Caribbean - Central America Weather

[cycloneye]

Afternoon discussion by NWS San Juan

Lets see how this rain event unfolds.

http://forecast.weather.gov/product.php ... glossary=1

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
328 PM AST FRI MAR 5 2010

.SYNOPSIS...A COLD FRONT WILL SLOWLY PUSH THROUGH THE AREA TONIGHT
AND SATURDAY...BECOMING STATIONARY SOUTH OF PR SATURDAY NIGHT WHERE IT
WILL LINGER INTO THE MIDDLE OF NEXT WEEK.

&&

.DISCUSSION...A PRE FRONTAL FEATURE NOW LOCATED OVER THE NORTHWEST
PORTIONS WILL CONTINUE TO MOVE EASTWARD INCREASING THE SHOWER
COVERAGE ACROSS THE EASTERN PORTIONS OF PUERTO RICO THROUGH THE EVENING.
THE COLD FRONT BEGAN TO SLOW DOWN THIS AFTERNOON AND THIS MOMENT
IS NEAR STATIONARY OVER THE MONA PASSAGE.

SATURDAY...EXPECT MOSTLY CLOUDY CONDITIONS AND MODERATE SHOWERS
ACROSS THE AREA. THE COLD FRONT IS EXPECTED TO MOVE ACROSS THE
LOCAL FORECAST AREA ON SATURDAY...THIS WEATHER FEATURE WILL
COMBINE WITH A STRONG UPPER LEVEL TROUGH. THIS UPPER LEVEL FEATURE
WILL GENERATE STRONG DIVERGENCE ALOFT PRODUCING A VERY UNSTABLE
ATMOSPHERE ON SUNDAY...THEREFORE THE POTENTIAL FOR HEAVY RAIN ON
SUNDAY AFTERNOON REMAIN HIGH.

&&

.AVIATION...A COLD FRONT IS VERY SLOWLY INCHING OVER WRN PR. MVFR
CEILINGS IN SHRA HAVE MOVED INTO THE NRN PR SITES (TJSJ...TJBQ AND
TJMZ) AND WILL CONTINUE THROUGH AT LEAST 04Z. IFR CONDS LIKELY AT
TJBQ AND TJMZ. PREVAILING MVFR CIGS ALSO EXPECTED AT TIST AND TISX
BEGINNING 00Z LASTING THROUGH THE 24 HR PERIOD WITH SHRA AND TEMPO
IFR LIKELY DURING 00-06Z. WINDS ARE STILL LIGHT BUT VEERING AND
EXPECTED TO INCREASE THIS AFTER 00Z BECOMING NORTHERLY AND FINALLY
NORTHEASTERLY.


&&

.MARINE...A NORTHWEST SWELL WILL CONTINUE TO AFFECT THE LOCAL
WATERS THROUGH AT LEAST SUNDAY...BUT MARINE CONDITIONS ARE
EXPECTED TO BECOME MORE ROUGH AS WINDS ASSOCIATED TO THE FRONT ARE
EXPECTED TO INCREASE SIGNIFICANTLY ON SATURDAY NIGHT. MARINERS
SHOULD EXPECT CHOPPY AND WINDY CONDITIONS FROM LATE SATURDAY
THROUGH SUNDAY NIGHT. THERE IS A SMALL CRAFT ADVISORY IN EFFECT FOR
ALL ATLANTIC WATERS AND THE MONA PASSAGE UNTIL SUNDAY NIGHT.

[Gustywind]

[cycloneye]

Updated discussion by NWS San Juan

Raining in San Juan while I make this post.

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE SAN JUAN PR
1040 PM AST FRI MAR 5 2010

.UPDATE...MOISTURE HAS INCREASED CONSIDERABLY DURING THE LAST 12
HOURS AS THE PRECIPITABLE WATER MOVED FROM 1.54 TO 1.93 INCHES
OVER SAN JUAN...CORRESPONDING TO THE NEAR SATURATION OF THE LOWER
LAYERS BELOW 700 MB. LOWER DEWPOINTS CAN ALSO BE SEEN AT BUOY 41043
AND OVER THE DOMINICAN REPUBLIC BEHIND THE FRONT. THE DISCUSSION
BELOW STILL HOLDS...THOUGH THE MODELS NO LONGER SHOW THE FRONT
SOUTH OF PUERTO RICO AND THE U.S. VIRGIN ISLANDS. WINDS DO TURN TO
THE NORTH BRIEFLY SEVERAL TIMES OVER THE WEEKEND...BUT DEWPOINTS AND
MOISTURE REMAIN HIGH WITH THERMAL AND DROSOTHERMAL PACKING STAYING
OVER THE OUTER ATLANTIC WATERS OR JUST NORTH OF US. THE FRONT HAS
PASSED BUOY 41043 AND IS OVER THE EASTERN DOMINICAN REPUBLIC OR
THE MONA CHANNEL AT THE MOMENT. THE PRE-FRONTAL FEATURE MENTIONED
BELOW APPEARS TO BE EAST OF CABO ROJO AND CAMUY...BUT THE ONSHORE
WINDS OVER THE NORTH COAST MAY HOLD SHOWERS OVER THE AREA FOR MUCH
OF THE NIGHT AS A LINE INTENSIFIES RIGHT ALONG THE COAST.
NEVERTHELESS THERE IS A STRONG POSSIBILITY THAT IT WILL MOVE
OFFSHORE BY 06/04Z. FLOW CONTINUES FROM THE SOUTH OVER THE SOUTH
COAST AND SHOULD DO SO FOR AT LEAST ANOTHER 18 HOURS. THE GFS
KEEPS WET SHOWERY WEATHER OVER THE AREA THROUGH WEDNESDAY
NOW...THOUGH THERE COULD BE SOME BREAKS. ALSO MID LAYERS NEVER GET
VERY MOIST AND BY 08/06Z VERY DRY AIR MOVES IN AND STAYS UNTIL
WEDNESDAY...10/00Z. AT THIS TIME SEE LITTLE IN THE WAY OF HIGHER
CLOUD TOPS AND UPPER AIR THROUGH WEDNESDAY DOES NOT LOOK VERY
CONDUCIVE TO THUNDERSTORM FORMATION AND HAVE NOT INCLUDED THEM IN
THE UPDATED GRIDS...ESPECIALLY SINCE MOISTURE FALLS OFF QUICKLY
ABOVE 650 MB FOR MUCH OF THE NEXT 7 DAYS.

