Caribbean - Central America Weather

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1048 PM AST TUE JUL 6 2010

.UPDATE...SHOWER ACTIVITY CONTINUES TO DIMINISH ACROSS THE LOCAL
ISLANDS THIS EVENING AS THE TROPICAL WAVE ACROSS EASTERN
HISPANIOLA CONTINUES TO TRACK WEST AND AWAY FROM THE LOCAL
ISLANDS. WILL LIKELY SEE SCATTERED SHOWERS TO AFFECT SOUTHEASTERN
PUERTO RICO THROUGH THE OVERNIGHT HOURS IN THE PREVAILING ESE WIND
FLOW...BUT LITTLE SHOWER ACTIVITY IS EXPECTED ELSEWHERE. WHILE
RELATIVELY MORE STABLE SAHARAN AIR IS FILTERING IN ACROSS THE
LOCAL ISLANDS BEHIND THIS WAVE...STILL EXPECT SOME DIURNAL SHOWER
DEVELOPMENT OVER THE INTERIOR AND WESTERN SECTIONS OF PUERTO RICO
EACH AFTERNOON...BEFORE THE NEXT TROPICAL WAVE BRINGS ANOTHER
SURGE IN SHOWER ACTIVITY OVER THE UPCOMING WEEKEND.

&&

.AVIATION...PREVAILING VFR CONDS EXPECTED ALL TAF SITES THROUGH
08/16Z IN A LLVL SE WIND FLOW OF 10 TO 15 KTS. BRIEF MVFR CONDS OR
EVEN IFR CONDS ONCE AGAIN BE POSSIBLE ACROSS TJMZ AND TJBQ FROM
08/17Z-08/22Z...WITH PREVAILING VFR CONDITIONS ELSEWHERE. WHILE
HAZY SKIES ARE EXPECTED...VISIBILITIES ARE EXPECTED TO REMAIN
ABOVE 6 MILES.

[cycloneye]

Good morning.Drier weather from today until the weekend.


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
550 AM AST WED JUL 7 2010

.SYNOPSIS...AT UPPER LEVELS...WINDS REMAIN LESS THAN 20 KNOTS AND
VARY IN DIRECTION THROUGH THE NEXT 10 DAYS. A LOW NORTHEAST OF
THE AREA ON SATURDAY PULLS NORTHWEST BEFORE IT REACHES THE AREA.
FOR MUCH OF THE PERIOD OTHER LOWS HOLD WEST OF THE AREA WHILE
HIGHER HEIGHTS DOMINATE TO LOCAL AREA.

AT MID LEVELS...AN INVERTED AND NEGATIVELY TILTED TROUGH NEAR 50
WEST WILL MOVE NORTHWEST AND WEAKEN BEFORE IT CROSSES NORTH OF
THE LOCAL AREA SATURDAY AND SUNDAY. NEXT WEEK EASTERLY FLOW IS
MORE OR LESS CONTINUOUS.

AT LOWER LEVELS...A TROPICAL WAVE THAT PASSED THROUGH ON MONDAY
NIGHT WILL CONTINUE NORTHWEST AND HAS GENERATED CONSIDERABLE
CONVECTION NORTH OF PUERTO RICO AND 20 NORTH. A TROPICAL WAVE NEAR
40 WEST IS EXPECTED TO PASS THROUGH ON SATURDAY NIGHT IN TANDEM
WITH THE UPPER LEVEL LOW. ANOTHER WAVE WILL FOLLOW ON WEDNESDAY OF
NEXT WEEK.

&&

.DISCUSSION...DRIER AND MORE STABLE AIR IS ANTICIPATED OVER PUERTO
RICO AND THE U.S. VIRGIN ISLANDS...BUT HAS NOT YET ARRIVED. ITS
ARRIVAL MAY BE TOO LATE TOO IMPEDE THE FIRING OF AFTERNOON
CONVECTION OVER NORTHWEST PUERTO RICO...EVEN IF THE U.S. VIRGIN
ISLANDS SEE ONLY MINIMAL ACTIVITY IN DOWNSTREAM CUMULUS LINES.
WITH SOUTHEAST FLOW THIS MAY HAVE LITTLE EFFECT ON OTHER LAND
AREAS EXCEPT PERHAPS THE SOUTHEAST COAST OF PUERTO RICO. CANNOT
RULE OUT STRONG THUNDERSTORMS IN NORTHWEST PUERTO RICO TODAY...BUT THE
LIFTED INDEX IS PORTRAYED AS RISING THROUGH THE DAY AND UNSTEADILY
OVER THE NEXT 10 DAYS. THE NEXT WAVE IS DEPICTED AS ARRIVING LATE
SATURDAY IN ALL THE MODELS...BUT THE LIFTED INDEX IS SEVERAL
POINTS HIGHER THEN THAN IT IS NOW. WITH LESS MOISTURE AND HIGHER
STABILITY EXPECT THE WEATHER OVER THE WEEKEND TO BE LESS DRAMATIC
THAN THE LAST WAVE OR THE EVENTS THAT HAVE OCCURRED IN THE PAST
SEVEN DAYS. NEVERTHELESS THIS SHOULD STILL RESULT IN SIGNIFICANT
RAINS FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS. THE WAVE
FOLLOWING ON THE WEDNESDAY OF THE FOLLOWING WEEK SHOWS LESS
AMPLITUDE STILL...BUT WINDS INCREASE JUST AS MUCH BEHIND THE AXIS.
AGAIN THE ECMWF SEEMS TO BE HANDLING THIS SUCCESSION OF WAVES THE
BEST AND FORECAST IS TEMPERED BY ITS TIMING AND INDICATIONS OF
MOISTURE WITH EACH WAVE.


