Caribbean - Central America Weather

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
307 PM AST SAT SEP 20 2014

.SYNOPSIS...AS TUTT LOW CONTINUES TO WEAKEN...RIDGE PATTERN WILL
BUILD ACROSS THE AREA FROM THE EAST. A SECOND TUTT IS EXPECTED
TO AMPLIFY INTO THE EASTERN CARIBBEAN WEDNESDAY AND THURSDAY.
TROPICAL WAVE WILL MOVE ACROSS THE AREA MONDAY AFTERNOON INTO
TUESDAY.

&&

.DISCUSSION...LATEST GFS AND WRF GUIDANCE INDICATED NEAR TO BELOW
NORMAL PRECIPITABLE WATER ACROSS THE LOCAL AREA THROUGH AT LEAST
EARLY MONDAY MORNING. THIS FACT COMBINED WITH BUILDING RIDGE ALOFT...
WILL RESULT IN A TYPICAL WEATHER PATTERN TONIGHT AND SUNDAY.
THEREFORE EXPECT A FEW PASSING SHOWERS ACROSS WINDWARD AREAS IN
THE MORNING FOLLOWED BY AFTERNOON SHOWERS AND THUNDERSTORMS
ACROSS W AND NW PUERTO RICO.

A WETTER PATTERN WILL PREVAIL MONDAY AND TUESDAY AS TROPICAL WAVE
MOVES ACROSS THE EASTERN CARIBBEAN. THEREFORE THE CHANCE OF
SHOWER AND THUNDERSTORM ACTIVITY WILL INCREASE ACROSS THE LOCAL
ISLANDS AND COASTAL WATERS. A DRIER AIR MASS IS EXPECTED TO MOVE
IN FROM THE EAST ON WEDNESDAY AS THE AFOREMENTIONED TROPICAL WAVE
MOVES FURTHER WEST AND AWAY FROM THE LOCAL AREA. ALTHOUGH PWAT
VALUES WILL REMAIN NEAR NORMAL...SHOWER AND THUNDERSTORM
DEVELOPMENT STILL EXPECTED AS A RESULT OF TUTT LOW POSITION
WEDNESDAY THRU SATURDAY. AS TUTT AXIS MOVES TO THE SOUTHEAST OF
LOCAL ISLANDS...A DECREASE IN COVERAGE/INTENSITY IS EXPECTED.

&&

.AVIATION...MVFR CONDITIONS WILL REMAIN POSSIBLE AT JBQ TIL
20/20Z. ELSEWHERE VFR DURING THE FORECAST PERIOD WITH SE SFC
WINDS AT 5-10 KTS.

&&

.MARINE...SEAS 2-4 KTS AND WINDS NEAR 17KT BUT HIGHER NEAR
THUNDERSTORMS.

&&

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

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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
326 AM AST SUN SEP 21 2014

.DISCUSSION...NUMEROUS SHOWERS/THUNDERSTORMS MOVING THROUGH SOUTH
MONA PASSAGE ARE RIDING JUST AHEAD OF A 850 MB SPEED MAXIMUM
WHICH WILL CLEAR WEST OF THE PASSAGE THIS MORNING NEAR OR SOON
AFTER 12Z. ISOLATED/SCATTERED CONVECTION CONTINUES BEHIND IN
HIGH TOTAL PRECIPITABLE WATER IN EXCESS OF 2 INCHES AS SHOWN BY
SSMI AND MIMIC-TPW IMAGES. 00Z GFS HAS A NICE HANDLE ON THE
DISTRIBUTION OF THIS MOISTURE AND SUGGESTS A HIGH NORTH TO SOUTH
MOISTURE GRADIENT OVER PR/USVI AND EXTENDING TO NORTHERN LEEWARD
ISLANDS TODAY. WRF AND NAM TAKE PRECIPITATION ACROSS EASTERN PR
AND NORTH OF THE ISLAND THIS MORNING WHILE GFS KEEPS IT FARTHER
SOUTH...STILL OVER PR. SIGNIFICANT CONVECTION OVER PR THIS MORNING
SEEMS HIGHLY UNLIKELY GIVEN THE POSITION OF THE 850 MB FLOW...A
CURRENTLY COOL ISLAND AND RELATIVE LACK OF CURRENT UPSTREAM
ACTIVITY.

WIND FLOW SHOULD NOT BE A SIGNIFICANT FACTOR AT ANY LEVEL IN
CONVECTIVE DEVELOPMENT TODAY OR NEXT SEVERAL DAYS...INSTEAD
DEPENDENT MORE ON HOW MUCH SOLAR HEATING OCCURS AND WHERE SEA
BREEZES SET UP. HIGH CLOUDS FROM THUNDERSTORMS OVER CARIBBEAN
COASTAL WATERS ARE SPREADING BUT MOST OF THIS WILL DISSIPATE AND
MOVE WEST BEFORE MUCH SUNSHINE OCCURS. GFS SHOWS 2+ INCHES OF
PRECIPITABLE WATER AT 18Z TODAY OVER WEST AND SOUTH PR...EXPECT
MOST AFTERNOON CONVECTIVE DEVELOPMENT TODAY OVER WEST PR WHERE THE
BEST HEATING WILL OCCUR AND RESULTANT SEA BREEZES FOCUS.

MOISTURE DECREASES SOMEWHAT ON MON BUT REBOUNDS IMMEDIATELY
FOLLOWING ARRIVAL OF A TROPICAL WAVE ON MON NIGHT. GFS SHOWS
PRECIPITABLE WATER PERSISTENTLY NEAR 2 INCHES FROM TUE-THU.
CONVECTION AGAIN HIGHLY DEPENDENT ON SUNSHINE.

&&

.AVIATION...SHRA ACTIVITY WILL CONTINUE WITH ISOLATED TSRA TOPS TO
FL400-450 MAINLY OVER THE LOCAL CARIBBEAN WATERS. AFTER 21/16Z AREAS
OF MVFR OR EVEN IFR CONDITIONS IN SHRA/TSRA WILL DEVELOP OVER
WESTERN AND CENTRAL PUERTO RICO WITH MOUNTAIN OBSCURATIONS.
OTHERWISE VFR CONDITIONS EXPECTED. LLVL WINDS ELY UP TO 20 KT WITH
LAND/SEA BREEZE VARIATIONS.

&&

.MARINE...MINOR SWELL IS MOVING WESTWARD NORTHEAST OF LEEWARD
ISLANDS. BUOY 41044 IS CURRENTLY RECORDING 5 FT SEAS AND ABOUT A
FOOT HIGHER THAN MODELS CURRENTLY SHOW. THESE SEAS WILL PASS
NORTH OF PR ON MON AND MAINLY NORTH OF 20N. MAINTAINING 4 FT IN
COASTAL WATERS GOOD.

&&

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

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
233 PM AST SUN SEP 21 2014

.SYNOPSIS...TUTT LOW ACROSS THE CENTRAL ATLANTIC WILL AMPLIFY
INTO THE NORTH AND EASTERN CARIBBEAN BY MIDWEEK. TROPICAL WAVE
WILL MOVE ACROSS THE AREA MONDAY NIGHT INTO TUESDAY.

&&

.DISCUSSION...MODEL GUIDANCE CONTINUES TO INDICATE NEAR TO BELOW
NORMAL PRECIPITABLE WATER ACROSS THE NORTHERN HALF OF THE FORECAST
AREA THROUGH MONDAY AFTERNOON WITH HIGHER VALUES ACROSS THE SOUTHERN
PORTIONS. HOWEVER MOISTURE ADVECTION IS EXPECTED ACROSS THE REGION AS
SOON AS MONDAY AFTERNOON INTO TUESDAY MORNING AS TROPICAL WAVE NOW
LOCATED NEAR 59 W MOVES ACROSS THE EASTERN CARIBBEAN. GFS AND WRF
SHOW PRECIPITABLE WATER PERSISTENTLY NEAR 2 INCHES THROUGH THURSDAY.

UNDER THIS EVOLVING PATTERN....EXPECT PASSING SHOWERS AND ISOLATED
THUNDERSTORMS ACROSS THE CARIBBEAN WATERS AND WINDWARD AREAS TONIGHT
AND MONDAY MORNING WITH SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS
THE CORDILLERA AND WEST PUERTO RICO MONDAY AFTERNOON. MONDAY NIGHT
AND INTO TUESDAY AND POSSIBLY WEDNESDAY...FREQUENT PASSING SHOWERS
WITH THUNDERSTORMS COULD BE EXPECTED ACROSS USVI AND THE EASTERN
HALF OF PUERTO RICO. CONVECTION HIGHLY DEPENDENT ON SUNSHINE.

AS TUTT AXIS MOVES TO THE SOUTHEAST OF LOCAL ISLANDS LATE THURSDAY
AND INTO THE UPCOMING WEEKEND...LOW LEVEL MOISTURE WILL SLOWLY ERODE.
SHOWER AND THUNDER ACTIVITY STILL EXPECTED DURING THE PERIOD BUT
COVERAGE/INTENSITY WILL DECREASE.

&&

.AVIATION...SHRA/TSRA ACTIVITY IS EXPECTED TO CONTINUE OVER WESTERN
PR UNTIL AROUND 21/22Z...WITH MVFR CONDS AND MOUNTAIN OBSCURATIONS.
TSTMS MOVING WEST OVER THE CARIBBEAN WATERS ARE EXPECTED TO CONTINUE
DURING THE EVENING HOURS. DURING THE OVERNIGHT HOURS VFR CONDITIONS
ARE EXPECTED ACROSS ALL TERMINALS. LOW LEVEL WINDS WILL CONTINUE FROM
THE EAST AT 10 TO 20 KTS...WITH HIGHER GUSTS NEAR TSTMS.

&&

.MARINE...SEAS 2-4 KTS AND WINDS NEAR 17KT BUT HIGHER NEAR THUNDERSTORMS.

&&

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

[cycloneye]

Good morning. Tropical Wave will bring plenty of rain to PR and adjacent islands today thru Wednesday.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
505 AM AST MON SEP 22 2014

.SYNOPSIS...SYNOPSIS...TUTT LOW OVER THE CENTRAL ATLANTIC NORTHEAST OF THE
REGION...WILL AMPLIFY INTO THE NORTHEAST CARIBBEAN BY MIDWEEK.
TROPICAL ACROSS THE EASTERN CARIBBEAN WILL MOVE OVER THE REGION LATE
TODAY AND TUESDAY...INDUCING A GENERAL INCREASE IN CLOUDINESS.

&&

.DISCUSSION...THE DOPPLER WEATHER RADAR DETECTED ISOLATED TO
SCATTERED SHOWERS OVER THE ATLANTIC WATERS MOVING WEST SOUTHWESTWARD
OVER EASTERN AND NORTHERN SECTIONS OF PUERTO RICO OVERNIGHT AND
EARLY THIS MORNING. UNDER AN EAST NORTHEAST WIND FLOW...PASSING
SHOWERS ARE EXPECTED TO AFFECT PARTS OF THE NORTHERN AND EASTERN
SECTIONS OF PUERTO RICO AS WELL AS VIEQUES...CULEBRA AND THE U.S.
VIRGIN ISLANDS DURING THE REST OF THE MORNING HOURS. HOWEVER...NOT
SIGNIFICANT OR WIDESPREAD PRECIPITATION IS EXPECTED. FOR THE
AFTERNOON HOURS...THIS MOISTURE WILL COMBINE WITH DAYTIME HEATING
AND LOCAL EFFECTS TO INDUCE THE DEVELOPMENT OF SHOWERS AND
THUNDERSTORMS OVER WESTERN...INTERIOR AND SOUTHWEST SECTIONS OF
PUERTO RICO.