SEAS AT BUOY 41043 HAVE INCREASED TO MORE THAN 8 FEET AND A
MARGINAL HIGH SURF CONTINUES TO BE EXPECTED THROUGH SATURDAY.

&&

.AVIATION...
MVFR CONDITIONS WILL PREVAIL ACROSS TJSJ AND POSSIBLE
VERY BRIEF PERIODS OF IFR CONDITIONS AT LEAST THROUGH 06/12Z. -RA
COULD PERSIST THROUGH THE OVERNIGHT HOURS. ELSEWHERE...VFR
CONDITIONS ARE EXPECTED. HOWEVER...BRIEF PERIODS OF MVFR CONDITIONS
ARE POSSIBLE ACROSS TJBQ...TJMZ AND TJPS IN PASSING SHOWERS.

[Macrocane]

It seems that the northerly winds will continue for a couple of days more as the high pressure system rebuilds. They are covering the whole region from southern Mexico to Panama.

GAP WINDS...
FRESH TO STRONG WINDS IN THE 20 TO 30 KT RANGE ACROSS THE GAP
AREAS...GULF OF TEHUANTEPEC...GULF OF FONSECA...GULF OF PAPAGAYO
AND GULF OF PANAMA ARE FORECAST TO PERSIST THROUGH THE NEXT FEW
DAYS AS HIGH PRESSURE BUILDS SOUTHWARD ACROSS CENTRAL AMERICA.
THE WINDS ARE GREATEST DURING THE OVERNIGHT AND EARLY MORNING
HOURS WITH THE AID OF THE DRAINAGE FLOW.

[Gustywind]

Yellow alert has been requiered by Meteo-France for a risk strong showers, sea, and winds in the Northern Leewards (St Marteen and St Barth)
http://www.meteo.gp/donnees/bulletin/vi ... ilance.php
How lucky you are Msbee you should have some nice amount of water from this cold front! Nothing is expected in Guadeloupe during the week end, but given Meteo-France, Monday could see some sporadic and pretty light showers, should it verifies first. The drought continues desesperately in the Butterfly Island ...

[cycloneye]

Flash Flood Watch for Puerto Rico / Virgin Islands

Good morning to all.Lets see how much rain falls here in the next couple of days that may trigger flood warnings.

FLOOD WATCH
NATIONAL WEATHER SERVICE SAN JUAN PR
346 AM AST SAT MAR 6 2010

PRZ001-002-004>006-012-013-VIZ001-062000-
/O.NEW.TJSJ.FF.A.0002.100306T1600Z-100307T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN JUAN AND VICINITY-NORTHEAST-EASTERN INTERIOR-NORTH CENTRAL-
CENTRAL INTERIOR-CULEBRA-VIEQUES-
ST. THOMAS/ST. JOHN/ADJACENT ISLANDS-
INCLUDING THE MUNICIPALITIES AND/OR ISLANDS OF...SAN JUAN...
CAROLINA...FAJARDO...HUMACAO...CAGUAS...ARECIBO...VEGA BAJA...
DORADO...COAMO...COROZAL...AIBONITO...VILLALBA...JAYUYA...CULEBRA...
ESPERANZA...ANNA`S RETREAT...CHARLOTTE AMALIE...
CHARLOTTE AMALIE EAST...CHARLOTTE AMALIE WEST...CRUZ BAY
346 AM AST SAT MAR 6 2010

...FLASH FLOOD WATCH IN EFFECT FROM NOON AST TODAY THROUGH SUNDAY
AFTERNOON...

THE NATIONAL WEATHER SERVICE IN SAN JUAN HAS ISSUED A

* FLASH FLOOD WATCH FOR PORTIONS OF PUERTO RICO AND VIRGIN
ISLANDS...INCLUDING THE FOLLOWING AREAS...IN PUERTO RICO...
CENTRAL INTERIOR...CULEBRA...EASTERN INTERIOR...NORTH CENTRAL...
NORTHEAST...SAN JUAN AND VICINITY AND VIEQUES. IN VIRGIN
ISLANDS...ST. THOMAS/ST. JOHN/ADJACENT ISLANDS.

* FROM NOON AST TODAY THROUGH SUNDAY AFTERNOON

* A SLOW MOVING COLD FRONT WILL MOVE THROUGH PUERTO RICO AND THE
NORTHERN U.S. VIRGIN ISLANDS TODAY. AT THE SAME TIME...A STRONG
UPPER LEVEL DISTURBANCE ACROSS THE WESTERN ATLANTIC WILL
CONTINUE TO DIVE SOUTHWARD AND GRAZE PUERTO RICO AND THE VIRGIN
ISLANDS OVER THE NEXT 36 HOURS. THIS WILL ALLOW FOR DEEP
MOISTURE TO ENVELOP THE AREA WITH PERIODS OF HEAVY RAINFALL THAT
COULD TRIGGER FLASH FLOODING.

