[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 261749
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU APR 26 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
1715 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 09N13W TO
06N17W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
06N17W TO THE EQUATOR NEAR 44W. SCATTERED MODERATE CONVECTION IS
FROM 02N-07N BETWEEN 19W-33W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL TROUGH CONTINUES TO DIG SOUTHWARD OVER THE
YUCATAN PENINSULA WITH AN AXIS EXTENDING FROM THE NE GULF NEAR
27N84W TO 16N92W. MOSTLY NORTHERLY FLOW ALOFT IS OVER A MAJORITY
OF THE GULF BASIN THIS AFTERNOON WITH WATER VAPOR IMAGERY
INDICATING VERY DRY AIR AND STRONG SUBSIDENCE ACCOMPANYING THE
TROUGH. AT THE SURFACE...THE STRONG SUBSIDENCE MANIFESTS ITSELF
AS A RIDGE ANCHORED BY A 1023 MB HIGH CENTERED OVER THE SW NORTH
ATLC WATERS NEAR 29N71W. THE RIDGE AXIS EXTENDS FROM THE HIGH
ACROSS THE FLORIDA PENINSULA ALONG 27N TO THE NW GULF NEAR
27N95W. LIGHT ANTICYCLONIC WINDS ARE NOTED E OF 88W...HOWEVER
S-SE WINDS IN THE RANGE OF 15 TO 20 KT ARE FOUND W OF 88W ON
RECENT SHIP...BUOY...AND OFFSHORE OIL PLATFORMS. VISIBLE
SATELLITE IMAGERY SHOWS THAT SKIES REMAIN CLEAR. THE RIDGE IS
EXPECTED TO HOLD ALONG 27N THROUGH FRIDAY AND GRADUALLY DRIFT
NORTHWARD OVER THE UPCOMING WEEKEND. AS A RESULT...MODERATE TO
FRESH E-SE WINDS WILL DOMINATE ACROSS THE SOUTHEASTERN PERIPHERY
OF THE RIDGE THROUGH EARLY NEXT WEEK.

CARIBBEAN SEA...
SOUTHWESTERLY UPPER LEVEL FLOW DOMINATES ACROSS THE CARIBBEAN W
OF 67W THIS AFTERNOON BETWEEN AN UPPER LEVEL TROUGH DIGGING
SOUTHWARD OVER THE YUCATAN PENINSULA AND SE GULF OF MEXICO AND
AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER NORTH-
CENTRAL VENEZUELA NEAR 10N67W. MIDDLE TO UPPER LEVEL MOISTURE
CONTINUES TO BE CONCENTRATED TO THE SE OF THE TROUGH AXIS THAT
SUPPORTS A STATIONARY FRONT EXTENDING FROM THE SW NORTH ATLC
ACROSS NW HISPANIOLA TO 19N74W. A SURFACE TROUGH IS ALSO
ANALYZED OVER THE SW CARIBBEAN FROM 18N83W TO 12N80W TO 10N76W.
WITH THESE BOUNDARIES IN PLACE ACROSS THE CENTRAL AND WESTERN
CARIBBEAN...MAXIMUM LOW-LEVEL MOISTURE CONVERGENCE COUPLED WITH
FAVORABLE UPPER LEVEL DIFFLUENCE CONTINUES TO GENERATE SCATTERED
TO NUMEROUS SHOWERS AND SCATTERED TSTMS FROM 10N-20N BETWEEN
71W-81W. TRADES HAVE INCREASE OVER THE CENTRAL CARIBBEAN DUE TO
AN TIGHTENING PRESSURE GRADIENT AS A 1023 MB HIGH HAS SETTLED
INTO THE SW NORTH ATLC CENTERED NEAR 29N71W THE PAST 24 HOURS.
THE FRONT WILL CONTINUE TO BECOME MORE DIFFUSE BY FRIDAY...
HOWEVER LOW-LEVEL MOISTURE WILL LINGER ACROSS THE NORTH-CENTRAL
AND SW CARIBBEAN FOR THE NEXT DAY OR TWO. AS A RESULT..AN
INCREASED PROBABILITY OF PRECIPITATION FOR HISPANIOLA...
JAMAICA...AND EASTERN CUBA INCLUDING THE ADJACENT COASTAL WATERS
WILL PERSIST THROUGH THE WEEKEND. THE POTENTIAL FOR LOCALLY
HEAVY RAINFALL AND FLOODING ACROSS HAITI AND PORTIONS OF THE
DOMINICAN REPUBLIC AND EASTERN CUBA ARE EXPECTED THE NEXT FEW
DAYS. OF NOTE...PRECIPITATION TOTALS ACROSS THE DOMINICAN
REPUBLIC HAVE TRENDED DOWNWARD FROM A PEAK 24 HOUR RAINFALL
TOTAL OF 6.9 INCHES REPORTED AT MONCION ON APR 24 TO 1.5 INCHES
REPORTED AT EL SEIBO ON APR 25.

ATLANTIC OCEAN...
AN UPPER LEVEL SHORTWAVE TROUGH IS PROGRESSING ACROSS THE
MID-ATLC STATES THIS AFTERNOON WITH MOST CONVECTION AND STRONGER
SOUTHERLY WINDS REMAINING NORTH OF THE DISCUSSION AREA. WATER
VAPOR INDICATES THAT DRY AIR ALOFT REMAINS OVER THE SW NORTH
ATLC FROM 25N-32N BETWEEN 64W-81W AND CONTINUES TO SUPPORT
OVERALL SUBSIDENCE IN THE FORM OF A 1023 MB SURFACE HIGH
CENTERED NEAR 29N71W AND ASSOCIATED RIDGE AXIS FROM BERMUDA TO
THE FLORIDA PENINSULA. ANOTHER UPPER LEVEL TROUGH IS EAST OF THE
SHORTWAVE AND EXTENDS AN AXIS FROM 35N57W TO 30N60W. A COLD
FRONT IS ANALYZED FROM 35N56W TO 31N59W THEN BECOMES STATIONARY
ALONG 26N61W TO 23N64W AND THEN DIFFUSE TO NW HISPANIOLA NEAR
19N73W. ISOLATED SHOWERS ARE OCCURRING WITHIN 60 NM EITHER SIDE
OF THE FRONT N OF 26N AND FROM 19N-26N BETWEEN 58W-77W. FARTHER
EAST...A MIDDLE TO UPPER LEVEL LOW IS CENTERED NEAR 21N37W AND
SUPPORTS A SURFACE TROUGH EXTENDING FROM 23N34W TO 17N39W ACROSS
THE EASTERN ATLC. WHILE THE SURFACE TROUGH REMAINS RELATIVELY
WEAK...MIDDLE TO UPPER LEVEL DIFFLUENCE IS MAXIMIZED EAST OF THE
LOW WITH SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING FROM
16N-24N BETWEEN 28W-38W. THIS MIDDLE TO UPPER LEVEL TROUGH IS
EXPECTED TO LIFT TO THE NORTHEAST OVER THE NEXT 24 TO 36 HOURS
AS A STRONGER POLAR FRONT...CURRENTLY ANALYZED ALONG 30N BETWEEN
19W-36W DIVES SOUTHWARD OVER THE NORTHEASTERN PORTION OF EASTERN
ATLC. ISOLATED SHOWERS ARE POSSIBLE WITHIN 90 NM EITHER SIDE OF
THE COLD FRONT.

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

$$
HUFFMAN




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