Atlantic Tropical Weather Discussion

000
AXNT20 KNHC 112350
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON MAY 11 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 6N10W 3N20W 1N30W CROSSING THE 
EQUATOR NEAR 34W EXTENDING TO NE BRAZIL NEAR 1S46W. NO 
SIGNIFICANT AREAS OF CONVECTION IN THE VICINITY OF THE ITCZ.

...DISCUSSION...

GULF OF MEXICO...
W TO NW MID TO UPPER LEVEL FLOW IS PRESENT ACROSS THE REGION... 
WITH A WEAK SHORTWAVE TROUGH ACROSS ERN TEXAS. THIS TROUGH IS  
ENHANCING SCATTERED SHOWERS AND TSTMS ALONG A FRONTAL BOUNDARY 
LOCATED 60/90 NM INLAND OVER THE SE CONUS. THIS ACTIVITY IS 
EXPECTED TO CONTINUE SKIRTING ALONG THE IMMEDIATE NRN GULF COAST 
AND DIMINISH WITH THE LOSS OF MAXIMUM DAYTIME HEATING AS IT 
MOVES E-SE AROUND THE NRN PERIPHERY OF THE UPPER RIDGE. 
ELSEWHERE...MAINLY FAIR WEATHER EXISTS ACROSS THE ENTIRE ZONE AS 
A SURFACE RIDGE CONTINUES TO BE NEARLY STATIONARY ACROSS THE NE 
GULF WITH AN EMBEDDED 1019 MB HIGH CENTERED NEAR 27N86W. GIVEN 
THIS SYNOPTIC PATTERN...GENERALLY LIGHT WINDS ARE OBSERVED OVER 
MUCH OF THE ERN AND MIDDLE WATERS AND E TO SE 10-15 KT WINDS ARE 
LOCATED OVER A PORTION OF THE WRN WATERS...DUE TO A TIGHTENED 
PRESSURE GRADIENT BETWEEN THE HIGH AND BROAD TROUGHING OVER 
MEXICO. LITTLE CHANGE IN THE PATTERN IS EXPECTED OVER THE NEXT 
COUPLE OF DAYS AS THE SURFACE RIDGE HOLDS IN PLACE OVER THE NE 
GULF. 

CARIBBEAN SEA...
BROAD RIDGING ALOFT COVERS MUCH OF THE CARIBBEAN...EXTENDING 
FROM CENTRAL VENEZUELA NW TO HONDURAS. UPPER DIFFLUENCE BETWEEN 
THE HIGH AND BROAD TROUGHING OVER THE EPAC...ALONG WITH THE 
PROXIMITY OF LOW-LEVEL CONVERGENCE ALONG THE ITCZ AXIS SOUTH OF 
PANAMA IS PRODUCING SCATTERED SHOWERS AND TSTMS OVER THE SW 
CARIBBEAN S OF 12N. ELSEWHERE...SURFACE HIGH PRESSURE N OF THE 
CARIBBEAN SEA IS RESULTING IN FRESH ELY TRADE WIND FLOW ACROSS 
THE BASIN. THESE TRADES ARE FORECAST TO PERSIST THROUGH THE WEEK 
WITH THE STRONGEST WINDS OF UP TO 25 KTS EXPECTED TO CONTINUE 
NEAR THE COAST OF COLOMBIA.

ATLANTIC OCEAN...
A SURFACE RIDGE ASSOCIATED WITH A 1026 MB SURFACE HIGH OVER THE 
CENTRAL ATLC NEAR 30N47W IS AFFECTING MUCH OF THE ATLC PORTION 
OF THE DISCUSSION AREA. THIS SURFACE HIGH IS FORECAST TO SHIFT 
NE DURING THE NEXT 24 HOURS. SUBSIDENCE ASSOCIATED WITH THE 
SURFACE RIDGE IS RESULTING IN GENERALLY FAIR WEATHER CONDITIONS 
ACROSS MUCH OF THE ATLC. HOWEVER...POCKETS OF LOW-LEVEL MOISTURE 
WITH ISOLATED SHOWERS ARE MOVING W ACROSS PORTIONS OF THE SW N 
ATLC AND TROPICAL N ATLC. THE MOST CONCENTRATED AREA OF 
SCATTERED SHOWERS ARE ASSOCIATED WITH A SURFACE TROUGH THAT 
EXTENDS FROM 15N60W TO 21N59W. THIS TROUGH IS MOVING W NEAR 15 
KT TOWARD THE LEEWARD AND WINDWARD ISLANDS. OBSERVATIONS ACROSS 
THE NRN WINDWARD ISLANDS SHOW WINDS BACKING TO A NELY DIRECTION 
WITH THE APPROACH OF THIS FEATURE AS INCREASED SHOWER ACTIVITY 
IS FORECAST FOR THE NE CARIBBEAN AND ISLANDS OVER THE NEXT DAY 
OR TWO. ALSO...A MID/UPPER-LEVEL TROUGH WITH AXIS ALONG 32N23W 
27N31W 24N44W 16N53W SUPPORTS A SURFACE TROUGH OVER THE E ATLC 
THAT EXTENDS FROM THE CANARY ISLANDS W-SW TO 25N31W. LOW-LEVEL 
CONVERGENCE ALONG THE TROUGH IS GENERATING SCATTERED SHOWERS 
WITHIN 90 NM EITHER SIDE OF THE BOUNDARY. ACROSS THE TROPICAL 
ATLC...AN UPPER LEVEL RIDGE IS PRESENT S OF 10N W OF 20W...WITH 
AN UPPER LEVEL HIGH NEAR 4N35W. ASSOCIATED UPPER LEVEL  
DIVERGENCE IS ENHANCING SCATTERED SHOWERS ALONG THE ITCZ.

$$
HUFFMAN