LATEST SATELLITE IMAGES AND SURFACE ANALYSIS THIS MORNING DEPICTED A
TROPICAL WAVE OVER THE EASTERN CARIBBEAN. THIS WAVE WILL CONTINUE TO
MOVE WESTWARD TODAY AND TUESDAY. THE MOISTURE ASSOCIATED WITH THE
WAVE WILL AFFECT THE LOCAL REGION LATE TODAY AND TUESDAY...INDUCING
A GENERAL INCREASE IN SHOWER AND THUNDERSTORM ACTIVITY OVER THE
REGION. THE GFS COMPUTER GUIDANCE SUGGESTS PWAT VALUES SLIGHTLY
ABOVE 2.00 INCHES INTO THE MIDDLE OF WEEK. LATE THIS AFTERNOON...
TONIGHT AND INTO TUESDAY...FREQUENT PASSING SHOWERS WITH
THUNDERSTORMS COULD BE EXPECTED ACROSS USVI AND THE EASTERN PUERTO
RICO.

&&

.AVIATION...PREVAILING VFR CONDS EXPECTED ACROSS THE LOCAL TERMINALS
TIL 22/10Z. THEREAFTER...LOW TO MID LEVEL CLOUDINESS AND PASSING
SHRA/ISOLD TSRA IS EXPECTED TO INCREASE ACROSS THE LOCAL FLYING AREA
AS A TROPICAL WAVE APPROACHES THE LOCAL AREA. VCTS/VCSH LIKELY AT
TKPK AND TNCM FM 22/10Z-22/15Z THEN SPREADING OVR RMNDR OF TAF SITES
AFT 22/15Z-22/23Z AS TROPICAL WAVE MOVES ACROSS THE REGION WITH
BRIEF MVFR CONDS. SFC WINDS FM NE AT 5 KTS OR LESS BCMG FM E-ESE AT
10-15 KTS AFT 22/14Z. L/LVL WNDS FM E- ENE AT 5-15 KTS BLO FL200
BCMG MAINLY LGT/VRB ABV AND UP TO FL 350. HIGHER SFC WND GUST NR
CONVCT ACTVTY DURG PRD.

&&

.MARINE...NO SIGNIFICANT CHANGES TO MARINE GRIDS OTHER THAN THE
ADDITION OF MORE WEATHER TONIGHT AND A SLIGHT INCREASE IN SEAS IN
OUTER ATLANTIC WATERS. WINDS SHOULD REMAIN BELOW SMALL CRAFT
ADVISORY CONDITIONS FOR THE REST OF THE WEEK WITH SEAS GENERALLY
BELOW 5 FEET EXCEPT IN THE VICINITY OF THUNDERSTORMS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 79 88 78 / 60 50 50 30
STT 88 79 87 78 / 70 50 50 40

[cycloneye]

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE SAN JUAN PR
252 PM AST MON SEP 22 2014

.SYNOPSIS...WEATHER CONDITIONS WILL DETERIORATE TONIGHT AND TUESDAY
AS TROPICAL WAVE MOVES ACROSS THE EASTERN CARIBBEAN. TUTT ACROSS THE
CENTRAL ATLANTIC WILL EXTEND INTO THE NORTH AND EASTERN CARIBBEAN BY
THE END OF THE WEEK.

&&

.DISCUSSION...WEATHER CONDITIONS WILL DETERIORATE TONIGHT AND
TUESDAY AS TROPICAL WAVE NOW LOCATED NEAR 65W CONTINUES TO MOVE
WEST. AS WAVE AXIS CROSSES THE USVI AND PUERTO RICO OVERNIGHT...A
SHARP INCREASE IN PRECIPITABLE WATER IS ANTICIPATED WITH GFS AND
WRF MODEL GUIDANCE SHOWING PRECIPITABLE WATER PERSISTENTLY NEAR 2
INCHES THROUGH THURSDAY. THIS WILL RESULT IN SHOWERS WITH THUNDERSTORMS
ACROSS THE LOCAL WATERS...USVI AND THE EASTERN HALF OF PUERTO RICO
TONIGHT...WITH FREQUENCY OF SHOWERS AND THUNDERSTORMS INCREASING
BY DAYBREAK. THESE SHOWERS AND THUNDERSTORMS WILL SPREAD TO THE
WESTERN HALF OF PUERTO RICO TUESDAY AFTERNOON. HOWEVER...CONVECTION
ACROSS THE WESTERN HALF HIGHLY DEPENDENT ON SUNSHINE. AT THIS TIME
MOST ACTIVE WEATHER COULD BE EXPECTED AFTER DAYBREAK THROUGH THE
EVENING HOURS WITH THE HEAVIEST SHOWERS AND THUNDERSTORMS
RESULTING IN MINOR FLOODING...FREQUENT LIGHTING AND GUSTY WINDS.

AS TROPICAL WAVE MOVES FURTHER WEST...LOW LEVEL MOISTURE IS
EXPECTED TO DECREASE SOMEWHAT WEDNESDAY AND THURSDAY. ALTHOUGH...
THERE IS DEEP MOISTURE TO COMBINE WITH AMPLIFYING TUTT AND LOCAL
EFFECTS TO PRODUCE FREQUENT TRADE WIND SHOWERS ACROSS WINDWARD
AREAS IN THE MORNING AND AFTERNOON THUNDERSTORMS ACROSS THE
CORDILLERA CENTRAL AND WESTERN PR BOTH DAYS. FRIDAY AND INTO THE
UPCOMING WEEKEND...TUTT LOCATION WILL WARRANT ABUNDANT DYNAMICAL
FORCING TO PRODUCE ORGANIZED DEEP CONVECTION EACH DAY.

&&

.AVIATION...MVFR/IFR CONDS AND MOUNTAIN OBSCURATIONS LIKELY IN AND
AROUND TJMZ AND TJPS TIL 21Z. WX CONDS WILL DETERIORATE LATER
TODAY AS A TROPICAL WAVE MOVES INTO THE FLYING AREA. LLVL NE WINDS
OF 10-20 KT CAN BE EXPECTED THROUGH 23/00Z...THEN VEERING FM THE
SE ON TUESDAY. GUSTY WINDS LIKELY NEAR TSRA.

&&

.MARINE...SEAS OF 3-5 FT EXPECTED OVER THE NEXT SEVERAL DAYS.
HOWEVER...STRONG GUSTY WINDS...LOCALLY HIGHER SEAS AND DANGEROUS
LIGHTNING ARE LIKELY NEAR THUNDERSTORMS. THEREFORE...BOATERS
SHOULD AVOID THUNDERSTORMS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 79 88 78 88 / 80 80 20 30
STT 79 87 78 88 / 60 60 50 50

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
508 AM AST TUE SEP 23 2014

.UPDATE...TUTT LOW OVER THE CENTRAL ATLANTIC NORTHEAST OF THE
REGION...WILL AMPLIFY INTO THE NORTHEAST CARIBBEAN DURING THE
NEXT FEW DAYS. TROPICAL WAVE ACROSS THE MONA PASSAGE WILL MOVE
WESTWARD AND AWAY FROM THE LOCAL ISLANDS TONIGHT.

&&

.DISCUSSION...THE DOPPLER WEATHER RADAR DETECTED SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS ACROSS THE SURROUNDING COASTAL WATERS.
UNDER AN EAST SOUTHEAST WIND FLOW...SHOWERS AND THUNDERSTORMS MOVED
OVER SOUTHEAST AND SOUTH SECTIONS OF PUERTO RICO AS WELL AS ACROSS
VIEQUES...CULEBRA AND THE U.S. VIRGIN ISLANDS. HOWEVER...NOT
SIGNIFICANT OR WIDESPREAD PRECIPITATION IS EXPECTED. FOR THE
AFTERNOON HOURS...THIS MOISTURE WILL COMBINE WITH DAYTIME HEATING
AND LOCAL EFFECTS TO INDUCE THE DEVELOPMENT OF SHOWERS AND
THUNDERSTORMS OVER WESTERN...INTERIOR AND NORTHWEST SECTIONS OF
PUERTO RICO.

LATEST SATELLITE IMAGES AND SURFACE ANALYSIS THIS MORNING DEPICTED A
TROPICAL WAVE OVER THE MONA PASSAGE. THIS WAVE WILL CONTINUE TO MOVE
WESTWARD AND AWAY FROM THE REGION TODAY AND TONIGHT. THE MOISTURE
ASSOCIATED WITH THE WAVE WILL CONTINUE TO AFFECT THE LOCAL REGION
TODAY...INDUCING AN INCREASE IN SHOWER AND THUNDERSTORM ACTIVITY
OVER THE REGION. THE GFS COMPUTER GUIDANCE SUGGESTS PWAT VALUES
SLIGHTLY ABOVE 2.00 INCHES INTO THE MIDDLE OF WEEK. LATE THIS
AFTERNOON...TONIGHT AND INTO TUESDAY...FREQUENT PASSING SHOWERS
WITH THUNDERSTORMS COULD BE EXPECTED ACROSS USVI...EASTERN AND
SOUTHERN SECTIONS OF PUERTO RICO.

&&

.AVIATION...TROPICAL WAVE BRINGING SHRA/TSRA ACTIVITY ACROSS THE
LOCAL AREA OVERNIGHT AND TUESDAY. CONDS SHOULD PREVAIL VFR UNTIL
ABOUT 23/08Z. THEREAFTER...SHRA/TSRA ACTIVITY IS EXPECTED TO START
AFFECTING THE TKPK AND TNCM TERMINALS...THEN TIST AND TISX A FEW
HOURS AFTER THAT AND SO ON AS THE WAVE CONTINUES TO MOVE WEST. MVFR
CONDITIONS ARE POSSIBLE ACROSS THE LOCAL TERMINALS BUT LIKELY ACROSS
WESTERN PR...IN AND AROUND TJBQ AND TJMZ AFTER 23/16Z WHERE TSRA ARE
EXPECTED TO DEVELOP.

&&

.MARINE...SEAS OF 3-5 FT EXPECTED OVER THE NEXT SEVERAL DAYS.
HOWEVER...STRONG GUSTY WINDS...LOCALLY HIGHER SEAS AND DANGEROUS
LIGHTNING ARE LIKELY NEAR THUNDERSTORMS TODAY. THEREFORE...BOATERS
SHOULD AVOID THUNDERSTORMS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 78 88 78 / 60 20 30 20
STT 88 78 88 79 / 60 50 50 30

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
229 PM AST TUE SEP 23 2014

.SYNOPSIS...TUTT LOW NORTHEAST OF THE AREA WILL REMAIN NEARLY
STATIONARY THROUGH THE END OF THE WEEK WHILE SLOWLY WEAKENING.
A TROPICAL WAVE WILL MOVE ACROSS THE AREA FRI NIGHT OR SAT.

