[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 282344
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED MAY 28 2008

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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

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

...TROPICAL WAVES...

TROPICAL WAVE MOVING ACROSS THE CAPE VERDE ISLANDS ALONG 24W/25W
S OF 18N MOVING W 15-20 KT. THE TPW PRODUCT INDICATES A
SIGNIFICANT DEEP-LAYERED MOISTURE SURGE EXTENDING OFF THE
AFRICAN COAST TO NEAR 30W. SCATTERED SHOWERS/ISOLATED MODERATE
CONVECTION IS CONCENTRATED S OF THE ISLANDS NEAR THE ITCZ FROM
3N-8N BETWEEN 23W-33W.

TROPICAL WAVE ALONG 39W S OF 9N...OR 800 NM E OF FRENCH
GUIANA...MOVING W 15 KT. ALTHOUGH THIS WAVE HAS BEEN DIFFICULT
TO LOCATE FOR SEVERAL DAYS...THE CIMSS MIMIC-TPW PRODUCT
CURRENTLY SHOWS A SMALL INFLECTION OF DEEP MOISTURE NEAR THE
ANALYZED AXIS...PROBABLY AS A RESULT OF THE WAVE TO THE E
AMPLIFYING THE PATTERN A BIT. NO SIGNIFICANT CONVECTION.

TROPICAL WAVE MOVING ACROSS PUERTO RICO AND VENEZUELA ALONG
65W/66W S OF 21N MOVING W 15-20 KT. THE WAVE AXIS HAS BECOME
STRETCHED N/S AND BECOME SOMEWHAT LESS DEFINED OVER THE PAST 24
HRS. SURFACE OBSERVATIONS AND SCATTEROMETER DATA INDICATE A
15-20 KT SURGE IN THE TRADES OCCURRING E OF THE AXIS PAST THE
LESSER ANTILLES BACK INTO THE ATLANTIC. NUMEROUS
SHOWERS/SCATTERED TSTMS EXTEND ACROSS PUERTO RICO AND THE VIRGIN
ISLANDS FROM 17N-22N BETWEEN 62W-68W. SCATTERED MODERATE/STRONG
CONVECTION IS ALSO MOVING W ACROSS MUCH OF VENEZUELA FROM THE
GUIANA HIGHLANDS NW TO LAKE MARACAIBO.

TROPICAL WAVE LIES ACROSS PANAMA AND THE WESTERN CARIBBEAN ALONG
81W S OF 19N MOVING W 15 KT. THE WAVE IS NOW INTERACTING WITH
THE LARGE AREA OF LOW PRES EXTENDING FROM THE FAR EASTERN
PACIFIC NE ACROSS COSTA RICA AND NICARAGUA...MAKING IT DIFFICULT
TO ISOLATE A WELL-DEFINED AXIS. HOWEVER...THE WAVE'S INFLUENCE
HAS BEGUN TO DRAW ABUNDANT MOISTURE/SCATTERED SHOWERS AND TSTMS
NWD FROM COLOMBIA ACROSS THE W/CENTRAL CARIBBEAN...AND BEGINNING
TO OVERSPREAD HISPANIOLA AND JAMAICA. SCATTERED MODERATE
CONVECTION S OF 19N BETWEEN 70W-85W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 9N10W 5N17W 6N24W 4N52W. NUMEROUS
MODERATE/STRONG CONVECTION MOVING OFF THE AFRICAN COAST S OF 12N
BETWEEN 7W-18W. ISOLATED MODERATE WITHIN 120 NM OF AXIS BETWEEN
23W-33W AND W OF 45W INTO THE GUIANAS.

...DISCUSSION...

GULF OF MEXICO...
A LARGE BLOCKING UPPER LEVEL HIGH IS CENTERED ALONG THE W
COAST OF MEXICO WITH A RIDGE AXIS CONTINUING NE ACROSS THE
NORTHERN COAST OF THE GULF OF MEXICO. ANOTHER WEAKER UPPER HIGH
IS CENTERED NEAR SOUTH FLORIDA...AND IS SEPARATED BY THE FIRST
RIDGE BY A CYCLONIC SHEAR AXIS WHICH EXTENDS FROM THE FLORIDA
PANHANDLE TO THE BAY OF CAMPECHE. ALL TOLD...MAINLY MODERATE
SUBSIDENCE COVERS THE ENTIRE REGION WITH ONLY PASSING PATCHES OF
LOW/MID LEVEL CLOUDINESS AND EMBEDDED SHOWERS MOVING FROM E TO
W. A WEAK SURFACE RIDGE AXIS ALSO LIES ALONG THE N GULF COAST
WITH LIGHT/MODERATE WINDS OVER THE OFFSHORE WATERS...BUT THIS
FEATURE IS BEING WEAKENED BY A COLD FRONT WHICH IS CURRENTLY
MOVING ACROSS THE DEEP SOUTH TO TEXAS. DEEPER MOISTURE HAS
RETURNED TO THE SE AND S/CENTRAL PART OF THE GULF WITH SCATTERED
SHOWERS/TSTMS S OF 26N E OF 85W AND NEAR THE YUCATAN COAST.

