000 AXNT20 KNHC 071733 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT FRI AUG 07 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 1700 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 35W S OF 17N MOVING W NEAR 13 KT. THIS WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. SATELLITE IMAGERY AND SATELLITE DERIVED WINDS INDICATE LOW/MID-LEVEL CYCLONIC FLOW IN THE VICINITY OF THE WAVE AXIS. A DRY SAHARAN AIR LAYER IS JUST E OF THE WAVE AXIS INHIBITING DEEP CONVECTION NEAR THE WAVE. A TROPICAL WAVE IS ALONG 53W S OF 15N MOVING W 15-20 KT. THIS WAVE IS LOW AMPLITUDE AND EMBEDDED WITHIN THE ITCZ. WAVE POSITION IS BASED MAINLY ON CONTINUITY. HOWEVER...RECENT SATELLITE DERIVED WINDS DO SHOW SLIGHT LOW/MID-LEVEL CYCLONIC FLOW NEAR THE WAVE AXIS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS LIMITED TO THE ITCZ FROM 9N-12N BETWEEN 52W-57W. A TROPICAL WAVE IS ALONG 70W S OF 20N MOVING W NEAR 13 KT. THIS WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. NO DEEP CONVECTION IS CURRENTLY ASSOCIATED WITH THIS WAVE. HOWEVER...SCATTERED SHOWERS ARE FROM 13N-17N BETWEEN 68W-72W...AND FROM 18N-21N BETWEEN 69W-71W. A TROPICAL WAVE IS ALONG 89W S OF 21N MOVING W 15-20 KT. THIS WAVE LIES IN A BROAD AREA OF DEEP LAYER MOISTURE OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. THIS WAVE IS UNDER A DIFFLUENT PATTERN ALOFT ENHANCING SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 10N-15N BETWEEN 91W-94W. ...ITCZ... 70 THE ITCZ AXIS IS CENTERED ALONG 14N17W 11N25W 14N39W 11N52W 10N64W. SCATTERED MODERATE CONVECTION IS FROM 12N-17N BETWEEN 20W-23W. SIMILAR CONVECTION IS FROM 7N-12N BETWEEN 24W-31W. A SURFACE TROUGH IS EMBEDDED IN THE ITCZ EXTENDING FROM 15N43W TO 9N48W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 10N-13N BETWEEN 45W-50W...ENHANCED BY THE SURFACE TROUGH. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ALSO FROM 9N-11N BETWEEN 58W-61W. ...DISCUSSION... GULF OF MEXICO... SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS MUCH OF THE GULF OF MEXICO ESPECIALLY FROM 21N-26N W OF 91W...AND FROM 25N-29N BETWEEN 83W-89W. THIS ACTIVITY IS ENHANCED BY SURFACE CONVERGENCE NEAR A SURFACE TROUGH EXTENDING ACROSS THE CENTRAL GULF FROM 23N90W TO 29N84W. AN UPPER LEVEL TROUGH EXTENDS ACROSS THE GULF FROM AN UPPER LEVEL LOW NEAR 22N93W TO THE FLORIDA PANHANDLE NEAR 30N85W. UPPER LEVEL DIFFLUENCE BETWEEN THIS UPPER LEVEL TROUGH AND UPPER LEVEL RIDGING TO THE W CENTERED OVER NRN MEXICO NEAR 28N106W...AND TO THE E CENTERED N OF CUBA NEAR 24N78W...IS ALSO SUPPORTING THE SHOWERS/THUNDERSTORMS. A SECOND SURFACE TROUGH IS ACROSS S FLORIDA EXTENDING FROM 25N82W TO 28N80W GENERATING SCATTERED SHOWERS/THUNDERSTORMS FROM 25N-27N BETWEEN 80W-84W. LIGHT WINDS ARE ACROSS MUCH OF THE GULF REACHING UP TO 15 KT IN THE SW GULF. EXPECT A TROPICAL WAVE CURRENTLY OVER THE YUCATAN PENINSULA TO ENTER THE BAY OF CAMPECHE LATER TODAY. CARIBBEAN SEA... AN UPPER LEVEL DIFFLUENT PATTERN IS OVER THE NW CARIBBEAN BETWEEN AN UPPER LEVEL LOW IN THE SRN GULF OF MEXICO NEAR 22N93W...AN UPPER LEVEL HIGH N OF CUBA NEAR 24N78W...AND AN UPPER LEVEL HIGH OFF THE COAST OF NICARAGUA NEAR 13N83W. THIS DIFFLUENT PATTERN IS SUPPORTING ISOLATED SHOWERS/THUNDERSTORMS OVER ERN CUBA N OF 21N BETWEEN 80W-85W...AS WELL AS OFF THE COASTS OF HONDURAS AND BELIZE FROM 16N-19N W OF 84W. SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO ACROSS THE SW CARIBBEAN S OF 13N BETWEEN 75W-85W. THIS ACTIVITY IS ENHANCED BY SURFACE CONVERGENCE NEAR THE E PACIFIC ITCZ AND A 1010 MB SURFACE LOW OVER COLUMBIA NEAR 8N77W. A TROPICAL WAVE ALONG 70W IS SUPPORTING SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS FROM 13N-17N BETWEEN 68W-72W...AND FROM 18N-21N BETWEEN 69W-71W. FRESH TO STRONG TRADE WINDS ARE ACROSS MUCH OF THE E AND CENTRAL CARIBBEAN. EXPECT THE TROPICAL WAVE ALONG 70W TO CONTINUE WWD...AND ANOTHER TROPICAL WAVE CURRENTLY ALONG 53W WILL ENTER THE ERN CARIBBEAN OVER THE WEEKEND. ATLANTIC OCEAN... SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS THE NW ATLC NW OF A LINE FROM 23N79 TO 32N74WW. THIS ACTIVITY IS ENHANCED BY SURFACE CONVERGENCE AHEAD OF A COLD FRONT N OF THE DISCUSSION AREA. NEAR S FLORIDA AND THE BAHAMAS THIS ACTIVITY IS ENHANCED BY SURFACE CONVERGENCE NEAR A SURFACE TROUGH ACROSS S FLORIDA EXTENDING FROM 25N82W TO 28N80W. UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL TROUGH OVER THE ERN CONUS AND AN UPPER LEVEL HIGH N OF CUBA NEAR 24N78W IS ALSO ENHANCING THIS ACTIVITY. A SECOND SURFACE TROUGH IS N OF THE ERN BAHAMAS EXTENDING FROM 24N72W TO 29N71W. SURFACE CONVERGENCE NEAR THIS TROUGH IS SUPPORTING ISOLATED SHOWERS WITHIN 150 NM W OF THE TROUGH AXIS. ISOLATED SHOWERS ARE ALSO IN THE CENTRAL ATLC FROM 28N-32N BETWEEN 41W-49W ENHANCED BY AN UPPER LEVEL LOW NEAR 27N43W. THE REMAINDER OF THE ATLC IS DOMINATED BY A BROAD SURFACE RIDGE ANCHORED BY A 1028 MB SURFACE HIGH NEAR 35N44W. ACROSS THE TROPICAL ATLC...AN UPPER LEVEL HIGH IS CENTERED E OF THE LESSER ANTILLES NEAR 17N58W ENHANCING CONVECTION ALONG THE WRN PORTION OF THE ITCZ. A SECOND UPPER LEVEL RIDGE CENTERED NEAR 22N25W IS ENHANCING CONVECTION ALONG THE ERN PORTION OF THE ITCZ. $$ WALTON