&&

.DISCUSSION...MOISTURE REMAINS VERY DEEP WITH PWS AROUND 2.2
INCHES. A DRYING TREND IS EXPECTED TO BEGIN TONIGHT THROUGH
FRIDAY. NEXT WAVE IS CURRENTLY ANALYZED ALONG 42W. CONVECTION HAS
PERSISTED OVER THE PAST FEW DAYS WITH THIS WAVE BUT IS EXPECTED TO
ENCOUNTER MORE HOSTILE CONDITIONS AS IT APPROACHES THE TUTT AXIS
WEST OF 50W BUT EXPECT SOME INCREASE IN RAINFALL CHANCES FRIDAY
NIGHT THROUGH SATURDAY NIGHT WITH DRYING EXPECTED AGAIN FOR SUNDAY
THROUGH TUESDAY OF NEXT WEEK. OTHERWISE...EXPECT TYPICAL AFTERNOON
CONVECTION OVR WRN PR EACH AFTERNOON. A TROPICAL WAVE NEAR THE
COAST OF AFRICA IS LIKED BY GFS AND SEVERL GEFS MEMBERS. BY
MIDDLE OF NEXT WEEK...OP GFS AND GEFS SHOW A TROPICAL CYCLONE
APPROACHING THE SRN WINDWARD ISLANDS. ABOUT 10 OF 20 ENSEMBLE
MEMBERS SHOW A WEAK LOW PRESSURE WITH MSLP`S 1005 MB OR WEAKER. AS
THE CURRENT TUTT PATTERN WEAKENS...THIS WAVE MAY HAVE A BETTER
CHANCE TO ORGANIZE INTO A TROPICAL CYCLONE.

&&

.AVIATION...MVFR CIGS POSSIBLE AT JBQ...JMZ THIS AFTERNOON AND
AGAIN AT JMZ ONLY. OTHERWISE...VFR CONDITIONS EXPECTED.

&&

.MARINE...SEAS 2-4 KT AND WINDS 10-15 KT.

&&

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

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
527 AM AST WED SEP 24 2014

.SYNOPSIS...AT MID AND UPPER LEVELS...LOW PRESSURE CENTERED 730
MILES NORTHEAST OF CULEBRA WILL EXTEND A TROUGH SOUTHWEST OVER THE
LOCAL AREA TONIGHT THROUGH FRIDAY. THE TROUGH WILL WEAKEN BUT
REMAIN IN THE LOCAL AREA THROUGH MONDAY. HIGH PRESSURE MOVES INTO
THE CARIBBEAN FROM THE TROPICAL ATLANTIC EARLY NEXT WEEK.

AT LOWER LEVELS...HIGH PRESSURE IN THE NORTH CENTRAL ATLANTIC WILL
BE JOINED BY ANOTHER HIGH FROM THE WEST ON THURSDAY WHILE LOW
PRESSURE DOMINATES THE SOUTHERN AND WESTERN CARIBBEAN. HIGH
PRESSURE WILL FADE THURSDAY THROUGH SUNDAY AND GRADIENTS WILL
RELAX DURING THAT TIME. NEXT WEEK HIGH PRESSURE REBUILDS IN THE
NORTHEAST CENTRAL ATLANTIC AND EXTENDS INTO THE CARIBBEAN CREATING
MODERATE EAST SOUTHEASTERLY TRADE WINDS. MOIST...UNSTABLE CONDITIONS
WILL PREVAIL BUT LESSEN TODAY THROUGH FRIDAY ONLY TO PEAK AGAIN
OVER THE WEEKEND.

&&

.DISCUSSION...SHOWERS INCREASED OVERNIGHT OVER MOST OF THE WATERS
NOT IN THE WESTERN SHADOW OF PUERTO RICO WITH SOME BRIEF HEAVY
SHOWERS MOVING ONSHORE IN EASTERN AND SOUTHEASTERN PUERTO RICO.
AMOUNTS OF UP TO THREE QUARTERS OF AN INCH WERE OBSERVED ON RADAR.
THE GFS WAS GENERALLY DRIER THAN THE NAM5 TODAY THROUGH MUCH OF
THE NEXT 5 DAYS AND CURRENT FORECAST OUT 5 DAYS REPRESENTS THE
NAM5 TEMPERED BY THE GFS AND PREVIOUS FORECASTS. NEVERTHELESS RAIN
IS LIKELY ACROSS MUCH OF THE FORECAST AREA TODAY AND ACROSS
SOUTHWEST PUERTO RICO TOMORROW. PRECIPITABLE WATER AND LOWER LEVEL
RELATIVE HUMIDITIES DIMINISH TODAY THROUGH FRIDAY...BUT EVEN AT
LOW EBB PRECIPITABLE WATER VALUES ONLY DROP TO 1.70 INCHES BEFORE
SPIKING BACK UP TO NEAR 2 INCHES BOTH SATURDAY AND SUNDAY
AFTERNOONS.

THIS MOISTURE WILL COMBINE WITH THE INFLUENCES OF AN UPPER LEVEL
LOW PRESSURE SPREADING ACROSS THE AREA THURSDAY THROUGH SUNDAY TO
SPAWN INCREASINGLY FREQUENT THUNDERSTORMS ACROSS THE AREA. THE GFS
SHOWS 500 MB TEMPERATURES DROPPING FROM AROUND MINUS 5 DEGREES
TODAY TO MINUS 8 DEGREES SUNDAY NIGHT WITH A CORRESPONDING DROP
IN THE LIFTED INDEX FROM MINUS 4 DEGREES TO MINUS 8 DEGREES. WOULD
EXPECT SHOWERS AND THUNDERSTORMS TO BECOME MORE INTENSE OVER THE
WEEKEND AND INTO EARLY NEXT WEEK. WITH THE FREEZING LEVEL STILL
FAIRLY HIGH ON SATURDAY...14.5 KFT...AND RISING FROM THEN ON...WOULD
EXPECT SOME SMALL HAIL OCCURRENCES AND STRONG THUNDERSTORMS WINDS
OVER THE WEEKEND AND INTO EARLY NEXT WEEK...MAINLY INTERIOR PUERTO
RICO. THE U.S. VIRGIN ISLANDS WILL SEE AN INCREASE OF SHOWERS
OVER THE WEEKEND BUT AMOUNTS SHOULD BE MODERATE...BUT IN PUERTO
RICO TODAY THROUGH TUESDAY THUNDERSTORMS MAY PRODUCE LOCALIZED
URBAN AND SMALL STREAM FLOODING. WIDESPREAD FLOODING OR FLOODING
OF LARGE RIVERS IS NOT ANTICIPATED TODAY THROUGH FRIDAY. LOW LEVEL
WINDS DECREASE THROUGH SATURDAY AND WILL MAKE UP FOR THE LESSENING
MOISTURE LEVELS IN THE AMOUNT OF RAIN THAT CAN FALL IN ANY ONE
PLACE.

&&

.AVIATION...THROUGH THE MORNING HOURS...PASSING -SHRA CREATING VCSH
WITH POSSIBLE BRIEF MVFR CIGS AT TIST/TISX AND TJSJ. BETWEEN
24/16Z-21Z...SHRA/TSRA CREATING MVFR CONDS AND MOUNTAIN OBSCURATIONS
OVER THE WESTERN INTERIOR OF PR AFFECTING MAINLY TJMZ/TJBQ.
VCSH/VCTS ARE ALSO POSSIBLE WITH MOUNTAIN OBSCURATIONS NEAR
TJSJ/TJPS IN THE AFTERNOON. LOW LEVEL WINDS FROM THE EAST AT 10-15
KT WITH SEA BREEZE VARIATIONS. TOPS BEFORE DAWN WERE UP TO 38 KFT
SOUTH OF PUERTO RICO BUT LESS THEN 30 KFT AROUND THE ISLAND EAST
AND NORTH.

&&

.MARINE...CONDITIONS REMAIN RELATIVELY TRANQUIL THROUGH THE NEXT 7
DAYS WITH SEAS GENERALLY 4 FEET OR LESS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 79 87 79 / 70 70 50 50
STT 88 78 88 79 / 50 70 40 60

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
304 PM AST WED SEP 24 2014

.SYNOPSIS...TUTT NORTHEAST OF THE AREA IS TO AMPLIFY SWD OVER THE
NEXT FEW DAYS AND EXTEND A TROUGH INTO THE SRN CARIBBEAN. A
TROPICAL WAVE WILL MOVE ACROSS THE AREA FRI NIGHT.

&&

.DISCUSSION...DRYING IS EXPECTED TONIGHT THROUGH THURSDAY WITH A
DECREASE IN AREAL COVERAGE OF SHOWERS AND T-STORMS BUT NOT
UNNECESSARILY IN INTENSITY. MID-LEVEL DRY AIR MAY ENHANCE TSTM
ACTIVITY OVR WRN PR.

AS TUTT NORTHEAST OF THE AREA AMPLIFIES SOUTHWARD IT IS TO
MODULATE THE LOW-LEVEL EASTERLIES WITH WINDS BECOMING MORE
SOUTHERLY THROUGH TIME. THIS WILL ALLOW FOR DEEP MOISTURE TO
ADVECT NWD INTO THE AREA FRI NIGHT THROUGH SUNDAY AFTERNOON.
INFLOW OF CYCLONIC VORTICITY WILL HELP TRIGGER SHOWERS AND
T-STORMS AND POSSIBLE MCS FORMATION ACROSS THE AREA DURING THE
WEEKEND. THE STEERING FLOW WILL ALSO BECOME QUITE WEAK LESS THAN
10 KT AND ALLOW FOR SLOW STORM MOTION. THE DEGREE OF
INSTABILITY...FORCING AND SLOW STORM MOTION INDICATE THE POTENTIAL
FOR A SIGNIFICANT HEAVY RAINFALL EVENT DURING THE WEEKEND
ESPECIALLY ON SATURDAY. DRYING IS EXPECTED MONDAY THROUGH WEDNESDAY.

&&

.AVIATION...VFR TONIGHT BUT TSTMS AGAIN POSSIBLE THU AFTERNOON
AT MAYAGUEZ. MORE UNSETTLED WX EXPECTED DURING THE WEEKEND WITH
NMRS T-STORMS WITH HEAVY RAINFALL AND FREQ LIGHTNING.

&&

.MARINE...WINDS 10-15 KT DIMINISHING TO LESS THAN 10 KT DURING THE WEEKEND.
SEAS 2-4 KT BUT LOCALLY HIGHER NEAR THUNDERSTORMS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 79 87 79 88 / 20 20 20 20
STT 78 88 79 87 / 20 20 20 20

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
526 AM AST THU SEP 25 2014

.SYNOPSIS...AT UPPER LEVELS...A TROUGH FROM A LOW PRESSURE LOCATED
ALMOST 600 MILES NORTHEAST OF SAINT CROIX WILL EXTEND SOUTHWEST
OVER THE AREA TONIGHT AND TOMORROW GREATLY ENHANCING INSTABILITY
IN THE AREA. THE LOW WILL CONTINUE OVER THE AREA THROUGH SUNDAY. A
SECOND LOW WILL DROP SOUTHEAST INTO THE ATLANTIC NORTH OF PUERTO
RICO DURING THE WEEK NEXT WEEK.

AT MID LEVELS...LOW PRESSURE EAST NORTHEAST OF THE AREA WILL MOVE
OVER PUERTO RICO ON SATURDAY. HIGH PRESSURE OVER THE TROPICAL
ATLANTIC WILL EDGE SLOWLY TOWARD THE CARIBBEAN NEXT WEEK. WEAK
HIGH PRESSURE WILL BE FOUND OVER THE FORECAST AREA BY THE
FOLLOWING WEEKEND.

