000 AXNT20 KNHC 091748 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SAT MAY 09 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 5N9W 3N17W 1N24W CROSSING THE EQUATOR NEAR 28W EXTENDING TO 1S36W AND INTO NE BRAZIL NEAR 3S42W. NUMEROUS MODERATE CONVECTION IS FROM 4N-6N BETWEEN 9W-14W. SCATTERED MODERATE CONVECTION IS FROM 1N-5N BETWEEN 21W-28W. SCATTERED MODERATE CONVECTION IS ALSO S OF 2N BETWEEN 41W-51W INCLUDING THE COAST OF NE BRAZIL. ...DISCUSSION... GULF OF MEXICO... SUBSIDENCE IN NORTHERLY FLOW ALOFT AND DEEP LAYER DRY AIR ARE PRESENT ACROSS MUCH OF THE GULF REGION. THIS SUBSIDENCE IS BEING SUPPORTED BY A SURFACE RIDGE OVER THE N GULF THAT EXTENDS WESTWARD FROM A SURFACE HIGH OVER THE CENTRAL ATLC. THE SUBSIDENCE AND STABLE ATMOSPHERIC CONDITIONS ARE RESULTING IN GENERALLY FAIR WEATHER CONDITIONS ACROSS MUCH OF THE GULF REGION. HOWEVER...UPPER LEVEL MOISTURE CONTINUES MOVING SOUTHWARD ACROSS THE FAR N GULF...WHERE HIGH LEVEL CLOUD COVERAGE IS INCREASING. THE RETURN FLOW AROUND THE AFOREMENTIONED SURFACE HIGH AND SURFACE RIDGE IS RESULTING IN SE SURFACE WINDS ACROSS THE GULF...WITH WIND SPEEDS UP TO 20 KT ACROSS PORTIONS OF THE W AND MIDDLE GULF. CARIBBEAN SEA... A SURFACE HIGH OVER THE CENTRAL ATLC AND AN ASSOCIATED SURFACE RIDGE N OF THE CARIBBEAN ARE RESULTING IN FRESH TRADE WINDS ACROSS THE CARIBBEAN SEA. THESE FRESH TRADE WINDS ARE FORECAST TO PERSIST ACROSS THE CARIBBEAN SEA INTO THE MIDDLE OF NEXT WEEK. THE STRONGEST WINDS ARE FOUND NEAR THE COAST OF COLOMBIA...WHERE NE TO E WINDS OF 20 TO 25 KT ARE OCCURRING. THE TRADE WINDS ARE ADVECTING POCKETS OF LOW LEVEL MOISTURE WITH ISOLATED SHOWERS WESTWARD ACROSS THE CARIBBEAN. THE GREATEST CONCENTRATION OF THESE SHOWERS IS N OF 16N BETWEEN 64W-71W INCLUDING PORTIONS OF HISPANIOLA AND PUERTO RICO. ALSO...A BROAD UPPER LEVEL RIDGE IS PRESENT ACROSS THE CARIBBEAN SEA. ATMOSPHERIC STABILITY ASSOCIATED WITH THIS RIDGE IS RESULTING IN GENERALLY FAIR WEATHER CONDITIONS ACROSS MUCH OF THE CARIBBEAN. UPPER LEVEL DIVERGENCE ASSOCIATED WITH THE UPPER LEVEL RIDGE IS RESULTING IN SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER THE SW CARIBBEAN S OF 11N BETWEEN 78W-82W INCLUDING PORTIONS OF PANAMA. ALSO...UPPER LEVEL MOISTURE AND HIGH LEVEL CLOUDS CONTINUE TO STREAM NORTHEASTWARD ACROSS THE E AND S CARIBBEAN. ATLANTIC OCEAN... A SURFACE RIDGE ASSOCIATED WITH A 1028 MB SURFACE HIGH OVER THE CENTRAL ATLC NEAR 32N49W IS AFFECTING MUCH OF THE ATLC PORTION OF THE DISCUSSION AREA. THE SURFACE HIGH IS FORECAST TO MOVE SOUTHWARD DURING THE NEXT DAY AND BE LOCATED NEAR 31N49W AS A 1026 MB SURFACE HIGH AT 10/1200 UTC. SUBSIDENCE ASSOCIATED WITH THE SURFACE HIGH AND SURFACE RIDGE ARE RESULTING IN GENERALLY FAIR WEATHER CONDITIONS ACROSS MUCH OF THE ATLC PORTION OF THE DISCUSSION AREA. HOWEVER...POCKETS OF LOW LEVEL MOISTURE WITH ISOLATED SHOWERS ARE MOVING WESTWARD ACROSS PORTIONS OF THE SW NORTH ATLC...WITH THE GREATEST OF THESE SHOWERS S OF 23N BETWEEN 64W-71W INCLUDING PORTIONS OF HISPANIOLA AND PUERTO RICO. ACROSS THE TROPICAL ATLC...AN UPPER LEVEL RIDGE IS PRESENT S OF 12N E OF 60W...WITH AN UPPER LEVEL HIGH NEAR 7N43W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH THE UPPER LEVEL RIDGE AND UPPER LEVEL HIGH IS ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ. ALSO...UPPER LEVEL DIVERGENCE ASSOCIATED WITH THE UPPER LEVEL HIGH NEAR 7N43W SUPPORTED THE RECENT CONVECTION AND RECENT MAJOR FLOODING ACROSS PORTIONS OF NE BRAZIL. THE GREATEST CONCENTRATION OF CONVECTION OVER BRAZIL IS NOW LOCATED OVER WESTERN PORTIONS OF BRAZIL...THOUGH SCATTERED MODERATE CONVECTION ASSOCIATED WITH THE ITCZ IS AFFECTING THE COAST OF NE BRAZIL. $$ COHEN