000 AXNT20 KNHC 101721 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SUN MAY 10 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 1645 UTC. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 6N9W 3N19W 1N28W CROSSING THE EQUATOR NEAR 37W EXTENDING TO NE BRAZIL NEAR 2S46W. SCATTERED MODERATE CONVECTION IS FROM 3N-5N BETWEEN 4W-6W. SCATTERED MODERATE CONVECTION IS ALSO S OF 6N BETWEEN 11W-29W. SIMILAR CONVECTION IS S OF 2N BETWEEN 49W-51W. ...DISCUSSION... GULF OF MEXICO... SUBSIDENCE IN NORTHWESTERLY 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...AS WELL AS A 1020 MB SURFACE HIGH OVER THE N GULF NEAR 29N85W. DURING THE NEXT DAY...THE SURFACE HIGH OVER THE N GULF IS EXPECTED TO REMAIN STATIONARY AND BE A 1019 MB SURFACE HIGH AT 11/1200 UTC. 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 SOUTHEASTWARD ACROSS THE W GULF...WHERE HIGH LEVEL CLOUD COVERAGE IS INCREASING. THE RETURN FLOW AROUND THE AFOREMENTIONED SURFACE HIGHS AND SURFACE RIDGE IS RESULTING IN SE SURFACE WINDS OF 10 TO 15 KT ACROSS MUCH OF THE GULF. HOWEVER...NE TO E SURFACE WINDS OF 15 TO 20 KT ARE EXPECTED ACROSS PORTIONS OF THE SW GULF DURING THE NEXT DAY. CARIBBEAN SEA... SURFACE HIGH PRESSURE N OF THE CARIBBEAN SEA IS RESULTING IN FRESH E TRADE WINDS ACROSS THE CARIBBEAN SEA. THESE FRESH E TRADE WINDS ARE FORECAST TO PERSIST ACROSS THE CARIBBEAN SEA THROUGH THE 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 FROM 15N-18N BETWEEN 63W-67W. 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. HOWEVER...UPPER LEVEL DIVERGENCE ASSOCIATED WITH THE UPPER LEVEL RIDGE IS RESULTING IN SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER THE SW CARIBBEAN S OF 12N BETWEEN 76W-84W INCLUDING PORTIONS OF COSTA RICA...PANAMA....AND NW COLOMBIA. 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 1025 MB SURFACE HIGH OVER THE CENTRAL ATLC NEAR 31N49W IS AFFECTING MUCH OF THE ATLC PORTION OF THE DISCUSSION AREA. THIS SURFACE HIGH IS FORECAST TO MOVE SOUTHEASTWARD DURING THE NEXT DAY AND BE LOCATED NEAR 30N48W AS A 1024 MB SURFACE HIGH AT 11/1200 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 25N BETWEEN 73W-80W INCLUDING PORTIONS OF CUBA AND THE BAHAMAS. THIS ACTIVITY IS BEING SUPPORTED BY ATMOSPHERIC INSTABILITY ASSOCIATED WITH AN UPPER LEVEL TROUGH WITH AN AXIS EXTENDING FROM 23N82W TO 26N78W TO 29N75W. ALSO...A MID/UPPER-LEVEL TROUGH N OF THE DISCUSSION AREA IS ASSOCIATED WITH A SURFACE COLD FRONT OVER THE E ATLC THAT EXTENDS FROM 30N35W TO 30N29W TO 32N21W TO NE OF THE DISCUSSION AREA. THIS COLD FRONT IS DISSIPATING W OF 24W. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF THIS COLD FRONT. ACROSS THE TROPICAL ATLC...AN UPPER LEVEL RIDGE IS PRESENT S OF 11N E OF 57W...WITH AN UPPER LEVEL HIGH NEAR 7N38W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH THE UPPER LEVEL RIDGE AND UPPER LEVEL HIGH IS ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ. $$ COHEN