AT LOWER LEVELS...A WEAK TROUGH INDUCED BY THE TUTT LOW WILL FORM
OVER THE AREA. A BAND OF MOISTURE OVER THE WINDWARD ISLANDS WILL
MOVE SLOWLY TOWARD THE AREA...FIRST WESTWARD AND THEN
NORTHWARD...PASSING THROUGH ON SATURDAY. THE NEXT TROPICAL WAVE
WILL PASS ON WEDNESDAY NIGHT FOLLOWED IMMEDIATELY BY A MUCH
STRONGER WAVE PASSING WELL SOUTH OF THE AREA LATE THURSDAY.

&&

.DISCUSSION...SINCE FLOW HAS TURNED MORE EAST NORTHEAST AND THE
UPPER LEVEL LOW IS ENHANCING SHOWERS TO THE NORTHEAST...NUMEROUS
SHOWERS MADE THEIR WAY ACROSS PUERTO RICO AND THE U.S. VIRGIN
ISLANDS AND DISSIPATED A SHORT WAY INLAND. SHOWERS MOVED AT ALMOST
20 MPH SO THEY WERE BRIEF...NEVERTHELESS WINDWARD SLOPES IN THE
LUQUILLO RANGE RECEIVED BETWEEN ONE HALF AND ONE INCH OF RAIN.

THE ATMOSPHERE IS MOISTURE RICH NO MATTER WHICH DIRECTION IS
UPSTREAM. CURRENTLY MOISTURE IS MOVING IN FROM THE NORTHEAST OUT
OF THE ATLANTIC AIDED BY AN UPPER LEVEL LOW. LOW LEVEL FLOW IS
EXPECTED TO BECOME MORE SOUTHEASTERLY ON FRIDAY AND MOISTURE
CURRENTLY OVER THE WINDWARD ISLANDS WILL MAKE ITS WAY OVER THE
FORECAST AREA SATURDAY AND SUNDAY. AT THE SAME TIME LOW PRESSURE
AT UPPER LEVELS WILL EXTEND A TROUGH SOUTHWEST OVER THE AREA AND
LOWER MID-LEVEL TEMPERATURES BY SEVERAL DEGREES CELSIUS. THIS WILL
RAMP UP INSTABILITY TONIGHT THROUGH SUNDAY. PRESENTLY THE NAM5 IS
DOING A BETTER JOB OF FORECASTING GOOD CONVECTION AND WIDESPREAD
COVERAGE OF AT LEAST SOME RAIN THAN THE GFS AS IT DID
WEDNESDAY...THEREFORE HAVE LEANED HEAVILY ON ITS SOLUTION THROUGH
THE END OF THE WEEK AND EXTRAPOLATED OUT TO SUNDAY. THE GFS HAS
BEEN INDICATING LIFTED INDICES OF UNDER 8 DEGREES SATURDAY AND
SUNDAY AND CONSIDERING THE WINDS THAT OCCURRED IN NORTHWEST PUERTO
RICO WEDNESDAY WITH A LIFTED INDEX OF ONLY MINUS 5 OR 6...AM
CONCERNED THAT STRONGER CONVECTION APPROACHING SEVERE LIMITS MAY
OCCUR IN SOME PLACES IN WESTERN AND INTERIOR PUERTO RICO IF 500 MB
TEMPERATURES VERIFY OVER THE WEEKEND. CERTAINLY THIS WOULD INCLUDE
AT LEAST SMALL HAIL AND DAMAGING WIND GUSTS OVER A SUBSTANTIAL
AREA IF MOISTURE IS PRESENT IN QUANTITIES GRATER THAN THE GFS
INDICATES. IT MUST BE NOTED THAT THE GFS MISSED THE PRECIPITABLE
WATER FORECAST FOR WEDNESDAY BY MORE THAN ONE QUARTER INCH AND HAS
A SIMILAR FORECAST OF DIPPING VALUES FOR TODAY. MOISTURE INCREASES
TO AT LEAST 1.9 INCHES SATURDAY AND SUNDAY...AND SUSPECT THAT
THESE VALUES MAY BE TOO LOW. THEREFORE WILL CONSIDER SHOWERS AND
THUNDERSTORMS LIKELY DURING THE AFTERNOONS EACH DAY THROUGH MONDAY
WITH THE STRONGEST DAY BEING SUNDAY...WITH THE BEST ACTIVITY
DOWNWIND OVER INTERIOR PUERTO RICO. THE GFS IS TRYING TO MOVE MUCH
DRIER AIR AT LOW LEVELS OVER THE AREA FROM THE SOUTHEAST ON
SUNDAY...BUT PRECIPITABLE WATER LEVELS DO NOT FALL APPRECIABLY
UNTIL MONDAY. AFTER MONDAY...GFS MODEL SOLUTIONS ARE ERRATIC FROM
RUN TO RUN ALTHOUGH EVEN THE RUNS WITH MORE ACTIVE WEATHER WILL
NOT IMPACT PUERTO RICO AND THE U.S. VIRGIN ISLANDS VERY MUCH. A
STRONG TROPICAL WAVE IS FORECAST BY THE 12Z AND 00Z RUNS TO PASS
THROUGH THE SOUTHERN CARIBBEAN NEXT THURSDAY AND FRIDAY AND WITH
IT SHOWERS AND THUNDERSTORMS ARE EXPECTED TO INCREASE...BUT MOST
OF THE MOISTURE AND THE BEST WIND FIELD REMAIN SOUTH OF US.

&&

.AVIATION...VCSH EXPECTED AT TIST/TISX/TJSJ THROUGH THE FCST PERIOD
WITH BRIEF MVFR CIGS. BETWEEN 25/16Z-22Z...SHRA/TSRA CREATING MVFR
CONDS AND MOUNTAIN OBSCURATIONS OVER THE CENTRAL MOUNTAIN RANGE OF
PR AND WESTERN PR AFFECTING MAINLY TJMZ AND TJBQ. VCTS ARE ALSO
POSSIBLE AT TJSJ/TJPS IN THE AFTERNOON. LOW LEVEL WINDS FROM THE
EAST AT 10-15 KT WITH SEA BREEZE VARIATIONS. HIGHER GUSTS EXPECTED
NEAR TSRA.


&&

.MARINE...SEAS REMAIN BETWEEN 3 TO 5 FEET THROUGHOUT THE NEXT 10
DAYS. WINDS WILL BE GENERALLY BELOW 18 KNOTS BUT WILL INCREASE
NEAR THE END OF NEXT WEEK IN THE SOUTHERN PORTION OF OUR
CARIBBEAN WATERS. GUSTY WINDS WILL BE ENCOUNTERED NEAR
THUNDERSTORMS.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 78 87 77 / 50 40 70 40
STT 87 78 88 78 / 40 40 60 60

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
302 PM AST THU SEP 25 2014

.SYNOPSIS...UPPER LEVEL LOW/TUTT ABOUT 350 MILES NORTHEAST OF
PUERTO RICO WILL MOVE SOUTHWESTWARD OVER THE NORTHEAST CARIBBEAN
DURING THE NEXT 24 HOURS. AS A RESULT...MOISTURE AND INSTABILITY
WILL INCREASE SIGNIFICANTLY ACROSS THE LOCAL REGION FRIDAY AND
SATURDAY...RESULTING IN PERIODS OF INTENSE RAINFALL AND FREQUENT
LIGHTNING ACROSS MOST OF THE ISLANDS. CONDITIONS WILL GRADUALLY
IMPROVE NEXT WEEK AS THE UPPER LOW WEAKENS/DISSIPATES AND DRIER
AIR ADVECTS OVER THE LOCAL AREA.

&&

.DISCUSSION...LOOPS OF WATER VAPOR IMAGERY REVEALS A WELL-DEFINED
CYCLONIC ROTATION ASSOCIATED WITH AN UPPER LOW OVER CENTRAL CARIBBEAN
OR ABOUT 350 MILES NORTHEAST OF PUERTO RICO THIS AFTERNOON. THIS
UPPER LOW ENHANCED THE TRADE WIND SHOWERS UPSTREAM OF PR/USVI...
RESULTING IN SCATTERED TO NUMEROUS SHOWERS AFFECTING THE EAST AND
NORTH PORTIONS OF PR MOST OF THE DAY. OVER TWO INCHES OF RAIN WAS
OBSERVED IN PORTIONS OF FAJARDO...NAGUABO AND CEIBA THIS MORNING.
SEA BREEZE ACROSS WEST AND SOUTHWEST PR INDUCED THE DEVELOPMENT
OF SHOWERS AND THUNDERSTORMS ACROSS THE SOUTHWEST QUADRANT OF
PUERTO RICO. THE HEAVIEST RAINFALL SO FAR THIS AFTERNOON HAVE
FALLEN OVER LAJAS...CABO ROJO AND SABANA GRANDE. ADDITIONAL
SHOWERS ARE ADVECTING OVER PR AND THE USVI FROM THE NORTHEAST.

UPPER LOW/TUTT IS EXPECTED TO AMPLIFY OVER THE NEXT 24 HRS AS MOVES
CLOSER TO THE LOCAL AREA. AS IT DEEPENS AND ADVECT OVER THE
NORTHEAST CARIBBEAN REGION...SYNOPTIC SCALE FORCING INCREASES
DRASTICALLY...RESULTING WIDESPREAD CONFECTION ACCOMPANIED OF
PERIODS OF INTENSE RAIN AND FREQUENT LIGHTNING. OPERATIONAL MODELS
AGREE THAT THE 0-6KM MEAN FLOW WILL CHANGE FROM THE SOUTH FRIDAY
MORNING...ALLOWING FOR PWAT TO INCREASE OVER 2.25 INCHES...PERSISTING
THROUGH AT LEAST SUNDAY MORNING. IN GENERAL...EXPECT WEATHER CONDITIONS
TO DETERIORATE AND BECOME MORE ACTIVE LATE TONIGHT AND PERSIST THROUGH
AT LEAST SUNDAY MORNING UNDER THE INFLUENCE OF THE UPPER LOW AND THE
INDUCED SURFACE TROUGH. THE POTENTIAL OF EXPERIENCED FLASH FLOODING
IS HIGH BETWEEN FRIDAY AND SATURDAY...THEREFORE...WE DECIDED TO
ISSUE A FLASH FLOOD WATCH FOR PR/USVI. PLEASE REFER TO SJUFFASJU
FROM MORE INFORMATION AND THE START TIMES.

&&

.AVIATION...SHRA/TSRA WILL INCREASE ACROSS THE FLYING AREA OVER
THE NEXT 24-48 HRS. THEREFORE...TEMPO PDS OF MVFR/IFR CONDS ARE
LIKELY AS THE STORMS PASS BY. LLVL NE WINDS WILL WEAKEN AND SHIFT
FM THE SOUTH ON FRIDAY. WIND SPEEDS WILL BE AT 10 KT OR
LESS...WITH HIGHER GUST NEAR TSRA.

