000 AXNT20 KNHC 221749 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED JUL 22 2008 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. ...SPECIAL FEATURES... TROPICAL STORM DOLLY IS CENTERED NEAR 24.3N 94.9W AT 22/1800 UTC OR ABOUT 170 NM SE OF BROWNSVILLE TEXAS MOVING NW AT 9 KT. THE MINIMUM CENTRAL PRESSURE RECENTLY REPORTED BY A NOAA HURRICANE HUNTER PLANE WAS 990 MB.MAXIMUM SUSTAINED WIND SPEED IS 60 KT WITH GUSTS TO 75 KT. PLEASE SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC AND THE PUBLIC ADVISORY UNDER MIATCPAT4/WTNT34 KNHC FOR MORE DETAILS. DOLLY IS EXPECTED TO BECOME A HURRICANE LATER TODAY OR WEDNESDAY BEFORE MAKING LANDFALL. BROAD OUTFLOW COVERS MOST OF THE GULF EXTENDING S ON THE E SIDE INTO THE NW CARIBBEAN. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 150 NM E OF THE CENTER WITH SIMILAR CONVECTION WITHIN 120 NM BOTH N AND S OF THE CENTER. CLUSTERS OF SIMILAR CONVECTION ARE TO THE W OF THE CENTER BETWEEN 22N-27N MOVING TO THE COAST OF MEXICO AND 30 NM OF THE TEXAS COAST. HEAVY SHOWERS/WITH EMBEDDED THUNDERSTORMS ARE TO THE N WITHIN 102 NM OF LINE FROM 26N89W 29N92W TO 29N95W INCLUDING THE COAST OF LOUISIANA AND TEXAS. SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS ARE POSSIBLE OVER THE REMAINDER OF THE GULF N OF 20N W OF 86W. DOLLY IS EXPECTED TO PRODUCE TOTAL RAIN ACCUMULATIONS OF 4 TO 8 INCHES...WITH ISOLATED AMOUNTS OF 15 INCHES...OVER MUCH OF S TEXAS AND NE MEXICO OVER THE NEXT FEW DAYS. COASTAL STORM SURGE FLOODING OF 4 TO 6 FEET ABOVE NORMAL TIDE LEVELS...ALONG WITH LARGE AND DANGEROUS BATTERING WAVES...CAN BE EXPECTED NEAR AND TO THE NORTH OF WHERE THE CENTER MAKES LANDFALL. TROPICAL STORM CRISTOBAL IS CENTERED NEAR 40.9N 65.9W AT 22/1500 UTC OR ABOUT ABOUT 245 MB SSW OF HALIFAX NOVA SCOTIA MOVING NE AT 22 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. MAXIMUM SUSTAINED WIND SPEED IS 55 KT WITH GUSTS TO 65 KT. PLEASE SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC AND THE PUBLIC ADVISORY UNDER MIATCPAT3/ WTNT33 KNHC FOR MORE DETAILS. SURFACE CIRCULATION SUGGESTS IT IS BECOMING ELONGATED FROM SE TO NW AND NOW THAT CRISTOBAL HAS PASSED N OF THE GULF STREAM AND MOVING OVER COOLER WATERS... RAPID EXTRATROPICAL TRANSITION IS FORECAST. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 21W/22W S OF 23N WITH A 1009 MB LOW ALONG THE WAVE NEAR 17N MOVING W NEAR 15 KT. WELL DEFINED CIRCULATION IN THE LOW/MID LEVELS WITH AN UPPER INVERTED TROUGH WELL DEFINED IN THE UPPER LEVELS. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 15N-19N BETWEEN 21W-26W INCLUDING THE CAPE VERDE ISLANDS. TROPICAL WAVE IS ALONG 51W/52W S OF 13N MOVING W 15 KT. WEAK INVERTED-V CURVATURE IS OBSERVED ON SATELLITE IMAGERY. HOWEVER THE WAVE HAS BEEN BROADENING OVER THE PAST 24 HOURS WHICH LEADS THE WAVE AXIS TO APPEAR TO BE MOVING SLOWER. NO ASSOCIATED SHOWER ACTIVITY/CONVECTION. TROPICAL WAVE IN THE A CENTRAL CARIBBEAN IS ALONG 75W S OF 19N MOVING W NEAR 15 KT. WAVE CONTINUES TO MOVE BENEATH AN UPPER TROUGH AND THROUGH AN AREA OF DRIER AIR. THUS...NO REAL SATELLITE SIGNATURE OF SHOWERS ACTIVITY. