000 AXNT20 KNHC 252359 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT MON MAY 25 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 2245 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 30W/31W S OF 10N MOVING W NEAR 15 KT. TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS INDICATES THAT THIS WAVE COINCIDES WITH A MAXIMUM IN DEEP LAYER MOISTURE. ALSO... CIMSS WAVETRAK PRODUCT INDICATES A MAXIMUM IN LOW LEVEL CYCLONIC CIRCULATION AROUND THE WAVE. SUBSIDENCE ASSOCIATED WITH A SURFACE RIDGE ACROSS THE E ATLC IS SUPPRESSING DEEP CONVECTION NEAR THIS WAVE. HOWEVER...SCATTERED SHOWERS ARE OCCURRING FROM 3N-7N BETWEEN 25W-30W. A TROPICAL WAVE IS ALONG 62W/63W S OF 14N MOVING W 15-20 KT. RECENT SURFACE OBSERVATIONS SHOW CYCLONIC CURVATURE IN THE LOW LEVEL WINDS AROUND THIS WAVE. THIS WAVE IS ASSOCIATED WITH A MAXIMUM IN DEEP LAYER MOISTURE BASED ON TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS. SCATTERED MODERATE CONVECTION IS OCCURRING FROM 3N-10N BETWEEN 61W-64W...INCLUDING PORTIONS OF E VENEZUELA AND NW GUYANA. FARTHER TO THE NORTH...DEEP CONVECTION IN THE VICINITY OF THIS WAVE IS BEING SUPPRESSED BY SUBSIDENCE IN NORTHWESTERLY FLOW ALOFT. HOWEVER...SCATTERED SHOWERS ARE OCCURRING WITHIN 90 NM EITHER SIDE OF THE WAVE AXIS FROM 10N-13N INCLUDING PORTIONS OF THE WINDWARD ISLANDS. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 8N12W 4N19W 2N26W CROSSING THE EQUATOR NEAR 32W EXTENDING TO 2S39W AND INTO NE BRAZIL NEAR 3S46W. SCATTERED MODERATE CONVECTION IS FROM 1N-3N BETWEEN 19W-22W...S OF 1N BETWEEN 23W-29W...AND S OF 2N BETWEEN 35W-44W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL TROUGH IS PRESENT ACROSS THE N GULF...WITH AN ASSOCIATED SURFACE TROUGH ACROSS THE NW GULF EXTENDING FROM 26N96W TO 30N93W TO 32N92W TO N OF THE DISCUSSION AREA. LOW LEVEL CONVERGENCE NEAR THE SURFACE TROUGH...AS WELL AS ATMOSPHERIC INSTABILITY ASSOCIATED WITH THE UPPER LEVEL TROUGH...ARE SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE GULF N OF 25N AS WELL AS ADJACENT INLAND LOCATIONS ALONG THE GULF COAST. ACROSS THE S GULF...DEEP LAYER DRY AIR IN WESTERLY FLOW ALOFT IS SUPPORTING GENERALLY FAIR WEATHER. SOUTHERLY RETURN FLOW IS FORECAST TO INCREASE ACROSS THE FAR W GULF ON TUESDAY BETWEEN A TROUGH OVER TEXAS AND HIGH PRES BUILDING OVER THE E GULF. CARIBBEAN SEA... SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE OCCURRING ACROSS THE CARIBBEAN FROM 11N-15N BETWEEN 78W-82W. THIS ACTIVITY IS BEING SUPPORTED BY UPPER LEVEL DIVERGENCE AND DEEP LAYER MOISTURE AROUND AN UPPER LEVEL RIDGE ACROSS THE SW CARIBBEAN. ADDITIONALLY...ATMOSPHERIC INSTABILITY OVER HIGHER TERRAIN IS RESULTING IN SCATTERED SHOWERS AND THUNDERSTORMS