&&

.MARINE...SEAS REMAIN BETWEEN 3 TO 5 FEET THROUGHOUT THE FORECAST
PERIOD. WINDS WILL BE GENERALLY BELOW 18 KNOTS BUT WILL INCREASE
NEAR THE END OF NEXT WEEK IN THE SOUTHERN PORTION OF OUR CARIBBEAN
WATERS. GUSTY WINDS WILL BE ENCOUNTERED NEAR THUNDERSTORMS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 78 87 77 87 / 50 70 60 80
STT 78 87 78 88 / 80 80 80 80

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
508 AM AST FRI SEP 26 2014

.SYNOPSIS...AT UPPER LEVELS...LOW PRESSURE NOW APPROACHING PUERTO
RICO WITH A TROUGH TO THE NORTHEAST WILL SLOWLY FADE OVER THE
WEEKEND AND EARLY NEXT WEEK WHILE KEEPING INSTABILITY HIGH OVER
THE AREA. THIS LOW WILL THEN PERSIST JUST NORTH OF THE AREA
SUSTAINING COOLER THAN NORMAL TEMPERATURES AT MID LEVELS.

AT MID LEVELS...LOW PRESSURE WILL BECOME WEAKER...SPREAD SOUTHWEST
AND THEN SLIDE WESTWARD OVER THE CENTRAL CARIBBEAN DURING THE
WEEKEND. HIGH PRESSURE OVER THE TROPICAL ATLANTIC WILL GRADUALLY
INVADE THE CARIBBEAN UNTIL IT IS CENTERED OVER PUERTO RICO AND THE
U.S. VIRGIN ISLANDS ON THURSDAY. THIS HIGH PERSISTS OVER THE
GREATER ANTILLES INTO THE FOLLOWING WEEKEND.

AT LOWER LEVELS...A WEAK TROUGH INDUCED BY THE MID AND UPPER LEVEL
LOW WILL FAVOR SHOWERS AND THUNDERSTORMS TODAY AND TOMORROW.
DRIER AIR INVADES FROM THE SOUTHEAST SATURDAY NIGHT AND
SUNDAY...BUT WILL NOT ELIMINATE THE POSSIBILITY OF THUNDERSTORMS
OVER THE NORTHWEST AND NORTH CENTRAL PORTIONS OF PUERTO RICO.
ANOTHER PULSE OF MOISTURE WILL MOVE THROUGH THE AREA FROM THE
SOUTHEAST ON TUESDAY. THE NEXT TROPICAL WAVE WILL BE ACCOMPANIED
BY CONSIDERABLE MOISTURE THURSDAY NIGHT AND FRIDAY...BUT WILL
ARRIVE IN A MUCH WEAKENED CONDITION.

&&

.DISCUSSION...SHOWERS AND A FEW THUNDERSTORMS GRADUALLY GREW OVER
THE ATLANTIC WATERS AND THE WATERS IN A LARGE SWATH OF THE
CARIBBEAN AROUND THE U.S. VIRGIN ISLANDS. A FEW LIGHT SHOWERS
FELL ON THE COAST OF PUERTO RICO FROM SAN JUAN TO RIO GRANDE...BUT
AMOUNTS WERE LIMITED TO A TRACE. NO RAIN WAS MEASURED AT THE
AIRPORTS IN THE U.S. VIRGIN ISLANDS BY 4:30 AM AST. FOR THIS
REASON THE FLASH FLOOD WATCH WAS CANCELED FOR THE OVERNIGHT AND
MORNING HOURS TODAY.

THE UPPER LEVEL LOW HAS DEGRADED CONSIDERABLY FROM ITS ROBUST
STATE NORTHEAST OF THE AREA OVER THE LAST FEW DAYS BUT HAS STILL
BEEN ABLE TO GENERATE CONSIDERABLE SHOWER AND THUNDERSTORM ACTIVITY
THROUGH THE INDUCED INSTABILITY GENERATED BY THE COOL POOL OF AIR
ALOFT. SINCE SKIES WERE GENERALLY CLEAR OVER PUERTO RICO AND THE
U.S. VIRGIN ISLANDS OVERNIGHT RAINFALL THAT WANTED TO PUSH TOWARD
THE COAST IN THE EASTERLY FLOW WAS HAMPERED BY THE OPPOSING LAND
BREEZES AND BY THE STABILITY OF GROUND COOLING BY RADIATION EVEN
IN THIS MOIST ATMOSPHERE.

AS HEATING FROM THE SUN INCREASES TODAY THE FULL MEASURE OF THE
INSTABILITY WILL BE TAPPED TO FORM VIGOROUS SHOWERS AND
THUNDERSTORMS OVER MOST AREAS OF PUERTO RICO. BECAUSE OF THE WEAK
WINDS...GENERALLY LESS THAN 12 KNOTS...AT LEVELS UP THROUGH 30 KFT...
AND THE GENERAL VEERING OF THE WINDS WITH HEIGHT...SOME OF THE
THUNDERSTORMS` HEAVY RAINS WILL LIKELY PRODUCE SOME URBAN AND SMALL
STREAM FLOODING WITH FLASH FLOODING IN VERY LOCALIZED AREAS.
SUFFICIENT MOISTURE EXISTS TO PUSH EVEN A FEW MAJOR RIVERS CLOSE
TO FLOOD STAGE SINCE THE LAST SEVERAL DAYS HAVE GREATLY ADDED TO
GROUND SATURATION. THEREFORE...THE FLOOD WATCH FOR THIS AFTERNOON WILL
BE KEPT. FLOW WILL TURN TO THE SOUTHEAST AT THE SURFACE AND
TO THE SOUTH BETWEEN 5 AND 10 KFT. THIS WILL ALSO ENHANCE THE
HEAVY RAINS THAT ARE LIKELY TO FORM TODAY AND WILL INCREASE THE
LIKELIHOOD OF HEAVY RAIN DURING THE EVENING HOURS IN SOUTHERN AND
SOUTHEASTERN PUERTO RICO. ALTHOUGH THE U.S.VIRGIN ISLANDS ARE NOT
AS LIKELY TO FLOOD THERE IS SOME CHANCE THAT LINES OF CLOUDS COULD
BECOME ORGANIZED IN THE FAVORABLE ENVIRONMENT AIDED BY THE UPPER
LEVEL LOW THAT COULD DUMP CONSIDERABLE RAINFALL.

CONDITIONS WILL BECOME SLIGHTLY MORE UNSTABLE AND THE FREEZING
LEVEL IS EXPECTED TO LOWER AROUND 1 KFT TO NEAR 14 KFT ON
SATURDAY. THEREFORE SMALL HAIL WORDING HAS BEEN ADDED TO THE ZONE
FORECAST FOR SATURDAY AND SUNDAY WHEN SHOWERS AND THUNDERSTORMS
REDEVELOP. SUNDAY WILL SEE THE BEGINNING OF THE END OF THE
HEAVIEST RAINFALL...EVEN THOUGH UNSTABLE CONDITIONS WILL CONTINUE
INTO MONDAY. A MASS OF MUCH DRIER AIR ENTERS THE FORECAST AREA
SATURDAY NIGHT AND SPREADS OVER PUERTO RICO AND THE ATLANTIC WATERS
ON SUNDAY AND SUNDAY NIGHT. ALTHOUGH STRONG CONVECTION CAN STILL
OCCUR IN THE CENTRAL AND WESTERN PORTION OF PUERTO RICO DUE TO
HEATING...MUCH LESS RAINFALL IS EXPECTED. BECAUSE OF THE DRYING
AIR MASS AND SOUTHERLY WINDS ON SUNDAY AND MONDAY...TEMPERATURES
ON THE NORTH COAST ARE EXPECTED TO BE SOME OF THE WARMEST OF THE
MONTH...WITH HIGHS REACHING THE LOWER 90S AND POSSIBLY THE MID 90S
IN THE MORE INLAND COASTAL AREAS. SHOWERS AND THUNDERSTORMS ON
TUESDAY SHOULD BRING THOSE TEMPERATURES CLOSER TO NORMAL ISLAND-
WIDE. BUT EAST TO SOUTHEAST FLOW WILL CONTINUE THROUGH MUCH OF THE
WEEK ALONG WITH STRONG AFTERNOON THUNDERSTORMS AND SOMEWHAT ABOVE
NORMAL TEMPERATURES. AT THIS TIME NO SIGNIFICANT TROPICAL SYSTEMS
CAN BE SEEN DEVELOPING IN OR PASSING THROUGH THE LOCAL FORECAST
AREA FOR THE NEXT 10 DAYS.

&&

.AVIATION...SHRA/TSRA WILL INCREASE ACROSS THE FLYING AREA OVER THE
NEXT 24 HRS. VCSH/VCTS AT TJSJ/TIST/TISX/TNCM/TKPK EXPECTED THRU THE
MORNING HOURS. AFTER 26/16Z...+TSRA EXPECTED AT TJSJ/TJPS/TJMZ/TJBQ.
THEREFORE...TEMPO PDS OF MVFR/IFR CONDS ARE LIKELY AS THE STORMS
PASS BY. MOUNTAIN OBSCURATIONS ARE EXPECTED. EAST SOUTHEAST WINDS
AROUND 10 KT...WITH HIGHER GUSTS NEAR TSRA. SOME SMALL HAIL MAY BE
ENCOUNTERED ABOVE 8 KFT TODAY AND TOMORROW IN AND NEAR TSRA.

&&

.MARINE...EXCEPT FOR GENERALLY DETERIORATING WEATHER CONDITIONS
AND SOME WEAK SWELL FROM THE NORTHEAST PUSHING SEAS ABOVE 5 FEET
IN PARTS OF THE ATLANTIC...CONDITIONS WILL REMAIN BELOW 5 FEET WITH
WINDS GENERALLY BELOW 15 KNOTS. STRONG GUSTY WINDS AND FREQUENT
LIGHTING ARE EXPECTED AROUND THUNDERSTORMS TODAY THROUGH
MONDAY...BUT CONDITIONS WILL GENERALLY IMPROVE AFTER SATURDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 75 88 77 / 70 60 80 50
STT 87 77 88 79 / 50 80 80 50

[cycloneye]

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SAN JUAN PR
1059 AM AST FRI SEP 26 2014

.SYNOPSIS...UPPER LEVEL LOW OVER THE VIRGIN ISLANDS WILL DRIFT
NORTH OVER THE NEXT SVRL DAYS WHILE WEAKENING.

&&

.DISCUSSION...UPPER LEVEL LOW AND ASSOCIATED MID-UPPER LEVEL COLD
POOL ALMOST OVERHEAD OVR PR WITH -9C AND -19C AT 500 MB AND 400 MB
RESPECTIVELY. ALSO...0-6 KM STEERING FLOW IS ALMOST NON-EXISTENT
MEANING THAT THUNDERSTORMS WHERE THEY FORM WILL REMAIN NEARLY
STATIONARY AND REMAIN OVER ONE SINGLE LOCATION FOR SEVERAL HOURS.
LATER THIS EVENING... RISK OF MCS FORMATION APPEARS QUITE HIGH AND
MAY TRY TO LIFT NORTH TOWARD PR AND USVI AS STEERING FLOW BECOMES A
LITTLE BETTER DEFINED FROM THE SOUTH. SO THE NEXT 24 HRS...THE
ENVIRONMENT APPEARS QUITE FVRBL FOR HEAVY RAINFALL AND FLASH
FLOODING. RISK OF HEAVY RAINFALL ON SAT STILL REMAINS HIGH AS DEEP
MOISTURE LIFTS NORTH OVER THE AREA. BY SATURDAY EVENING...THINGS
APPEAR WILL BEGIN TO IMPROVE AS LOW-LEVELS BEGIN TO DRY OUT SOMEWHAT.

