[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 301033
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT APR 30 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTION 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...ITCZ...

ITCZ AXIS IS FROM 05N08W TO THE EQUATOR NEAR 15W...THEN SOUTH OF
THE EQUATOR ALONG 03S23W 06S30W AND INTO NE BRAZIL NEAR 03S39W.
WIDELY SCATTERED MODERATE CONVECTION IS FROM 01N-06N BETWEEN
01W-07W...AND FROM THE EQUATOR TO 03N BETWEEN 11W-20W. ISOLATED
MODERATE CONVECTION IS FROM THE EQUATOR TO 04N BETWEEN 26W-30W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL SHORTWAVE TROUGH IS OVER THE FLORIDA PENINSULA
AND IS PART OF A BROADER SCALE UPPER LEVEL TROUGH WITH AXIS
EXTENDING ALONG THE EASTERN U.S. SEABOARD FROM THE NEW ENGLAND
STATES TO NEAR 30N78W THEN TO A BASE NEAR 26N81W. THIS UPPER
LEVEL FEATURE SUPPORTS A COLD FRONT THAT EXTENDS ACROSS THE W
ATLC AND SOUTHERN TIP OF THE FLORIDA PENINSULA AND CONTINUES AS
A DISSIPATING STATIONARY FRONT INTO THE SE GULF FROM 26N81W TO
25N89W. MOST CONVECTION ASSOCIATED WITH THE FRONT ACROSS THE W
ATLC HAS DISSIPATED OVER THE PAST 6 HOURS AS MOSTLY DRY AND
SUBSIDENT W-NW FLOW DOMINATES ACROSS THE GULF AS NOTED ON RECENT
WATER VAPOR IMAGERY. A WEAK SURFACE RIDGE IS OVER THE NE GULF
ANCHORED BY A 1018 MB HIGH CENTERED OVER SOUTHERN GEORGIA NEAR
31N83W. RETURN S-SE FLOW IN THE RANGE OF 10 TO 20 KT...HIGHEST
OVER THE NW GULF...IS LOCATED ON THE WESTERN PERIPHERY OF THE
RIDGE AND IS EXPECTED TO PERSIST THROUGH EARLY TUESDAY.
THEREAFTER...A COLD FRONT IS FORECAST TO EMERGE OFF THE TEXAS
AND LOUISIANA GULF COASTS AND QUICKLY SWEEP EASTWARD INTO THE W
ATLC BY EARLY WEDNESDAY.

CARIBBEAN SEA...
MOSTLY ZONAL WESTERLY UPPER LEVEL FLOW DOMINATES ACROSS MUCH OF
THE CARIBBEAN AND WATER VAPOR IMAGERY INDICATES MODERATELY DRY
AIR AND SUBSIDENCE IS PROVIDING FOR OVERALL STABLE ATMOSPHERIC
CONDITIONS THIS MORNING. HOWEVER...A WEAK UPPER LEVEL SHORTWAVE
TROUGH IS LOCATED OVER THE NE CARIBBEAN AND IS HELPING TO
ENHANCE WIDELY SCATTERED LOW-TOPPED SHOWERS OVER THE BASIN EAST
OF 70W. THIS AREA COINCIDES WITH STRONGER EASTERLY TRADES AS
DEPICTED ON EARLIER OVERNIGHT WINDSAT AND ASCAT SCATTEROMETER
PASSES. WINDS TO 20 KT WERE NOTED IN THOSE PASSES E OF 74W. THE
RELATIVELY TRANQUIL CONDITIONS ACROSS A MAJORITY OF THE BASIN
ARE EXPECTED OVER THE NEXT 24 TO 36 HOURS.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH AXIS EXTENDS FROM THE NEW ENGLAND STATES
S-SW ALONG THE EASTERN U.S. SEABOARD AND SUPPORTS A COLD FRONT
EXTENDING INTO THE SW NORTH ATLC NEAR 32N72W. THE FRONT
CONTINUES SW TO THE FAR SOUTHERN FLORIDA PENINSULA NEAR FORT
LAUDERDALE AND INTO THE SE GULF OF MEXICO AS A DISSIPATING
STATIONARY FRONT. LOW-LEVEL CONVERGENCE EAST OF AND ALONG THE
FRONT IS GENERATING WIDELY SCATTERED SHOWERS WITHIN 120 NM EAST
OF THE FRONT AND IN THE VICINITY OF THE NW BAHAMAS FROM 24N-27N
BETWEEN 75W-79W. THE FRONT IS FORECAST TO SHIFT NE OF 30N70W BY
LATE SATURDAY INTO EARLY SUNDAY WITH LIGHT EASTERLY FLOW ONCE
AGAIN ESTABLISHING ITSELF OVER THE SW NORTH ATLC W OF 70W. THE
REMAINDER OF THE CENTRAL AND EASTERN ATLC THIS MORNING IS UNDER
THE INFLUENCE OF A VERY BROAD SURFACE RIDGE ANCHORED BY A 1028
MB HIGH CENTERED NEAR 35N49W. A WEAK AND DISSIPATING COLD FRONT
EXTENDS ALONG 30N BETWEEN 21W-34W AND CONTINUES TO BECOME MORE
DIFFUSE AS IT MOVES SOUTHWARD. THIS FRONT IS SUPPORTED BY AN
UPPER LEVEL LOW CENTERED WEST OF THE IBERIAN PENINSULA NEAR
36N17W.

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

$$
HUFFMAN




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