AREA OF DEEP
TROPICAL MOISTURE ACCOMPANYING THIS WAVE. DOPPLER RADAR HAVE BEEN
DETECTING EARLY THIS MORNING...SHOWERS AND THUNDERSTORMS OVER THE
CARIBBEAN WATERS...USVI AND THE EASTERN HALF OF PUERTO RICO.
MOISTURE CONVERGENCE ALONG THE NORTHERN PORTION OF THE WAVE WILL
CONTINUE TO BRING SHOWERS AND THUNDERSTORMS ACROSS PR AND USVI
THROUGH AT LEAST THIS EVENING. AS A RESULT...EXPECT NEW CONVECTION
DEVELOPING ACROSS USVI...CULEBRA...VIEQUES AND EASTERN PR THIS
MORNING AND THEN QUICKLY SPREADING ACROSS THE CENTRAL AND WESTERN
PUERTO RICO BY LATE MORNING AND AFTERNOON HOURS. LOCAL HI-RES WRF
SUGGEST THE MOST ACTIVE PERIOD FROM 18/12Z THROUGH 18/22Z. DURING
THIS PERIOD...SOME POOR DRAINAGE/URBAN TYPE FLOODING WILL OCCUR AS
HEAVIEST BURSTS OF RAIN MOVE THROUGH THE ISLANDS. FLASH FLOODING...
IF ANY...WILL BE IN ISOLATED AREAS.

&&

.AVIATION...TROPICAL WAVE CURRENTLY GRADUALLY INCR SHRA/TSRA ACROSS
LCL ISLANDS WHILE A LARGE AREA OF SHRA MOVG ENE HAS REACHED ST.
CROIX. TIMING OF SHRA AT EACH TAF SITE IS TOUGH BUT MOST WILL LIKELY
SEE MOST ACTIVITY DURING THE MORNING. VFR WILL PREVAIL BUT SHRA WILL
CAUSE A COUPLE OF MVFR PDS. LLVL WIND GENERALLY E 10-15 KT.

&&

.MARINE...SEAS 3-5 FT EXPECTED THROUGH MOST OF THE WEEK. SHOWERS
AND THUNDERSTORMS ARE LIKELY ACROSS THE REGIONAL WATERS TODAY AS
THE TROPICAL WAVE MOVES THROUGH THE CARIBBEAN WATERS. TORRENTIAL
RAIN...LOW VISIBILITIES...DANGEROUS LIGHTNING AND LOCALLY HIGHER
WINDS/WAVES ARE POSSIBLE NEAR THUNDERSTORMS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 79 90 79 / 80 30 30 30
STT 88 79 89 80 / 70 30 40 40

[cycloneye]

AFDSJU

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SAN JUAN PR
1226 PM AST TUE SEP 18 2012

.UPDATE...THE 18/12Z SOUNDING CAME IN WETTER AND MORE UNSTABLE
THAN YESTERDAY. SHOWERS AND LIGHT TO MODERATE RAIN HAVE FORMED
OVER PUERTO RICO AND ACTIVE CONVECTION CAN BE FOUND SOUTHEAST OF A
NORTHEAST/SOUTHWEST LINE THROUGH SAINT CROIX AND OVER HORMIGUEROS
AND NEAR CAYEY. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CONTINUE
TO INCREASE. ONLY MINOR CHANGES TO THE GRIDS FROM WHICH THE NEWLY
ISSUED ZONES WERE RUN.


&&

.DISCUSSION...MOISTURE OVER BAYAMON AND CHRISTIANSTED HAS
INCREASED TO 2.3-2.4 INCHES OF PRECIPITABLE WATER AND IS GENERALLY
IN LINE TO CROSS OVER PUERTO RICO. WESTERN PUERTO RICO HAS ALSO HAD
SUN MOST OF THE MORNING AND IS NOW WELL SET UP FOR AN ACTIVE
AFTERNOON OF THUNDERSTORMS...SOME WITH HEAVY RAIN. WITH RAIN
COVERAGE NEAR 100 PERCENT OVER THE SOUTHEAST QUADRANT OF PUERTO
RICO THIS MEANS THAT MOST OF PUERTO RICO AND POSSIBLY SAINT CROIX ARE
AT RISK FOR URBAN AND SMALL STREAM FLOODING SHOULD HEAVY
THUNDERSTORMS DEVELOP OVER THEM OR SHOULD THE MODERATE RAIN
CONTINUE FOR MUCH OF THE AFTERNOON. CURRENTLY SHOWERS THAT REACH
THE WATERS BETWEEN PUERTO RICO AND SAINT CROIX ARE WEAKENING INTO
RAIN AND DO NO POSE AS GREAT A THREAT AS CONVECTION MIGHT WHEN IT
DEVELOPS IN THE AFTERNOON HEATING IN THE WESTERN PORTIONS OF
PUERTO RICO.