&&

.AVIATION...MVFR/IFR CONDITIONS NEXT 24 HRS THROUGH 28/00Z AT MOST
TAF SITES AS T-STORMS REMAIN NEARLY STATIONARY AND RISK OF MCS
REMAINS HIGH. WX CONDITIONS SHOULD BEGIN TO IMPROVE SATURDAY EVENING.

&&

.MARINE...WINDS 10-15 KT AND SEAS 2-4 FT XCPT HIGHER NEAR
THUNDERSTORMS. FREQ LIGHTNING AND VERY HEAVY RAINFALL CAN BE
EXPECTED WITH ANY THUNDERSTORMS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 75 88 77 / 50 60 80 50
STT 87 77 88 79 / 50 80 80 50

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
314 PM AST FRI SEP 26 2014

.SYNOPSIS...UPPER LEVEL LOW/TUTT WILL REMAIN OVER THE NORTHEAST
CARIBBEAN REGION THROUGH THE WEEKEND...BEFORE WEAKENS EARLY NEXT
WEEK. AS A RESULT...VERY UNSTABLE ATMOSPHERE AND DEEP TROPICAL
MOISTURE WILL PERSIST THE REST OF TODAY THROUGH AT LEAST SUNDAY
MORNING... MAINTAINING THE POTENTIAL OF SHOWERS AND THUNDERSTORMS
VERY HIGH ACROSS PR/USVI REGION. CONDITIONS WILL GRADUALLY IMPROVE
NEXT WEEK AS THE UPPER LOW WEAKENS/DISSIPATES AND DRIER AIR ADVECTS
OVER THE LOCAL AREA.

&&

.DISCUSSION...WATER VAPOR IMAGERY REVEALS THE UPPER LOW/TUTT OVER
PUERTO RICO. SATELLITE LOOPS SHOWED MOSTLY SUNNY SKIES PREVAILING
ACROSS MOST OF THE ISLANDS THIS MORNING...WHILE SCATTERED
THUNDERSTORMS AFFECTING MOST OF THE REGIONAL WATERS. IN CONTRAST...
DIURNAL HEATING/SEA BREEZE CONVERGENCE COMBINED WITH VERY UNSTABLE
CONDITIONS TO PRODUCE NUMEROUS SHOWERS AND STRONG THUNDERSTORMS
ACROSS MOST OF THE ISLANDS THIS AFTERNOON. AT LEAST TWO TO THREE
INCHES OF RAIN HAVE BEEN OBSERVED SO FAR THIS AFTERNOON ACROSS
CENTRAL PR. NEW SHOWERS AND THUNDERSTORMS WILL DEVELOP OVER THE SAME
AREAS THROUGH EARLY THIS EVENING. FOR TONIGHT AND OVERNIGHT...THE STEERING
FLOW WILL CHANGE FROM THE SOUTH BRINGING ADDITIONAL DEEP TROPICAL
MOISTURE INTO THE LOCAL AREA. THE BEST MOISTURE CONVERGENCE WILL
LIKELY OCCUR OVER THE CARIBBEAN WATERS...USVI...SOUTH AND EASTERN
PR. DEEP MOISTURE AND STRONG SYNOPTIC SCALE FORCING REMAIN HIGH
ACROSS THE REGION THROUGH LATE SATURDAY NIGHT...RESULTING IN
WIDESPREAD SHOWERS AND SCATTERED THUNDERSTORMS ACROSS MOST OF THE
FORECAST AREA OVER THE NEXT 24-36 HOURS. THEREFORE...THE FLASH
FLOODING WATCH CONTINUES IN EFFECT UNTIL LATE SATURDAY NIGHT FOR ALL
PUERTO RICO AND THE U.S. VIRGIN ISLANDS. THE CONDITIONS ARE
FAVORABLE FOR HEAVY RAIN AND FLASH FLOODING ACROSS PORTIONS OF
PR/USVI.

&&

.AVIATION...MVFR/IFR CONDITIONS NEXT 24 HRS THROUGH 28/00Z AT MOST
TAF SITES AS T-STORMS REMAIN NEARLY STATIONARY AND RISK OF MCS
REMAINS HIGH. WX CONDITIONS SHOULD BEGIN TO IMPROVE SATURDAY EVENING.

&&

.MARINE...WINDS 10-15 KT AND SEAS 2-4 FT XCPT HIGHER NEAR
THUNDERSTORMS. FREQ LIGHTNING AND VERY HEAVY RAINFALL CAN BE
EXPECTED WITH ANY THUNDERSTORMS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 75 88 77 91 / 60 70 50 50
STT 77 88 79 87 / 80 90 50 40

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
507 AM AST SAT SEP 27 2014

.SYNOPSIS...AT UPPER LEVELS...LOW PRESSURE JUST NORTH OF THE
NORTHWEST TIP OF PUERTO RICO WILL DRIFT NORTH THROUGH MONDAY AND
BECOME ABSORBED INTO A MUCH STRONGER LOW ALMOST 1000 MILES NORTH
NORTHEAST OF SAN JUAN. THE TIP OF THE TROUGH OF THAT LOW WILL
CALVE OFF A WEAK LOW NORTH OF HISPANIOLA ON TUESDAY THAT WILL
APPROACH WITHIN 180 MILES NORTHWEST OF ARECIBO PUERTO RICO BY
WEDNESDAY NIGHT AND REMAIN NEAR THAT AREA AND THE NORTH COAST OF
THE DOMINICAN REPUBLIC THROUGH SUNDAY. THIS LOW WILL BE WEAKER
THAN THE ONE THAT BROUGHT THE SHOWERS AND THUNDERSTORMS THIS
WEEK...BUT WILL STILL BRING UNSETTLED WEATHER TO THE AREA.

AT MID LEVELS...HIGH PRESSURE OVER THE TROPICAL ATLANTIC WILL
BUILD OVER THE EASTERN CARIBBEAN AND PUSH A TROUGH THAT STRETCHES
FROM THE MONA CHANNEL TO COLOMBIA OVER CENTRAL AMERICA BEGINNING TODAY
AND FINISHING TUESDAY. THE AXIS OF THAT HIGH PRESSURE ON TUESDAY WILL
SHIFT GRADUALLY NORTH OF THE AREA BY FRIDAY OF NEXT WEEK.

AT LOWER LEVELS...LOW PRESSURE IN THE SOUTHWEST CARIBBEAN AND WEAK HIGH
PRESSURE TO THE NORTHEAST OF THE AREA WILL KEEP LIGHT TO MODERATE
SOUTHEASTERLY FLOW OVER THE AREA. BANDS OF MOISTURE WILL PASS
THROUGH THE AREA...BUT THE CHARACTER AND INTENSITY OF THE WEATHER
WILL BE COLORED MAINLY BY THE UPPER LEVEL LOWS IN THE AREA
GENERATING INSTABILITY AND UNSETTLED WEATHER.

&&

.DISCUSSION...SHOWERS AND THUNDERSTORMS CONTINUED OVERNIGHT AROUND
PUERTO RICO AND THE U.S. VIRGIN ISLANDS. SOME THUNDERSTORMS MOVED
ONSHORE IN SOUTHEAST PUERTO RICO...EXITING THE NORTH COAST AS
LIGHT SHOWERS. OTHER LIGHT SHOWERS PUSHED INLAND OVER SOUTHERN
PUERTO RICO AND DISSIPATED OVER THE CORDILLERA CENTRAL BUT MOST OF
PUERTO RICO WAS DRY OVERNIGHT. SAINT CROIX HAD ONLY TWO ONE
HUNDREDTHS OF AN INCH BETWEEN 10 AND 11 LAST NIGHT AND SAINT
THOMAS DID NOT REPORT RAIN OVERNIGHT.

OWING TO THE UPPER LEVEL LOW AND GENEROUS MOISTURE IN THE AREA
CONVECTIVE WEATHER CONTINUES AT WELL ABOVE NORMAL LEVELS. DUE TO
COOLER THAN NORMAL TEMPERATURES AT MID LEVELS THE LIFTED INDEX
FORECAST BY THE GFS DOES NOT RISE ABOVE MINUS 5 DEGREES CELSIUS
UNTIL LATE NEXT WEEKEND AND TOUCHES MINUS 9 DEGREES AT 28/12Z.
HENCE SHOWERS...LOCALLY GUSTY WINDS NEAR THUNDERSTORMS AND HEAVY
RAIN WILL CONTINUE OVER THE AREA...WITH THE HEAVIEST
RAINFALL...DURING THE DAYTIME AT LEAST...OVER PUERTO RICO`S
NORTHERN HALF. FREQUENT LIGHTNING WILL OCCUR AS NUMEROUS
THUNDERSTORMS DEVELOP...SOME SMALL HAIL IS ALSO EXPECTED IN A FEW
OF THE MOST UNSTABLE AREAS ON SUNDAY AND POSSIBLY MONDAY IN
NORTHWEST AND/OR INTERIOR PUERTO RICO. WHEN CLOUDS CLEAR AWAY ON
SUNDAY WITH THE ARRIVAL OF A MASS OF DRIER AIR...TEMPERATURES ON THE
NORTH COAST WILL RISE INTO THE LOWER 90S...AND...ALTHOUGH
THUNDERSTORMS WILL NOT BE AS NUMEROUS...SOME OF THE THUNDERSTORMS
WILL GROW STRONG ENOUGH TO CREATE THE CONDITIONS JUST MENTIONED.
WITH THE UPPER LEVEL LOW FADING DURING THE WEEK CONDITIONS WILL
TEMPER SOMEWHAT...BUT AN UPPER LEVEL LOW REDEVELOPS NEAR THE AREA
BY WEDNESDAY AND UNSETTLED WEATHER IS EXPECTED TO CONTINUE THROUGH
MOST OF NEXT WEEK.

&&

.AVIATION...VCSH/VCTS AT ALL TAF SITES UNTIL 28/00Z WITH POSSIBLE
BRIEF PDS OF MVFR/IFR CONDITIONS DUE TO +SHRA/TSRA. MOUNTAIN
OBSCURATIONS LIKELY OVER EASTERN PR DURING THE MORNING HOURS THEN
THRU THE DAY OVER THE CENTRAL MTN RANGE OF PR. LOW LEVEL WINDS ARE
MAINLY FROM THE SOUTH-SOUTHEAST AT 8-12 KT.