&&

.AVIATION...
PREVAILING VFR CONDITIONS ARE EXPECTED ACROSS ALL TAFS
SITES. DRIER AIR MASS IS EXPECTED TO MOVE ACROSS REGION AFTER
07/12Z...LIMITING THE SHRA ACTIVITY OVER PR AND THE USVI.
HOWEVER...AFTERNOON CONVECTION IS POSSIBLE ONCE AGAIN ACROSS PARTS
OF THE INTERIOR AND NORTHWESTERN PR. THIS ACTIVITY WILL PRODUCE
BRIEF MVFR CONDS OR EVEN IFR CONDS ACROSS TJMZ AND TJBQ FROM
07/17Z-07/22Z...WITH VFR CONDITIONS ELSEWHERE. WINDS WILL PREVAIL
FROM THE SOUTHEAST AT 10 TO 15 KNOTS EXCEPT FOR SEA BREEZE VARIATIONS.

&&

.MARINE...SEAS OF 4 TO 6 FEET ARE EXPECTED IN EXPOSED WATERS WITH
RISING SEAS THROUGH NEXT WEEK. SMALL CRAFT ADVISORY SEA CONDITIONS
ARE POSSIBLE BY TUESDAY OR WEDNESDAY OF NEXT WEEK BUT WILL BE
MARGINAL.


&&

[Gustywind]

[cycloneye]

It was very warm today in Puerto Rico.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
324 PM AST WED JUL 7 2010

.SYNOPSIS...
MID TO UPPER LEVEL HIGH PRESSURE RIDGE WILL CONTINUE TO BUILD
INTO THE NORTHEAST CARIBBEAN.THIS IS SUPPORTED BY STRONG ATLANTIC
SURFACE HIGH PRESSURE RIDGE ACROSS THE NORTH CENTRAL ATLANTIC...
WHICH WILL ALSO BUILD INTO THE NORTHEAST CARIBBEAN OVER THE NEXT
FEW DAYS. THIS WILL LEAD TO THE TIGHTENING OF THE SURFACE PRESSURE
GRADIENT ACROSS THE REGION AND THUS INCREASE THE LOCAL TRADE WIND
FLOW. THE BUILDING RIDGE TO OUR NORTH AND DEPARTING TROPICAL WAVE
NOW ACROSS HISPANIOLA AND THE CENTRAL CARIBBEAN IS INDUCING A
SOUTH-SOUTHEAST LOW LEVEL WIND FLOW ACROSS THE REGION. HOWEVER...
EXPECT WINDS TO BECOME MORE EASTERLY BY THURSDAY...AS THE HIGH
BUILDS SOUTHWARDS ACROSS THE REGION. GFS MODEL GUIDANCE SUGGESTS
SIGNIFICANT INCREASE IN LOCAL WINDS OF 15-20 KTS OR GREATER
DURING THE NEXT FEW DAYS. ALSO SUGGEST A TUTT NOW ACROSS THE
TROPICAL ATLANTIC TO SHIFT WEST ACROSS THE REGION BY FRIDAY.
THIS IN TURN WILL FLATTEN THE UPPER RIDGE ACROSS THE LOCAL
REGION.

&&

.DISCUSSION...
LATEST SATELLITE IMAGERY SHOWED A SLOT OF DRIER AIR NOW ACROSS
THE VIRGIN ISLANDS AND QUICKLY APPROACHING THE REGION . LATEST TPW
PRODUCTS AS WELL AS SAL ANALYSIS INDICATED DECREASING PRECIPITABLE
WATER OVER NEXT FEW DAYS...SO EXPECT OVERALL DRYING TREND THROUGH
THURSDAY. HOWEVER...SURGE OF TRADE WIND MOISTURE WILL BRING
CLOUDINESS AND PERIODS OF EARLY MORNING SHOWERS TO SOME OF THE
VIRGIN ISLANDS AS WELL AS EAST COASTAL SECTION OF PUERTO RICO BUT
NO WIDESPREAD RAINFALL EXPECTED. FOR THE REST OF THE WORK WEEK...
EXPECT TYPICAL LOCAL AND DIURNAL INFLUENCES TO AID IN AFTERNOON
SHOWERS AND ISOLATED THUNDERSTORMS ESPECIALLY ACROSS THE WEST AND
WEST INTERIOR SECTIONS OF PUERTO RICO. IN ADDITION THE INCREASED
TRADE WILL FLOW WILL LEAD TO THE FORMATION OF STREAMERS ACROSS
LEE SIDE OF THE VIRGIN ISLANDS AS WELL AS OVER PARTS OF THE EAST
INTERIOR SECTIONS OF PUERTO RICO.

BY FRIDAY INTO THE WEEKEND...EXPECT TROPICAL WAVE AND ASSOCIATED WIND
SURGE..ALONG WITH THE DEVELOPING TUTT MENTIONED ABOVE IS EXPECTED TO
TO MOVE ACROSS THE REGION. THIS WILL BRING INCREASING MOISTURE
WITH HIGHER PWAT VALUES ONCE AGAIN ACROSS THE LOCAL AREA AND ALSO
INCREASE THE CHANCES FOR ACTIVE AND SQUALLY WEATHER CONDITIONS
ACROSS THE ISLANDS AND SURROUNDING WATERS LATE FRIDAY INTO THE
UPCOMING WEEKEND.

&&

.AVIATION...
PREVAILING VFR CONDITIONS ARE EXPECTED ACROSS ALL TAF SITES THE
NEXT 24 HOURS. HOWEVER...AFTERNOON CONVECTION IS POSSIBLE ONCE
AGAIN ACROSS PARTS OF THE INTERIOR AND WEST SECTIONS OF PR.
THIS ACTIVITY WILL PRODUCE BRIEF MVFR CONDS OR EVEN IFR CONDS
ACROSS MAINLY AT TJMZ AND TJBQ BTW 07/17Z-07/22Z...WITH VFR
CONDITIONS ELSEWHERE. LOW LEVEL WNDS WILL PREVAIL FROM THE EAST
SOUTHEAST AT 10 TO 15 KNOTS.

&&

CLIMATE...
A RECORD TEMPERATURE OF 93 DEGREES WAS SET AT THE LUIS MUNOZ MARIN
INTERNATIONAL AIRPORT IN SAN JUAN. THIS BROKE THE RECORD OF 92 DEGREES
PREVIOUSLY SET IN 1988.

