Caribbean - Central America Weather

[Gustywind]

Looks pretty strong for a twave given its location and we should hope that this could bring some water needed, really! Thus, that's a good a way to keep a closed eye on the tropical activity

[cycloneye]

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE JUL 24 2012

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.


...TROPICAL WAVES AND TROPICAL LOW...

A 1011 MB LOW IS ANALYZED ABOUT 180 NM OFF THE COAST OF
GUINEA-BISSAU NEAR 11N19W MOVING W AT 10 KT. SCATTERED MODERATE
CONVECTION IS FROM 10N-13N BETWEEN 19W-25W.

TROPICAL WAVE EXTENDS FROM 21N38W TO 12N41W MOVING W AT 15 KT.
THE WAVE IS WITHIN A DEEP LAYER MOISTURE MAXIMUM AS INDICATED ON
TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED RAIN AND SHOWERS ARE
WITHIN 120 NM OF THE WAVE AXIS.

TROPICAL WAVE EXTENDS FROM 18N70W TO 11N70W IN THE E CARIBBEAN
MOVING W AT 15 KT. CYCLONIC TURNING IS EVIDENT IN THE LOW-LEVEL
CLOUD FIELD IN THE VICINITY OF THE WAVE AXIS. SCATTERED MODERATE
CONVECTION IS E OF THE WAVE AXIS FROM 15N-17N BETWEEN 65W-70W.

TROPICAL WAVE EXTENDS FROM 20N78W TO 12N79W IN THE CENTRAL
CARIBBEAN MOVING W AT 15 KT. THE WAVE ALSO EXHIBITS BROAD
CYCLONIC TURNING. WIDELY SCATTERED MODERATE CONVECTION IS IN THE
VICINITY OF JAMAICA FROM 18N-19N BETWEEN 77W-80W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE COAST OF SENEGAL AT 14N17W
TO A 1011 MB LOW AT 11N19W TO 12N30W TO 11N40W TO 9N45W. THE
ITCZ CONTINUES FROM 9N45W TO THE COAST OF FRENCH GUIANA AT
5N53W. SCATTERED MODERATE CONVECTION IS FROM 10N-13N BETWEEN
19W-25W. RAIN AND SCATTERED SHOWERS ARE WITHIN 120 NM OF THE
REMAINDER OF THE MONSOON TROUGH AND ITCZ AXIS W OF 25W.


CARIBBEAN SEA...
A TROPICAL WAVE IS OVER THE E CARIBBEAN. ANOTHER TROPICAL WAVE
IS OVER THE CENTRAL CARIBBEAN. SEE ABOVE. ELSEWHERE...A 1006 MB
LOW IS CENTERED OVER N COLOMBIA NEAR 9N75W. WIDELY SCATTERED
MODERATE CONVECTION AROUND THE LOW. 15-25 KT TRADEWINDS ARE
NOTED BETWEEN THE TROPICAL WAVES. STRONGEST SURFACE WINDS ARE
OVER THE CENTRAL CARIBBEAN BETWEEN 68W-80W. SCATTERED MODERATE
TO STRONG CONVECTION IS NOTED OVER COSTA RICA AND THE SW
CARIBBEAN FROM 9N-12N BETWEEN 80W-86W. IN THE UPPER LEVELS...AN
UPPER LEVEL HIGH IS CENTERED OVER THE W CARIBBEAN NEAR 16N82W
WITH STRONG SUBSIDENCE. EXPECT THE TROPICAL WAVES TO MOVE W OVER
THE NEXT 24 HOURS WITH CONVECTION.

[cycloneye]

Good morning. We continue to watch the waves as they move thru the Atlantic,while variable weather prevails with a mix of sun and some showers for the next couple of days.


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
413 AM AST WED JUL 25 2012

.SYNOPSIS...AT UPPER LEVELS...A WEAK CUT-OFF LOW CONTINUES NORTHEAST
OF THE AREA WITH A TROUGH EXTENDING WEST SOUTHWEST AND NORTH OF
PUERTO RICO. BY WEEK`S END HIGH PRESSURE WILL REPLACE THE TROUGH.

AT MID LEVELS...A WEAK RIDGE EXTENDS ACROSS THE ATLANTIC BETWEEN
20 AND 30 NORTH LATITUDE...INSULATING THE AREA FROM THE MUCH
STRONGER TROUGH TO THE NORTH. THEN OVER THE WEEKEND STRONGER HIGH
PRESSURE MOVES INTO THE WATERS NORTHEAST OF THE LOCAL AREA AS A
WEAK TROUGH PASSES THROUGH FROM THE EAST. DURING THE MIDDLE OF
NEXT WEEK A LOW FORMS BETWEEN 20 AND 30 NORTH AND 40 AND 50 WEST
IN THE CENTRAL ATLANTIC WITH HIGH PRESSURE DIRECTLY TO THE NORTH
OF IT.

AT LOWER LEVELS...HIGH PRESSURE RIDGES SOUTHWEST FROM THE
NORTHEAST CENTRAL ATLANTIC AND THEN TO THE WEST FROM 50 WEST
BETWEEN 20 AND 30 NORTH. A WEAK WAVES PASSES THROUGH ON SATURDAY
FOLLOWED BY MOISTURE ON SUNDAY. ANOTHER WETTER WAVE IS EXPECTED
NEXT WEDNESDAY.

&&

.DISCUSSION...A FEW SHOWERS WERE SEEN SOUTHWEST OF SAINT CROIX AND OFF
THE NORTH AND EASTERN COASTS OF PUERTO RICO...AND A FEW SHOWERS
DRIFTED INLAND OVER THE NORTHEAST COAST...OTHERWISE IT WAS MOSTLY
DRY AND SOMEWHAT HAZY FROM THE PERSISTENT SAHARAN DUST. NOW THAT
THE WAVE HAS MOVED TO THE EAST AND DRIER AIR FROM THE NORTHEAST IS
IN PLACE...SHOWERS WILL BE FEW...AND CONCENTRATED MAINLY BETWEEN
MAYAGUEZ AND RINCON AREAS DURING THE AFTERNOON HOURS. THE RIDGE TO
THE NORTH OF THE AREA CONTINUES FOR AT LEAST THE NEXT SEVEN
DAYS...WHILE HIGH PRESSURE STRENGTHENS NEXT WEEK IN THE NORTHEAST
ATLANTIC. THE LOW PRESSURE THAT THE GFS WAS SPINNING UP FOR THE
FIRST FEW DAYS OF AUGUST IS NOW QUITE ORDINARY AND WAVE ACTION IS
ALSO RELATIVELY WEAK...IN PART DUE TO THE CONTINUED DRIER AIR BOTH
FROM THE SAHARA AND THE NORTHEAST ATLANTIC. THE LOCAL AREA WILL
REMAIN GENERALLY DRY THROUGH AT LEAST FRIDAY...MOISTEN UP ON
SATURDAY AND SUNDAY AND THEN CONTINUE WITH SCATTERED SHOWERS INTO
THE EARLY PART OF NEXT WEEK AS BETTER MOISTURE FROM THE EASTERN
TROPICAL ATLANTIC ARRIVES. NEVERTHELESS THE TRANSITION WILL BE
GRADUAL AND SERVE ONLY TO RETURN THE AREA TO A MORE NORMAL
PRECIPITATION PATTERN.

