Atlantic Tropical Weather Discussion

000
AXNT20 KNHC 060547
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT WED MAY 06 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 4N10W 1N20W CROSSING THE EQUATOR NEAR 22W 
AND CONTINUING S OF THE EQUATOR ALONG 2S26W 2S40W INTO NE BRAZIL 
NEAR 2S45W. SCATTERED TO NUMEROUS STRONG CONVECTION IS ALONG AND 
IMMEDIATELY OFFSHORE OF THE COAST OF W AFRICA FROM 3N-9N BETWEEN 
8W-15W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG 
CONVECTION ARE ELSEWHERE FROM THE EQUATOR TO 4N E OF 15W. A 
SMALLER AREA OF SIMILAR CONVECTION IS FROM 2N-7N BETWEEN 18W-24W.

...DISCUSSION...

GULF OF MEXICO...
THE GULF REMAINS RATHER TRANQUIL THIS EVENING AS SELY SURFACE 
FLOW DOMINATES ACROSS THE ENTIRE REGION S OF A STATIONARY 
BOUNDARY LOCATED WELL NORTH OF THE GULF COAST ACROSS THE SE 
CONUS. AN UPPER LEVEL SHORTWAVE TROUGH ACROSS SW ARKANSAS 
SUPPORTS THE FRONTAL BOUNDARY WITH A PUSH OF MIDDLE TO HIGH 
LEVEL CLOUDINESS STREAMING SEWD FROM SRN TEXAS OUT OVER THE NW 
GULF WATERS. THE FRONTAL BOUNDARY IS EXPECTED TO REMAIN WELL 
NORTH OF THE GULF COAST AS A SURFACE RIDGE ANCHORED IN THE W 
ATLC HOLDS IN PLACE ACROSS THE FLORIDA PENINSULA AND THE GULF 
WATERS. LITTLE CHANGE IS EXPECTED IN THE OVERALL PATTERN DURING 
THE NEXT 24-48 HOURS WITH FAIR WEATHER CONDITIONS PREVAILING 
THROUGH EARLY SUNDAY.

CARIBBEAN SEA...
A BROAD UPPER LEVEL RIDGE DOMINATES THE WRN CARIBBEAN ANCHORED 
OVER NICARAGUA WHICH IS ADVECTING TROPICAL MOISTURE OVER THE 
YUCATAN PENINSULA...THE GULF OF HONDURAS AND WRN CARIBBEAN TO 
73W. THIS MOISTURE IS RESULTANT DEBRIS CLOUDINESS FROM SCATTERED 
SHOWERS AND ISOLATED TSTMS OVER CENTRAL AMERICA. ALOFT ACROSS 
THE ERN CARIBBEAN...UPPER LEVEL TROUGHING IS FOUND E OF 70W. 
WEAK OVERALL CYCLONIC FLOW OF THE ELY TRADES ALONG WITH THIS 
WEAK MIDDLE TO UPPER LEVEL TROUGHING IS GENERATING SCATTERED 
SHOWERS AND POSSIBLE ISOLATED TSTMS E OF 70W. ELSEWHERE...LIGHT 
TO MODERATE TRADE WINDS COVER THE CARIBBEAN PRIMARILY DUE TO A 
RELAXED PRESSURE GRADIENT LEAVING THE REMAINDER OF THE CARIBBEAN 
UNDER SOME ISOLATED LOW LEVEL SHOWERS MOVING WESTWARD IN 
CONVERGENT SURFACE FLOW ACROSS THE BASIN. 

ATLANTIC OCEAN...
THE W ATLC IS DOMINATED BY A SURFACE HIGH PRESSURE RIDGE 
ANCHORED BY A 1032 MB HIGH LOCATED NORTH OF THE DISCUSSION AREA 
NEAR 35N53W. ONE WEAKNESS IN THIS SURFACE RIDGE IS LOCATED UNDER 
BROAD UPPER LEVEL TROUGHING ACROSS THE W ATLC THAT IS PROVIDING 
SUPPORT FOR A SURFACE TROUGH THAT EXTENDS FROM THE SE BAHAMAS 
ALONG 75W TO NEAR 30N75W. SCATTERED SHOWERS AND ISOLATED TSTMS 
ARE OBSERVED WELL E OF THE SURFACE TROUGH FROM 18N-31N BETWEEN 
63W-71W. THIS ACTIVITY IS LOCATED ON THE E SIDE OF THE UPPER 
TROUGHING WHERE A LARGE MID/UPPER LEVEL DIFFLUENT ZONE IS 
DRAWING TROPICAL MOISTURE FROM THE ERN CARIBBEAN NORTHWARD. 
SCATTERED SHOWERS AND POSSIBLE ISOLATED TSTMS EXTEND FARTHER TO 
THE SE ACROSS THE LESSER ANTILLES AND THE TROPICAL ATLC FROM 
13N-21N BETWEEN 54W-65W. THE SECOND WEAKNESS IN THE ATLC SURFACE 
RIDGE EXTENDS OVER THE CENTRAL ATLC AS A SECOND LARGER UPPER 
LEVEL LOW SPINS NEAR 32N36W PROVIDING SUPPORT FOR A SURFACE 
TROUGH THAT EXTENDS FROM 25N41W TO 32N37W GENERATING SCATTERED 
SHOWERS FROM 27N TO BEYOND 32N BETWEEN 31W-40W.

$$
HUFFMAN