[cycloneye]

Good morning.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
459 AM AST THU JUL 8 2010

.SYNOPSIS...AT UPPER LEVELS...WEAK WINDS OF LESS THAN 20 KNOTS
PERSIST THROUGH MID WEEK NEXT WEEK. A TUTT LOW COMES WITHIN 650
MILES TO THE NORTHEAST OF SAINT JOHN FRIDAY NIGHT BUT WILL HAVE
LITTLE EFFECT ON THE LOCAL AREA. A WEAK RIDGE CONTINUES IN THE
AREA AFTERWARD.

AT MID LEVELS...LOW PRESSURE NEAR 23 NORTH 52 WEST WILL CONTINUE
WESTWARD AS IT DISSIPATES SUNDAY NIGHT NORTH OF PUERTO RICO.
OTHERWISE FLOW IS EASTERLY FOR THE REST OF NEXT WEEK.

AT LOWER LEVELS...WEAK TROUGHINESS PASSES THROUGH THE AREA ON
THURSDAY NIGHT FOLLOWED BY A TROPICAL WAVE ON SATURDAY AND A WIND
SURGE ON SUNDAY. ANOTHER WAVE IS EXPECTED ON WEDNESDAY WITH
STRONGER WINDS. A BAND OF MOISTURE MAY FORM OVER THE AREA ON THE
WEEKEND AFTER NEXT IN EAST SOUTHEAST FLOW.

&&

.DISCUSSION...MINOR SHOWERS HAVE BEEN PUSHING ON SHORE IN NAGUABO
AND CEIBA AS WELL AS YABUCOA OVERNIGHT AS A BAND OF INCREASED
MOISTURE PASSES BY. ACTIVITY IN THE WEST TODAY SHOULD BE A LITTLE
BIT BETTER THAN YESTERDAY BY THE SAME TOKEN. GFS AND ECMWF ARE
SIMILAR IN TIMING NEXT 10 DAYS...BUT GFS HAS STRONGER LOW LEVEL WINDS.
KEPT SURFACE WINDS BELOW 22 KNOTS DURING ENTIRE PERIOD...WHICH
WOULD BE A COMPROMISE BETWEEN THE TWO MODELS. WIND SURGES MAY NOT
BE AS STRONG AS INDICATED SUNDAY...WEDNESDAY AND THE SATURDAY
AFTER NEXT.

PRECIPITABLE WATER ROSE A FEW TENTHS OF AN INCH SINCE YESTERDAY
EVENING AND SHOULD MAINTAIN VALUES AROUND 1.7 INCHES. WITH BANDS OF
MOISTURE EVIDENT IN INFRA RED IMAGERY EXPECT THAT SCATTERED
SHOWERS WILL CONTINUE IN THE WEST WITH ISOLATED THUNDERSTORMS. A
FEW SHOWERS CANNOT BE RULED OUT IN THE EASTERN INTERIOR...BUT
GENERALLY CONDITIONS THERE WILL BE DRIER THERE. THE TROPICAL WAVE
MAY ARRIVE JUST AFTER A WEAK BAND OF MOISTURE SET TO TRACK ACROSS
THE AREA FRIDAY NIGHT...SO FORECAST WILL NOT BE DRY ON THE EAST
COAST TONIGHT OR TOMORROW NIGHT AND WILL BE SQUALLY ON SATURDAY
NIGHT. SHOWERS SHOULD LINGER SUNDAY AS ECMWF HINTS...BUT GFS IS
CONSIDERABLY DRIER. ECMWF HAS HAD A BETTER TRACK RECORD LATELY AND
EXPECT SHOWERY WEATHER ON SUNDAY. WAVE ON WEDNESDAY IS TOO FAR OUT
TO DETERMINE IF IT WILL REALLY BE BETTER THAN THE ONE ON SATURDAY
BUT CURRENT INDICATION SUGGEST THAT IT WILL BE.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL AT ALL LOCAL TAF SITES THROUGH THE
FORECAST PERIOD. HOWEVER...BETWEEN 08/17Z-22Z...EXPECT BRIEF
MVFR/IFR CONDS AND LOCAL MOUNTAIN OBSCURATIONS IN PASSING
SHRA/TSRA ACROSS TJBQ AND TJMZ. LLVL WINDS WILL BE MAINLY FROM THE
EAST AT 10 TO 15 KNOTS...WITH HIGHER GUSTS NEAR SHRA/TSRA. SEA
BREEZE VARIATIONS WILL AFFECT MOST OF THE TAFS SITES BY EARLY
AFTERNOON.

&&

.MARINE...HAVE NOT RAISED SEAS FROM THE 6 FOOT LEVELS INHERITED
THIS MORNING...MAINLY DUE TO THE EXPECTATION THAT THE GFS HAS BEEN
OVER-FORECASTING THE WINDS AND THEREFORE THE SEAS. STILL THINK
THERE IS SOME POSSIBILITY OF SMALL CRAFT CONDITIONS WINDS OR SEAS
WEDNESDAY...BUT WILL WAIT TO SEE IF WAVE HOLDS TOGETHER OR
INTENSIFIES BEFORE RAISING SEAS AND WINDS THEN. IN THE MEANTIME IT
LOOKS LIKE WE WILL HAVE ONE MORE PERIOD WITHOUT EXERCISE CAUTION
STATEMENTS.