CARIBBEAN...
THE UPPER LEVEL PATTERN OVER THE CARIBBEAN IS DOMINATED BY AN
UPPER HIGH OVER NORTHERN COLOMBIA WITH SW/W FLOW ALOFT SPREADING
FROM CENTRAL AMERICA EWD TO THE LESSER ANTILLES. A STRONG AREA
OF LOW PRES OVER THE FAR EASTERN PACIFIC...WHICH HAS THE
POTENTIAL TO BECOME A TROPICAL DEPRESSION OVER THE NEXT DAY OR
SO...IS CENTERED JUST W OF THE NICOYA PENINSULA OF COSTA RICA
AND IS DRAWING COPIOUS DEEP-LAYERED MOISTURE NWD ACROSS
PANAMA...COSTA RICA...NICARAGUA...AND MUCH OF THE WESTERN
CARIBBEAN WATERS. HEAVY RAIN HAS BEEN FALLING OVER THESE AREAS
AND IS EXPECTED TO CONTINUE FOR THE NEXT DAY OR SO THEN LIFT N
TO OTHER PORTIONS OF CENTRAL AMERICA...POSING A THREAT OF FLASH
FLOODING AND MUDSLIDES. OVER THE PAST 24 HRS...PANAMA CITY
PANAMA HAS OBSERVED 1.73" AND SAN JOSE COSTA RICA HAS REPORTED
0.79". ALSO...SOME OF THE CONVECTIVE ACTIVITY OVER THE W/CENTRAL
CARIBBEAN WILL LIFT N AND BEGIN TO PRODUCE WIDESPREAD
SHOWERS/TSTMS OVER JAMAICA...THE CAYMAN ISLANDS...AND PARTS OF
CUBA OVER THE NEXT 48 HRS. FARTHER E...A DRIER AIR MASS HAS
BEGUN TO FILTER IN ACROSS THE EASTERN CARIBBEAN AND LESSER
ANTILLES BEHIND THE TROPICAL WAVE ALONG 65W/66W. THIS AIR MASS
WILL SLOWLY CREEP W AND REACH TO NEAR 72W BY FRI EVENING.

WEST ATLANTIC...
FAST UPPER LEVEL FLOW EXTENDS ACROSS MUCH OF THE CONTINENTAL
U.S. INTO THE NW ATLANTIC...WITH AN EMBEDDED SHORTWAVE TROUGH
JUST E/SE OF BERMUDA FROM 32N62W TO 25N63W. THIS TROUGH CAUSED
THE NORTHERN EXTENSION OF THE EASTERN CARIBBEAN TROPICAL WAVE TO
BREAK OFF...AND LEAVE A SEGMENT FROM 29N59W TO 23N64W. NUMEROUS
MODERATE CONVECTION HAS DEVELOPED NEAR THIS TROUGH FROM 23N-28N
BETWEEN 59W-65W AS WELL AS WITHIN 270 NM NE OF PUERTO RICO.
FARTHER W...A WEAK UPPER LOW IS CENTERED OVER THE CENTRAL
BAHAMAS AND HAS BEEN PRODUCING ISOLATED SHOWERS/TSTMS MAINLY NE
OF THE ISLAND CHAIN FROM 22N-25N BETWEEN 70W-76W. OTHERWISE A
STRONG UPPER HIGH NEAR 27N72W IS PRODUCING MODERATE/STRONG
SUBSIDENCE N OF 24N W OF 70W WITH FAIR WIND/SKY CONDITIONS.

EAST/CENTRAL ATLANTIC...
A MID/UPPER LOW IS LOCATED S OF THE AZORES NEAR 31N30W WITH A
TROUGH EXTENDING SW TO 20N40W THEN PARTIALLY CUT-OFF TO 15N50W.
A 70-95 KT JET LIES ON THE SE SIDE OF THE TROUGH FROM 26N30W NE
TO 30N20W THEN TURNS E ACROSS THE CANARY ISLANDS AND MOROCCO.
THERE IS VERY LITTLE AVAILABLE MOISTURE OVER THE E ATLANTIC E OF
55W SO THE REGION IS PRACTICALLY VOID OF DEEP CONVECTION. AN
UPPER HIGH IS CENTERED OVER THE CAPE VERDE ISLANDS...AND COUPLED
WITH THE UPPER TROUGH...IS PULLING ONLY HIGH LEVEL MOISTURE FROM
THE DEEP TROPICS TO THE CANARY ISLANDS.

$$
BERG





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