&&

.AVIATION...
VFR CONDS CONT AND EVEN ISOLD SHRA OFFSHORE AT NIGHT
AND OVER W PR IN AFTERNOON WILL NOT LOWER CONDS. SAHARAN DUST TO
CAUSE HAZE BUT AIRPORT VSBYS WILL REMAIN BETWEEN 7 TO 12 MILES.

&&

.MARINE...ALTHOUGH MODERATE TRADE WINDS WILL PERSIST...SEAS ARE
NOT EXPECTED TO EXCEED 5 FEET EXCEPT BRIEFLY IN ISOLATED AREAS
WHERE WINDS ARE STRONGEST. SHOWER ACTIVITY WILL INCREASE OVER THE
WEEKEND...OTHERWISE FAIR WEATHER IS EXPECTED.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 79 89 80 / 10 10 10 10
STT 89 79 90 80 / 10 10 10 20

[cycloneye]

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT WED JUL 25 2012

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1135 UTC.

...TROPICAL WAVES...

A 1010 MB LOW IS OFF THE W COAST OF AFRICA NEAR 13N21W MOVING W
10-15 KT. LOW IS EMBEDDED WITHIN AN AREA OF DEEP LAYER MOISTURE
AS DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 12N-15N BETWEEN
21W-24W.

MID ATLC TROPICAL WAVE EXTENDS FROM 21N39W TO 13N43W MOVING W
NEAR 15 KT. WAVE IS ALONG THE LEADING EDGE OF A SURGE OF DEEP
LAYER MOISTURE AS DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY.
NO ASSOCIATED DEEP CONVECTION.

TROPICAL WAVE IS IN THE CENTRAL CARIBBEAN EXTENDING FROM 19N74W
TO 11N75W MOVING W 20-25 KT. WAVE IS ALONG THE LEADING EDGE OF
LOW AMPLITUDE SURGE OF DEEP LAYER MOISTURE AS DEPICTED ON TOTAL
PRECIPITABLE WATER IMAGERY. NO ASSOCIATED SHOWERS/DEEP
CONVECTION.

TROPICAL WAVE IS IN THE CENTRAL CARIBBEAN EXTENDING FROM 20N81W
TO 12N82W MOVING W 15-20 KT. WAVE IS EMBEDDED WITHIN DRIER AIR
AS DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY MASKING THE
SATELLITE SIGNATURE. NO ASSOCIATED SHOWERS/DEEP CONVECTION.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE E TROPICAL
ATLC NEAR 17N16W THROUGH THE 1010 MB LOW CONTINUING ALONG 12N25W
13N33W TO 11N41W WHERE THE ITCZ CONTINUES ALONG 7N50W TO INLAND
OVER SOUTH AMERICA NEAR 6N57W. CLUSTERS OF SCATTERED MODERATE
CONVECTION ARE WITHIN 150/180 NM S OF THE MONSOON TROUGH BETWEEN
25W-32W AND WITHIN 150 NM EITHER SIDE OF THE ITCZ BETWEEN
44W-52W.

[cycloneye]

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
705 AM EDT WED JUL 25 2012

PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI. THE UPPER LEVEL ANALYSIS SHOWS A SHORT WAVE RIDGE WITH AXIS WEST ACROSS THE ISLAND CHAIN TO THE EASTERN CARIBBEAN. NORTH OF THIS AXIS...A WEAK TUTT MEANDERS OVER THE WESTERN ATLANTIC JUST NORTH OF THE ISLANDS. THE TUTT ALOFT IS A SHALLOW FEATURE...AND AS A RESULT IT IS HAVING LITTLE TO NO IMPACT ON LOCAL WEATHER CONDITIONS. IN THIS PATTERN...THE PWAT ANALYSIS SHOWS LOW MOISTURE CONTENT VALUES ACROSS THE CENTRAL ATLANTIC INTO THE EASTERN CARIBBEAN. AT LOW LEVELS... EASTERLY TRADES PREVAIL...WITH 850 HPA WINDS OF 10-15KTS.

UPPER LEVEL SHORT WAVE RIDGE PATTERN IS TO PERSIST ACROSS THE EASTERN CARIBBEAN DURING THE NEXT FEW DAYS. THE TUTT TO THE NORTH...MEANWHILE...IS TO RETROGRESS INTO HISPANIOLA THROUGH FRIDAY MORNING. IN THIS PATTERN...UNFAVORABLE ENVIRONMENTAL CONDITIONS ARE TO PERSIST ACROSS THE FORECAST AREA DURING THE NEXT 60 HRS...WITH MODELS SHOWING A STRONG CAP INVERSION AND LOW PWAT AMOUNTS. THIS IS TO GENERALLY FAVOR FAIR WEATHER CONDITIONS WITH
LITTLE TO NO CONVECTION EXPECTED. ON FRIDAY TO SATURDAY...AS THE TUTT PULLS ACROSS HISPANIOLA AND UPPER DIVERGENCE INTENSIFIES...DEEPER MOISTURE WILL START TO SURGE ACROSS THE NORTHEAST CARIBBEAN ISLES. MODELS THEN AGREE ON ISOLATED TO SCATTERED CONVECTION CLUSTERING ACROSS THE VIRGIN ISLES TO EASTERN PORTIONS OF PUERTO RICO.