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
303 PM AST THU JUL 8 2010

.SYNOPSIS...
TUTT LOW ACROSS THE TROPICAL ATLANTIC AND JUST NORTHEAST OF THE
LEEWARD ISLANDS WILL SLOWLY SHIFT WESTWARDS AND TO JUST NORTH OF
THE REGION BY LATE FRIDAY INTO SATURDAY...WHERE IT WILL LINGER
THROUGH THE EARLY PART OF NEXT WEEK. THIS WILL RESULT IN
FLATTENING OF UPPER RIDGE NOW IN PLACE ACROSS THE NORTHEAST
CARIBBEAN. AN INDUCED LOW LEVEL TROUGH JUST EAST OF THE LESSER
ANTILLES IS FORECAST TO MERGE WITH A TROPICAL WAVE NOW JUST EAST
OF THE SOUTHERN WINDWARD ISLANDS. THIS FEATURE WILL ENTER THE
EASTERN CARIBBEAN BY FRIDAY AFTERNOON...THEN MOVE ACROSS THE
REGION SATURDAY AND SUNDAY MORNING.

&&

.DISCUSSION...EXPECT LOW LEVEL TROUGH/TROPICAL WAVE TO MOVE ACROSS
THE REGION LATE FRIDAY THROUGH SATURDAY. THIS WILL BRING AN INCREASE
IN LOW TO MID LEVEL TROPICAL MOISTURE ACROSS THE REGION AND THUS INCREASE
THE CHANCES FOR MORE WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORM ACTIVITY
ACROSS THE REGION THROUGH AT LEAST EARLY SUNDAY. THIS WILL BE FOLLOWED
BY A GRADUAL IMPROVEMENT LATER SUNDAY AND INTO THE EARLY PART OF NEXT
WEEK...AS A WIND SURGE AND EXTENSIVE AREA OF SAHARAN DUST WILL BRING
DRIER AIR TO THE REGION. UNTIL THEN HOWEVER...EXPECT FAIRLY ACTIVE
AND SQUALLY WEATHER CONDITIONS LATE FRIDAY THROUGH SATURDAY AND
POSSIBLY INTO SUNDAY MORNING.

&&

.AVIATION...CONDITIONS ALMOST AS EXPECTED SO FAR WITH THUNDERSTORMS
OCCURRING OVER THE HIGHEST TERRAIN OF WESTERN PR...THEN STREAMING
WESTWARD TO THE SHORE. THEY HAVE BEEN A FEW MILES SOUTH OF TJMZ
BUT CLOSE ENOUGH TO KEEP THE CHANCE OF TSTM THERE. THOUGHT THEY
MIGHT DEVELOP A LITTLE FARTHER NORTH TOO BUT NOT SO FAR. CONTINUED
MVFR WITH GUSTY WIND IN AND NEAR TSTMS BUT THESE SHOULD BEGIN TAPERING
OFF NEXT FEW HOURS.

&&

[alanstover]

My, I wish there was this kind of weather info available for Central America!
Does anyone know where I can get more detailed data and/or weather maps for the region?

We´ve had cloudy, rainy weather the last two days, and I´d like to find out why...

-alan

[abajan]

Is that the ITCZ becoming active East of Barbados? Our mets state that unstable conditions are affecting the island and forecast scattered moderate to heavy showers and isolated thunderstorms throughout the day.
Official forecast

[cycloneye]

Good morning.


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
543 AM AST FRI JUL 9 2010

.SYNOPSIS...AN UPPER LEVEL LOW TO THE NORTHEAST OF PUERTO RICO WILL
PULL NORTH BEGINNING ON SATURDAY. A TROUGH ROTATING AROUND THE LOW
WILL PINCH OFF NORTH OF SAINT JOHN ON TUESDAY AND MOVE SOUTHWEST
TO JUST NORTH OF THE DOMINICAN REPUBLIC BY WEDNESDAY. A RIDGE OF
HIGH PRESSURE WILL REMAIN OVER PUERTO RICO AND THE U.S. VIRGIN
ISLANDS AFTERWARD.

AT MID LEVELS...A WEAK LOW NORTHEAST OF THE LEEWARD ISLANDS WILL
MOVE EAST WHILE DISSIPATING TODAY THROUGH SUNDAY. AN INVERTED
TROUGH NEAR 50 WEST ON SUNDAY WILL MOVE ACROSS THE LOCAL AREA ON
TUESDAY OR WEDNESDAY. HIGH PRESSURE REMAINS STRONG OVER THE
CENTRAL ATLANTIC THROUGH THE FORECAST PERIOD.

AT LOWER LEVELS...
HIGH PRESSURE DOMINATES THE NORTH AND CENTRAL ATLANTIC THROUGH THE
PERIOD. A TROPICAL WAVE AT 52 WEST DUE EAST OF PUERTO RICO WILL
ARRIVE EARLY SUNDAY MORNING. A SECOND WAVE NEAR 20 WEST WILL
ARRIVE ON THURSDAY.