.MARINE...SHOWERS ARE ALSO DEVELOPING IN THE SOUTHERN PORTION OF
THE MONA CHANNEL WITH TOPS APPROACHING 40 KFT AS OF 12:30 PM AST.
SEAS REMAIN LESS THAN 5 FEET.

&&

.AVIATION...CONDITIONS HAVE DETERIORATED OVER SOUTHEAST PUERTO
RICO WITH MOST MOUNTAINS OBSCURED. DETERIORATING CONDITIONS WILL
CONTINUE TO SPREAD ACROSS THE ISLAND WITH IFR/MVFR PSBL ALL AREAS
FOR PERIODS UNTIL AFT 19/04Z. LLVL WINDS ARE 10 TO 20 KT BELOW 10
KFT AND THUNDERSTORMS HAVE PRODUCED GUSTS IN EXCESS OF 25 KT.

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
304 PM AST TUE SEP 18 2012

.SYNOPSIS...A MID TO UPPER LEVEL RIDGE PATTERN WILL CONTINUE TO
PREVAIL ACROSS THE LOCAL AREA THROUGH WEDNESDAY. CUTT OFF LOW IS
EXPECTED TO DEVELOP ACROSS THE CENTRAL ATLANTIC WITH A TROUGH
EXTENDING ACROSS THE LOCAL AREA THURSDAY THROUGH AT LEAST THE
UPCOMING WEEKEND. TROPICAL WAVE WILL CONTINUE TO MOVE ACROSS THE
CARIBBEAN WATERS THROUGH THE REST OF THE DAY.

&&

.DISCUSSION...UPPER LEVEL RIDGE IS EXPECTED TO HOLD OVER THE NEXT
24 HOURS OR SO...WITH UPPER LEVEL ENVIRONMENT REMAINING FAVORABLE
FOR DEEP CONVECTION. THIS WILL COMBINE WITH AFOREMENTIONED
TROPICAL WAVE TO PRODUCE PERIODS OF SHOWERS AND THUNDERSTORMS
ACROSS PORTIONS OF THE LOCAL ISLANDS THIS AFTERNOON THROUGH AT
LEAST EARLY WEDNESDAY MORNING.

CUT OFF LOW IS EXPECTED TO DEVELOP ACROSS THE CENTRAL ATLANTIC WITH
A TROUGH EXTENDING ACROSS THE LOCAL AREA THURSDAY THROUGH AT LEAST
THE UPCOMING WEEKEND. AS THE TROUGH ENTERS THE EASTERN CARIBBEAN...
A RAPID EROSION OF AVAILABLE MOISTURE IS EXPECTED. HOWEVER...LOCAL
AND DIURNAL EFFECTS WILL COMBINE TO PRODUCE AFTERNOON SHOWERS AND
STRONG THUNDERSTORMS ACROSS CENTRAL AND WEST PUERTO RICO THURSDAY
AND FRIDAY. ENVIRONMENTAL CONDITIONS WILL QUICKLY IMPROVE DURING
THE WEEKEND AS THE TUTT MOVES FURTHER WEST AND LIKELY FAVOR AN
INCREASE IN CONVECTIVE ACTIVITY.

&&

.AVIATION...SEVERAL UNDULATIONS IN THE TROPICAL WAVE ARE BRINGING A
SERIES OF SHRA/TSRA BANDS TO THE AREA. ONE IS JUST EAST OF THE
LEEWARD ISLANDS AND ONE HAS PASSED TISX...THE LATTER IS MOVING AWAY
FROM THE AREA. EXPECT BRIEF MVFR AND WIDESPREAD MTN OBSCURATIONS NOW
THROUGH AT LEAST 19/04Z AT MOST TAF SITES...BUT ESPECIALLY ARND TJMZ
AND TKPK. LLVL WINDS ESE ARND 15 KT UP THROUGH 19 KFT AND CHANGING
LITTLE.

&&

.MARINE...SEAS 3-5 FT EXPECTED THROUGH MOST OF THE WEEK. SHOWERS
AND THUNDERSTORMS ARE LIKELY ACROSS THE REGIONAL WATERS TODAY AS
THE TROPICAL WAVE MOVES THROUGH THE CARIBBEAN WATERS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 79 90 79 90 / 50 50 30 50
STT 79 89 80 89 / 60 60 40 40