* THE PROLONGED NATURE OF THIS EVENT COULD RESULT IN FLOODING OF
AREA STREAMS AND RIVERS AS WELL AS URBAN FLOODING.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WATCH MEANS THAT CONDITIONS ARE FAVORABLE FOR HEAVY
RAIN ACROSS THE WATCH AREA...WHICH MAY LEAD TO FLOODING. IF YOU
ARE IN THE WATCH AREA...CHECK YOUR PREPAREDNESS REQUIREMENTS...
ESPECIALLY IF YOU HAVE INTERESTS ALONG AREA RIVERS. KEEP
INFORMED...AND BE READY FOR QUICK ACTION IF FLOODING IS OBSERVED
OR IF A FLASH FLOOD WARNING IS ISSUED.

PEOPLE IN THE WATCH AREA SHOULD CONTINUE TO BE AWARE OF THE
POSSIBILITY FOR HEAVY RAINFALL. AVOID LOW LYING AREAS...AND BE
CAREFUL WHEN APPROACHING HIGHWAY DIPS AND UNDERPASSES. THE
HEAVY RAIN COULD ALSO CAUSE MUDSLIDES IN AREAS OF STEEP TERRAIN.

STAY TUNED TO NOAA WEATHER RADIO...LOCAL TV...RADIO OR YOUR
CABLE TELEVISION PROVIDER FOR LATER STATEMENTS AND POSSIBLE
WARNINGS.

THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGICAL AND
CLIMATE INFORMATION...IS AVAILABLE ON THE WEB AT
HTTP://WWW.SRH.NOAA.GOV/SJU OR AT HTTP://WEATHER.GOV.

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
343 AM AST SAT MAR 6 2010

.SYNOPSIS...A SLOW MOVING COLD FRONT WILL PUSH THROUGH THE AREA
TODAY AND BECOME STATIONARY SOUTH OF PUERTO RICO TONIGHT WHERE IT
WILL LINGER INTO THE MIDDLE OF NEXT WEEK.


&&

.DISCUSSION...GFS MODEL LATEST RUN MOVES COLD FRONT ACROSS PUERTO
RICO AND THE U.S VIRGIN ISLANDS TODAY THROUGH TONIGHT. BY LATE
SUNDAY FRONT MOVES INTO THE LEEWARDS BUT SURGES BACK TO THE VIRGIN
ISLANDS ON TUESDAY. SHOWERS HAVE PERSISTED OVERNIGHT UNDER
SOUTHWEST FLOW IN THE LOW LEVELS AND THE ACTIVITY HAS BECOME
SOMEWHAT MORE GENERAL. GIVEN THE PRESENT WEATHER PATTEN WOULD
EXPECTED SHOWERS TO INCREASE IN COVERAGE AS THE FRONT MOVES OVER
THE ISLANDS LATER TODAY AND THESE SHOULD PERSIST INTO SUNDAY. DUE
TO THIS A FLASH FLOOD WATCH WAS ISSUED FOR THE SECTIONS OF PUERTO
RICO AND THE USVI THAT USUALLY EXPERIENCE FLOODING DURING COLD
FRONTS COUPLED WITH FAVORABLE UPPER LEVEL CONDITIONS. TRAINING ECHOS
POSE A RISK OF FLASH FLOODING FOR ST THOMAS AND ST JOHN LATER TODAY.
WET AND GREY WEATHER SHOULD PREVAIL TODAY AND SUNDAY WITH THE
POTENTIAL FOR HEAVY RAIN.

&&

.HYDROLOGY...SHOWERS HAVE INCREASED IN COVERAGE OVERNIGHT...AS
A SLOW MOVING COLD FRONT CONTINUES TO APPROACH THE LOCAL AREA
AND MOVE THROUGH PUERTO RICO AND THE NORTHERN U.S. VIRGIN ISLANDS
TODAY. COUPLED WITH STRONG UPPER LEVEL DISTURBANCE ACROSS THE
WESTERN ATLANTIC WHICH WILL CONTINUE TO DIVE SOUTHWARD AND GRAZE
PUERTO RICO AND THE VIRGIN ISLANDS OVER THE NEXT 36 HOURS. THIS
WILL ALLOW FOR DEEP MOISTURE TO ENVELOP THE AREA WITH PERIODS OF
HEAVY RAINFALL THAT COULD CAUSE FLASH FLOODING.


&&

AVIATION...PREDOMINANT IFR CONDITIONS AT JSJ AND JBQ NEXT 30 HRS
WITH FREQUENT SHOWERS. JMZ/JPS/IST/ISX WILL SEE CONDITIONS
DETERIORATE TO MVFR AFTER 15Z AND FURTHER DETERIORATING TO IFR AFTER
23Z. NCM/KPK WILL HAVE VFR MOST OF THE TIME WITH MVFR CIGS NOT
EXPECTED UNTIL AFTER 03Z SUN. VRB WINDS AT THIS TIME MOST AIRPORTS
BUT WINDS WILL SHIFT TO THE NORTHEAST AFTER 15Z XCPT USVI AND
NCM/KPK AIRPORTS. WINDS ALSO PICKUP SPEED AFTER 23Z WITH GUSTS OVER
20 KTS NOT OUT OF THE QUESTION. WIND SHIFT AT IST/ISX/NCM/KPK NOT
EXPECTED UNTIL AFTER 23Z.


