000 AXNT20 KNHC 261747 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SUN APR 26 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... ITCZ AXIS IS CENTERED ALONG 5N9W 3N16W CROSSING THE EQUATOR NEAR 20W EXTENDING TO 2S24W 2S33W AND INTO NE BRAZIL NEAR 3S40W. CLUSTERS OF SCATTERED MODERATE CONVECTION IS S OF 6N E OF 22W. ELSEWHERE...A SMALL CLUSTER OF SCATTERED MODERATE CONVECTION IS FROM THE EQUATOR TO 2N BETWEEN 43W-48W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL TROUGH IS PRESENT ACROSS THE GULF REGION WITH THE AXIS EXTENDING FROM THE FLORIDA BIG BEND THROUGH THE ERN BAY OF CAMPECHE. TO THE W OF THE TROUGH AXIS...UPPER LEVEL MOISTURE IS EVIDENT ON WATER VAPOR IMAGERY AS HIGH LEVEL CLOUDS ARE OBSERVED W OF 95W. ALSO...UPPER LEVEL DIVERGENCE E OF THE TROUGH AXIS IS SUPPORTING INCREASED CLOUDINESS AND POSSIBLE SCATTERED SHOWERS FROM 23N-27N BETWEEN 83W-87W. HOWEVER...SUBSIDENCE ASSOCIATED WITH A SURFACE RIDGE EXTENDING WESTWARD INTO THE SE CONUS FROM A 1031 MB SURFACE HIGH OVER THE W ATLC NEAR 33N70W IS RESULTING IN GENERALLY FAIR WEATHER CONDITIONS ACROSS MUCH OF THE GULF THIS AFTERNOON. THE FLOW AROUND THE SURFACE RIDGE IS RESULTING IN E TO SE WINDS OF 20 TO 25 KT ACROSS PORTIONS OF THE GULF...WITH E WINDS UP TO 30 KT THROUGH THE STRAITS OF FLORIDA. THESE CONDITIONS ARE EXPECTED TO PERSIST THROUGH LATE MONDAY WHEN THE PRESSURE GRADIENT RELAXES ACROSS THE GULF. CARIBBEAN SEA... A 1031 MB SURFACE HIGH OVER THE W ATLC NEAR 33N70W IS MAINTAINING FRESH TO STRONG TRADE WINDS ACROSS THE CARIBBEAN SEA. THE STRONGEST WINDS ARE FOUND NEAR THE COAST OF COLOMBIA... WHERE NE TO E SURFACE WINDS UP TO 30 KT ARE OCCURRING. A BROAD UPPER LEVEL RIDGE COVERS THE CARIBBEAN SEA WHERE ATMOSPHERIC STABILITY IS RESULTING IN GENERALLY FAIR WEATHER CONDITIONS. HOWEVER...THE TRADE WINDS ARE ADVECTING POCKETS OF LOW LEVEL MOISTURE WITH ISOLATED SHOWERS WESTWARD ACROSS THE CARIBBEAN. THE GREATEST CONCENTRATION OF THESE SHOWERS IS ACROSS THE WINDWARD ISLANDS S OF 15N...SOUTH OF HISPANIOLA FROM 16N-19N BETWEEN 70W-73W...AND OVER JAMAICA. ALSO...UPPER LEVEL MOISTURE AND HIGH LEVEL CLOUDS CONTINUE TO STREAM NORTHEASTWARD ACROSS THE WRN CARIBBEAN. ATLANTIC OCEAN... A DEEP LAYER TROUGH OVER THE CENTRAL ATLC IS ASSOCIATED WITH A SURFACE STATIONARY FRONT THAT EXTENDS FROM 24N65W TO 27N56W TO 31N53W AND NE BEYOND THE DISCUSSION AREA. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 120 NM E OF THE FRONT N OF 27N. ELSEWHERE ALONG THE BOUNDARY...ISOLATED SHOWERS ARE WITHIN 50 NM. THIS ACTIVITY IS ALSO BEING SUPPORTED BY UPPER LEVEL DIVERGENCE IN THE NE QUADRANT OF AN 80-90 KT UPPER LEVEL WIND SPEED MAXIMUM LOCATED SE OF THE STATIONARY SURFACE FRONT. TO THE NW OF THE BOUNDARY...DEEP LAYER DRY AIR AND SUBSIDENCE ASSOCIATED WITH A 1031 MB SURFACE HIGH NEAR 33N70W ARE RESULTING IN GENERALLY FAIR WEATHER CONDITIONS. THIS HIGH PRESSURE RIDGE IS FORECAST TO REMAIN QUASI-STATIONARY OVER THE NEXT 24 HOURS. FARTHER TO THE E...SUBSIDENCE IN THE VICINITY OF A SURFACE RIDGE IS RESULTING IN GENERALLY FAIR WEATHER CONDITIONS ACROSS MUCH OF THE CENTRAL AND E ATLC. HOWEVER...AN UPPER TROUGH IS LOCATED OVER THE FAR NE ATLC NW OF THE CANARY ISLANDS WITH AN UPPER LOW CENTERED NEAR 30N20W. ATMOSPHERIC INSTABILITY AND UPPER LEVEL DIVERGENCE IN THE VICINITY OF THIS UPPER LOW ARE RESULTING IN SCATTERED SHOWERS N OF 24N E OF 21W. ACROSS THE TROPICAL ATLC...AN UPPER LEVEL ANTICYCLONE CENTERED OVER W AFRICA EXTENDS A RIDGE ALONG 9N14W 1N37W. UPPER LEVEL DIVERGENCE ON THE SRN PERIPHERY OF THE RIDGE IS ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ. $$ HUFFMAN