000 AXNT20 KNHC 260523 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0430 UTC. ...TROPICAL WAVES... A TROPICAL WAVE HAS BEEN ADDED TO THE 0000 UTC SURFACE ANALYSIS ALONG 30W S OF 17N MOVING W NEAR 20 KT. THIS WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED ON TOTAL PRECIPITABLE WATER IMAGERY. SATELLITE IMAGERY AND SATELLITE DERIVED WINDS ALSO INDICATE LOW/MID-LEVEL CYCLONIC FLOW IN THE VICINITY OF THE WAVE AXIS. THE WESTWARD PROPAGATION OF THIS WAVE CAN BE SEEN IN TROPICAL HOVMOLLER DIAGRAMS. NO DEEP CONVECTION IS CURRENTLY ASSOCIATED WITH THIS WAVE. A TROPICAL WAVE EXTENDS FROM 16N49W TO 4N45W MOVING W 25-30 KT. THIS WAVE IS JUST E OF A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. SATELLITE IMAGERY INDICATES LOW-LEVEL CYCLONIC TURNING NEAR THE WAVE AXIS ALONG 12N. A CLUSTER OF NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS EMBEDDED WITHIN THE ITCZ FROM 8N-10N BETWEEN 46W-49W. TROPICAL WAVE IS ALONG 85W S OF 21N MOVING NEAR W 20 KT. THIS WAVE IS EMBEDDED WITHIN A BROAD AREA OF DEEP LAYER MOISTURE AS OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE CONVECTION IS FROM 7N-10N BETWEEN 82W-86W...AND FROM 12N-16N BETWEEN 83W-86W. THIS CONVECTION IS ENHANCED BY UPPER LEVEL DIFFLUENCE NEAR AN UPPER LEVEL HIGH NEAR 16N88W. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 14N17W 11N29W 9N38W 10N50W 10N63W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS JUST OFF THE COAST OF AFRICA FROM 8N-11N BETWEEN 13W-20W. SCATTERED MODERATE CONVECTION IS FROM 9N-11N BETWEEN 35W-39W. ...DISCUSSION... GULF OF MEXICO... A BROAD SURFACE RIDGE IS ACROSS THE GULF OF MEXICO EXTENDING W ALONG 25N FROM THE SUBTROPICAL RIDGE IN THE ATLC. AN UPPER LEVEL TROUGH IS ACROSS THE NW GULF OF MEXICO WITH AXIS ALONG 30N89W TO CENTRAL MEXICO NEAR 22N100W. UPPER LEVEL DIFFLUENCE BETWEEN THIS UPPER LEVEL TROUGH AND AN UPPER LEVEL RIDGE OVER THE YUCATAN PENINSULA CENTERED NEAR 16N88W ALONG WITH MOIST SWLY FLOW ALOFT ARE SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS ACROSS THE SRN GULF S OF A LINE EXTENDING FROM 30N83W TO 22N98W. ANTI-CYCLONIC FLOW IS PRESENT AROUND THE SURFACE RIDGE WITH WINDS REACHING 15 KT IN THE W GULF...AND REACHING 20 KT NEAR THE YUCATAN PENINSULA COAST. EXPECT THE SURFACE RIDGE TO LIFT N BY MID WEEK...AND SE FLOW WILL INCREASE OVER THE WRN GULF BY TUE AS LOW PRES DEVELOPS OVER W TEXAS. CARIBBEAN SEA... SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS THE W CARIBBEAN N OF 12N W OF 83W INCLUDING PORTIONS OF NICARAGUA...HONDURAS...AND WRN CUBA. THIS ACTIVITY IS ENHANCED BY LOW-LEVEL CONVERGENCE NEAR A TROPICAL WAVE ALONG 85W ALONG WITH UPPER LEVEL DIFFLUENCE ASSOCIATED WITH AN UPPER LEVEL HIGH NEAR 16N88W. ELSEWHERE ACROSS THE CENTRAL AND E CARIBBEAN...GENERALLY FAIR WEATHER PREVAILS UNDER THE PRESENCE OF A DRY SAHARAN AIR LAYER E OF 78W. HOWEVER...ATMOSPHERIC INSTABILITY IS GENERATING ISOLATED SHOWERS N OF 18N BETWEEN 65W-81W INCLUDING HISPANIOLA AND PUERTO RICO. FRESH TO STRONG TRADE WINDS ARE PRESENT ACROSS MUCH OF THE CARIBBEAN WITH SURFACE WINDS REACHING 30 KT NEAR THE COAST OF COLUMBIA. EXPECT A TROPICAL WAVE CURRENTLY IN THE ATLC TO APPROACH THE LESSER ANTILLES MON. ATLANTIC OCEAN... ISOLATED SHOWERS/THUNDERSTORMS ARE ACROSS THE FAR W ATLC N OF 22N W OF 75W. THIS ACTIVITY IS SUPPORTED BY UPPER LEVEL DIFFLUENCE BETWEEN A SHORTWAVE UPPER LEVEL TROUGH OVER THE FLORIDA PENINSULA AND AN UPPER LEVEL HIGH CENTERED NEAR 28N71 ALONG WITH MOIST SWLY FLOW ALOFT. A SURFACE TROUGH IS ANALYZED N OF THE BAHAMAS FROM 25N73W TO 27N71W. NO SHOWER ACTIVITY IS CURRENTLY ASSOCIATED WITH THIS TROUGH. A SECOND SURFACE TROUGH IS ANALYZED IN THE CENTRAL ATLC FROM 18N50W TO 26N47W. THIS TROUGH IS A FRACTURED OFF PORTION OF THE TROPICAL WAVE THAT EXTENDS FROM 16N49W TO 4N45W. NO SHOWER ACTIVITY IS ASSOCIATED WITH THIS SURFACE TROUGH. ELSEWHERE ACROSS THE ATLC...A BROAD SURFACE RIDGE IS PRESENT ANCHORED BY A 1030 MB HIGH CENTERED NEAR 34N42W BRINGING GENERALLY FAIR WEATHER ACROSS THE BASIN. AN UPPER LEVEL HIGH CENTERED NEAR 23N47W IS ENHANCING CONVECTION ALONG THE ITCZ. $$ WALTON