000 AXNT20 KNHC 200603 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SAT JUN 20 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0530 UTC. ...TROPICAL WAVES... A TROPICAL WAVE EXTENDS FROM 10N43W TO 6N44W TO 1N45W MOVING W AROUND 10-12 KT. THIS WAVE COINCIDES WITH A RELATIVELY LOW AMPLITUDE MAXIMUM IN DEEP LAYER MOISTURE BASED ON THE TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS. THE QUIKSCAT PASS AROUND 19/2045 UTC INDICATED CYCLONIC CURVATURE IN THE LOW FLOW IN THE VICINITY OF THIS WAVE. ADDITIONALLY...RECENT SATELLITE IMAGERY DEPICTS CYCLONIC CIRCULATION IN THE MOTION OF LOW LEVEL CLOUDS NEAR THIS WAVE...WHICH IS CONFIRMED BY THE CIMSS WAVETRAK PRODUCT. SCATTERED MODERATE CONVECTION IS FROM 6N-9N BETWEEN 43W-45W. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 10N14W 7N23W 5N36W 5N49W AND INTO NE BRAZIL NEAR 4N53W. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS FROM 2N-13N BETWEEN 9W-14W INCLUDING ADJACENT PORTIONS OF W AFRICA. SCATTERED MODERATE CONVECTION IS FROM 3N-5N BETWEEN 15W-17W. SCATTERED MODERATE CONVECTION IS ALSO FROM 8N-10N BETWEEN 21W-26W. ...DISCUSSION... GULF OF MEXICO... ATMOSPHERIC INSTABILITY ASSOCIATED WITH AN UPPER LEVEL LOW CENTERED OVER THE NW CARIBBEAN NEAR 21N84W IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS OVER THE S GULF S OF 21N W OF 90W. ACROSS THE N AND CENTRAL GULF...DEEP LAYER DRY AIR IS SUPPORTING GENERALLY FAIR WEATHER...WHERE EASTERLY FLOW ALOFT IS OCCURRING BETWEEN THE AFOREMENTIONED UPPER LEVEL LOW OVER THE CARIBBEAN AND AN UPPER LEVEL HIGH OVER THE SE UNITED STATES. THIS UPPER LEVEL HIGH IS ASSOCIATED WITH A 1015 MB SURFACE HIGH OVER THE CENTRAL GULF NEAR 29N88W. ANTICYCLONIC FLOW AROUND THE SURFACE HIGH IS AFFECTING MUCH OF THE GULF...WITH SE WINDS OF 15 TO 20 KT OCCURRING ACROSS PORTIONS OF THE W GULF IN RESPONSE TO A BROAD SURFACE TROUGH OVER MEXICO AND THE SOUTHERN PLAINS OF THE UNITED STATES. THIS SURFACE HIGH IS FORECAST TO MEANDER OVER THE CENTRAL GULF WATERS THROUGH SATURDAY NIGHT...BEFORE A WEAK COLD FRONT MOVES SOUTHEASTWARD INTO THE NE GULF LATE SUNDAY. CARIBBEAN SEA... AN UPPER LEVEL LOW IS OVER THE NW CARIBBEAN AND IS CENTERED NEAR 21N84W. ATMOSPHERIC INSTABILITY ASSOCIATED WITH THIS UPPER LEVEL LOW IS IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS OVER THE W CARIBBEAN N OF 13N W OF 77W INCLUDING PORTIONS OF CUBA...HONDURAS...NICARAGUA...AND COSTA RICA. ACROSS THE E CARIBBEAN...UPPER LEVEL MOISTURE AND HIGH LEVEL CLOUDS ARE STREAMING NORTHEASTWARD TO THE E OF AN UPPER LEVEL TROUGH AXIS THAT EXTENDS FROM 18N71W TO 12N71W. THIS MOISTURE IS INTERACTING WITH ATMOSPHERIC INSTABILITY TO RESULT IN SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER THE NE CARIBBEAN N OF 16N E OF 72W INCLUDING PORTIONS OF HISPANIOLA. MODERATE TO FRESH EASTERLY TRADES ARE FORECAST TO OCCUR S OF 16N THROUGH SUNDAY TO THE S OF A SURFACE RIDGE OVER THE CENTRAL ATLC. ATLANTIC OCEAN... SUBSIDENCE IN NORTHWESTERLY FLOW ALOFT IS SUPPORTING GENERALLY FAIR WEATHER ACROSS THE SW NORTH ATLC. HOWEVER...UPPER LEVEL DIFFLUENCE AND UPPER LEVEL MOISTURE ARE SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS FROM 23N-27N W OF 68W INCLUDING PORTIONS OF THE NW BAHAMAS. TO THE E...AN UPPER LEVEL TROUGH OVER THE CENTRAL ATLC IS ASSOCIATED WITH A WARM FRONT EXTENDING FROM NW OF THE DISCUSSION AREA TO 32N60W TO 31N58W...A STATIONARY FRONT EXTENDING FROM 31N58W TO 31N59W...AND A COLD FRONT EXTENDING FROM 31N49W TO 32N47W TO NE OF THE DISCUSSION AREA. LOW LEVEL CONVERGENCE NEAR THESE FEATURES IS INTERACTING WITH MOISTURE IN DIFFLUENT AND MOIST WESTERLY FLOW ALOFT TO RESULT IN SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS N OF 28N BETWEEN 45W-55W. ACROSS MUCH OF THE CENTRAL AND E ATLC... GENERALLY FAIR WEATHER IS PRESENT WHERE SUBSIDENCE IS OCCURRING NEAR A BROAD SURFACE RIDGE. HOWEVER...A DEEP LAYER LOW OVER THE E ATLC IS ASSOCIATED WITH A SURFACE TROUGH EXTENDING FROM 31N20W TO 32N20W TO N OF THE DISCUSSION AREA. LOW LEVEL CONVERGENCE NEAR THIS SURFACE TROUGH IS SUPPORTING SCATTERED SHOWERS N OF 30N BETWEEN 18W-22W. ACROSS THE TROPICAL ATLC...A BROAD UPPER LEVEL RIDGE IS S OF 15N E OF 53W WITH AN UPPER LEVEL HIGH NEAR 13N23W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH THE UPPER LEVEL HIGH AND UPPER LEVEL RIDGE IS SUPPORTING THE CONVECTION ASSOCIATED WITH THE ITCZ AND WITH THE TROPICAL WAVE THAT EXTENDS FROM 10N43W TO 6N44W TO 1N45W. $$ COHEN