[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 070544
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU MAY 07 2009

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...THE ITCZ...

THE ITCZ AXIS IS ALONG 4N7W 2N20W CROSSING THE EQUATOR NEAR 29W
AND CONTINUING S OF THE EQUATOR ALONG 1S33W AND INTO NE BRAZIL
NEAR 1S46W. SCATTERED MODERATE/STRONG CONVECTION IS FROM THE
EQUATOR TO 7N BETWEEN THE PRIME MERIDIAN TO 12W. WIDELY
SCATTERED MODERATE CONVECTION IS ELSEWHERE FROM THE EQUATOR TO
7N BETWEEN 12W-23W.

...DISCUSSION...

GULF OF MEXICO...
THE GULF REMAINS UNDER 10-20 KT E TO SE SURFACE FLOW AS A
SURFACE RIDGE OF HIGH PRESSURE EXTENDS FROM THE W ATLC ACROSS
THE FLORIDA PENINSULA INTO THE GULF. ALOFT IN THE MIDDLE TO
UPPER LEVELS...NW FLOW IS OBSERVED WITH WEAK TROUGHING ACROSS
THE NE GULF AND NRN FLORIDA. A WEAK SHORTWAVE TROUGH CONTINUES
TO MOVE ACROSS THE SE CONUS AND TRACK NEWD KEEPING ANY FRONTAL
BOUNDARIES WELL NORTH OF THE GULF WATERS. THIS EVENING ONLY
MIDDLE TO HIGH LEVEL CLOUDINESS IS NOTED ON SATELLITE IMAGERY N
OF 24N E OF 90W...INCLUDING MUCH OF THE STATE OF FLORIDA.
LOOKING AHEAD...LITTLE CHANGE IS EXPECTED IN THE OVERALL PATTERN
DURING THE NEXT 24-48 HOURS WITH FAIR WEATHER CONDITIONS
PREVAILING THROUGH SUNDAY.

CARIBBEAN SEA...
A BROAD UPPER LEVEL RIDGE AXIS EXTENDS FROM COLOMBIA NW ACROSS
CENTRAL AMERICA AND IS PROVIDING THE WRN CARIBBEAN WITH MAINLY
WLY ZONAL FLOW AND A DRY SUBSIDENT ATMOSPHERE IN THE MIDDLE AND
UPPER LEVELS. ACROSS THE ERN CARIBBEAN...AN UPPER LEVEL TROUGH
RESIDES E OF 70W WITH ABUNDANT MOISTURE NOTED ON WATER VAPOR
IMAGERY THAT IS BEING LIFTED IN A LARGE DIFFLUENT ZONE E OF THE
TROUGH AXIS. THIS ZONE ALONG WITH A SURFACE TROUGH THAT EXTENDS
ACROSS THE CENTRAL CARIBBEAN FROM 13N71W TO 19N72W IS GENERATING
SCATTERED SHOWERS N OF 14N AND E OF THE SURFACE TROUGH. THIS
AREA OF PRECIPITATION ACROSS THE NE CARIBBEAN IS FORECAST TO
PERSIST THROUGH THE WEEKEND UNTIL THE MIDDLE TO UPPER LEVEL
TROUGH SHIFTS EWD INTO THE CENTRAL ATLC BY LATE SUNDAY.
ELSEWHERE...MODERATE TO FRESH TRADE WINDS COVER THE CARIBBEAN
WITH POSSIBLE ISOLATED LOW LEVEL SHOWER ACTIVITY MOVING WESTWARD
IN CONVERGENT SURFACE FLOW ACROSS THE BASIN.

ATLANTIC OCEAN...
THE W ATLC CONTINUES TO BE DOMINATED BY A SURFACE HIGH PRESSURE
RIDGE ANCHORED BY A 1032 MB HIGH LOCATED N OF THE DISCUSSION
AREA NEAR 35N54W. A WEAKNESS IN THE SURFACE RIDGE...ANALYZED AS
A SURFACE TROUGH EXTENDS FROM 28N74W TO 23N72W. THIS ALONG WITH
A BROAD UPPER LEVEL TROUGH WITH AXIS ALONG 70W IS GENERATING AN
AREA OF UPPER LEVEL DIFFLUENCE TO THE E OF THE SURFACE TROUGH
PRODUCING SCATTERED SHOWERS AND POSSIBLE ISOLATED TSTMS
EXTENDING WITHIN 150 NM OF A LINE FROM THE U.S. VIRGIN ISLANDS
N-NW TO 27N73W. SCATTERED SHOWERS ARE FARTHER TO THE SE ACROSS
THE LESSER ANTILLES AND TROPICAL ATLC FROM 15N-22N BETWEEN
57W-65W. THE SECOND WEAKNESS IN THE ATLC SURFACE RIDGE EXTENDS
OVER THE E/CENTRAL ATLC AS AN UPPER LEVEL TROUGH WITH AXIS ALONG
32N29W 22N40W IS PROVIDING SUPPORT FOR A SURFACE TROUGH THAT
EXTENDS FROM 32N34W TO 26N35W. THIS FEATURE CONTINUES TO
GRADUALLY WEAKEN AS THE UPPER TROUGH MOVES NEWD.

$$
HUFFMAN




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