LATER OVER THE WEEKEND...ENVIRONMENTAL CONDITIONS ARE TO BECOME SOMEWHAT MORE FAVORABLE AS A TROPICAL WAVE ENTERS THE FORECAST AREA. MODEL GUIDANCE SHOWS MOISTURE POOLING AROUND THIS FEATURE AS IT ENTERS THE LESSER ANTILLES ON SATURDAY EVENING...AND EXPANDING INTO THE USVI/PUERTO RICO DURING THE MORNING HOURS ON SUNDAY. DURING THAT PERIOD PWAT WILL PEAK AT 40-45MM...FAVORING ORGANIZED
CONVECTION WITH MODERATE RAINFALL AMOUNTS ACROSS THE ENTIRE FORECAST AREA.

MARINERO...DGOA/MARN (EL SALVADOR)
CANTILLO...IDEAM (COLOMBIA)
GALVEZ...HPC (USA)

[cycloneye]

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED JUL 25 2012

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1745 UTC.


...TROPICAL WAVES...

TROPICAL WAVE IS WEST OF CAPE VERDE ISLANDS ANALYZED FROM 18N17W
TO A 1012 MB LOW EMBEDDED IN THE MONSOON TROUGH NEAR 11N17W.
THIS SYSTEM IS EMBEDDED WITHIN A REGION OF DEEP LAYER OF
MOISTURE DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY. CLUSTERS
OF SCATTERED MODERATE TO STRONG CONVECTION COVER THE AREA FROM
10N-15N BETWEEN 20W-27W. THIS CONVECTION IS ALSO ASSOCIATED TO
THE MONSOON TROUGH DISCUSSED BELOW.

TROPICAL WAVE MOVES ACROSS THE CENTRAL TROPICAL ATLC WITH AXIS
ANALYZED FROM 23N39W TO THE MONSOON TROUGH AXIS NEAR 12N40W
MOVING W AT ABOUT 5-10 KT. THE WAVE REMAINS ALONG THE WRN EDGE
OF A SURGE OF DEEP LAYER MOISTURE AS DEPICTED ON TOTAL
PRECIPITABLE WATER IMAGERY. HOWEVER...THIS SYSTEM IS EMBEDDED IN
A DENSE REGION OF SAHARAN DUST LIMITING THE CONVECTIVE ACTIVITY
AROUND THE WAVE TO NEAR ZERO.

A TROPICAL WAVE MOVES ACROSS THE WESTERN CARIBBEAN WITH AXIS
ANALYZED FROM 20N75W TO 12N78W. WAVE REMAINS ON THE WRN EDGE OF
A SURGE OF DEEP MOISTURE NOTED ON TOTAL PRECIPITABLE WATER
IMAGERY. HOWEVER...THIS SYSTEM IS EMBEDDED IN REGION OF STRONG
SUBSIDENCE ALOFT AND SAHARAN DUST LIMITING THE CONVECTIVE
ACTIVITY AROUND THE WAVE TO JUST A FEW ISOLATED SHOWERS IN THE
VICINITY OF THE WAVE AXIS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE TROPICAL
ATLC THROUGH THE COAST OF MAURITANIA ALONG 18N16W TO THE
TROPICAL WAVES 1012 MB LOW NEAR 11N17W CONTINUING WESTWARD ALONG
10N27W 12N40W TO 7N50W...WHERE A SHORT SECTION OF THE ITCZ
CONTINUES TO THE COAST OF GUYANA NEAR 6N58W. CLUSTERS OF WEAK
SCATTERED CONVECTION ARE FROM 4N-10N BETWEEN 46W-55W. CLUSTERS
OF SCATTERED MODERATE TO STRONG CONVECTION ARE WITHIN 100-150 NM
ON EITHER SIDE OF THE MONSOON TROUGH BETWEEN 20W-33W.

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
300 PM AST WED JUL 25 2012

.SYNOPSIS...TUTT NORTH OF THE AREA WILL SLOWLY RETROGRADE THROUGH
THE END OF THE WORK WEEK WITH UPPER RIDGE EXPECTED TO BUILD IN
OVER THE WEEKEND. WEAK UPPER RIDGE WILL THEN HOLD THROUGH MID
NEXT WEEK. A TROPICAL WAVE WILL MOVE ACROSS THE AREA SUN FOLLOWED
BY A MORE SIG ONE NEXT TUE.

&&

.DISCUSSION...VERY DRY STABLE WX REGIME WILL PREVAIL THROUGH SAT
UNDER SAHARAN AIR LAYER. A TROPICAL WAVE ALONG 42W WITH LARGE
INVERTED-V SIGNATURE ON VIS IMAGERY IS FCST TO MOVE ACROSS THE
AREA SUN. THIS WAVE WILL BRING AN INCREASE IN MOISTURE AND
INSTABILITY FOR BETTER CHANCES OF SHOWERS AND THUNDERSTORMS.
HOWEVER...LINGERING MID LEVEL DRY AIR WILL LIKELY LIMIT COVERAGE
AND INTENSITY OF SHOWERS.

FEATURE OF MOST INTEREST IS TROPICAL WAVE ALONG 22W/23W AND
ACCOMPANYING SFC LOW PRES. 12Z GFS AND MEDIUM RANGE GUIDANCE FROM
NHC/HPC HAVE AEW MOVING FASTER THAN YESTERDAY AND STAYING MOSTLY
SOUTH OF THE LOCAL AREA. THE 12Z GFS AND GFES NOW SHOW A SLIGHTLY
BETTER UPPER LEVEL ENVIRONMENT WITH WEAK H25 ANTICYCLONE MOVING IN
TANDEM WITH THE WAVE WITH 7 OUT OF 12 GFES MEMBERS INDICATING A
CLOSED SFC CIRCULATION BETWEEN 1010-1012 MB. THERE IS CONSIDERABLE
SPREAD WITH TIMING OF WAVE PASSAGE SEEN ON THE SPAGHETTI PLOT BUT
HAVE SPED UP THE ASSOCIATED WX WITH THIS WAVE TO MON NIGHT THRU
TUE NIGHT TO BE MORE IN LINE WITH THE 12Z GFS/GFES AND NHC/HPC MEDIUM
RANGE GUIDANCE. MAIN LIMITING FACTOR FOR SIG DEVELOPMENT OF THIS
WAVE CONTINUES TO BE UNFVRBL PHASE OF THE MJO AND H25 POSITIVE
VELOCITY POTENTIAL ANOMALIES.

&&

.AVIATION...VFR CONDITIONS THROUGH SAT WITH NO SIG WX.

&&

.MARINE...SEAS 3-5 FT AND WINDS AROUND 15 KNOTS.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 80 89 80 89 / 10 10 10 20
STT 80 90 80 90 / 10 10 20 20

[cycloneye]

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED JUL 25 2012


BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.