&&

.MARINE...SEAS WILL GRADUALLY SUBSIDE BACK TO 4 FEET OR LESS TODAY
AND WINDS WILL CONTINUE LIGHT TO MODERATE AS HIGH PRESSURE OVER
THE CENTRAL ATLANTIC REMAINS WEAK AND RIDDLED WITH SMALL LOWS. NO
SMALL CRAFT ADVISORY CONDITIONS EXPECTED WITHIN THE NEXT 10 DAYS.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 76 90 78 / 70 50 50 20
STT 87 77 89 78 / 90 50 40 20

[Macrocane]

Severe flash floods occurred on september 24 in Santa Ana, the most important city in the west part of El Salvador. 54 mm (2.1 inches) fell in just 1 hour making a small creek that crosses the city overflow, plus the storm drains couldn't manage all the water taht fell in such a short time. Several cars were dragged by the floods and business and homes were damaged. Fortunatey no deaths were reported. Here's a video of the flood:

[youtube]http://www.youtube.com/watch?v=mX-2TahY2aU[/youtube]

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
247 PM AST SAT SEP 27 2014

.SYNOPSIS...AN UPPER LEVEL LOW IS CENTERED ACROSS PUERTO RICO AND
THE MONA PASSAGE WITH ASSOCIATED TROUGH AXIS EXTENDING SOUTHWEST
ACROSS THE NORTHEASTERN CARIBBEAN INTO THE SOUTHWESTERN CARIBBEAN.
THIS IS HELPING TO CREATE UPPER LEVEL DIFFLUENCE AND UNSTABLE
CONDITIONS ACROSS THE NORTHEASTERN CARIBBEAN. A TROPICAL WAVE WITH
AXIS NOW CROSSING THE DOMINICAN REPUBLIC WILL CONTINUE MOVING
WESTWARD OVERNIGHT THROUGH SUNDAY...WHILE A BROAD SURFACE TROUGH
WILL CONTINUE TO EXTEND NORTHWARDS ACROSS THE NORTHEASTERN
CARIBBEAN AND INTO THE SOUTHWEST ATLANTIC. SATELLITE IMAGERY
SHOWED SIGNIFICANT AMOUNTS OF DEEP TROPICAL MOISTURE TRAILING THE
WAVE AND BEING LIFTED NORTHWARDS ACROSS THE REGION TODAY. THIS
MOISTURE IS CONTINUING TO INTERACT WITH THE UPPER-LEVEL LOW AND IS
PRODUCING ENHANCED CLUSTERS OF CONVECTION ACROSS THE ISLANDS AND
SURROUNDING WATERS ESPECIALLY BETWEEN EASTERN PUERTO RICO AND THE
VIRGIN ISLANDS.

&&

.DISCUSSION...AFTERNOON SHOWERS AND THUNDERSTORMS ENHANCED BY LOCAL
SEA BREEZE VARIATIONS...TERRAIN EFFECTS AND THE PRESENCE OF THE
UPPER LOW...CONTINUED TO DEVELOP AND MOVE SLOWLY NORTHWARDS ACROSS
THE ISLANDS AND LOCAL WATERS. AREAS OF MODERATE TO LOCALLY HEAVY
RAINFALL WERE NOTED ACROSS PARTS OF THE NORTH AND EAST SECTIONS OF
PUERTO RICO...AS WELL AS OVER AND IN THE VICINITY OF VIEQUES...CULEBRA
AND THE VIRGIN ISLANDS. EXPECT THIS ACTIVITY TO CONTINUE INTO THE
EVENING HOURS....THEN GRADUALLY DIMINISH OVER LAND DURING THE OVERNIGHT
HOURS.

LATEST MODEL GUIDANCE HOWEVER CONTINUE TO SUGGEST THE POTENTIAL
FOR FORMATION OF ADDITIONAL SHOWERS AND THUNDERSTORMS ACROSS THE
THE REGION THOUGH THE REST OF THE WEEKEND...AS THE UPPER LOW AND
SURFACE TROUGH...ALONG THE AMPLE AMOUNTS OF MOISTURE WILL LINGER
ACROSS THE REGION THROUGH SUNDAY. THE GENERAL FLOW WILL BE FROM
THE SOUTH SOUTHEAST...THEREFORE EXPECTED ACTIVITY TO BE FOCUSED
ACROSS THE NORTHWESTERN AND NORTHERN HALF OF PUERTO RICO DURING
THE DAY...AND OVER PORTIONS OF THE SOUTH AND EAST SECTIONS OF
PUERTO RICO...AND VIRGIN ISLANDS DURING THE OVERNIGHT AND EARLY
MORNING HOURS. SOME SHOWERS WILL AGAIN TO BE LOCALLY HEAVY AT
TIMES AND MAY EVENTUALLY LEAD TO MINOR FLOODING OF URBAN
AREAS...SMALL RIVERS AND STREAMS.

AS PREVIOUSLY MENTIONED...THE UPPER LOW AND SURFACE TROUGH IS
FORECAST TO LINGER ACROSS THE REGION THROUGH THE WEEKEND AND THUS
MAINTAIN VERY MOIST AND UNSTABLE ENVIRONMENT WITH GOOD POTENTIAL
FOR SHOWERS AND ISOLATED THUNDERSTORM DEVELOPMENT. HOWEVER...AN
OVERALL IMPROVEMENT IS EXPECTED BY MONDAY AND TUESDAY AS THE SURFACE
TROUGH AND TUTT LOW ARE FORECAST TO WEAKEN...WHILE A LOW TO MID
LEVEL RIDGE BUILDS ACROSS THE REGION. IN ADDITION...MOISTURE CONTENT
AND PRECIPITABLE WATER VALUES ARE ALSO EXPECTED TO DECREASE SIGNIFICANTLY
TO LESS THAN 1.50 INCHES BY MONDAY AFTERNOON AND INTO TUESDAY.

&&

.AVIATION...VCSH/VCTS ACROSS MOST OF THE TAF SITES THROUGH THIS
AFTERNOON WITH TEMPO SHRA/TSRA LIKELY FOR TJBQ UNTIL AROUND
27/22Z. MOUNTAIN OBSCD LIKELY OVER THE CENTRAL MTN RANGE OF PR
THROUGH THE AFTERNOON AND INTO THE EVENING. LOW LEVEL WINDS MAINLY
FROM THE S-SE AT 8-12 KT WITH SOME VARIATIONS NEAR THE SHRA/TSRA
ACTIVITY UNTIL 27/23Z. WINDS DECREASING THEREAFTER...MOSTLY
BECOMING LIGHT AND VARIABLE. VCSH POSSIBLE ACROSS MOST OF THE
LOCAL TERMINALS OVERNIGHT.

&&

.MARINE...CLUSTER OF SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE
TO FORM AND AFFECT THE COASTAL WATERS DURING THE EVENING AND OVERNIGHT
HOURS. FREQUENT TO OCCASIONAL LIGHTNING STRIKES WILL BE POSSIBLE
ESPECIALLY ACROSS THE CARIBBEAN WATERS...ANEGADA PASSAGE AND THE
LOCAL ATLANTIC WATERS. ALSO...THE SHOWERS AND THUNDERSTORMS WILL
BE CAPABLE OF PRODUCING SUDDEN WATERSPOUTS PARTICULARLY BETWEEN
EASTERN PUERTO RICO AND THE VIRGIN ISLANDS. ELSEWHERE WINDS AND
SEAS OF 17 KNOTS OR LESS AND 4 FEET OR LESS CAN BE EXPECTED
OUTSIDE OF THE CONVECTIVE ACTIVITY.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 76 90 78 90 / 50 50 20 40
STT 77 89 78 88 / 50 40 20 20

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
457 AM AST SUN SEP 28 2014

.SYNOPSIS...AT UPPER LEVELS...A TROUGH STRETCHING FROM SOUTH OF
HAITI TO NORTH OF THE MONA CHANNEL WILL WEAKEN AND SLIDE SLIGHTLY
EAST TODAY AND MONDAY. IT WILL CROSS OVER THE AREA ON TUESDAY
EVENING...BUT GREATLY WEAKENED. SLIGHTLY LOWER PRESSURE WILL BEGIN
TO FORM IN THE EASTERN CARIBBEAN AND WESTERN TROPICAL ATLANTIC MID
WEEK WITH THE EASTERN CARIBBEAN LOBE REMAINING NEAR PUERTO RICO
AND THE U.S. VIRGIN ISLANDS THROUGH EARLY NEXT WEEK.

AT MID LEVELS...HIGH PRESSURE WILL RIDGE OVER THE NORTHEASTERN
CARIBBEAN WEAKLY THROUGH MID WEEK AND THEN SHIFT TO NORTH OF THE
AREA. DRIER AIR MOVES IN OVER THE AREA ON MONDAY AND IS ONLY
BRIEFLY INTERRUPTED BY A WEAK TROPICAL WAVE ON FRIDAY.

AT LOWER LEVELS...LOW PRESSURE OVER THE SOUTHWESTERN CARIBBEAN AND
HIGH PRESSURE JUST NORTHEAST OF THE AREA WILL COMBINE TO GENERATE
GENTLE TO MODERATE SOUTHEASTERLY TRADE WINDS ACROSS THE AREA. LOW
LEVEL MOISTURE WILL DIMINISH TODAY AND MONDAY...BUT BANDS OF
MOISTURE WILL BRING BACK SOME SCATTERED SHOWERS BY MID WEEK. A
TROPICAL WAVE NOW TRAVERSING THE ATLANTIC WILL WEAKEN CONSIDERABLY
BEFORE PASSING THURSDAY NIGHT. SOME INCREASE IN SHOWER ACTIVITY
WILL BE SEEN THURSDAY NIGHT THROUGH FRIDAY ASSOCIATED WITH THIS WAVE.
DRIER WEATHER FILLS IN BEHIND THIS TROPICAL WAVE FOR THE FOLLOWING
WEEKEND.


&&

.DISCUSSION...MOST SHOWERS HAD CLEARED OFF OF PUERTO RICO AND THE
U.S. VIRGIN ISLANDS BY 6 PM AST...AND BY 11 PM IT WAS CLEAR THAT THE
FLASH FLOOD WATCH WOULD NO LONGER BE NEEDED. SHOWERS...SOME HEAVY
HAVE RE-DEVELOPED SOUTHWEST OF VIEQUES AND WILL MOVE INTO
SOUTHEASTERN PUERTO RICO THIS MORNING...BUT FLOODING IS NOT ANTICIPATED.
SHOWERS ALSO PASSED OVER SAINT THOMAS AND WERE LIKELY HEAVIER OVER
THE WESTERN END OF THE ISLAND THAN WAS MEASURED AT THE AIRPORT.

BEFORE THE LAST VESTIGES OF THE UPPER LEVEL LOW BEGIN TO FADE...THE
BEST OPPORTUNITY FOR STRONG...THOUGH ONLY SCATTERED...
THUNDERSTORMS WILL PRESENT ITSELF TODAY IN THE INTERIOR NORTHWEST
PORTION OF PUERTO RICO. THESE STORMS MAY PRODUCE GUSTY WINDS AND
SMALL HAIL ALONG WITH VERY HEAVY RAIN IN LOCALIZED AREAS AS
INDICATED BY 500 MB TEMPERATURES STILL NEAR MINUS 8 DEGREES AND A
LIFTED INDEX FORECAST TO BE THE SAME. SOME OF THESE THUNDERSTORMS
MAY PRODUCE URBAN AND SMALL STREAM FLOODING. OTHERWISE A GENERAL
DRYING TREND WILL BE SEEN TODAY AND MONDAY. SOUTHEAST FLOW WILL
CONTINUE LIGHTLY AT LOWER LEVELS AND WILL BOOST TEMPERATURES INTO
THE LOWER 90S ALONG THE NORTH COAST OF PUERTO RICO. THE EASTERN
END OF PUERTO RICO AND THE U.S. VIRGIN ISLANDS WILL SEE
CONSIDERABLY LESS SHOWERS THIS AFTERNOON THAN IN THE PAST FEW
DAYS. SOME HIGH CLOUDS WILL KEEP SKIES AT LEAST PARTLY CLOUDY
UNTIL LATE MORNING AND AFTERNOON CONVECTION CAN DEVELOP.