&&

.DISCUSSION...THIS HAS BEEN AN INTERESTING AND CHALLENGING
FORECAST SITUATION. MODELS ARE MOVING THE WAVE TOO FAST TOWARD THE
AREA. DURING THE PAST 24 HOURS...AS INTERPRETED FROM SATELLITE
IMAGERY...THE WAVE HAS BEEN MOVING AT ABOUT 14 KNOTS AND THIS HAS
CHANGED LITTLE DURING THE PAST 72 HOURS. AT THIS SPEED IT WILL
ARRIVE IN SAN JUAN AT 11/07Z AND SAINT THOMAS AT 11/03Z WITH MOST
OF THE WEATHER FOLLOWING IT. NAM SHOWS THE TROUGH AT 850 MB MOVING
THROUGH AT 10/21Z...THE GFS AT 10/15Z AND THE ECMWF AT A SIMILAR
TIME. PART OF THE PROBLEM MAY LIE IN INITIALIZATION. GOES WINDS BEHIND
THE WAVE AT 700 MB WERE GENERALLY EAST NORTHEAST AROUND 20 KNOTS
AT 10 NORTH 50 WEST. HOWEVER GFS WINDS IN THE SAME POSITION WERE
SOUTHEAST AT 35 TO 45 KNOTS. THIS LEVEL WAS CHOSEN SINCE CLOUD
TOPS ARE AROUND 11 DEGREES CELSIUS WHICH IS CLOSE TO 700 MB.
ANOTHER POSSIBILITY IS THAT THE TUTT LOW TO THE NORTHEAST...WHICH
UP TO NOW HAS BEEN MOVING SOUTH SOUTH WEST IN THE MID 50S WEST
LONGITUDE...IS HAVING AND WILL CONTINUE TO HAVE A RETARDING EFFECT
ON THE WAVE...CAUSING CONVECTION TO BUILD BEHIND THE AXIS...AND
THEN REFORMING ALONG THIS CONVECTION DUE TO UPPER LEVEL WESTERLIES
AROUND THE SOUTHERN PERIMETER OF THE LOW. EITHER WAY HAVE HAD TO
ABANDON MODEL INPUT FOR THE GRIDS AND DELAY ARRIVAL OF THE
MAJORITY OF THE WEATHER ABOUT 9 TO 12 HOURS. THIS MEANS THE
HEAVIEST SHOWERS AND WIDEST COVERAGE OF PRECIPITATION ON THE
SOUTHEAST COAST OF PUERTO RICO WILL ARRIVE AFTER MIDNIGHT SUNDAY
MORNING...AND WILL NOT ARRIVE IN THE U.S. VIRGIN ISLANDS BY
SATURDAY AFTERNOON. IT WILL NOT CHANGE THE LOCATION OF THE
CONVECTION THIS AFTERNOON IN WESTERN PUERTO RICO ...HOWEVER...
SINCE WINDS DO NOT BECOME APPRECIABLY NORTHEAST PRIOR TO THE
WAVE....BUT IT DOES DELAY THE COVERAGE OF NUMEROUS SHOWERS DURING
THE AFTERNOON IN THE CARIBBEAN EAST OF PUERTO RICO AND AROUND THE
U.S. VIRGIN ISLANDS UNTIL SATURDAY NIGHT. FOR THE SAME REASON WILL
STICK TO MOS MAXIMUMS OF 90 DEGREES FOR SAN JUAN TODAY AND TOMORROW.

LOOKING FURTHER AHEAD...PATCHES OF MOISTURE AND MORE THICK SAHARAN
DUST FOLLOW THIS WAVE MONDAY AND TUESDAY AND THE NEXT WAVE...WHICH
HAD BEEN EXPECTED ON WEDNESDAY...IS NOW EXPECTED ON THURSDAY.
GIVEN A TRAVEL TIME OF 7 DEGREES OF LONGITUDE PER DAY AND 44
DEGREES OF LONGITUDE TO COVER FROM ITS POSITION OF 20 WEST OFF THE
COAST OF AFRICA THIS SEEMS MOST REASONABLE.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES THE NEXT 24
HOURS. HOWEVER...ANOTHER DIURNAL INCREASE IN CLOUDINESS AND SHOWERS
ARE EXPECTED ACROSS THE INTERIOR AND WESTERN SECTIONS OF PR. THIS
SHRA/TSRA ACTIVITY WILL PRODUCE TEMPO PERIODS OF MVFR/IFR CONDITIONS
OVER TJMZ AND TJBQ BETWEEN 09/18Z-22Z. LATEST TJSJ SOUNDING AT
09/00Z INDICATED EASTERLY WIND FLOW AT 10 TO 20 KTS FROM SFC TO 5
KFT.

&&

.MARINE...AN INCREASE IN WINDS ON MONDAY WILL CAUSE SEAS TO RISE
WITH SMALL CRAFT ADVISORIES NOW EXPECTED BEGINNING MONDAY AFTERNOON
IN BOTH THE ATLANTIC AND CARIBBEAN WATERS.

[tailgater]

Looks like the windwards are gonna be pretty wet the next couple days.
http://www.ssd.noaa.gov/goes/east/catl/flash-avn.html

[bvigal]

yes, between 2 tropical waves

[abajan]

Barbados is actually under a flood watch because of this system.
Read more...

[cycloneye]

AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
306 PM AST FRI JUL 9 2010

.SYNOPSIS...HIGH PRESSURE ACROSS THE CENTRAL ATLANTIC WILL
MAINTAIN A MODERATE TO FRESH TRADE WIND FLOW ACROSS THE LOCAL
WATERS. UPPER LEVEL LOW WILL CONTINUE TO MOVE WEST AND WILL
CONTINUE NORTHEAST OF THE AREA THE NEXT FEW DAYS. A TROPICAL
WAVE WILL APPROACH THE LOCAL AREA SATURDAY.

&&

.DISCUSSION...AS USUAL IN SUMMER...SHOWERS DEVELOPED THIS
AFTERNOON ACROSS THE WESTERN PART OF THE ISLAND. SOME SHOWERS AND
THUNDERSTORMS WERE PRODUCING VERY HEAVY RAIN...AND GUSTY WINDS.
THIS ACTIVITY IS EXPECTED TO DISSIPATED NEAR SUNSET. A HIGH
PRESSURE SYSTEM WILL CONTINUE IN TOTAL CONTROL OF OUR LOCAL
WEATHER AT LEAST THROUGH TOMORROW. A TROPICAL WAVE LOCATED EAST OF
THE LESSER ANTILLES THIS MORNING WILL CONTINUE TO MOVE WEST
NORTHWEST TONIGHT...AND TOMORROW MORNING. LATEST COMPUTER MODELS
SUGGEST THIS WAVE WILL INTERACT WITH AN UPPER LEVEL LOW LOCATED
NORTHEAST OF THE LOCAL AREA...ENHANCING THE SHOWER ACTIVITY ACROSS
THE LOCAL AREA SATURDAY AFTERNOON...AND EVENING. HOWEVER...LATEST
COMPUTER MODELS RUNS INDICATED IS NOT GOING TO BE AS ACTIVE AS
PREVIOUSLY THOUGH. HOWEVER SATURDAY LOOKS THE WETTEST DAY...WITH
DRY AIR MOVING IN OVER THE LOCAL AREA SUNDAY. LOOKING AHEAD...NO
SIGNIFICANT WEATHER EVENTS ARE FORECAST TO AFFECT THE LOCAL AREA AT
THIS TIME.