...TROPICAL WAVES...

A 1011 MB TROPICAL LOW IS ANALYZED OFF THE COAST OF WEST AFRICA
NEAR 12N24W MOVING W AT 15 KT. WIDELY SCATTERED MODERATE
CONVECTION IS FROM 10N-14N BETWEEN 25W-28W.

TROPICAL WAVE EXTENDS FROM 21N41W TO 12N41W MOVING W AT 15 KT.
THE WAVE IS WITHIN A DEEP LAYER MOISTURE MAXIMUM AS INDICATED ON
TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED RAIN AND SHOWERS ARE
WITHIN 120 NM OF THE WAVE AXIS.

TROPICAL WAVE EXTENDS FROM 22N81W TO 13N81W IN THE WESTERN
CARIBBEAN MOVING W AT 15 KT. THE WAVE EXHIBITS BROAD LOW LEVEL
CYCLONIC TURNING. WIDELY SCATTERED MODERATE CONVECTION IS IN THE
VICINITY OF JAMAICA FROM 16N-19N BETWEEN 77W-80W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE COAST OF S MAURITANIA AT
18N17W TO A 1011 MB TROPICAL LOW AT 12N24W TO 10N30W TO 12N38W
TO 9N47W. THE ITCZ CONTINUES FROM 9N47W TO THE COAST OF GUYANA
AT 7N59W. SCATTERED MODERATE CONVECTION IS OFF THE COAST OF WEST
AFRICA S OF THE MONSOON TROUGH FROM 8N-10N BETWEEN 15W-17W.
WIDELY SCATTERED MODERATE CONVECTION IS IN THE VICINITY OF THE
TROPICAL LOW FROM 10N-14N BETWEEN 25W-28W. MORE WIDELY SCATTERED
MODERATE CONVECTION IS ALONG THE MONSOON TROUGH FROM 8N-12N
BETWEEN 30W-35W. SIMILAR CONVECTION IS IN THE VICINITY OF THE
ITCZ FROM 5N-9N BETWEEN 47W-55W.

[Macrocane]

SEVERE DROUGHT IN THE EAST COAST OF EL SALVADOR

Hi guys, I told you last week that June was the 3rd driest June on record in El Salvador, well in July the west and central parts of El Salvador recover from the dry pattern but in the east part the situation worsened and the SNET has declared a drought in that part of the country, it's the first time since 2007 that we have an official drought. This map shows the rainfall from July 1 to July 24, as you can see there's a huuuuge difference between the west and the east parts of the country, in Juayúa there have been 510 mm/20.08 inches but in La Union only 5 mm/0.20 inches have been registered.



From June 1 to July 24 there have been 38 dry days in parts of east El Salvador, 18 consecutive days in July. The next map shows in yellow the area under a weak drought, in orange the moderate drought and in red the severe drought.



It seems that the areas affected could see some relief by August but according to the SNET the amounts of rainfall will be below normal in the second half of the rainy season (Aug-Oct).

[cycloneye]

Good morning. We keep watching the waves as they move across the atlantic.


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
504 AM AST THU JUL 26 2012

.SYNOPSIS...A SERIES OF UPPER LEVEL LOWS MIGRATES WESTWARD BETWEEN 20 AND
30 NORTH LATITUDE BETWEEN NOW AND EARLY NEXT MONTH. WINDS ALOFT
REACH 25 KNOTS OVER AGUADILLA THURSDAY NIGHT WHEN A JET FROM THE
SOUTHWEST AROUND A LOW JUST NORTH OF THE DOMINICAN REPUBLIC PASSES
OVER...OTHERWISE FLOW IS GENERALLY LESS THAN 15 KNOTS. HIGH
PRESSURE DOMINATES AFTER MID WEEK NEXT WEEK.

AT MID LEVELS...HIGH PRESSURE REMAINS NORTH AND NORTHEAST OF THE
AREA...BUT MID LEVEL TROUGHS MOVE PAST THE AREA FROM THE EAST
SUNDAY AND TUESDAY.

AT LOWER LEVELS...A GENERALLY DRY AIR MASS PERSISTS UNTIL A WEAK
WAVE MOVES THROUGH ON FRIDAY NIGHT. ADDITIONAL MOISTURE FOLLOWS
ON SUNDAY...THEN A MUCH STRONGER WAVE APPROACHES ON MONDAY AND
CROSSES THROUGH ON MONDAY NIGHT. MOISTURE FOLLOWS THIS BAND UNTIL
FRIDAY ALTHOUGH THERE ARE BRIEF DRY SLOTS.

&&

.DISCUSSION...VERY FEW SHOWERS APPEARED ON RADAR OVERNIGHT AND
THESE WERE QUITE LIGHT. FLOW AT LOWER LEVELS HAS TURNED TO THE
EAST NORTHEAST AND IS EXPECTED TO MAKE TEMPERATURES ON THE NORTH
COAST SLIGHTLY COOLER TODAY. FEW SHOWERS ARE EXPECTED TODAY
BUT CHANCES INCREASE A LITTLE AS WE APPROACH THE WEEKEND. MOISTURE
CONTINUES TO INCREASE SUNDAY THROUGH MONDAY AS A MUCH STRONGER
WAVE APPROACHES THE AREA. MODELS ARE HINTING AT GUSTY WINDS AND
THUNDERSTORMS...BUT IT IS TOO EARLY TO HIGHLIGHT THIS MUCH IN THE
FORECAST. THE GFS ALSO SHOWS THE LIFTED INDEX DROPPING BELOW MINUS
4 ON SUNDAY AND REMAINING BETWEEN MINUS 4 AND MINUS 6 THROUGH 4
AUGUST. VERY STABLE INDICES...FOR OUR AREA...OF GREATER THAN MINUS
1 ARE INDICATED FOR FRIDAY AND SATURDAY AHEAD OF THE FIRST WEAK
TROPICAL WAVE...AND THE FORECAST CONTINUES TO CALL FOR ONLY
ISOLATED SHOWERS UNTIL SATURDAY AFTERNOON. SCATTERED THUNDERSTORMS
SHOULD BE EXPECTED MONDAY AND TUESDAY...WITH PERIODS OF SHOWERS
AND THUNDERSTORMS LINGERING THROUGH THE END OF THE WEEK IN
SOUTHEAST FLOW. ALL CLOSED LOWS LEAVING AFRICA BECOME OPEN WAVES
IN THE 26/00Z GFS RUN BEFORE REACHING THE LOCAL AREA NOW THROUGH
4 AUGUST. SYSTEMS ALSO APPEAR WEAKER IN THE ECMWF.

