000 AXNT20 KNHC 240634 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT FRI JUL 24 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 0500 UTC. ...TROPICAL WAVES... A TROPICAL WAVE EXTENDS FROM 20N33W TO 9N28W MOVING W NEAR 15 KT. THIS WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. SATELLITE IMAGES INDICATE BROAD LOW-LEVEL CYCLONIC FLOW IN THE VICINITY OF THE WAVE AXIS. SATELLITE DERIVED WINDS ALSO INDICATE GOOD CYCLONIC TURNING IN THE LOW-MID LEVELS. CONVECTION IS LIMITED DUE TO THE THE PRESENCE OF A DRY SAHARAN AIR LAYER EXCEPT FOR A SMALL PORTION OF SCATTERED MODERATE CONVECTION EMBEDDED IN THE ITCZ FROM 9N-11N BETWEEN 29W-32W. A TROPICAL WAVE IS ALONG 67W S OF 20N MOVING W NEAR 25 KT. THIS WAVE HAS BEEN RELOCATED FARTHER WEST THAN THE MOTION SUGGESTS TO COINCIDE BETTER WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. NO DEEP CONVECTION IS CURRENTLY ASSOCIATED WITH THIS WAVE DUE TO DRY AIR AND SUBSIDENCE IN NELY FLOW ALOFT. A TROPICAL WAVE IS ALONG 80W S OF 22N MOVING W NEAR 25 KT. CURRENT POSITION IS BASED MAINLY ON CONTINUITY DUE TO THE LACK OF GOOD PRESENCE IN SATELLITE IMAGERY. LITTLE CONVECTION IS CURRENTLY ASSOCIATED WITH THE WAVE DUE TO DRY SAHARAN AIR DIRECTLY TO THE E OF THE WAVE AXIS. HOWEVER...SCATTERED MODERATE CONVECTION IS N OF CUBA FROM 22N-24N BETWEEN 77W-79W. THIS CONVECTION IS ENHANCED BY UPPER LEVEL DIFFLUENCE. A TROPICAL WAVE IS ALONG 95W S OF 21N MOVING W NEAR 25 KT. THIS WAVE IS EMBEDDED IN A BROAD AREA OF DEEP LAYER MOISTURE OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. WHILE THE MAJORITY OF THE WAVE AXIS IS IN THE E PACIFIC...SCATTERED MODERATE CONVECTION IS OVER MEXICO FROM 15N-18N BETWEEN 93W-95W. THIS CONVECTION IS BEING ENHANCED BY UPPER LEVEL DIFFLUENCE. REFER TO THE TWDEP FOR MORE DETAILS ABOUT THE SRN PORTION OF THIS WAVE IN THE E PACIFIC. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 11N12W 10N27W 9N44W 9N61W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 7N-11N BETWEEN 18W-22W. SCATTERED MODERATE CONVECTION IS FROM 9N-11N BETWEEN 41W-46W. ...DISCUSSION... GULF OF MEXICO... LOW-LEVEL CONVERGENCE AHEAD OF A STATIONARY FRONT ACROSS SRN LOUISIANA AND TEXAS ALONG WITH UPPER LEVEL DIFFLUENCE AND MOISTURE IN WESTERLY FLOW ALOFT ARE SUPPORTING SCATTERED SHOWERS OVER THE NRN GULF OF MEXICO N OF 28N BETWEEN 88W-93W. UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL HIGH OVER THE YUCATAN PENINSULA NEAR 18N91W AND A SHORTWAVE UPPER LEVEL TROUGH OVER THE BAHAMAS IS SUPPORTING SCATTERED SHOWERS IN THE FAR SE GULF INCLUDING THE STRAITS OF FLORIDA S OF 24N E OF 85W. ELSEWHERE ACROSS THE GULF...A BROAD SURFACE RIDGE ANCHORED BY A 1016 MB HIGH NEAR 26N88W DOMINATES BRINGING GENERALLY FAIR WEATHER...AND IS SUPPORTED BY DRY AIR AND SUBSIDENCE ALOFT. WEAK ANTICYCLONIC FLOW IS PRESENT AROUND THE RIDGE WITH STRONGER WINDS IN THE SW GULF ESPECIALLY NEAR THE YUCATAN PENINSULA COAST. EXPECT THE SURFACE RIDGE TO GRADUALLY SHIFT SE AND EASTWARD THROUGH THE WEEKEND. E TO SE FLOW WILL INCREASE ACROSS THE W GULF BY LATE IN THE WEEKEND. CARIBBEAN SEA... UPPER LEVEL DIFFLUENCE ASSOCIATED WITH AN UPPER LEVEL HIGH OVER THE YUCATAN PENINSULA CENTERED NEAR 18N91W IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS ACROSS THE NW CARIBBEAN N OF 16N W OF 81W. THIS SHOWER ACTIVITY MAY BE ENHANCED BY THE TROPICAL WAVE ALONG 80W. THE TROPICAL WAVE MAY ALSO BE ENHANCING A FEW ISOLATED SHOWERS IN THE SW CARIBBEAN S OF 11N BETWEEN 78W-83W. A TROPICAL WAVE IN THE E CARIBBEAN ALONG 67W IS SUPPORTING A FEW ISOLATED SHOWERS S OF 13N BETWEEN 62W-65W. ELSEWHERE ACROSS THE CARIBBEAN...FAIR WEATHER PREVAILS UNDER THE PRESENCE OF A DRY SAHARAN AIR LAYER BETWEEN 70W-80W ALONG WITH SUBSIDENCE IN NELY FLOW ALOFT. FRESH TO STRONG TRADE WINDS ARE PRESENCE ACROSS THE MAJORITY OF THE CARIBBEAN. EXPECT THE TRADE WINDS TO INCREASE EARLY NEXT WEEK. ATLANTIC OCEAN... UPPER LEVEL DIFFLUENCE BETWEEN A MID-UPPER LEVEL TROUGH OVER THE W ATLC AND AN UPPER LEVEL HIGH CENTERED N OF THE BAHAMAS NEAR 24N72W IS SUPPORTING AN AREA OF SCATTERED SHOWERS/THUNDERSTORMS FROM 24N-28N BETWEEN 70W-75W. SHOWERS/THUNDERSTORMS ARE ALSO N OF CUBA FROM 22N-24N BETWEEN 77W-79W ENHANCED BY A TROPICAL WAVE ALONG 80W. UPPER LEVEL DIFFLUENCE ASSOCIATED WITH AN UPPER LEVEL LOW CENTERED NEAR 27N57W IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS FROM 24N-27N BETWEEN 60W-62W. A SURFACE TROUGH IS ANALYZED IN THE CENTRAL ATLC EXTENDING FROM 27N41W TO 29N48W. NO SHOWER ACTIVITY IS CURRENTLY ASSOCIATED WITH THIS SURFACE TROUGH. THE REMAINDER OF THE ATLC IS DOMINATED BY A BROAD SURFACE RIDGE ANCHORED BY A 1027 MB HIGH N OF THE DISCUSSION AREA NEAR 37N38W BRINGING GENERALLY FAIR WEATHER ACROSS THE MAJORITY OF THE BASIN. AN UPPER LEVEL HIGH DOMINATES THE UPPER LEVELS IN THE E ATLC CENTERED NEAR 21N35W. THIS UPPER LEVEL HIGH IS ENHANCING CONVECTION ALONG THE ITCZ. $$ WALTON