000 AXNT20 KNHC 210535 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SUN JUN 21 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 11N47W TO 7N49W TO 3N50W MOVING W AROUND 12 KT. THIS WAVE COINCIDES WITH A RELATIVELY LOW AMPLITUDE MAXIMUM IN DEEP LAYER MOISTURE BASED ON THE TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS. SATELLITE-DERIVED WINDS INDICATE CYCLONIC CURVATURE IN THE LOW FLOW IN THE VICINITY OF THIS WAVE...WHICH IS CONFIRMED BY THE CIMSS WAVETRAK PRODUCT. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 7N-10N BETWEEN 45W-49W. SCATTERED MODERATE CONVECTION IS FROM 3N-5N BETWEEN 48W-50W. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 12N15W 7N24W 6N35W 7N45W AND INTO NE BRAZIL NEAR 5N53W. SCATTERED MODERATE CONVECTION IS FROM 6N-9N BETWEEN 33W-40W. ...DISCUSSION... GULF OF MEXICO... ATMOSPHERIC INSTABILITY ASSOCIATED WITH AN UPPER LEVEL LOW CENTERED OVER THE YUCATAN PENINSULA NEAR 20N90W IS SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER THE S GULF S OF 22N BETWEEN 89W-93W EXTENDING E OVER THE STRAITS OF FLORIDA AND FLORIDA KEYS. 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 YUCATAN AND AN UPPER LEVEL HIGH OVER ARKANSAS. THIS UPPER LEVEL HIGH IS ASSOCIATED WITH A 1014 MB SURFACE HIGH OVER THE N GULF NEAR 27N89W. ANTICYCLONIC FLOW AROUND THE SURFACE HIGH IS AFFECTING MUCH OF THE GULF...WITH SE WINDS OF 15 TO LOCALLY 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. THE SURFACE HIGH IS FORECAST TO MOVE W ACROSS THE N GULF THROUGH NEXT WEEK. A WEAK COLD FRONT WILL THEN MOVE SOUTHWARD ACROSS PORTIONS OF THE E WATERS MONDAY AND DISSIPATE TUESDAY...LEAVING BROAD LOW PRESSURE IN NE GULF THROUGH MID TO LATE WEEK. CARIBBEAN SEA... AN UPPER LEVEL LOW IS OVER THE YUCATAN PENINSULA AND IS CENTERED NEAR 20N90W. ATMOSPHERIC INSTABILITY ASSOCIATED WITH THIS UPPER LEVEL LOW IS IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS OVER THE W CARIBBEAN FROM 16N-20N W OF 83W INCLUDING PORTIONS OF HONDURAS...BELIZE AND GUATEMALA. ACROSS THE CENTRAL CARIBBEAN... UPPER LEVEL MOISTURE AND HIGH LEVEL CLOUDS ARE GENERALLY STREAMING EASTWARD. THIS MOISTURE IS INTERACTING WITH ATMOSPHERIC INSTABILITY AND UPPER LEVEL DIFFLUENCE TO RESULT IN SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER CUBA...HISPANIOLA...AND THE NEARBY COASTAL WATERS. MODERATE TO FRESH EASTERLY TRADES ARE FORECAST TO OCCUR ACROSS THE SE CARIBBEAN THROUGH THURSDAY. ATLANTIC OCEAN... SUBSIDENCE IN NORTHERLY 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 25N-28N BETWEEN 64W-69W. TO THE E...AN UPPER LEVEL TROUGH OVER THE CENTRAL ATLC IS ASSOCIATED WITH A STATIONARY FRONT SKIRTING THE FAR NORTHERN PORTION OF THE AREA ALONG 32N BETWEEN 42W AND 53W. LOW LEVEL CONVERGENCE NEAR THESE FEATURES IS RESULTING IN SCATTERED SHOWERS N OF 30N BETWEEN 45W-50W. ACROSS MUCH OF THE CENTRAL AND E ATLC... GENERALLY FAIR WEATHER IS PRESENT WHERE SUBSIDENCE IS OCCURRING NEAR A BROAD SURFACE RIDGE. ACROSS THE TROPICAL ATLC...A BROAD UPPER LEVEL RIDGE IS S OF 16N E OF 55W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH THE UPPER LEVEL RIDGE IS SUPPORTING THE CONVECTION ASSOCIATED WITH THE ITCZ AND THE TROPICAL WAVE THAT EXTENDS FROM 11N47W TO 7N49W TO 3N50W...AS WELL AS SCATTERED SHOWERS AND THUNDERSTORMS OFF THE W AFRICA COAST FROM 4N-6N BETWEEN 11W-13W. $$ COHEN/COBB