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 10N14W 11N22W 7N31W 5N45W 7N58W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 6N-13N BETWEEN 20W TO INLAND OVER W AFRICA. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 2N-10N BETWEEN 37W-50W WITH SCATTERED CLUSTERS OF SIMILAR CONVECTION FROM 5N-11N BETWEEN 25W-35W. ...DISCUSSION... GULF OF MEXICO... THE MAIN CONCERN FOR THE GULF THIS AFTERNOON IS T.S. DOLLY MOVING ACROSS THE W GULF...SEE SPECIAL FEATURES ABOVE. WEAK UPPER LEVEL SHORTWAVE TROUGH EXTENDS FROM SW GEORGIA TO OVER THE FLORIDA PENINSULA. THIS COUPLED WITH THE BROAD UPPER HIGH ASSOCIATED WITH DOLLY IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS INLAND AND ALONG THE IMMEDIATE COAST WATERS OF THE NE GULF COAST FROM TAMPA FLORIDA ALONG THE FLORIDA PANHANDLE TO S MISSISSIPPI. AFTERNOON SEA BREEZED INDUCED THUNDERSTORMS ARE DEVELOPING ALONG THE E COAST OF FLORIDA. CARIBBEAN SEA... UPPER LEVEL OUTFLOW FROM T.S. DOLLY COVERS THE NW CARIBBEAN W OF 81W. POSSIBLE ISOLATED SHOWERS/THUNDERSTORMS COULD DEVELOP OVER THIS AREA. BROAD COMPLEX UPPER TROUGH SYSTEM IN THE W ATLC EXTENDS S OVER THE CENTRAL CARIBBEAN BETWEEN 63W-81W. THIS IS DRYING OUT THE CENTRAL CARIBBEAN WITH THE EXCEPTION OF THE FAR SW CARIBBEAN WHERE UPPER DIFFLUENCE COUPLED WITH LOW LEVEL CONVERGENCE ARE GENERATING CLUSTERS OF SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS S OF 11N BETWEEN COLOMBIA AND CENTRAL AMERICA. OTHERWISE THE REMAINDER OF THE CARIBBEAN REMAINS REMARKABLY CLEAR THIS AFTERNOON. ATLANTIC OCEAN... T.S. CRISTOBAL IS MOVING NE AWAY FROM THE E SEABOARD OF NEW ENGLAND...SEE SPECIAL FEATURES ABOVE. AFTERNOON SEA BREEZE INDUCED SHOWERS/THUNDERSTORMS ARE DEVELOPING ALONG THE E COAST OF FLORIDA S OF DAYTONA BEACH TO MIAMI. BROAD AREA UPPER TROUGH COVERS THE W ATLC W OF 60W EXTENDING S INTO THE CENTRAL CARIBBEAN WITH SEVERAL EMBEDDED UPPER LOWS. SCATTERED SHOWERS/ THUNDERSTORMS ARE BEING GENERATED WITHIN 75 NM OF LINE FROM 31N75W TO OFF THE FLORIDA COAST NEAR PALM BEACH AND A SECOND AREA WITHIN 90 NM OF LINE FROM 25N61W TO 28N69W. ISOLATED CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS COVERS THE BAHAMAS AND COULD DEVELOP OVER THE AREA W OF 65W. THE REMAINDER OF THE ATLC IS DOMINATED BY BENIGN UPPER LEVEL FEATURES...STRONG SUBSIDENCE...DRY STABLE AIR...AND A SURFACE RIDGE ANCHORED BY A 1032 MB HIGH N OF THE REGION GIVING THE ATLC E OF 60W FAIR WEATHER CLOUDS AND DRY CONDITIONS WITH THE EXCEPTION OF THE AREA NEAR THE TROPICAL WAVE ALONG 21W/22W...SEE TROPICAL WAVES ABOVE. $$ WALLACE