&&

.AVIATION...
VFR CONT NEXT COUPLE OF DAYS XCP ALL TAF SITES HAVE AN
OUTSIDE SHOT OF GETTING BARELY VFR CIGS...MAINLY IN AFTERNOON ISOLD
CONVECTION. LLVL WINDS (BLO FL150) WILL GRADUALLY INCREASE...ENE 12-20
KT BY LATE AFTERNOON THEN 15-28 KT BY 27/12Z.

&&

.MARINE...WINDS INCREASE UNSTEADILY NOW THROUGH TUESDAY. DEPENDING
ON THE STRENGTH OF THE TROPICAL WAVE THAT PASSES ON TUESDAY...SMALL
CRAFT ADVISORIES MAY BE NEEDED FOR WINDS AND SEAS TUESDAY...OTHERWISE
MARINERS WILL NEED TO EXERCISE CAUTION IN SOME WATERS DUE TO WINDS
UP TO 18 TO 20 KNOTS.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 79 89 79 / 10 10 20 10
STT 90 79 90 80 / 10 20 20 20

[Gustywind]

Again fair and dry weather conditions continue in much of the Lesser Antilles... but twaves becoming more frequent and a little more organized as we're progressively approaching the heart of the hurricane season.

[cycloneye]

HPC discussion of Caribbean.

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
727 AM EDT THU JUL 26 2012

PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI. DRY AND
STABLE CONDITIONS PREVAIL AT THIS TIME...WITH STRONG SUBSIDENCE
CAP ACROSS THE FORECAST AREA SUSTAINING A PWAT MINIMA. UPPER FLOW
IS UNDER INFLUENCE OF A SHORT WAVE RIDGE ACROSS THE EASTERN
CARIBBEAN ISLANDS...AND A TUTT TO THE NORTH OF THE FORECAST AREA.
ANOTHER TUTT LIES FARTHER TO THE EAST...WITH FEATURE RETROGRESSING
ACROSS THE TROPICAL ATLANTIC.

THE TUTT LOW TO THE NORTH RETROGRESSES TO HISPANIOLA EARLY IN THE
CYCLE......AND THROUGH SATURDAY MORNING IT PULLS FARTHER WEST
ACROSS CUBA/THE BAHAMAS. ALTHOUGH TROUGH MOVES TO THE
WEST...STRONG SUBSIDENCE CAP IS TO PERSIST THROUGH FRIDAY
EVENING/EARLY SATURDAY. MEANWHILE...FAIR WEATHER CONDITIONS ARE
EXPECTED TO PREVAIL. AFTERNOON CONVECTION IS TO AFFECT INTERIOR
PORTIONS OF PUERTO RICO...WITH HIGHER RESOLUTION GUIDANCE SHOWING
ACTIVITY CLUSTERING ALONG THE CORDILLERA CENTRAL AND WESTERN
PORTIONS OF THE ISLAND. BUT FOR THE MOST PART ONLY SHOWING LIGHT
RAINFALL AMOUNTS.

THE NEXT TUTT APPROACHES THE FORECAST AREA LATER ON SATURDAY. THIS
HAS A STRONGER MID LEVEL PRESENCE...AND WILL BE STRONG ENOUGH TO
BREACH SUBSIDENCE CAP ACROSS THE FORECAST AREA. AT LOW LEVELS
EXPECTING TROPICAL WAVE TO ENTER THE ISLAND CHAIN EARLY ON
SATURDAY...AND PULL ACROSS THE USVI/PUERTO RICO LATER IN THE DAY.
DEEP MOISTURE WILL GRADUALLY INCREASE ACROSS THE FORECAST AREA...
PRESENTING RISK OF SCATTERED CONVECTION ACROSS THE NORTHEAST
CARIBBEAN ISLES. MODEL GUIDANCE...HOWEVER...ARE TRENDING TOWARDS
LOWER AMOUNTS THAN WHAT THEY PREVIOUSLY INDICATED.

LONG RANGE GUIDANCE SHOWING STRONGER PERTURBATION ENTERING THE
FORECAST AREA BY THE MIDDLE OF NEXT WEEK. THEY AGREE QUITE WELL ON
INTENSITY OF THIS FEATURE AND POTENTIAL FOR HEAVY RAINFALL AMOUNTS.

MARINERO...DGOA/MARN (EL SALVADOR)
CANTILLO...IDEAM (COLOMBIA)
GALVEZ...HPC (USA)

[cycloneye]

SEVERE DROUGHT IN THE EAST COAST OF EL SALVADOR

Hi guys, I told you last week that June was the 3rd driest June on record in El Salvador, well in July the west and central parts of El Salvador recover from the dry pattern but in the east part the situation worsened and the SNET has declared a drought in that part of the country, it's the first time since 2007 that we have an official drought. This map shows the rainfall from July 1 to July 24, as you can see there's a huuuuge difference between the west and the east parts of the country, in Juayúa there have been 510 mm/20.08 inches but in La Union only 5 mm/0.20 inches have been registered.

http://img23.imageshack.us/img23/1995/s ... de2012.png

From June 1 to July 24 there have been 38 dry days in parts of east El Salvador, 18 consecutive days in July. The next map shows in yellow the area under a weak drought, in orange the moderate drought and in red the severe drought.

http://img560.imageshack.us/img560/8459 ... uajuli.png

It seems that the areas affected could see some relief by August but according to the SNET the amounts of rainfall will be below normal in the second half of the rainy season (Aug-Oct).

Wow,even with a Moonson trough around there is a drought. What I find surprising is the SNET forecast of below normal rainfall in August thru October period as El Nino for sure will be in the Pacific and that causes plenty of TC activity.

[Gustywind]

Here is the the twave with its low pressure moving westward...

[Macrocane]

Wow,even with a Moonson trough around there is a drought. What I find surprising is the SNET forecast of below normal rainfall in August thru October period as El Nino for sure will be in the Pacific and that causes plenty of TC activity.

Yep, the problem is that during El Niño years those tropical systems usually go west and don't reach us and with below normal activity in the Atlantic we don't have significant rainmakers from there either. There have been exceptions though, like Ida and Invest 96E in 2009 that brought the yearly rainfall to normal levels but they also caused one of the worst disasters in our history. Let's hope that the lack of rainfall won't be as severe in the next months but sure we don't want an dangerous cyclone either.