MARINE...A NORTHWEST SWELL WILL CONTINUE TO AFFECT
THE LOCAL WATERS THROUGH AT LEAST SUNDAY...BUT MARINE CONDITIONS
ARE EXPECTED TO BECOME MORE ROUGH AS WINDS ASSOCIATED TO THE FRONT
ARE EXPECTED TO INCREASE SIGNIFICANTLY TONIGHT. MARINERS SHOULD
EXPECT CHOPPY AND WINDY CONDITIONS FROM LATE TODAY THROUGH SUNDAY
NIGHT. THERE IS A SMALL CRAFT ADVISORY IN EFFECT FOR ALL ATLANTIC
WATERS AND THE MONA PASSAGE UNTIL MONDAY NIGHT.

[cycloneye]

The members can see what is going on in Puerto Rico and the Virgin Islands as this front moves slowly thru the area.

[Gustywind]

[Gustywind]

The members can see what is going on in Puerto Rico and the Virgin Islands as this front moves slowly thru the area.

Thanks Cycloneye we appreciate.

[msbee]

thanks Luis
hope some of that moisture reaches Gusty and me too

[Gustywind]

thanks Luis
hope some of that moisture reaches Gusty and me too

Yeah absolutely Barbara let's hope that, keeping our fingers crossed.

[cycloneye]

Latest Summary for Puerto Rico / Virgin Islands

WEATHER SUMMARY FOR PUERTO RICO
NATIONAL WEATHER SERVICE SAN JUAN PR
1104 AM AST SAT MAR 6 2010

MOSTLY CLOUDY SKIES PREVAILED ACROSS PUERTO RICO AND CULEBRA AND
VIEQUES DURING THE MORNING HOURS. SCATTERED TO NUMEROUS SHOWERS
OCCURRED...MAINLY OVER THE EAST HALF OF PUERTO RICO...CULEBRA AND
VIEQUES AND ACROSS THE COASTAL WATERS. BY LATE MORNING...
TEMPERATURES GENERALLY RANGED FROM THE MID 60S TO AROUND 70
DEGREES OVER THE MOUNTAINS TO MOSTLY IN THE 70S ELSEWHERE. THE
WIND WAS NORTH TO NORTHEAST AT 15 MPH OR LESS.

SKIES WILL REMAIN MOSTLY CLOUDY ACROSS THE LOCAL ISLANDS THIS
AFTERNOON. NUMEROUS TO WIDESPREAD SHOWERS WILL OCCUR...AGAIN
ESPECIALLY OVER THE EASTERN HALF OF PUERTO RICO AND CULEBRA AND
VIEQUES. PERIODS OF HEAVY RAINFALL AND AT LEAST SOME URBAN AND
SMALL STREAM FLOODING ARE EXPECTED. HIGH TEMPERATURES WILL
GENERALLY RANGE FROM THE UPPER 60S TO THE MID 70S OVER THE
MOUNTAINS TO THE MID 70S TO THE LOWER 80S ELSEWHERE. THE WIND
WILL BE NORTH TO NORTHEAST AT 10 TO 20 MPH.

A COLD FRONT WILL MOVE SLOWLY EAST SOUTHEAST ACROSS PUERTO RICO
AND THE U.S. VIRGIN ISLANDS THIS AFTERNOON AND TONIGHT...AND WILL
THEN LIKELY BECOME NEARLY STATIONARY JUST SOUTHEAST OF THE U.S.
VIRGIN ISLANDS LATE SUNDAY. THIS FEATURE AND ITS ASSOCIATED
MOISTURE WILL COMBINE WITH FAVORABLE MID TO UPPER LEVEL CONDITIONS
AND LOCAL EFFECTS THIS AFTERNOON THROUGH SUNDAY...TO PRODUCE
CLOUDINESS AND SHOWERS ACROSS THE LOCAL ISLANDS. PERIODS OF HEAVY
RAINFALL ARE EXPECTED IN SOME AREAS AND THIS COULD LEAD TO
FLOODING OF SMALL STREAMS AND RIVERS. A FLASH FLOOD WATCH REMAINS
IN EFFECT FOR MUCH OF EASTERN PUERTO RICO INCLUDING VIEQUES AND
CULEBRA THROUGH SUNDAY AFTERNOON.

LONG PERIOD...NORTHWEST SWELLS WILL CONTINUE TO AFFECT THE
ATLANTIC WATERS AND THE CARIBBEAN PASSAGES THROUGH AT LEAST
EARLY SUNDAY...RESULTING IN HAZARDOUS MARINE AND SURF CONDITIONS.

[HUC]

Hop,hop,i HOOOPPPE . I HOPE , yes i hooooopppppeeee.....

[Gustywind]

Hop,hop,i HOOOPPPE . I HOPE , yes i hooooopppppeeee.....

it's an EUPHEMISMA HUC

Updates from the Islands -
- - Dominica - -
http://www.stormcarib.com/reports/curre ... nica.shtml
- Fire and No Rain.
By Jackie Fullbrook <fullbrookt at gmail.com>
Date: Fri, 5 Mar 2010 10:14:44 -0400

Good morning everyone,
The ridge to the east of the house is very dry, and late yesterday afternoon
it caught fire. Sitting out on the front balcony, saw smoke going up, then loud
popping noises, then bright orange flame flickering amongst the trees. It is a very
dense area of woodland. Watched it make it's way south, and it was still burning
late into the evening. No one living up there to our knowledge, so the only damage
will be to the forest. Looking up there this morning, it could have been a lot worse
than it is considering the conditions up there. Unable to see any smoke, so hopefully
it's burnt itself out.
Have some fairly thick grey cloud up there this morning. A little rain perhaps.
Nice breeze. Humidity up a bit. Sea a little rough looking, and a dark blue.
I'm off for that other coffee, check out that view. Then take my neighbours
guaver's back to her. Collected a whole bag full which fell in the wind yesterday.
You all take care and have a great day.

