[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 251750
TWDAT

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

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 09N13W TO
04N20W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
04N20W TO THE EQUATOR NEAR 31W THEN ALONG THE EQUATOR TO 43W.
ISOLATED MODERATE CONVECTION IS FROM 02N-04N BETWEEN 14W-20W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL TROUGH AXIS EXTENDS ALONG THE EASTERN U.S.
SEABOARD EXTENDING INTO THE GULF OF MEXICO ALONG 27N82W TO A
BROAD BASE OVER THE SW GULF NEAR 20N92W. WATER VAPOR IMAGERY
INDICATES VERY DRY AIR ALOFT ACCOMPANIES THE TROUGHING WITH N-NW
FLOW LOCATED WEST OF THE TROUGH AXIS. THIS OVERALL STABLE
ENVIRONMENT FILTERS TO THE SURFACE AS A 1020 MB HIGH CENTERED
OFF THE WESTERN COAST OF THE FLORIDA PENINSULA NEAR 28N84W WITH
CLEAR SKIES NOTED ON VISIBLE SATELLITE IMAGERY. WITH THE RIDGE
SLOWLY SHIFTING EASTWARD OVER THE PAST 24 HOURS...E-SE WINDS IN
THE RANGE OF 10 TO 15 KT INFLUENCE THE SOUTHEASTERN HALF OF THE
BASIN WITH 10 TO 20 KT S-SW WINDS ESTABLISHING OVER THE
NORTHWESTERN THIRD OF THE BASIN. THURSDAY INTO FRIDAY THE RIDGE
WILL CONTINUE TO SLIDE INTO THE SW NORTH ATLC AS SOUTHERLY
RETURN FLOW SPREADS EASTWARD OVER MUCH OF THE GULF FOR THE
WEEKEND.

CARIBBEAN SEA...
SOUTHWESTERLY UPPER LEVEL FLOW DOMINATES ACROSS THE CARIBBEAN
THIS AFTERNOON BETWEEN UPPER LEVEL TROUGHING TO THE NORTH OVER
THE GULF OF MEXICO AND AN UPPER LEVEL ANTICYCLONIC CIRCULATION
CENTERED OVER THE SE CARIBBEAN NEAR 11N64W. 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 15N77W. A SURFACE TROUGH
IS ALSO ANALYZED EAST OF THE FRONT FROM 18N70W TO 15N74W TO
10N76W. WITH THESE BOUNDARIES IN PLACE ACROSS THE CENTRAL
CARIBBEAN...MAXIMUM LOW-LEVEL MOISTURE CONVERGENCE COUPLED WITH
FAVORABLE UPPER LEVEL DIFFLUENCE CONTINUES TO GENERATE SCATTERED
TO NUMEROUS SHOWERS AND WIDELY SCATTERED TSTMS WITHIN 240 NM
EITHER SIDE OF A LINE FROM 20N70W TO 12N78W. THE FRONT IS
EXPECTED TO WEAKEN OVER THE NEXT 24 TO 36 HOURS AS SURFACE
RIDGING BUILDS TO THE NORTH AND EASTERLY TRADES INCREASE DUE TO
A STRONGER PRESSURE GRADIENT. IT IS POSSIBLE THAT LOW-LEVEL
MOISTURE WILL LINGER ACROSS THE NORTH-CENTRAL CARIBBEAN FOR THE
NEXT DAY OR TWO AS THE FRONT BECOMES MORE DIFFUSE AND WILL
CONTINUE TO PROVIDE INCREASED PROBABILITY OF PRECIPITATION FOR
HISPANIOLA AND THE ADJACENT COASTAL WATERS THROUGH THE WEEKEND.
THE POTENTIAL FOR LOCALLY HEAVY RAINFALL AND FLOODING ACROSS
HAITI AND PORTIONS OF THE DOMINICAN REPUBLIC ARE EXPECTED THE
NEXT FEW DAYS.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH AXIS EXTENDS ALONG THE U.S. EASTERN
SEABOARD AND INTO THE GULF OF MEXICO. MOSTLY SOUTHWESTERLY UPPER
LEVEL FLOW IS ACROSS THE SW NORTH ATLC REGION TO 57W WITH WATER
VAPOR IMAGERY INDICATING THIS FLOW REMAINS VERY DRY ALOFT S OF
30N. WHILE MOST OF THE STRONGER UPPER LEVEL DYNAMICS REMAIN
NORTH OF THE DISCUSSION AREA...THE TROUGH CONTINUES TO SUPPORT A
STATIONARY FRONT ANALYZED FROM 32N62W TO 25N65W TO NORTHERN
HISPANIOLA NEAR 20N70W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE
OCCURRING WITHIN 210 NM EITHER SIDE OF THE FRONT S OF 30N AND
WITHIN 150 NM EAST OF THE FRONT N OF 30N. HIGH PRESSURE IS
EXPECTED TO BUILD IN FROM THE GULF OF MEXICO ACROSS THE SW NORTH
ATLC OVER THE WEEKEND. FARTHER EAST...SUBTROPICAL RIDGING
DOMINATES ANCHORED BY A 1036 MB HIGH CENTERED WELL NORTH OF THE
REGION NEAR 49N43W. A SLIGHT WEAKNESS REMAINS ON THE SOUTHERN
PERIPHERY OF THE RIDGE DUE TO AN UPPER LEVEL LOW CENTERED NEAR
26N39W. A SURFACE TROUGH ANALYZED FROM 30N49W TO 19N46W
CONTINUES TO DRIFT WESTWARD WHILE MOST OF THE SCATTERED ELEVATED
CONVECTIVE SHOWERS ARE OCCURRING FROM 22N-28N BETWEEN 35W-44W.

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

$$
HUFFMAN




This weather bulletin was brought to you by:
www.nashvilleweather.net