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1055 AM AST THU JUL 26 2012

.UPDATE...ONLY ISOLATED PASSING SHOWERS WERE DETECTED THIS MORNING
MAINLY ACROSS EASTERN SECTIONS OF PUERTO RICO AS WELL AS ACROSS
THE SURROUNDING COASTAL WATERS. THE MODERATE TO FRESH LOW TO MID
LEVEL WINDS HAS ALLOWED CELLS TO MOVE RATHER QUICKLY...SO ONLY
VERY LIMITED PCPN AMOUNTS HAS OCCURRED ACROSS THE LOCAL ISLANDS SO
FAR THIS MORNING. TJSJ 26/12Z SOUNDING INDICATED THAT PWAT HAS
DECREASED TO AROUND 1.30 OVERNIGHT. A DRY AND STABLE AIR
MASS...AND A SAHARAN AIR LAYER IS EXPECTED TO CONTINUE ACROSS THE
LOCAL ISLANDS TODAY THROUGH AT LEAST FRIDAY. IN FACT...GFS
COMPUTER GUIDANCE...SUGGESTS PWAT VALUES WILL CONTINUE BELOW 1.5
INCHES TONIGHT AND TOMORROW. HOWEVER...A WEAK TROPICAL WAVE WILL
MOVE ACROSS THE REGION LATE SATURDAY AND SUNDAY...SLIGHTLY
INCREASING THE CLOUDINESS AND THE CHANCES OF SHOWERS ACROSS THE
LOCAL ISLANDS. A MUCH STRONGER TROPICAL WAVE IS EXPECTED TO
APPROACH TO THE REGION EARLY MONDAY AND TUESDAY INDUCING A
GENERALLY INCREASE IN SHOWERS ND THUNDERSTORMS ACROSS THE LOCAL
ISLANDS.

[cycloneye]

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU JUL 26 2012


BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1735 UTC.

...TROPICAL WAVES...

TROPICAL WAVE AXIS MOVES ACROSS THE ERN TRPCL ATLC ANALYZED FROM
18N30W TO 10N32W. THIS SYSTEM WAS LABELED AS A LOW PRESSURE
SYSTEM ON PREVIOUS SURFACE MAPS. HOWEVER...AS THE SYSTEM MOVES
OVER UNFAVORABLE REGIONS OF DEVELOPMENT...IT'S LOW LEVEL CENTER
HAS WEAKENED EXPOSING ONLY A WAVE AXIS. THIS SCENARIO WAS
CONCLUDED THIS MORNING AS AN ASCAT SCATTEROMETER PASS WENT OVER
THIS REGION INDICATING THE ELONGATED CYCLONIC CURVATURE ALONG
THE WAVE AXIS...WHICH IS FOUND WEST OF A REGION OF DEEP LAYER OF
MOISTURE DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY. SOME MID
LEVEL CYCLONIC CURVATURE REMAINS AROUND THE WAVE AXIS ON THE
CLOUD PATTERN ON EARLY VISIBLE SATELLITE PICTURES OF THE DAY.
THE RAIN AND THUNDERSTORM ACTIVITY REMAINS MOSTLY S OF THE WAVE
AXIS WHERE THE MONSOON TROUGH IS ANALYZED.

TROPICAL WAVE MOVES ACROSS THE CENTRAL TROPICAL ATLC WITH AXIS
ANALYZED FROM 23N45W TO THE MONSOON TROUGH AXIS NEAR 11N48W
MOVING W AT ABOUT 5-10 KT. THE WAVE REMAINS ALONG THE WRN EDGE
OF A SURGE OF DEEP LAYER MOISTURE DEPICTED ON TOTAL PRECIPITABLE
WATER IMAGERY. HOWEVER...THIS SYSTEM IS EMBEDDED IN A DENSE
REGION OF SAHARAN DUST LIMITING THE CONVECTIVE ACTIVITY AROUND
THE WAVE TO NEAR ZERO.

A TROPICAL WAVE MOVES ACROSS THE N-WESTERN CARIBBEAN WITH AXIS
ANALYZED FROM THE WRN TIP OF CUBA NEAR 22N84W TO INLAND OVER
N-CENTRAL NICARAGUA NEAR 14N85W. WAVE REMAINS ON THE WRN EDGE OF
A SURGE OF DEEP MOISTURE NOTED ON TOTAL PRECIPITABLE WATER
IMAGERY. AN UPPER LEVEL INVERTED TROUGH MOVES ACROSS CENTRAL
AMERICA AND YUCATAN PENINSULA ON WATER VAPOR IMAGERY. THIS
FEATURE ALONG WITH LOW LEVEL MOISTURE CONVERGENCE IN THE
VICINITY OF THE WAVE AXIS IS GENERATING AN AREA OF SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS S OF 19N W OF 82W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE TROPICAL
ATLC THROUGH THE COAST DAKAR SENEGAL TO JUST EAST OF THE ERN
ATLC TROPICAL WAVE NEAR 13N28W...RESUMING SW OF THE SAME
TROPICAL WAVE NEAR 10N32W CONTINUING WESTWARD ALONG 11N44W TO
9N52W...WHERE A SHORT SECTION OF THE ITCZ CONTINUES TO THE COAST
OF GUYANA NEAR 7N58W. CLUSTERS OF SCATTERED MODERATE TO STRONG
CONVECTION ARE FROM 6N-11N BETWEEN 50W-60W. SIMILAR CONVECTION
IS FOUND S OF ERN ATLC TROPICAL WAVE FROM 6N-11N BETWEEN
28W-38W. SCATTERED WEAK TO ISOLATED MODERATE CONVECTION IS
WITHIN 170 NM OFF THE COAST OF WEST AFRICA FROM SIERRA LEONE TO
GUINEA-BISSAU.

[cycloneye]

Good afternoon. Those who live in the Eastern Caribbean islands,let's pay close attention to the wave WSW of CV islands as it may bring heavy showers and some gusts next Monday thru Tuesday.


