000 AXNT20 KNHC 222334 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT MON JUN 22 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 EXTENDS FROM 15N56W TO 9N59W TO 3N60W MOVING W 15-20 KT. THIS WAVE IS NEAR THE LEADING EDGE OF A RATHER ELONGATED MAXIMUM IN DEEP LAYER MOISTURE BASED ON THE TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS. COMPUTER MODEL GUIDANCE INDICATES CYCLONIC CURVATURE IN THE LOW LEVEL FLOW IN THE VICINITY OF THIS WAVE. SCATTERED MODERATE CONVECTION IS FROM 11N-15N BETWEEN 52W-61W. SCATTERED MODERATE CONVECTION IS ALSO FROM 8N-10N BETWEEN 50W-52W. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 12N16W 7N26W 5N38W 6N45W AND INTO NE BRAZIL NEAR 5N53W. SCATTERED MODERATE CONVECTION IS FROM 5N-8N BETWEEN 13W-28W. SCATTERED MODERATE CONVECTION IS ALSO FROM 4N-7N BETWEEN 32W-36W. ...DISCUSSION... GULF OF MEXICO... ATMOSPHERIC INSTABILITY ASSOCIATED WITH AN UPPER LEVEL LOW ACROSS E MEXICO IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS OVER THE S GULF S OF 25N W OF 90W. THIS ACTIVITY IS ALSO BEING SUPPORTED BY LOW LEVEL CONVERGENCE ASSOCIATED WITH A SURFACE TROUGH OVER THE SW GULF THAT EXTENDS FROM 23N96W TO 20N96W TO THE COAST OF MEXICO NEAR 19N95W. ACROSS THE N AND E GULF...DEEP LAYER DRY AIR IS SUPPORTING GENERALLY FAIR WEATHER...WHERE SOUTHEASTERLY FLOW ALOFT IS OCCURRING BETWEEN THE AFOREMENTIONED UPPER LEVEL LOW OVER E MEXICO AND AN UPPER LEVEL HIGH OVER N LOUISIANA. THE UPPER LEVEL HIGH IS ASSOCIATED WITH A 1013 MB SURFACE HIGH OVER THE N GULF NEAR 28N91W. ANTICYCLONIC FLOW AROUND THE SURFACE HIGH IS AFFECTING MUCH OF THE GULF...WITH E TO SE WINDS OF 15 TO 20 KT OCCURRING ACROSS PORTIONS OF THE SW GULF. THE SURFACE HIGH IS FORECAST TO MOVE WESTWARD TONIGHT AND THEN MEANDER OVER THE WESTERN WATERS OF THE GULF THROUGH WEDNESDAY. CARIBBEAN SEA... UPPER LEVEL MOISTURE IN DIFFLUENT NORTHERLY FLOW ALOFT ACROSS THE N CARIBBEAN IS INTERACTING WITH ATMOSPHERIC INSTABILITY TO RESULT IN SCATTERED SHOWERS AND THUNDERSTORMS N OF 17N BETWEEN 70W-83W INCLUDING PORTIONS OF CUBA...JAMAICA...AND HISPANIOLA. ACROSS THE SW CARIBBEAN...ATMOSPHERIC INSTABILITY ASSOCIATED WITH AN UPPER LEVEL TROUGH IS SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS S OF 12N BETWEEN 73W-84W INCLUDING PORTIONS OF NICARAGUA...COSTA RICA...PANAMA...AND N COLOMBIA. ACROSS THE E CARIBBEAN...DEEP LAYER DRY AIR AND CONFLUENT WESTERLY FLOW ALOFT ARE PRESENT...WHERE GENERALLY FAIR WEATHER IS OCCURRING. HOWEVER...UPPER LEVEL MOISTURE AND HIGH LEVEL CLOUDS ARE STREAMING NORTHEASTWARD ACROSS THE FAR SE CARIBBEAN. THE TROPICAL WAVE EXTENDING FROM 15N56W TO 9N59W TO 3N60W IS FORECAST TO MOVE INTO THE E CARIBBEAN ON TUESDAY. ATLANTIC OCEAN... A DEEP LAYER TROUGH OVER THE W ATLC IS ASSOCIATED WITH A 990 MB SURFACE LOW NEAR 40N67W. THE TIGHT PRESSURE GRADIENT SE OF THIS SURFACE LOW IS SUPPORTING GALE FORCE WINDS WITHIN 660 NM IN THE SE QUADRANT OF THE SURFACE LOW N OF 31N. THE DEEP LAYER LOW IS ALSO ASSOCIATED WITH A STATIONARY FRONT EXTENDING FROM NW OF THE DISCUSSION AREA TO 32N82W TO 31N81W...A COLD FRONT EXTENDING FROM 31N81W TO 29N74W TO 32N65W TO NE OF THE DISCUSSION AREA...AND A SURFACE TROUGH EXTENDING FROM 29N69W TO 27N75W TO 28N79W. LOW LEVEL CONVERGENCE NEAR THE FRONTS AND SURFACE TROUGH...AS WELL AS ATMOSPHERIC INSTABILITY...UPPER LEVEL DIFFLUENCE...AND ABUNDANT DEEP LAYER MOISTURE...ARE SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS N OF 21N BETWEEN 64W-79W INCLUDING THE BAHAMAS. FARTHER TO THE E...GENERALLY FAIR WEATHER IS PRESENT ACROSS MUCH OF THE CENTRAL AND E ATLC...WHERE SUBSIDENCE IS OCCURRING NEAR A BROAD SURFACE RIDGE. THIS SURFACE RIDGE IS ASSOCIATED WITH A 1024 MB SURFACE HIGH NEAR 35N35W. ACROSS THE TROPICAL ATLC...A BROAD UPPER LEVEL RIDGE IS S OF 15N E OF 42W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH THE UPPER LEVEL RIDGE IS SUPPORTING THE CONVECTION ASSOCIATED WITH THE ITCZ. $$ COHEN