&&

.AVIATION...MVFR CONDITIONS WILL PREVAIL ACROSS TJMZ...AND TJBQ AT
LEAST THROUGH 09/22Z. VFR CONDITIONS ARE EXPECTED TO PREVAIL
ACROSS ALL TAF SITES THROUGH AT LEAST 10/16Z. SOME PASSING SHOWERS
ARE POSSIBLE ACROSS TNCM...AND TKPK.

[cycloneye]

Here comes the tropical wave towards the Eastern Caribbean.

[cycloneye]

TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT FRI JUL 9 2010

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

THE HYDROMETEOROLOGICAL PREDICTION CENTER IS ISSUING ADVISORIES ON
TROPICAL DEPRESSION TWO...LOCATED INLAND OVER NORTHEASTERN MEXICO
ABOUT 90 MILES WEST OF LAREDO TEXAS. THESE ADVISORIES CAN BE
FOUND UNDER AWIPS HEADER TCPAT2 AND WMO HEADER WTNT32 KWNH.

A TROPICAL WAVE LOCATED OVER THE EXTREME SOUTHWESTERN CARIBBEAN SEA
IS PRODUCING A LARGE AREA OF SHOWERS AND THUNDERSTORMS AS IT MOVES
WESTWARD AT AROUND 20 MPH. WHILE TROPICAL CYCLONE FORMATION IS NOT
EXPECTED BEFORE THIS SYSTEM REACHES CENTRAL AMERICA...HEAVY
RAINFALL IS POSSIBLE TONIGHT AND SATURDAY ACROSS PORTIONS OF
HONDURAS AND NICARAGUA. THERE IS A LOW CHANCE...NEAR 0 PERCENT...OF
THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.
FOR ADDITIONAL INFORMATION ON THIS SYSTEM...PLEASE REFER TO
PRODUCTS FROM YOUR NATIONAL METEOROLOGICAL SERVICE.

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

$$
FORECASTER BRENNAN

[cycloneye]

Good morning.Some showers today because of the wave but nothing serious in terms of flooding is expected.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
613 AM AST SAT JUL 10 2010

.SYNOPSIS...A TUTT LOW WILL RECEDE TO THE NORTH FROM ITS POSITION
NOW ABOUT 700 MILES NORTHEAST OF SAN JUAN. A WEAK TROUGH WILL
CROSS THE AREA FROM EAST TO WEST ON TUESDAY. A PORTION OF THIS
TROUGH WILL DETACH AND SPIN UP NORTH OF THE ISLAND LATE NEXT
WEEK. WIND REMAINS LESS THAN 20 KNOTS THROUGH THE FORECAST
PERIOD...BUT VARIES IN DIRECTION.

AT MID LEVELS...A MID LATITUDE HIGH PRESSURE NORTH OF THE WINDWARD
ISLANDS WILL MOVE INTO THE CENTRAL ATLANTIC OVER THE WEEKEND...BUT
WILL RECONNECT WITH A GULF OF MEXICO HIGH BY MID WEEK. BY THE END
OF NEXT WEEK HIGH PRESSURE WILL STRETCH FROM FLORIDA TO THE CAPE
VERDE ISLANDS. DURING THE NEXT SEVERAL DAYS LOWS WILL MIGRATE OFF
THE AFRICAN CONTINENT AND WEAKEN OR OPEN INTO WAVES AS THEY
APPROACH THE LOCAL AREA.

AT LOW LEVELS...A TROPICAL WAVE STRETCHES FROM 400 MILES SOUTH OF
SAINT THOMAS TO ABOUT 400 MILES EAST OF THE LOCAL ISLANDS AND IS
MOVING WEST AT ABOUT 18 KNOTS. IT IS FOLLOWED BY AN AREA OF
SAHARAN DUST AND ANOTHER WAVE AT ABOUT 33 DEGREES WEST LONGITUDE
EXPECTED AROUND WEDNESDAY NIGHT.


&&

.DISCUSSION...THE TROPICAL WAVE CONTINUES TO INTERACT WITH THE
TUTT LOW NOW NEAR 27 NORTH 57 WEST. ON FRIDAY AN AREA OF
CONVECTION LAUNCHED NORTH ALONG THE AXIS OF THE WAVE TOWARD THE
CENTER OF THE TUTT LOW AND IS CONTINUING NORTH OF 18 DEGREES
NORTH. THIS CONVECTIVE ACTIVITY TRIGGERED A NUMBER OF GUSTS IN THE
30 TO 40 KNOT RANGE IN THE WINDWARD ISLANDS. MUCH LESS CONVECTIVE
ACTIVITY IS CURRENTLY SEEN ALONG THE WAVE AND THIS MAKES SENSE AS
IT NOW ENTERS THE SUPPRESSING SIDE OF THE TUTT LOW. CURRENTLY THE
WAVE IS MOVING 18 KNOTS TOWARD THE WEST AND IS EXPECTED TO CROSS
THROUGH SAINT THOMAS AROUND 10/21Z AND SAN JUAN AROUND 11/00Z.
PRECIPITABLE WATER HAS BOTTOMED OUT AROUND 1.6 INCHES AND
SATELLITE IMAGERY SUGGEST LITTLE CLOUDINESS BETWEEN THE FORECAST
AREA AND THE TROPICAL WAVE. ITS APPROACH HAS PRODUCED SOME
CEILINGS AROUND 4500 FEET IN GUADELOUPE...BUT WINDS THERE ARE NOW
QUITE LIGHT. WINDS ARE STILL EAST NORTHEAST AT 850 TO 700 MB AT
THIS LATITUDE BEHIND THE WAVE AND IT LOOKS LIKE THE MAJORITY OF
THE ENERGY IN THIS WAVE IS SOUTH OF 15 NORTH. THEREFORE AM
FORECASTING ONLY A MODEST INCREASE IN CONVECTIVE ACTIVITY ACROSS
THE CARIBBEAN...PUERTO RICO AND THE U.S. VIRGIN ISLANDS THROUGH
THIS AFTERNOON. AFTERNOON THUNDERSTORMS IN MODESTLY MOIST AIR WILL
BE GENERATED BEGINNING AROUND 1 PM AND ARE EXPECTED IN THE
NORTHWEST PORTION OF THE ISLAND...BUT ACTIVITY COULD OCCUR IN ANY
PART OF THE INTERIOR WITH GOOD INSOLATION. EXPECT MORE SHOWERS
AFTER SUNSET WHEN THE WAVE ARRIVES...EARLIER IN THE U.S. VIRGIN
ISLANDS. FLOODING...IF ANY WILL BE EXTREMELY LOCALIZED. SHOWER
ACTIVITY SHOULD GRADUALLY TAPER OFF ON SUNDAY...WITH EXCEPTION OF
THE AFTERNOON CONVECTIVE ACTIVITY WHICH SHOULD SPAWN NEAR THE
NORTH SLOPES OF THE CORDILLERA CENTRAL AND SPREAD OVER THE WESTERN
INTERIOR FROM THERE.