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
313 PM AST THU JUL 26 2012

.SYNOPSIS...MID TO UPPER LEVEL HIGH PRESSURE RIDGE WILL REMAIN IN
PLACE OVER THE NEXT COUPLE OF DAYS ALLOWING FOR A FAIRLY STRONG
SUBSIDENCE CAP ACROSS THE REGION. SURFACE HIGH PRESSURE RIDGE
LOCATED NORTH THROUGH NORTHEAST OF THE REGION WILL HELP MAINTAIN
MODERATE TRADE WINDS ACROSS THE NORTHEAST CARIBBEAN INTO EARLY NEXT
WEEK. A WEAK TUTT INDUCED LOW TO MID LEVEL TROUGH/EASTERLY WAVE NOW
NEAR 50 WEST IS FORECAST TO CROSS THE LESSER ANTILLES BY LATE
FRIDAY...THEN QUICKLY MOVE ACROSS THE EASTERN CARIBBEAN SATURDAY
THOUGH SUNDAY. A HIGH AMPLITUDE TROPICAL WAVE AND ASSOCIATED BROAD
MOISTURE FIELD WAS NOW NEARING 30 WEST. THE TROPICAL WAVE WILL
CONTINUE WESTWARD OVER THE NEXT FEW DAYS WITH WAVE AXIS EXPECTED TO
ARRIVE JUST EAST OF THE LESSER ANTILLES BY MONDAY.

&&

.DISCUSSION...LATEST TOTAL PRECIPITABLE WATER ANALYSIS...VISIBLE
SATELLITE IMAGERY AND DOPPLER WEATHER RADAR ALL SUGGEST FAIRLY DRY
AND STABLE CONDITIONS DOMINATING THE REGION TODAY. EARLIER UPPER AIR
SOUNDINGS ACROSS THE ISLANDS SUGGESTED PRECIPITABLE WATER RANGED
BETWEEN 1.15 TO 1.50 INCHES ACROSS THE NORTHEAST CARIBBEAN. ONLY
PATCHES OF TRADE WIND MOISTURE WERE NOTED QUICKLY MOVING WEST ACROSS
THE LOCAL AREA. THE TJSJ 26/12Z SOUNDING INDICATED FAIRLY STRONG
SUBSIDENCE CAP INVERSION AROUND 2 DEGREES. THE LACK OF LOW LEVEL
MOISTURE AND GOOD CAP SHOULD LIMIT ANY SIGNIFICANT CONVECTION TODAY
AND ALSO ON FRIDAY. THEREFORE EXPECT ONLY ISOLATED DIURNALLY INDUCED
SHOWERS TO DEVELOP ACROSS THE ISLANDS DURING THE REST OF TODAY WITH
ONLY A VERY SLIGHT CHANCE OF ANY LATE AFTERNOON THUNDERSTORM DEVELOPING
MAINLY IN THE WEST INTERIOR SECTION OF PUERTO RICO.

LATEST GFS MODEL GUIDANCE INITIALIZED FAIRLY WELL AND CONTINUE TO
SUGGEST A QUICK SURGE OF MOISTURE TO MOVE ACROSS THE REGION SATURDAY
INTO SUNDAY ACCOMPANYING THE EASTERLY PERTURBATION EXPECTED TO MOVE
ACROSS THE EASTERN CARIBBEAN. HOWEVER...A SHARP INCREASE IN PWAT
VALUES OF GREATER THAN 2 INCHES IS FORECAST LATE SUNDAY INTO THE
EARLY PARTS OF NEXT WEEK WITH THE APPROACH OF THE AFOREMENTIONED
TROPICAL WAVE. IN ADDITION THE TUTT NOW ACROSS THE CENTRAL TROPICAL
ATLANTIC IS ALSO FORECAST TO SHIFT FURTHER WEST AND ERODE THE MID
TO UPPER LEVEL RIDGE NOW OVERHEAD. THESE TWO FACTORS SUGGEST
INCREASING TROPICAL MOISTURE AND BETTER POTENTIAL FOR MORE ACTIVE
AND WETTER WEATHER CONDITIONS STARTING EARLY NEXT WEEK. FOR NOW
WILL ONLY GRADUALLY INCREASE THE CONVECTIVE POTENTIAL WITH MOSTLY
LOCAL TERRAIN AND DIURNALLY INDUCED CONVECTION ON SATURDAY THROUGH
SUNDAY...AND A BETTER CHANCE FOR MORE DYNAMICALLY INDUCED SHOWERS
AND THUNDERSTORMS BEGINNING ON MONDAY AND CONTINUING THROUGH AT
LEAST MID WEEK. AS USUAL...WILL CONTINUE TO MAKE MODIFICATIONS AND
ADJUSTMENTS TO THE LONG TERM FORECAST GRIDS BASED ON THE TIMING OF
THESE FEATURES.

&&

.AVIATION...PREVAILING VFR CONDITIONS WILL CONTINUE ACROSS THE LOCAL
ISLANDS AND AT ALL TAF SITES DURING THE NEXT 24 HOURS. SAHARAN DUST
WILL RESULT IN HAZY SKIES...BUT MOST VISIBILITIES ARE EXPECTED TO
REMAIN P6SM. TJSJ 26/12Z SOUNDING INDICATED AN EASTERLY WIND FLOW UP
TO 20 KNOTS FROM THE SURFACE TO 5K FEET...BECOMING EAST
NORTHEASTERLY 10-20K FEET AND LIGHT AND VARIABLE ALOFT.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 79 89 79 90 / 10 20 10 20
STT 79 90 80 89 / 20 20 20 20

[cycloneye]

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU JUL 26 2012

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS W OF THE CAPE VERDE ISLANDS FROM 20N31W TO
10N32W MOVING W AT 20 KT. THE WAVE IS WITHIN A DEEP LAYER
MOISTURE MAXIMUM AS INDICATED ON TOTAL PRECIPITABLE WATER
IMAGERY. A LARGE PLUME OF AFRICAN DUST IS HOWEVER SUPPRESSING
SIGNIFICANT CONVECTION. SCATTERED RAIN AND SHOWERS ARE WITHIN
120 NM OF THE WAVE AXIS.

TROPICAL WAVE EXTENDS FROM 23N47W TO 11N49W MOVING W AT 15 KT.
THE WAVE IS WITHIN A DEEP LAYER MOISTURE MAXIMUM AS INDICATED ON
TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED RAIN AND SHOWERS ARE
WITHIN 120 NM OF THE WAVE AXIS.


...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE COAST OF GUINEA-BISSAU AT
12N16W TO 13N23W TO 10N33W TO 11N44W. THE ITCZ CONTINUES FROM
11N44W TO 12N50W TO THE COAST OF GUYANA AT 8N59W. WIDELY
SCATTERED MODERATE CONVECTION IS ALONG THE COAST OF WEST AFRICA
FROM 8N-13N BETWEEN 15W-18W. WIDELY SCATTERED MODERATE
CONVECTION IS ALSO FROM 6N-9N BETWEEN 30W-39W. SCATTERED RAIN
AND SHOWERS ARE WITHIN 60 NM OF THE ITCZ BETWEEN 50W-59W.

