000 AXNT20 KNHC 161114 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SUN AUG 16 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...SPECIAL FEATURES... TROPICAL DEPRESSION FOUR WAS UPGRADED AT 16/0900 UTC CENTERED NEAR 27.7N 83.9W OR ABOUT 80 NM WEST-SOUTHWEST OF TAMPA FLORIDA AND ABOUT 135 NM SOUTH-SOUTHEAST OF APALACHICOLA FLORIDA MOVING NNW AT 14 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1011 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT4/WTNT34 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. DEEP CONVECTION IS TO THE EAST OF THE LOW LEVEL CENTER WITH SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 27N-28N BETWEEN 83W-84W. TROPICAL STORM ANA IS CENTERED NEAR 14.6N 53.8W AT 16/0900 UTC OR ABOUT 490 NM EAST-SOUTHEAST OF THE LEEWARD ISLANDS MOVING W AT 17 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT2/WTNT32 KNHC AND THE FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. SCATTERED MODERATE CONVECTION IS TO THE SW OF THE LOW LEVEL CENTER WITHIN 45 NM OF LINE FROM 13N51.5N TO 14.5N53.5W. TROPICAL STORM BILL IS CENTERED NEAR 11.4N 37.2W AT 16/0900 UTC OR ABOUT 1425 NM EAST OF THE LESSER ANTILLES MOVING W AT 11 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1002 MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/ WTNT23 KNHC FOR MORE DETAILS. BROAD AREA OF SCATTERED MODERATE/STRONG CONVECTION COVERS THE AREA WITHIN 120 NM OF LINE FROM 9N41W TO 13N35W. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 19W/20W S OF 19N MOVING W 10-15 KT. WAVE IS EMBEDDED WITHIN AN AREA OF DEEP LAYERED MOISTURE THAT CONTINUES TO MOVIE OFF THE COAST OF AFRICA AS INDICATED BY THE TOTAL PRECIPITABLE WATER IMAGERY WITH A MID LEVEL CYCLONIC CIRCULATION ALONG THE WAVE NEAR 15N. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE N OF THE ITCZ AXIS AND ON EITHER SIDE OF THE WAVE AXIS FROM 10N-13N BETWEEN 15W-24W. TROPICAL WAVE IS ALONG 86W/87W S OF 22N MOVING W NEAR 15 KT. WAVE IS EMBEDDED WITHIN A BROAD AREA OF DEEP LAYER MOISTURE AS INDICATED BY THE TOTAL PRECIPITABLE WATER IMAGERY. WAVE REMAINS ALONG THE EASTERN EDGE OF AN UPPER LOW ENHANCING THE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS THAT COVER THE NW CARIBBEAN S OF 20N W OF 80W TO INLAND OVER CENTRAL AMERICA AND PORTIONS OF THE YUCATAN PENINSULA. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 11N13W 10N21W 13N31W 9N40W 8N53W 11N62W AND OVER THE N PORTION OF SOUTH AMERICA AND SW CARIBBEAN SEA. SCATTERED MODERATE CONVECTION S OF THE ITCZ FROM 7N-9N BETWEEN THE COAST OF W AFRICA TO 16W AND WITHIN 120 NM ALONG THE COAST OF VENEZUELA BETWEEN THE BORDER OF THE GUYANA AND TRINIDAD. SMALL CLUSTERS OF SIMILAR CONVECTION ARE FROM 5N-10N BETWEEN 40W-50W. ...DISCUSSION... GULF OF MEXICO... AS OF 16/0900 UTC...SEE SPECIAL FEATURES ABOVE FOR T.D. FOUR. A NARROWING UPPER LEVEL TROUGH EXTENDS FROM THE LOWER MISSISSIPPI VALLEY OVER THE W GULF INTO THE W BAY OF CAMPECHE WHILE AN UPPER RIDGE COVERS THE E GULF. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS COVERS THE LARGE PORTION OF THE GULF N OF A LINE FROM FORT MYERS FLORIDA TO 22N90W TO ALONG THE N GULF COAST E OF THE LOUISIANA/TEXAS BORDER. DRY AIR CLEAR SKIES DOMINATE MOST OF THE SW GULF WITH THE EXCEPTION OF SOME ISOLATED SHOWERS MOVING OFF THE YUCATAN PENINSULA INTO THE E BAY OF CAMPECHE AHEAD OF THE TROPICAL WAVE CURRENTLY ALONG 86W/87W. CARIBBEAN SEA... THE ACTIVITY IN THE CARIBBEAN IS MAINLY DUE TO THE TROPICAL WAVE ALONG 86W/87W ENHANCED BY AN UPPER LOW CENTERED OVER N BELIZE. ACROSS THE CENTRAL AND E CARIBBEAN...DEEP LAYER DRY AIR AND GENERALLY FAIR WEATHER IS OBSERVED. FRESH TRADE WINDS ARE USHERING IN LOW LEVEL FAST MOVING ISOLATED SHOWERS WESTWARD ACROSS THE LESSER ANTILLES TO 72W. SMALL AREA OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN A 60/75 NM RADIUS OF 17.5N74.5W INCLUDING THE FAR SW COAST OF HAITI. ATLANTIC OCEAN... AN UPPER LOW COVERS THE W ATLC CENTERED NEAR 25N69W WITH A SECOND UPPER LOW TO THE E NEAR 27N53W...ALL SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM 31N62W TO 22N68W AND ISOLATED SHOWERS WITH POSSIBLE ISOLATED THUNDERSTORMS FROM 21N-29N BETWEEN 63W-75W. ISOLATED SHOWERS ARE ALSO WITHIN 75 NM OF LINE FROM 25N54W TO 29N50W. ATMOSPHERIC LIFT IN THE SOUTHERN FLOW ALOFT TO THE E OF AN SE TO NW ELONGATED UPPER TROUGH IN THE W TROPICAL ATLC TO THE NE OF ANA IS SUPPORTING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 120 NM OF LINE FROM 16N57W TO 23N60W. A BROAD SURFACE RIDGE DOMINATES THE REMAINDER OF THE ATLC ANCHORED BY A PAIR OF 1023 MB HIGHS N OF THE REGION CENTERED NEAR 33N55W AND 33N27W GIVING THE E ATLC FAIR WEATHER THIS MORNING. $$ PAW