TEMPERATURES APPEARED TO BE TOO WARM FROM MOS THIS MORNING. THE
HIGH WAS 92 FOR SAN JUAN AND SOME AREAS AROUND THE CITY HAD 96
DEGREES. WITH THE APPROACHING WAVE SOUTHEAST FLOW IS NOT OCCURRING
NOW AND IS NOT EXPECTED THIS AFTERNOON...BUT MODERATE TO FRESH SEA
BREEZES SHOULD KEEP TEMPERATURE RISES LIMITED TO LEVELS SIMILAR TO
YESTERDAY...THEREFORE HAVE LOWERED THE HIGH TO 90 DEGREES...SOME
INTERIOR AREAS COULD BE A TAD WARMER. SIMILAR REDUCTIONS WERE MADE
TO TOMORROWS TEMPERATURES DUE TO INCREASED CLOUDINESS AND THE LACK
OF SOUTHEAST WINDS BEHIND THE WAVE.

AFTER THE WAVE LITTLE IS SEEN IN THE WAY OF STRONG TRIGGERS. THE
TUTT LOW IS FORECAST TO RETURN IN A WEAKER FORM NEXT WEEK. THE NAM
PLACES IT FURTHER WEST AND NORTHWEST OF THE LOCAL AREA WHILE THE
GFS BRINGS THE TROUGH DOWN PRACTICALLY OVERHEAD AND A LITTLE
WEAKER. THIS SHOULD SET THE STAGE FOR THE NEXT WAVE
PASSAGE...WHICH AT THE MOMENT DOES NOT SEEM TOO IMPRESSIVE.
CONVECTION IS WEAK. MUCH BETTER CONVECTION IS MOVING OFF THE COAST
OF AFRICA NOW AND THIS COULD BE THE WAVE EXPECTED SATURDAY OR
SUNDAY. THE WAVE AFTER THIS HAS BEEN FODDER FOR TROPICAL STORM
AMPLIFICATION BY THE GFS...BUT THIS TREND IS BECOMING MUCH LESS
PRONOUNCED AND SEEMS UNLIKELY AT THE MOMENT.

&&

.AVIATION...
CLOUDINESS AND SHRA WILL GRADUALLY INCREASE ACROSS THE LOCAL
REGION TODAY AS A WEAK TROPICAL WAVE IS APPROACHING FROM THE EAST.
SHRA/TSRA ACTIVITY WILL AFFECT TNCM...TKPK AND THE USVI TAF SITES
DURING THE MORNING HOURS AND THEN OVERSPREAD ACROSS THE PR TAFS
SITES MAINLY DURING AFTERNOON THROUGH EVENING HOURS. BRIEFLY MVFR
CONDS AND MOUNTAIN OBSCURATIONS IN PASSING SHRA/TSRA ARE EXPECTED
AS THE WAVE PASS BY. WINDS FROM EAST-NORTHEAST AT 10 TO 20 KTS
WILL SHIFT TO EAST SOUTHEAST ONCE THE WAVE PASSES.

&&

.MARINE...THUNDERSTORMS IN THE APPROACHING WAVE COULD PRODUCE
WINDS IN EXCESS OF 25 KNOTS FOR A BRIEF PERIOD WITH GUSTS GREATER
THAN 35 KNOTS...BUT OTHERWISE WINDS AND SEAS SHOULD REMAIN IN THE
EXERCISE CAUTION RANGE THROUGH SUNDAY IN MOST UNPROTECTED WATERS.

A PERSISTENT SURFACE HIGH IN THE CENTRAL ATLANTIC IS
EXPECTED TO KEEP FRESH TRADE WINDS OVER THE LOCAL AREA AND MAY
ALSO PUSH SEAS UP TO SMALL CRAFT ADVISORY LEVELS BY EARLY NEXT
WEEK.

[cycloneye]

TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 AM EDT SAT JUL 10 2010

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

CLOUDINESS AND THUNDERSTORMS ASSOCIATED WITH A TROPICAL WAVE ARE
SPREADING OVER NICARAGUA AND EASTERN HONDURAS. DEVELOPMENT OF THIS
SYSTEM IS NOT ANTICIPATED AS IT MOVES INLAND TODAY AND THERE IS A
LOW CHANCE...NEAR 0 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL
CYCLONE. AS THE WAVE MOVES ACROSS CENTRAL AMERICA DURING THE NEXT
DAY OR SO...IT WILL LIKELY BRING LOCALLY HEAVY RAINFALL AND GUSTY
WINDS TO THE REGION. FOR ADDITIONAL INFORMATION ON THIS SYSTEM...
PLEASE REFER TO PRODUCTS FROM YOUR NATIONAL METEOROLOGICAL SERVICE.