LOWER MOISTURE AND THE WEAKENING UPPER LEVEL LOW WILL LOWER POPS
OVER MOST OF THE AREA...BUT SHOWERS AND SCATTERED THUNDERSTORMS
WILL FAVOR THE NORTHWESTERN QUARTER OF PUERTO RICO FOR MOST OF THE
WEEK. THE TROPICAL WAVE CROSSING ON THURSDAY NIGHT WILL HAVE A
VERY WEAK UPPER LEVEL LOW TO THE SOUTHWEST OF PUERTO RICO TO HELP
ENHANCE SHOWERS AND THUNDERSTORMS THURSDAY NIGHT AND FRIDAY...THEN THE
GFS IS SHOWING MUCH DRIER AIR MOVING IN OVER THE FIRST WEEKEND OF
OCTOBER.

&&

.AVIATION...ISOLD SHRA THIS MRNG BUT MOISTURE DECREASE TDY. PD SHRA/TSRA
IN BTWN 28/16-29/00Z OVR NW PR WI OBSCD MTNS AND POSSIBLE MVFR IN TSRA AT
TJBQ. OTHERWISE XPCT VFR ALL TAF SITES THRU MON WITH ISOLD SHRA. WIND SFC-
FL150 SE-SW 5-12 KT BCMG LGT/VRBL LESS THAN 10 KT THIS AFTERNOON THRU
MONDAY.

&&

.MARINE...SEAS WILL DIMINISH TO BELOW 3 FEET IN THE ATLANTIC
WATERS NOW THROUGH WEDNESDAY...BUT WILL INCREASE IN THE CARIBBEAN
THROUGH THE SAME PERIOD. SEAS WILL BE STRONGEST SOUTH AND LIKELY
NO MORE THAN 4 FEET THE ENTIRE TIME IN ANY OF OUR LOCAL WATERS. NO SMALL
CRAFT ADVISORIES ARE EXPECTED THROUGH AT LEAST THE NEXT 10 DAYS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 92 78 92 79 / 20 10 10 10
STT 86 81 90 81 / 20 10 10 20

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
320 PM AST SUN SEP 28 2014

.SYNOPSIS...WEAKENING TUTT LOW AND ASSOCIATED MID TO UPPER LEVEL
TROUGH JUST WEST AND NORTHWEST OF THE REGION IS TO LINGER ACROSS THE
SOUTHWEST ATLANTIC AND CENTRAL CARIBBEAN THROUGH AT LEAST MONDAY.
MEANWHILE...WEAK UPPER LEVEL RIDGING WILL REMAIN IN PLACE ACROSS
THE REGION AND OVER THE LESSER ANTILLES THOUGHT THE EARLY PART OF
THE UPCOMING WEEK. BROAD SURFACE TROUGH ACROSS THE CENTRAL AND EASTERN
CARIBBEAN EXTENDING NORTHWARDS ACROSS THE REGION TODAY...WILL SHIFT
FURTHER WEST OVER THE NEXT FEW DAYS...AS SURFACE HIGH BUILDS SOUTHWEST
ACROSS THE REGION FROM THE NORTHEAST ATLANTIC. THIS WILL MAINTAIN
A PREVAILING SOUTHEASTERLY WIND FLOW THROUGH AT LEAST TUESDAY.

&&

.DISCUSSION...AS ANTICIPATED SHOWERS AND ISOLATED THUNDERSTORMS
DEVELOPED ACROSS PARTS OF THE NORTHWEST AND NORTH CENTRAL COASTAL
SECTIONS OF PUERTO RICO DURING THE AFTERNOON. SOME OF THE STORMS
PRODUCED PERIODS OF LOCALLY HEAVY RAINFALL AND GRIEF GUSTY WINDS
MAINLY IN AND AROUND SAN SEBASTIAN AND ARECIBO. EXPECT THE ACTIVITY
TO GRADUALLY DIMINISH AND MOVE OFFSHORE DURING THE EARLY EVENING
HOURS LEAVING MOSTLY CLEAR TO PARTLY CLOUDY SKIES OVER LAND. A FEW
EARLY MORNING SHOWERS ARE EXPECTED TO AFFECT PARTS OF THE EAST
COASTAL SECTIONS OF THE ISLANDS...BUT SO FAR LATEST GFS MODEL
GUIDANCE AS WELL AS SATELLITE IMAGERY...AND BLENDED TOTAL PRECIPITABLE
WATER PRODUCTS...ALL SUGGEST A GRADUAL DRYING TREND OVER THE NEXT
FEW DAYS.

ON MONDAY AND TUESDAY...EXPECT OVERALL DRIER CONDITIONS WITH DECREASING
TROPICAL MOISTURE ADVECTION...AS PWAT VALUES DIP TO NEAR 1.25 INCHES
OR SO BY EARLY TUESDAY. THEREAFTER THE LAYERED PRECIPITABLE WATER
WATER IS TO INCREASE SLIGHTLY ONCE AGAIN WITH THE APPROACH OF A
WEAK EASTERLY PERTURBATION LATE TUESDAY THROUGH WEDNESDAY. THIS
WILL BE FOLLOWED BY THE NEXT TROPICAL WAVE FORECAST TO ENTER THE
EASTERN CARIBBEAN ON THURSDAY...THEN MOVE ACROSS THE REGION ON
FRIDAY. THIS WILL BRING ANOTHER INCREASE TROPICAL MOISTURE AND
THUS INCREASE THE CHANCES FOR SHOWERS AND THUNDERSTORM DEVELOPMENT
ACROSS THE ISLANDS AND LOCAL WATERS. SO FAR MODEL GUIDANCE SUGGEST
THAT THIS FEATURE IS TO MOVE QUICKLY ACROSS THE AREA AS A BROAD
SAHARAN AIR LAYER WITH ACCOMPANYING SUSPENDED DUST PARTICULATES
WILL QUICKLY FILTER IN ACROSS THE NORTHEASTERN CARIBBEAN TRAILING
THE WAVE ON SATURDAY AND SUNDAY BRINGING OVERALL DRIER AND STABLE
CONDITIONS.

&&

.AVIATION...SHRA/TSRA EXPECTED IN AND AROUND TJBQ AFTER 28/18Z WITH
VCTS POSSIBLE FOR TJMZ. THE REST OF THE LOCAL TERMINALS SHOULD
REMAIN UNDER PREVAILING VFR CONDITIONS WITH MAYBE VCSH. PREVAILING
SURFACE WINDS WILL BE FROM THE E-SE WITH SEA BREEZE VARIATIONS AT
5-15 KTS WITH HIGHER GUSTS NEAR THE TSRA EXPECTED ACROSS N-NW PR. WX
CONDS IMPROVING AFTER 28/22Z WITH LITTLE SHRA ACTIVITY. WINDS
BECOMING LIGHT AND VRB OVERNIGHT WITH LITTLE SHRA ACTIVITY ACROSS
THE LOCAL AREA.

&&

.MARINE...SEAS CONTINUED AT 4 FEET OR LESS AND WINDS UP TO 16 KNOTS
TODAY. THESE CONDITIONS ARE EXPECTED TO PERSIST AT LEAST THROUGH
TUESDAY...WITH NO SIGNIFICANT MARINE HAZARDS ANTICIPATED AT THIS
TIME. PLEASE REFER TO THE COASTAL WATERS FORECAST ISSUED BY WFO
SAN JUAN PR FOR THE LATEST LOCAL COASTAL WATERS UPDATES.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 79 90 79 90 / 20 10 10 30
STT 77 88 79 90 / 20 20 20 30

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
531 AM AST MON SEP 29 2014

.SYNOPSIS...UPPER LEVEL TROUGH/TUTT OVER THE CENTRAL CARIBBEAN WILL
CONTINUE TO WEAKEN THROUGH MIDWEEK. MID-LEVEL RIDGE ACROSS THE EASTERN
CARIBBEAN WILL EXPAND OVER THE CENTRAL CARIBBEAN DURING THE NEXT FEW
DAYS. SURFACE HIGH PRESSURE WILL STRENGTHEN AND SHIFT WESTWARD OVER
THE WESTERN ATLANTIC THROUGH THE WORK WEEK. A GENERALLY FAIR WEATHER
CONDITIONS ARE EXPECTED TO PREVAIL THE FIRST HALF OF THE WEEK...BEFORE
THE NEXT TROPICAL WAVE APPROACHES TO THE AREA ON THURSDAY.

&&

.DISCUSSION...UPPER LEVEL TROUGH OVER HISPANOLA HAVE PUSHED HIGH CLOUDS
ACROSS THE FORECAST AREA TODAY. DOPPLER RADAR HAVE SHOWED SCATTERED
CONVECTION ACROSS THE OFFSHORE WATERS AND MONA PASSAGE. NO RAINFALL
WAS OBSERVED OVER LAND AREAS SINCE MIDNIGHT. SATELLITE BLENDED PWAT
ANALYSIS INDICATED AN BROAD AREA OF LESS THAN 1.5 INCHES OF PRECIPITABLE
WATER OVER THE EASTERN CARIBBEAN. UNDER A SOUTHEASTERLY TRADE WIND
FLOW...A DRIER AIR MASS IS EXPECT TO ADVECT OVER THE AREA TODAY. LOW
MOISTURE CONTENT COMBINED WITH A GENERALLY STABLE CONDITIONS INDUCED
BY THE AFOREMENTIONED MID-LEVEL RIDGE WILL LIMIT THE SHOWER ACTIVITY
ACROSS PUERTO RICO AND THE U.S. VIRGIN ISLANDS THROUGH MIDWEEK.
SOUTHEASTERLY FLOW WILL PREVAIL MOST OF THE WEEK MAINTAINING ABOVE
NORMAL TEMPERATURES ACROSS THE ISLANDS. THEN...MOISTURE WILL SURGE
AGAIN BY THURSDAY AFTERNOON WHEN THE NEXT TROPICAL WAVE CROSSES
THE PR/USVI REGION. ATMOSPHERE ACROSS THE REGION WILL REMAIN
RELATIVELY MOIST SUPPORTING THE DEVELOPMENT OF SCATTERED SHOWERS
ACROSS THE REGION FRIDAY AND SATURDAY. STABLE AND EVEN DRIER AIR
MASS IS THEN EXPECTED ACROSS THE REGION SUNDAY INTO NEXT WEEK. THE
NAAPS AND NASA GEOS-5 AEROSOL MODELS SUGGEST A PULSE OF SAHARAN DUST
REACHING THE ISLANDS DURING THE WEEKEND.

&&

.AVIATION...VFR CONDS ARE EXPECTED THROUGH THE FORECAST PERIOD.
VCSH/VCTS POSSIBLE NEAR TJMZ AND TJBQ BETWEEN 18-21Z. SE WIND
AROUND 10KT WILL PREVAIL BELOW FL100.

&&

.MARINE...SEAS CONTINUED AT 2-4 FEET AND WINDS UP TO 16 KNOTS
EXPECTED MOST OF THE WEEK. NO SMALL CRAFT ADVISORY ANTICIPATED
THROUGH THE END OF THE WEEK.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 92 77 91 78 / 10 10 20 20
STT 87 78 89 81 / 10 20 20 40