000 AXNT20 KNHC 010549 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT TUE SEP 01 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 0345 UTC. ...SPECIAL FEATURES... BROAD AREA OF LOW PRESSURE ASSOCIATED WITH A 1007 MB LOW ROUGHLY CENTERED NEAR 14N56W OR ABOUT 305 NM E OF THE LEEWARD ISLANDS CONTINUES TO SHOW SIGNS OF ORGANIZATION BUT NOT A WELL-DEFINED SURFACE CIRCULATION CENTER. A SURFACE TROUGH EXTENDS FROM 17N52W THROUGH THE SURFACE LOW TO 10N58W. SCATTERED/NUMEROUS STRONG CONVECTION IS FROM 15N-18N BETWEEN 51W-54W. SCATTERED MODERATE/ ISOLATED STRONG CONVECTION IS FROM 14N-20N BETWEEN 50W-56W AND WITHIN 45 NM OF LINE FROM 12N54W TO 14N52W. THIS SYSTEM COULD BECOME A TROPICAL DEPRESSION OR TROPICAL STORM AT ANY TIME OVER THE NEXT COUPLE OF DAYS AS IT MOVES WNW NEAR 8 KT. INTERESTS IN THE LEEWARD ISLANDS...THE U.S. AND BRITISH VIRGIN ISLANDS...AND PUERTO RICO SHOULD MONITOR THE PROGRESS OF THIS SYSTEM. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 17N31W TO 9N28W MOVING W 10-15 KT. WAVE REMAINS ALONG THE LEADING EDGE OF DEEP LAYERED MOISTURE AS INDICATED BY TOTAL PRECIPITABLE WATER IMAGERY. HOWEVER...THIS WAVE IS ALSO EMBEDDED WITHIN SAHARAN DUST THUS LIMITING ANY SHOWERS/CONVECTION. TROPICAL WAVE IS ALONG 80W S OF 17N MOVING W NEAR 15 KT. THIS WAVE REMAINS EMBEDDED WITHIN AN AREA OF LIGHT MOISTURE AS INDICATED BY THE TOTAL PRECIPITABLE WATER IMAGERY AND WITH DRY STABLE AIR AT THE LOWER LEVELS...THERE ARE NO SHOWERS/CONVECTION. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 14N15W 14N19W 7N35W 14N47W 11N58W 10N63W. CLUSTERS OF SCATTERED STRONG CONVECTION ARE FROM 14N-18N BETWEEN 18W-22W. SMALL CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 120 NM S OF THE ITCZ FROM 33W-40W. ...DISCUSSION... GULF OF MEXICO... A STATIONARY FRONT IS MEANDERING ALONG THE N GULF COAST AND AT 0000 UTC EXTENDS FROM SW GEORGIA ALONG THE COAST FROM PENSACOLA FLORIDA TO INLAND OVER SE LOUISIANA NEAR NEW ORLEANS THEN BACK INTO THE GULF WATERS NEAR VERMILION BAY THEN INLAND OVER TEXAS NEAR CORPUS CHRISTI TEXAS. A SURFACE TROUGH IS TO THE SE OF THE FRONT EXTENDING FROM JACKSONVILLE FLORIDA ALONG 26N87W TO 26N92W WITH A SECOND TROUGH FURTHER TO THE E EXTENDING FROM THE W ATLC ACROSS CENTRAL FLORIDA FROM MELBOURNE TO NAPLES CONTINUING SW TO THE YUCATAN PENINSULA NEAR 21N88W. A BROAD UPPER RIDGE ANCHORED IN THE E PACIFIC EXTENDS ACROSS MEXICO INTO THE GULF NEAR TAMPICO TO NEAR 27N85W WITH A SHORTWAVE UPPER TROUGH OVER THE FLORIDA PENINSULA EXTENDING FROM A BROAD UPPER TROUGH COVERING THE E HALF OF THE U.S. THROUGH SW GEORGIA TO THE UPPER FLORIDA KEYS. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE IN THE SE GULF BETWEEN THE SURFACE TROUGHS E OF 88W AND FROM 24N-26N E OF 82W TO OVER THE FLORIDA KEYS AND INCLUDING THE FLORIDA PENINSULA S OF 29N. ISOLATED SHOWERS ARE ACROSS THE N GULF WATERS N OF 25N TO INLAND OVER THE SE U.S. AND S OF 25N W OF 95W. CARIBBEAN SEA... AN UPPER LEVEL RIDGE COVERS THE W AND CENTRAL CARIBBEAN W OF 73W ANCHORED NEAR 16N82W. DIFFLUENCE ALOFT IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS INLAND AND WITHIN 75 NM ALONG THE S COAST OF CUBA FROM 77W-83W WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS W OF 82W FROM CENTRAL AMERICA TO THE YUCATAN CHANNEL. AN UPPER TROUGH OVER THE W/CENTRAL ATLC EXTENDS S OVER THE GREATER ANTILLES TO THE COAST OF VENEZUELA/COLOMBIA BETWEEN THE WINDWARD PASSAGE AND THE LEEWARD ISLANDS PRODUCING CLUSTERS OF ISOLATED SHOWERS N OF 16N TO OVER HISPANIOLA. MODERATE/STRONG EASTERLY TRADE WINDS CONTINUE ACROSS THE AREA. LOW MENTIONED IN THE SPECIAL FEATURES IS EXPECTED TO MOVE OVER THE LESSER ANTILLES LATE TUE/EARLY WED WITH SHOWERS AND POSSIBLE THUNDERSTORMS MOVING OVER THE ISLANDS LATER TODAY. ATLANTIC OCEAN... THE MAIN FOCUS TONIGHT IS THE LOW E OF THE LESSER ANTILLES THAT HAS THE POTENTIAL OF DEVELOPING...SEE SPECIAL FEATURES ABOVE. A SURFACE TROUGH EXTENDS FROM 31N76W ACROSS THE FLORIDA PENINSULA NEAR MELBOURNE CONTINUING INTO THE GULF OF MEXICO. NARROW UPPER RIDGE IS OVER THE FAR W ATLC EXTENDING FROM E CUBA NEAR 23N80W TO 31N76W PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS W OF A LINE FROM CUBA NEAR 22N78W TO BEYOND 32N72W TO INLAND OVER GEORGIA AND THE FLORIDA PENINSULA AND TO THE COAST OF SOUTH CAROLINA. AN UPPER TROUGH EXTENDS ACROSS THE ATLC BASIN FROM THE E ATLC THROUGH 33N18W AND A SERIES OF UPPER LOWS CENTERED NEAR 30N23W... 26N39W...31N58W...TO AN ILL-DEFINED LOW NEAR 26N71W. A SURFACE TROUGH IS ALONG THE WESTERN BOUNDARY OF THIS UPPER TROUGH EXTENDING FROM THE WINDWARD PASSAGE NEAR 20N73W ACROSS THE TURKS AND CAICOS ALONG 24N74W TO 28N72W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE E OF THE SURFACE TROUGH WITHIN 120 NM OF LINE FROM 20N70W TO 28N68W AND N OF 29N BETWEEN 54-63W. OTHERWISE THE REMAINDER OF THE ATLC BASIN REMAINS TRANQUIL AGAIN TONIGHT AS A SURFACE RIDGE DOMINATES THE BASIN ANCHORED BY A 1028 MB HIGH WELL N OF THE REGION W OF THE AZORES. $$ WALLACE