Tommiegirl.

[cycloneye]

Updated Flash Flood Watch

FLOOD WATCH
NATIONAL WEATHER SERVICE SAN JUAN PR
217 PM AST SAT MAR 6 2010

PRZ001-002-004>006-012-013-VIZ001-070800-
/O.CON.TJSJ.FF.A.0002.000000T0000Z-100307T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN JUAN AND VICINITY-NORTHEAST-EASTERN INTERIOR-NORTH CENTRAL-
CENTRAL INTERIOR-CULEBRA-VIEQUES-
ST. THOMAS/ST. JOHN/ADJACENT ISLANDS-
INCLUDING THE MUNICIPALITIES AND/OR ISLANDS OF...SAN JUAN...
CAROLINA...FAJARDO...HUMACAO...CAGUAS...ARECIBO...VEGA BAJA...
DORADO...COAMO...COROZAL...AIBONITO...VILLALBA...JAYUYA...CULEBRA...
ESPERANZA...ANNA`S RETREAT...CHARLOTTE AMALIE...
CHARLOTTE AMALIE EAST...CHARLOTTE AMALIE WEST...CRUZ BAY
217 PM AST SAT MAR 6 2010

...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH SUNDAY AFTERNOON...

THE FLASH FLOOD WATCH CONTINUES FOR THE FOLLOWING AREAS

* IN PUERTO RICO...THE CENTRAL INTERIOR...EASTERN INTERIOR...NORTH
CENTRAL...NORTHEAST...SAN JUAN AND VICINITY...CULEBRA AND
VIEQUES. IN THE U.S. VIRGIN ISLANDS...ST THOMAS...ST JOHN AND
THE ADJACENT ISLANDS.

* THROUGH SUNDAY AFTERNOON

* A COLD FRONT WILL MOVE SLOWLY EAST SOUTHEAST ACROSS PUERTO RICO
AND THE U.S. VIRGIN ISLANDS THE REST OF THIS AFTERNOON AND
TONIGHT THROUGH SUNDAY AND WILL THEN LIKELY BECOME NEARLY
STATIONARY JUST SOUTHEAST OF THE U.S. VIRGIN ISLANDS LATE
SUNDAY. AT THE SAME TIME...A STRONG UPPER LEVEL DISTURBANCE WILL
GRAZE PUERTO RICO AND THE U.S. VIRGIN ISLANDS DURING THE NEXT 24
HOURS. THESE TWO FEATURES WILL COMBINE WITH A MOIST AND UNSTABLE
AIR MASS AND LOCAL EFFECTS TO PRODUCE PERIODS OF HEAVY RAINFALL
THAT COULD TRIGGER FLASH FLOODING AND MUDSLIDES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WATCH MEANS THAT CONDITIONS ARE FAVORABLE FOR HEAVY
RAIN ACROSS THE WATCH AREA...WHICH MAY LEAD TO FLOODING. IF YOU ARE
IN THE WATCH AREA...CHECK YOUR PREPAREDNESS REQUIREMENTS...
ESPECIALLY IF YOU HAVE INTERESTS ALONG AREA RIVERS. KEEP INFORMED...
AND BE READY FOR QUICK ACTION IF FLOODING IS OBSERVED OR IF A FLASH
FLOOD WARNING IS ISSUED.

PEOPLE IN THE WATCH AREA SHOULD CONTINUE TO BE AWARE OF THE
POSSIBILITY FOR HEAVY RAINFALL. AVOID LOW LYING AREAS...AND BE
CAREFUL WHEN APPROACHING HIGHWAY DIPS AND UNDERPASSES. THE HEAVY
RAIN COULD ALSO CAUSE MUDSLIDES IN AREAS OF STEEP TERRAIN.

PLEASE STAY TUNED TO NOAA ALL HAZARDS RADIO...LOCAL TV...RADIO OR
YOUR CABLE TELEVISION PROVIDER FOR LATER STATEMENTS AND POSSIBLE
WARNINGS.

THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGICAL AND CLIMATE
INFORMATION...IS AVAILABLE ON THE WEB AT HTTP://WWW.SRH.NOAA.GOV/SJU
OR AT HTTP://WEATHER.GOV.

[cycloneye]

Afternoon discussion by NWS San Juan

This is one of the best discussions I have seen from the San Juan office in a while.Read it carefully as it has some complicated terms that members may not understand but otherwise a great writeup discussion about what to expect from his front.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
250 PM AST SAT MAR 6 2010

.SYNOPSIS...MEANDERING COLD FRONT AND ASSOCIATED SHEAR LINE TO
MOVE ERRATICALLY AND SLOWLY NEXT 3 DAYS RESULTING IN MOSTLY CLOUDY
CONDITIONS WITH PERIODS OF RAINFALL...SOMETIMES HEAVY...THROUGH
EARLY NEXT WEEK. UPPER TROUGH MOVES NORTH OF AREA SUNDAY...BUT LOW
LEVEL MOISTURE LEFT BEHIND MAY LINGER AS LONG AS THROUGH THE
MIDDLE OF NEXT WEEK.