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

$$
FORECASTER BROWN

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1154 AM AST SAT JUL 10 2010

.UPDATE...PATCHES OF LOW TO MID LEVEL CLOUDS WITH SHOWERS AND
ISOLATED THUNDERSTORMS AHEAD OF A TROPICAL WAVE NOW ACROSS THE
SOUTHEAST CARIBBEAN...CONTINUED TO MOVE EAST TO WEST ACROSS THE
LOCAL AREA...AND REACH PARTS OF EASTERN PUERTO RICO. THE MODERATE
PREVAILING TRADES HOWEVER CONTINUED TO STEER THE SHOWER ACTIVITY
QUICKLY ACROSS THE ISLANDS...LEAVING NO SIGNIFICANT RAINFALL
ACCUMULATIONS AT THIS TIME. DURING THE AFTERNOON HOURS AND REST
OF THE EVENING HOWEVER...THE COMBINATION OF LOCAL AND DIURNAL
EFFECTS ALONG WITH THE APPROACH OF THE TROPICAL WAVE...EXPECT
SHOWERS AND ISOLATED THUNDERSTORM DEVELOPMENT ACROSS PARTS OF THE
INTERIOR AND WEST SECTIONS OF PUERTO RICO AS WELL AS OVER PARTS OF
THE VIRGIN ISLANDS. WHILE NO WIDESPREAD RAINFALL IS EXPECTED AT
THIS TIME....SOME OF THE SHOWERS AND STORMS WILL PRODUCE PERIODS
OF LOCALLY HEAVY DOWNPOURS THAT MAY LEAD TO URBAN AND SMALL STREAM
FLOODING. NO MAJOR CHANGES MADE TO INHERITED FORECAST WHICH LOOKED
GOOD FOR NOW.

&&

.AVIATION UPDATE...QUICK PASSING LOW LEVEL CLOUDS AND SHOWERS
MOVED IN VCNTY OF TJNR...TJSJ... AND TJPS DURING THE LATE MORNING
HOURS BUT OVERALL LOCAL AREA REMAINED VFR. FOR THE REST OF THE DAY
EXPECT INCR IN LOW TO MID LEVEL CLOUDINESS ACROSS THE REGION AS A
TROPICAL WAVE MOVES ACROSS THE EASTERN CARIBBEAN,. IN ADDITION
SHRA AND ISOLD TSTMS WILL DEVELOP ACROSS THE INTERIOR AND WEST
SECTIONS OF PR TO PRODUCED TEMPO MVFR/IFR CONDS BTW 10/17Z-10/22Z.
ELSEWHERE VFR CONDS WILL PREVAIL AT THIS TIME.

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
301 PM AST SAT JUL 10 2010

.SYNOPSIS...TROPICAL WAVE CURRENTLY SOUTH OF THE LOCAL
AREA WILL CONTINUE TO MOVE WEST NORTHWEST THROUGH SUNDAY. UPPER
LEVEL LOW WILL LINGER NORTHEAST OF THE LOCAL AREA NEXT FEW DAYS.

&&

.DISCUSSION...SCATTERED SHOWERS DEVELOPED THIS AFTERNOON ACROSS
THE NORTHWEST SECTION OF PUERTO RICO WITH ISOLATED THUNDERSTORMS
ALSO OBSERVED. REST OF PUERTO RICO WAS MOSTLY SUNNY. ONLY ISOLATED
TO SCATTERED SHOWERS ARE POSSIBLE ACROSS THE LOCAL AREA TONIGHT.
TROPICAL WAVE IS PASSING SOUTH OF THE LOCAL AREA...AND IS NOT
EXPECTED TO BRING ANY SIGNIFICANT SHOWER ACTIVITY ACROSS THE LOCAL
AREA. SUBSIDENCE AIR...IS MOVING IN ACROSS THE LOCAL AREA...WITH
SOME SAHARAN DUST SEEN IN LATEST VISIBLE SATELLITE IMAGES. LATEST
MIMIC TPW PRODUCT FROM CIMSS INDICATED ALSO A DECREASE IN
MOISTURE. THIS AREA OF DRY AIR WILL LINGER ACROSS THE LOCAL AREA AT
LEAST THROUGH SUNDAY. HOWEVER...PATCHES OF LOW LEVEL MOISTURE
BEHIND THE TROPICAL WAVE...WILL INCREASE SOMEWHAT THE CHANCES FOR
PRECIPITATION ACROSS THE LOCAL AREA SUNDAY AFTERNOON...AND MONDAY.
ALSO...A PERSISTENT UPPER LEVEL LOW...CURRENTLY NORTHEAST OF THE
LOCAL AREA...IS EXPECTED TO CONTINUE MOVING SLOWLY WEST NORTHWEST
AND WILL LINGER ENOUGH CLOSE TO THE LOCAL AREA...TO ENHANCE THE
DEVELOPMENT OF SHOWERS EACH AFTERNOON. IN THE LONG TERM...NO
SIGNIFICANT WEATHER EVENTS ARE FORECAST TO AFFECT THE LOCAL AREA
DURING THE UPCOMING WEEK.

&&

.AVIATION...AFTN SHOWERS AND ISOLD TSTMS WILL CONTINUE TO DEVELOP
AND MOVE WEST NORTHWEST ACROSS PARTS OF WEST INTERIOR AND NW
SECTIONS OF PUERTO RICO AT LEAST TIL 10/23Z. THIS MAY CAUSE TEMPO
MVFR OVR AND VCTY OF TJBQ AND TJMZ. EXPECT VFR CONDS ELSEWHERE AT
LEAST THROUGH 11/00Z. AN EASTERLY WIND SURGE AND PATCH OF LOW TO MID
LEVEL CLOUDINESS...WITH WNDS OF 15-25 KTS WILL MOVE ACROSS THE AREA
BTW 11/04Z-11/23. AN EXTENSIVE AREA OF SAHARAN DUST WILL ALSO SPREAD
WESTWARD ACROSS THE REGION DURING THE NEXT 24-36 HRS.

[cycloneye]

It was very hot today in parts of Puerto Rico one area was in Mayaguez on Western PR with the maximun temp of 96F.

http://weather.noaa.gov/weather/current/TJMZ.html