[cycloneye]

Good morning. We can see plenty of rain and some gusts as the wave moves thru by late Sunday thru Tuesday.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
535 AM AST FRI JUL 27 2012

.SYNOPSIS...AT UPPER LEVELS...A TUTT WITH MULTIPLE LOWS CONTINUES
BETWEEN 20 AND 30 NORTH LATITUDE THROUGH MID WEEK NEXT WEEK.
GENERALLY HIGH PRESSURE CONTINUES OVER THE CARIBBEAN. THE TROUGH
FROM THE STRONGEST LOW NORTHEAST OF THE AREA ON FRIDAY OF NEXT
WEEK PULLS ACROSS THE FORECAST AREA ON THE FOLLOWING SUNDAY.

AT MID LEVELS...HIGH PRESSURE DOMINATES THE ATLANTIC NORTH OF THE
ISLANDS UNTIL LATE NEXT WEEK. TROUGHS MOVE THROUGH ON SATURDAY
AND TUESDAY. A REFLECTION OF THE STRONGER TUTT LOW IS NORTHEAST OF
THE AREA AND MOVES CLOSER DURING THE WEEK. ALTHOUGH SOME MOISTURE
IS SEEN SATURDAY NIGHT AND SUNDAY...BEST MOISTURE AT MID LEVELS
COMES WITH THE SECOND TROPICAL WAVE TUESDAY AND CONTINUES UNTIL
LATE NEXT WEEK.

AT LOWER LEVELS... A WEAK WAVE MOVES THROUGH TODAY FOLLOWED BY
ANOTHER WEAK TROUGH ON SUNDAY MORNING. A MUCH STRONGER TROPICAL
WAVE WILL APPROACH THE AREA ON MONDAY AND MOVE THROUGH ON TUESDAY
WITH BETTER MOISTURE THAN HAS BEEN SEEN IN SEVERAL WEEKS. MOISTURE
WILL LINGER WITH RIPPLES IN THE FLOW THROUGH FRIDAY OF NEXT WEEK.

&&

.DISCUSSION...SCATTERED SHOWERS HAVE INVADED THE SOUTHEAST HALF
OF THE FORECAST AREA AS THE FIRST LEG OF A TROPICAL WAVE MOVES
INTO THE AREA. MIMIC PRODUCT SHOWS THAT THIS LEG DEVELOPED LATE
YESTERDAY AFTERNOON AND OVERNIGHT AS THE POSITIVELY-TILTED AXIS
OF THE WAVE LOCATED NEAR 20 NORTH AND 53 WEST AT 27/07Z
APPROACHED THE LESSER ANTILLES. THE MIMIC PRODUCT ALSO SHOWS THAT
THE MOISTURE IN THE WAVE HAS SEPARATED FROM THE ITCZ TO THE SOUTH
OF IT AND IS MOVING A LITTLE FASTER THAN THE WAVE THAT ORIGINALLY
GENERATED IT. THE TWO LEGS FORMING THE INVERTED V SHAPE OF THE
WAVE SHOULD PASS THIS AFTERNOON OR EVENING AND AGAIN ON SUNDAY.
THIS IS FOLLOWED ON SUNDAY EVENING BY DRYING AT 700 MB AND THE
SURFACE. BETTER LOW- LEVEL MOISTURE MOVES IN OVERNIGHT SUNDAY
NIGHT TO HOLD SCATTERED TO NUMEROUS SHOWERS IN THE FORECAST FOR
THE USVI AND THE WINDWARD PORTION OF PUERTO RICO DESPITE LOW TO
MID LEVEL DRYING. THE SECOND WAVE ARRIVES MONDAY AROUND NOON...OR
JUST BEFORE...IN THE USVI AS A GLOBE OF MOISTURE WITH A TAIL
STREAMING BACK FROM ITS TOP. IT CROSSES INTO PUERTO RICO DURING
THE AFTERNOON AND EVENING MONDAY SPREADING SHOWERS AND SCATTERED
THUNDERSTORMS ACROSS THE AREA THROUGH TUESDAY. THE MOISTURE
"TAIL" THEN CROSSES THROUGH THE LOCAL AREA ON WEDNESDAY.
PRESENTLY SATELLITE PRODUCTS CONFIRM THE MOISTURE IN THE SECOND
WAVE AND EXPECT THAT THIS WILL NOT WEAKEN VERY MUCH AS IT
APPROACHES THE CARIBBEAN. THIS WILL BRING CLOUDIER AND WETTER
WEATHER FOR THE UPCOMING WEEK IN CONTRAST TO THE DRIER AND HAZIER
WEATHER THIS WEEK. WITH THE UPPER LEVEL LOWS AND THEIR MOISTURE
ALSO EXPECT AN INCREASE IN THUNDERSTORM ACTIVITY. SOME OF THOSE
THUNDERSTORMS WILL PRODUCE GUSTY WINDS...ESPECIALLY AS THE SECOND
WAVE ENTERS THE AREA ON MONDAY.

&&

.AVIATION...
PREVAILING VFR CONDITIONS WILL CONTINUE ACROSS THE LOCAL ISLANDS
AND AT ALL TAF SITES THROUGH AT LEAST 27/22Z. HOWEVER... BRIEF
PERIODS OF MVFR CONDITIONS WITH MOUNTAIN OBSCURATIONS CAN BE
EXPECTED THIS AFTERNOON OVER TJMZ. SURFACE WINDS WILL CONTINUE
MAINLY EAST AT 10 TO 15 KTS WITH HIGHER GUSTS.

&&

.MARINE...WINDS AND SEAS WILL DECREASE SOMEWHAT SATURDAY AND
SUNDAY...BUT INCREASE CONSIDERABLY ON MONDAY. AT THIS TIME EXPECT
PREVAILING WINDS AND SEAS TO APPROACH SMALL CRAFT ADVISORY CRITERIA
MONDAY...BUT FORECAST FALLS JUST SHORT. NEVERTHELESS
THUNDERSTORMS...ESPECIALLY THOSE ACCOMPANYING THE INVADING
TROPICAL WAVE MONDAY...WILL CONTAIN VERY GUSTY WINDS DUE TO THE
RELATIVELY DRY AIR INTO WHICH THEY ARE MOVING.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 79 90 79 / 10 30 30 30
STT 90 79 90 81 / 30 10 20 40