&&

.DISCUSSION...HEAVY RAIN TO AFFECT NORTHEASTERN TO SOUTHEASTERN PR
AND THE US VIRGIN ISLAND THIS EVENING.

(NEAR TERM) VERY COMPLEX PATTERN UNDERWAY. SATELLITE
IMAGERY AND DEW POINT OBS POINT TO AN IRREGULARLY SHAPED COLD FRONT
DIGGING INTO THE SOUTH CENTRAL CARIBBEAN IN A LINE UP TOWARDS
SANTO DOMINGO CONTINUING NE TOWARDS BUOY 41403...200 MI NORTH OF ST
THOMAS (MEANING TO THE NORTH AND WEST OF PR). THIS SEEMS EVIDENCED
BY DEW POINTS IN THE LOW TO MID 60S TO THE LEFT (W-NW) OF THIS
JAGGED LINE...AND STILL IN THE LOW TO MID 70S TO THE RIGHT (E-SE
INCLUDING ALL OF PR/USVI AS OF 18Z). TO FURTHER COMPLICATE
THINGS...SHEAR LINE (AREA OF BEST CONVERGENCE...MOST WEATHER) APPEARS
TO BE HOOKING INTO THE SOUTHERN FLANK OF THE COLD FRONT AT 15.5N
72.5W (EXPERIENCING DEEP CONVECTION AT 18Z)...RUNNING
NORTHEASTWARD ROUGHLY IN A LINE GOING SOUTH OF MAINLAND PR BETWEEN
ST CROIX AND PR. RADAR AT 18Z SHOWED SOMEWHAT DEEPER CONVECTION
AND HEAVY RAIN ALONG THIS LINE...WHICH HAS NOT IMPACTED LAND
MASSES THUS FAR. THIS MAY BE CONFUSING...BUT PRESENTS A
SIGNIFICANT FORECAST ISSUE. BEHIND THE TRUE COLD FRONT BOUNDARY
(HISPANIOLA) ONE WOULD EXPECT TYPICALLY MORE STABLE COOL
ADVECTION...WHICH IS VERIFYING PER CURRENT OBS. HOWEVER...ALONG
THE SHEAR LINE CURRENTLY DRAPED TO THE SE OF PR MOISTURE
CONVERGENCE IS VERY HIGH AND COULD EVEN MEANDER A BIT BACK TOWARDS
MAINLAND PR THIS EVENING MAKING HEAVY RAIN A GREATER THREAT. MAJOR
QUESTION IS...WHERE WILL THE SHEAR LINE BE THROUGH 24 HOURS (OR
FOR THAT MATTER UP TO 72 HOURS)...AND WILL THE COLD AIR CATCH UP.

GOOD NEWS IS THAT MODELS HAVE COME IN LINE AND BOTH GFS AND NAM12
INITIALIZE THE SHEAR LINE MORE OR LESS WHERE WE HAVE IT MENTIONED
ABOVE...AND PROGRESSING IT SOUTHEASTWARD THROUGH 24 HOURS. THAT
WOULD RESULT IN BEST CONVERGENCE THIS EVENING (MOST ACTIVE PERIOD
EXPECTED IN THE NEAR TERM) OVER EXTREME ERN PR AND FOCUSED OVER
THE USVI. WILL SHIFT POPS AND WEATHER A BIT EAST AND MAY EXTEND
THE FFA TO ST CROIX TO ACCOUNT FOR THAT POSSIBILITY.

BACK TO THE COLD FRONT...BOTH MODELS INITIALIZING PRE FRONTAL THETA
E RIDGING OVER THE FA WITH TRUE THETA E PACKING (COLD FRONT) OVER
EASTERN DOMINICAN REP AND OUT OVER THE ALTC WATERS A GOOD 100 MI
NORTH OF PR. FIRST WAVE (WEAKER PORTION) OF THIS BOUNDARY TO MOVE
OVER THE NORTHERN HALF OF PR/USVI OVERNIGHT...WITH NORTHERLY LOW
LEVEL FLOW BEHIND IT...AND LAND BREEZE TO ENHANCE CONVERGENCE OVER
NRN PR AFTER 22Z. TO SUM IT ALL UP...SITUATION FAVORABLE FOR HEAVY
RAIN TO BUILD AND MOVE VERY SLOWLY OVER NRN PR AFTER 22Z...WITH
SHEAR LINE PUSHING EAST OF VI ALSO PROVIDING THE THREAT OF HEAVY
CONVECTION DOWN TO ST CROIX. THINK THE FFA IS GOOD WHERE IT IS
CURRENTLY LOCATED OVER NRN PR AND WILL EXTEND TO COVER ST CROIX
AND SOUTHEASTERN PR ZONE. SEVERAL FACTORS COULD SHIFT AREAS OF HEAVY
RAIN...INCLUDING THE SHORT WAVE FIRING DEEP CONVECTION OVER 15.5N
72.5W AND THE ABILITY FOR THE COLD AIR BOUNDARY TO DIG SOUTH.

