000 AXNT20 KNHC 261739 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SUN JUL 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. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 33W/34W S OF 17N MOVING W NEAR 20 KT. THIS WAVE COINCIDES WITH A BROAD MAXIMUM IN DEEP LAYER MOISTURE BASED ON THE TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS. SATELLITE-DERIVED WINDS INDICATE CYCLONIC CURVATURE IN THE LOW LEVEL FLOW WITHIN THE 950-800 MB LAYER IN THE VICINITY OF THIS WAVE. ALSO...RECENT SATELLITE IMAGERY INDICATES CYCLONIC MOTION OF LOW LEVEL CLOUDS NEAR THIS WAVE. SCATTERED MODERATE CONVECTION IS FROM 9N-12N BETWEEN 33W-37W. A TROPICAL WAVE EXTENDS FROM 17N58W TO 12N56W TO 7N54W MOVING W 25-30 KT. THIS WAVE COINCIDES WITH A WELL-DEFINED MAXIMUM IN DEEP LAYER MOISTURE BASED ON THE TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS. VISIBLE SATELLITE IMAGERY INDICATES AN INVERTED-V PATTERN IN THE COVERAGE OF LOW LEVEL CLOUDS NEAR THIS WAVE. STABLE ATMOSPHERIC CONDITIONS ASSOCIATED WITH AN UPPER LEVEL RIDGE ARE INHIBITING DEEP CONVECTION NEAR THIS WAVE. HOWEVER...SCATTERED SHOWERS ARE OCCURRING FROM 10N-15N BETWEEN 56W-59W. A TROPICAL WAVE IS ALONG 89W S OF 22N MOVING W NEAR 20 KT. THIS WAVE IS EMBEDDED WITHIN A BROAD MAXIMUM IN DEEP LAYER MOISTURE BASED ON THE TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS. SCATTERED MODERATE CONVECTION IS FROM 15N-19N BETWEEN 85W-91W. THIS CONVECTION IS BEING ENHANCED BY UPPER LEVEL DIVERGENCE ASSOCIATED WITH AN UPPER LEVEL HIGH OVER THE YUCATAN PENINSULA NEAR 17N89W. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 11N15W 11N27W 9N40W 10N54W 9N61W. SCATTERED MODERATE CONVECTION IS FROM 8N-12N BETWEEN 15W-20W. SCATTERED MODERATE CONVECTION IS ALSO FROM 11N-13N BETWEEN 59W-61W. ...DISCUSSION... GULF OF MEXICO... A SHARP UPPER LEVEL TROUGH IS OVER THE CENTRAL AND W GULF WITH AN AXIS EXTENDING FROM 30N88W TO 20N97W. ATMOSPHERIC LIFT IN MOIST SOUTHWESTERLY FLOW ALOFT TO THE E OF THE UPPER LEVEL TROUGH AXIS IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS OVER THE W CENTRAL GULF FROM 23N-26N BETWEEN 88W-94W...OVER THE BAY OF CAMPECHE S OF 21N W OF 92W...AND OVER THE E CENTRAL GULF FROM 25N-29N E OF 84W. THE SHOWER AND THUNDERSTORM ACTIVITY OVER THE W CENTRAL GULF IS ALSO BEING SUPPORTED BY LOW LEVEL CONVERGENCE DUE TO REGIONAL VARIATIONS IN LOW LEVEL WIND SPEED. ACROSS THE NW GULF...SUBSIDENCE IN NORTHERLY FLOW ALOFT W OF THE UPPER LEVEL TROUGH AXIS...AS WELL AS DEEP LAYER DRY AIR...ARE RESULTING IN GENERALLY FAIR WEATHER. SOUTHEASTERLY WINDS ARE FORECAST TO INCREASE OVER THE W GULF BY TUESDAY...AS A SURFACE RIDGE ACROSS THE N GULF MOVES NORTHWARD DURING THE NEXT FEW DAYS AND SURFACE LOW PRESSURE DEVELOPS OVER W TEXAS. CARIBBEAN SEA... AN UPPER LEVEL RIDGE IS PRESENT OVER THE NW CARIBBEAN THAT EXTENDS E OF AN UPPER LEVEL HIGH OVER THE YUCATAN PENINSULA 17N89W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH THIS UPPER LEVEL RIDGE IS SUPPORTING SCATTERED SHOWERS FROM 17N-19N BETWEEN 82W-84W. THIS UPPER LEVEL DIVERGENCE IS ALSO SUPPORTING CONVECTION OVER THE W CARIBBEAN ASSOCIATED WITH THE TROPICAL WAVE ALONG 89W S OF 22N. ACROSS THE SW CARIBBEAN...UPPER LEVEL DIFFLUENCE IN EAST-NORTHEASTERLY FLOW ALOFT IS COMBINING WITH DEEP LAYER MOISTURE TO RESULT IN SCATTERED SHOWERS AND THUNDERSTORMS S OF 10N W OF 81W INCLUDING PORTIONS OF W PANAMA AND S COSTA RICA. ACROSS MUCH OF THE CENTRAL AND E CARIBBEAN...DEEP LAYER DRY IS SUPPORTING GENERALLY FAIR WEATHER. FRESH TO STRONG TRADE WINDS ARE OCCURRING ACROSS THE E AND CENTRAL CARIBBEAN S OF A SURFACE RIDGE OVER THE CENTRAL AND E ATLC. THE STRONGEST WINDS ARE FOUND NEAR THE COAST OF COLOMBIA...WHERE E WINDS OF 25 TO 30 KT ARE OCCURRING. ATLANTIC OCEAN... AN UPPER LEVEL TROUGH IS PRESENT OVER THE E UNITED STATES AND THE W AND CENTRAL GULF OF MEXICO. ATMOSPHERIC LIFT IN MOIST SOUTHERLY FLOW ALOFT BETWEEN THIS UPPER LEVEL TROUGH AND AN UPPER LEVEL RIDGE FARTHER TO THE E OVER THE SW NORTH ATLC IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS N OF 23N BETWEEN 73W-80W INCLUDING PORTIONS OF THE NW BAHAMAS. TO THE E...AN UPPER LEVEL LOW IS CENTERED NEAR 29N61W. ATMOSPHERIC INSTABILITY IN THE VICINITY OF THIS UPPER LEVEL LOW IS SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS N OF 28N BETWEEN 59W-64W. FARTHER TO THE E...SUBSIDENCE AND ATMOSPHERIC STABILITY ASSOCIATED WITH A DEEP LAYER RIDGE IS RESULTING IN GENERALLY FAIR WEATHER ACROSS MUCH OF THE CENTRAL AND E ATLC. HOWEVER...A SURFACE TROUGH OVER THE CENTRAL ATLC EXTENDS FROM 26N52W TO 24N53W TO 20N54W. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF THIS SURFACE TROUGH. $$ COHEN