[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 300543
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON APR 30 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 09N13W TO
07N18W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
07N18W TO 03N35W TO THE EQUATOR NEAR 50W. SCATTERED MODERATE
CONVECTION IS FROM THE EQUATOR TO 06N BETWEEN 25W-37W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL TROUGH EXTENDS OVER THE EASTERN GULF FROM 28N85W
SOUTH-SOUTHEASTWARD OVER THE FLORIDA STRAITS TO EASTERN CUBA
NEAR 21N78W. WHILE MOST OF THE ACTIVE WEATHER ASSOCIATED WITH
THIS TROUGH CONTINUES TO BE ACROSS THE FLORIDA PENINSULA AND IN
THE SW NORTH ATLC...A FEW WIDELY SCATTERED SHOWERS ARE OCCURRING
OVER THE FLORIDA STRAITS AND IN THE VICINITY OF THE FLORIDA KEYS
S OF 26N E OF 84W. THE REMAINDER OF THE GULF IS UNDER THE
INFLUENCE OF WEST-NORTHWESTERLY FLOW ALOFT WITH MOSTLY DRY AIR
AND SUBSIDENCE NOTED ON WATER VAPOR IMAGERY BETWEEN 84W-90W. AT
THE SURFACE...A WEAK SURFACE RIDGE AXIS EXTENDS FROM NORTHERN
FLORIDA AND SOUTHERN GEORGIA NEAR 31N84W TO THE TEXAS GULF COAST
NEAR 27N97W. EAST TO SOUTHEAST WINDS IN THE RANGE OF 10 TO 20 KT
ARE EXPECTED TO CONTINUE THROUGH THE OVERNIGHT HOURS INTO LATE
MONDAY AS A WEAK SURFACE TROUGH...ANALYZED OVER THE FLORIDA
STRAITS AND NW CARIBBEAN SEA MOVES WEST-NORTHWESTWARD OVER THE
NEXT 24 TO 36 HOURS INTO THE CENTRAL GULF. WHILE THE ECMWF...
NAM...AND UKMET HAVE BEEN CONSISTENTLY SUGGESTING THIS WEAK
TROUGHING TO DRIFT WESTWARD...THIS EVENING THE GFS HAS TRENDED
LESS AGGRESSIVE WITH FORMING A SURFACE LOW OVER THE CENTRAL GULF
ON MONDAY AND COME MORE INTO LINE WITH THE OTHER GLOBAL MODEL
SOLUTIONS. THEREFORE...THE FORECAST CONTINUES TO INDICATE THIS
TROUGHING WHICH IS EXPECTED TO DISSIPATE BY TUESDAY OVER THE NW
GULF WATERS.

CARIBBEAN SEA...
A MIDDLE TO UPPER LEVEL LOW IS CENTERED OVER THE FLORIDA STRAITS
THIS EVENING AND EXTENDS A TROUGH AXIS SOUTH-SOUTHEASTWARD TO
EASTERN CUBA NEAR 21N78W. WATER VAPOR IMAGERY INDICATES A VERY
DRY AIRMASS IS IN PLACE SOUTHWEST OF THIS UPPER LEVEL TROUGH
AXIS AS WEST-NORTHWESTERLY FLOW ALOFT DOMINATES N OF 16N W OF
78W. HOWEVER...AS A RESULT OF THE UPPER LEVEL TROUGH...A WEAK
SURFACE TROUGH IS ANALYZED FROM THE FLORIDA STRAITS NEAR 24N82W
ACROSS WESTERN CUBA TO 18N83W. A FEW ISOLATED LOW-TOPPED SHOWERS
ARE OCCURRING IN THE VICINITY OF THE SURFACE TROUGH AXIS N OF
17N BETWEEN 75W-84W...INCLUDING JAMAICA AND MUCH OF CUBA. THIS
SURFACE TROUGH IS EXPECTED TO DRIFT WEST-NORTHWESTWARD OVER THE
NEXT 24 TO 36 HOURS INTO THE CENTRAL GULF OF MEXICO. THE
REMAINDER OF THE CARIBBEAN FALLS UNDER THE INFLUENCE OF
SOUTHWEST TO WESTERLY UPPER LEVEL FLOW DUE TO AN ANTICYCLONIC
CIRCULATION CENTERED OVER NORTH-CENTRAL VENEZUELA NEAR 10N66W.
MOST OF THE MIDDLE TO UPPER LEVEL MOISTURE ASSOCIATED WITH THIS
RIDGE IS LOCATED ON THE NORTHWESTERN PERIPHERY THAT CONTINUES TO
PROVIDE HIGH LEVEL CLOUDINESS E OF 75W. AT THE SURFACE...
MODERATE TO FRESH EASTERLIES ARE NOTED ON RECENT OBSERVATIONS
AND ASCAT SCATTEROMETER PASSES WHICH ARE FORECAST TO PERSIST
THROUGH WEDNESDAY.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL LOW AND ASSOCIATED TROUGH IS CENTERED
OVER THE FLORIDA STRAITS AND IS PROVIDING MOST OF THE SW NORTH
ATLC WITH PLENTY OF MOISTURE AND OVERCAST CLOUDINESS W OF 60W.
INFRARED SATELLITE IMAGERY INDICATES THAT SCATTERED SHOWERS AND
ISOLATED TSTMS ARE OCCURRING OVER A LARGE AREA FROM 20N-30N
BETWEEN 60W-81W. THE RIDGE AXIS OVER NORTHERN FLORIDA AND THE SW
NORTH ATLC PRESENT YESTERDAY HAS SLOWLY ERODED AND SHIFTED
EASTWARD AS A WEAK STATIONARY FRONT REMAINS ANALYZED TO THE
NORTH OF THE DISCUSSION AREA ALONG 33N BETWEEN 70W AND THE SOUTH
CAROLINA COAST. OTHERWISE...THE SW NORTH ATLC CONTINUES TO
EXPERIENCE E-SE WINDS IN THE RANGE OF 10 TO 20 KT WITH POSSIBLE
STRONGER WINDS S OF 27N W OF 70W DUE TO THE CLOSE PROXIMITY OF
THE SURFACE TROUGH ACROSS THE FLORIDA STRAITS. FARTHER EAST...AN
UPPER LEVEL LOW IS CENTERED NEAR 27N41W AND CONTINUES TO PROVIDE
SOUTHWESTERLY MIDDLE TO UPPER LEVEL FLOW WITH MOISTURE STREAMING
NORTHEASTWARD FROM THE TROPICS TO THE NORTHEAST AFRICAN COAST.
AT THE SURFACE HOWEVER...A SURFACE RIDGE HOLDS STRONG ANCHORED
BY A 1032 MB HIGH CENTERED NW OF THE AZORES NEAR 40N33W. FRESH
TO STRONG NE WINDS WERE NOTED ON EARLIER ASCAT PASSES OFF THE
COAST OF WESTERN SAHARA STRETCHING TO THE NORTHERN CAPE VERDE
ISLANDS TO 15N30W.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
HUFFMAN




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