(SUNDAY THROUGH LONG TERM)...BY THIS TIME SHEAR LINE WILL BE OUT
OF CWA...BUT COLD AIR BOUNDARY WILL WOBBLE WITH 2ND SHOT OF COLDER
AIR TO PUSH OVER PR/USVI BY 00Z MONDAY. AGAIN...TIMING OF THIS A
MAIN CONCERN...THE QUICKER IT MOVES THE LESS CHANCE OF DEEP
CONVECTION TOMORROW...THE SLOWER IT MOVES THE GREATER. ALSO DURING
THE DAY SUNDAY...THE UPPER LEVEL PORTION OF THE DEEP POLAR TROUGH
DIGS TO ITS SOUTHERNMOST POINT AND PUSHES JUST NORTH OF THE AREA
FROM WEST TO EAST. BEST U/L JET DYNAMICS WILL REMAIN ABOUT 100
MILES NORTH OF THE AREA...HOWEVER...IF ANY LOW LEVEL MECHANISMS
CAN FORCE DEEP CONVECTION TOMORROW...THEN ENHANCEMENT VIA THE
UPPER TROUGH IS VERY LIKELY. LOOKING AHEAD TO NEXT WEEK GFS SHOWS
RETROGRESSION OF LOW LEVEL MOISTURE ASSOCIATED WITH THE PRE
FRONTAL TROUGHINESS TO WORK BACK OVER AREA TUESDAY AND WED AND
WHICH COULD POSSIBLY RESULT IN BETTER CONDITIONS MONDAY...BUT BACK
TO MOSTLY CLOUDY WITH LIGHT RAIN FOR TUE/WED.


&&

.AVIATION...EXPECT MVFR TO LOCALLY IFR CONDITIONS WITH MOUNTAIN
OBSCURATIONS TO PREVAIL ACROSS MOST OF THE LOCAL ISLANDS AND TAF
SITES THROUGH 24 HOUR CYCLE. HEAVIEST RAIN AND MOST LIKELY IFR
CONDITIONS TO BE FOR TJSJ...TIST AND TISX 22Z-10Z.


&&

.MARINE...BUOYS AND LOCAL DATA REPORTS NOT REALLY ADDING UP TO HIGH SURF
ADVISORY CONDITIONS. ALTHOUGH BUOY 41043 SHOWING 7.5 FOOT SWELL
STEADY AT 10 SEC...BUOY 41406 (200 MILES NORTH OF THE TURKS/CAICOS)
ONLY SHOWING 4.5 FOOT SWELL...AND FEEL THAT THE 41406 OB IS MORE
REPRESENTATIVE OF WHATS HITTING NRN PR/USVI GIVEN MORE NORTH
NORTHWESTERLY DIRECTION. EVEN IF WE HEDGED TOWARDS AN
AVERAGE...THE MAX BREAKING WAVE HEIGHT WOULD STILL ONLY BE AROUND
10 FEET...WITH MOST PLACES LIKELY ONLY EXPERIENCING BREAKERS OF 6
TO 8 FEET. FOR THAT REASON WILL CANCEL THE HIGH SURF ADVISORY.
NONETHELESS...SEAS WILL CONTINUE QUITE CHOPPY AND STILL HAZARDOUS
TO MARINERS...BUT NOT GREATER THAN 10 FOOT BREAKERS (HIGH SURF
CRITERIA). BEACH GOERS SHOULD STILL BE CAUTIOUS...AS CONDITIONS
WILL REMAIN BORDERLINE FOR SEVERAL DAYS.

[cycloneye]

Updated discussion by NWS San Juan

Its a rainy and cool night here,very sharp contrast from the warm and dry past few days.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
942 PM AST SAT MAR 6 2010

.UPDATE...LIGHT SHOWERS HAVE PERSISTED ACROSS THE NORTHEAST SECTION
OF PUERTO RICO MOST OF THE NIGHT...WITH BRIEF PERIODS OF MODERATE
RAINFALL. LATEST TJSJ 00Z SOUNDING SHOWED AN INTERESTING
PROFILE...SHOWING A PRETTY MOIST SOUNDING FROM THE SURFACE TO
AROUND 500MB LEVEL. PW VALUES WERE 1.90 INCHES...WHICH HAS BEEN
THE CASE SINCE FRIDAY EVENING. AT 500MB LEVEL...PROFILE SHOWS VERY
DRY AIR IS IN PLACE. NO OVERALL CHANGED IS EXPECTED IN THIS
WEATHER PATTERN AT LEAST THROUGH MONDAY...WHEN DRIER CONDITIONS
ARE POSSIBLE. HOWEVER...MOISTURE WILL LINGER MOST OF THE WORK
WEEK...WITH RECENT PROGNOSIS SOUNDINGS INDICATING PW VALUES OVER
THE LOCAL AREA WILL DROP SIGNIFICANTLY MONDAY...THEN INCREASING
RAPIDLY TUESDAY AND WEDNESDAY...TO NEAR 2.0 INCHES. THIS INCREASE
IN MOISTURE WAS ANALYZED IN PREVIOUS DISCUSSION...THEREFORE...NO
NECESSARY BIG CHANGES WERE MADE TO FORECAST GRIDS. ONLY MINOR
CHANGES WERE MADE TO SHORT TERM GRIDS...TO ADJUST FORECAST WITH
ONGOING WEATHER SITUATION.

&&

.AVIATION...A ZONE OF CONVERGENCE THAT IS SETTLING INTO THE AREA
FROM THE NORTHWEST AND A DISSIPATING CONVERGENCE ZONE BETWEEN TIST
AND TISX AND VIEQUES EXTENDING WSW INTO THE CARIBBEAN WILL KEEP LOW
CIGS/VSBYS IN THE AREA NEXT 24 HOURS. MVFR IS LIKELY WITH OCNL IFR
CONDITIONS POSSIBLE AT ALL TAF SITES ALTHOUGH THEY MAY BE SEEN LESS
AT TNCM AND TKPK DUE TO THEIR SLIGHTLY LARGER DISTANCE FROM THE
FRONTAL ZONE. WIDESPREAD AND NEAR TOTAL MOUNTAIN OBSCURATIONS WILL
PERSIST THROUGHOUT THE PERIOD. IMPROVEMENT NOT EXPECTED BEFORE
08/00Z.