AFFECTING CUBA...HISPANIOLA...PUERTO RICO...NICARAGUA...HONDURAS...COSTA RICA...AND PANAMA...AND NEARBY COASTAL WATERS. UPPER LEVEL MOISTURE AND HIGH LEVEL CLOUDS ARE STREAMING GENERALLY EAST-SOUTHEASTWARD ACROSS THE CARIBBEAN. MEANWHILE...THE PRESSURE GRADIENT S OF SURFACE HIGH PRESSURE E OF BERMUDA IS MAINTAINING E WINDS OF 20 TO 25 KT ACROSS PORTIONS OF THE E CARIBBEAN. ADDITIONALLY...A TROPICAL WAVE IS OVER THE SE CARIBBEAN. PLEASE SEE ABOVE FOR FURTHER INFORMATION ON THIS TROPICAL WAVE. ATLANTIC OCEAN... SCATTERED SHOWERS AND THUNDERSTORMS ARE OCCURRING N OF 24N W OF 70W INCLUDING THE NW BAHAMAS AND ADJACENT INLAND LOCATIONS OF FLORIDA...AS WELL AS S OF 24N W OF 67W INCLUDING PORTIONS OF CUBA...HISPANIOLA...PUERTO RICO...AND THE SE BAHAMAS. THIS ACTIVITY IS BEING SUPPORTED BY LOW LEVEL CONVERGENCE NEAR A SURFACE TROUGH NEAR THE BAHAMAS EXTENDING FROM 25N76W TO 23N75W TO 21N74W. THE SURFACE TROUGH IS FORECAST TO MOVE TOWARD THE NORTH TO NORTHEAST DURING THE NEXT COUPLE OF DAYS...WITH THE POTENTIAL FOR AN INCREASING SURFACE PRESSURE GRADIENT E OF THE TROUGH. THE SHOWER AND THUNDERSTORM ACTIVITY IS ALSO BEING SUPPORTED BY UPPER LEVEL DIFFLUENCE IN MOIST SOUTHWESTERLY FLOW ALOFT BETWEEN AN UPPER LEVEL TROUGH OVER THE N GULF OF MEXICO AND AN UPPER LEVEL RIDGE ACROSS THE SW NORTH ATLC. ALSO...A 1023 MB SURFACE HIGH IS E OF BERMUDA NEAR 34N57W...WITH SUBSIDENCE RESULTING IN GENERALLY FAIR WEATHER NEAR THIS SURFACE HIGH. THE SURFACE HIGH IS FORECAST TO MOVE SOUTHWESTWARD DURING THE NEXT DAY AND BE LOCATED NEAR 31N59W AS A 1023 MB SURFACE HIGH AT 26/1800 UTC. FARTHER TO THE E...AN UPPER LEVEL TROUGH IS PRESENT WITH AN AXIS EXTENDING FROM 25N51W TO 29N48W TO 32N45W. THIS UPPER LEVEL TROUGH IS ASSOCIATED WITH A SURFACE TROUGH EXTENDING FROM A 1018 MB SURFACE LOW NEAR 30N50W TO 30N47W TO 24N49W TO 20N57W. ATMOSPHERIC INSTABILITY NEAR THE UPPER LEVEL TROUGH...UPPER LEVEL DIFFLUENCE IN MOIST SOUTHWESTERLY FLOW ALOFT E OF THE UPPER LEVEL TROUGH...AND LOW LEVEL CONVERGENCE NEAR THE SURFACE LOW AND TROUGH ARE SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS FROM 23N-29N BETWEEN 38W-52W AND FROM 19N-23N BETWEEN 44W-64W. DURING THE NEXT DAY...THE 1018 MB SURFACE LOW IS FORECAST TO DISSIPATE. ACROSS THE E ATLC...A SURFACE RIDGE IS PRESENT WHERE MAINLY ZONAL FLOW ALOFT IS OCCURRING AND FAIR WEATHER CONDITIONS PERSIST. ACROSS THE TROPICAL ATLC...AN UPPER LEVEL RIDGE IS PRESENT S OF 8N E OF 53W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH THIS UPPER LEVEL RIDGE IS ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ AND THE TROPICAL WAVE ALONG 30W/31W S OF 10N...AS WELL AS SCATTERED SHOWERS AND THUNDERSTORMS FROM 1N-5N BETWEEN 1W-5W. $$ COHEN