[Gustywind]

[cycloneye]

Good morning to all.A rainy and cool temps sunday here.


AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SAN JUAN PR
533 AM AST SUN MAR 7 2010

.SYNOPSIS...CDFNT NOW EXTENDING ALONG 17 NORTH WILL CONTINUE TO
PUSH SOUTH INTO THE LEEWARDS WHERE IT WILL STALL ON MON AND
POSSIBLY BEGIN TO RETREAT NORTH AS A WARM FRONT TUE.

&&

.DISCUSSION...FRONT HAS DEFINITELY MOVED SOUTH OF PR WHERE OBS AT
SJU AND ST. THOMAS SHOW DEWPOINTS NOW IN THE 60S AND PRESSURE
READINGS SIGNIFICANTLY HIGHER THAN 24 HRS AGO. LATEST TPW IMAGERY
ALSO SHOWS THAT PLUME OF HIGH PW AIR/MOISTURE AXIS HAS SHIFTED
SOUTH AND LIES OVR THE WATERS BETWEEN VIEQUES AND ST. CROIX. S/W
TROUGH AND ASSOCIATED 135-KT JET STREAK NOW OVR S FL AND THE
BAHAMAS WILL CONTINUE TO PUSH EAST THIS MORNING AND GRAZE PR LATER
THIS AFTERNOON. THE IMPROVING JET DYNAMICS AND OVERRUNNING
SITUATION WILL CONTINUE TO RESULT IN PERIODS OF LIGHT RAIN ALL DAY
TODAY. FLOODING POTENTIAL LOOKS LOW AT THIS POINT NOW THAT THE
FRONT HAS SHIFTED FURTHER SOUTH BUT FOR PRECAUTIONARY MEASUREMENTS
HAVE KEPT IT FOR THE ERN THIRD OF PR AND THE USVI WHERE MOST OF
THE RAIN FELL YESTERDAY AND WILL TAKE LESS RAIN TODAY TO CAUSE
FLOODING. PRECIP RATES SHOULD BE LOWER THAN YDAY WHICH SHOULD
LIMIT RAINFALL TOTALS. FELT CONFIDENT ABOUT DROPPING THE NORTH
CNTRL AND CNTR INTERIOR SECTIONS OF THE ISLAND AS PRECIP SHOULD BE
LIGHT AND NOT CAUSE ANY PROBLEMS. GUIDANCE SHOWS SHARP DRYING
AFTER 22Z SO SHOULD BE ABLE TO CANCEL FLOOD WATCH COMPLETELY BY
THAT TIME IF NOT SOONER. EVEN IF IT DOESNT RAIN OR FLOOD
ANTICIPATE A CLOUDY COOL AND DAMP DAY.

TONIGHT....DEPTH OF THE MOISTURE LAYER DECREASES SHARPLY BUT NRLY
UPSLOPE WINDS WILL LIKELY GENERATE AREAS OF LIGHT RAIN OR DRIZZLE
INTO MONDAY MORNING.

MONDAY...STILL LOTS OF CLOUDS AS MOISTURE GETS TRAPPED UNDER A
STRONG SUBSIDENCE INVERSION. MAY BE ABLE TO SEE A FEW BREAKS LATE
IN THE DAY BUT OVERALL A PRETTY CLOUDY DAY BUT DRY.

CONFIDENCE IN THE FCST DROPS SHARPLY TUE AND ON AS GFS NOW SHOWS
FRONT RETREATING TO THE NORTH WITH A RAPID SURGE IN MOISTURE
ACROSS THE AREA TUE NIGHT AND WED. POTENTIAL FOR MCS FORMATION
OVR THE WATERS NEAR ST. CROIX IF THE GFS IS RIGHT. THE 00Z GFS
SCENARIO LOOKS QUITE OMINOUS FOR ERN PR AND THE USVI BUT AGAIN MY
CONFIDENCE IN THIS SOLUTION IS QUITE LOW. SO WILL HAVE TO WAIT AND
SEE FOR NOW.

&&

.AVIATION...PREDOMINANT MVFR CIGS/VSBYS WITH OCASSIONAL RAIN NEXT
36 HRS. NORTH WINDS AROUND 10 KTS DROPPING TONIGHT AFTER SUNSET.


&&

.MARINE...SCA HAS BEEN EXPANDED TO INCLUDE CARIBBEAN WATERS AS
PRESSURE SURGE HAS CAUSED WINDS TO GUST UP TO 30 KTS. ALSO NORTH
SWELLS ARE GETTING THROUGH THE PASSAGES WITH 6-7 FT SEAS BEING
REPORTED BY SHIPS. BUOY 41043 SHOWS 7-FT SWELLS AT 11 SECS WHICH
WOULD RESULT IN 10-12 FT BREAKERS ALONG THE NORTH COAST. GUIDANCE
SHOWS SWELLS DECREASING TO 6 FT THIS EVENING BUT INCREASING AGAIN
TO 8 FT AFTER MIDNIGHT. WILL WAIT UNTIL DAYBREAK TO LOOK AT SURF
CAMERAS AND ISSUE A HIGH SURF IF NECESSARY.