000 AXNT20 KNHC 030000 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU SEP 02 2010 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURES... HURRICANE EARL IS NEAR 32.5N 75.2W AT 03/0000 UTC OR ABOUT 140 NM SSE OF CAPE HATTERAS NORTH CAROLINA AND ABOUT 540 NM SSW OF NANTUCKET MASSACHUSETTS MOVING N AT 16 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 948 MB. MAXIMUM SUSTAINED WIND SPEED IS 95 KT WITH GUSTS TO 115 KT. NUMEROUS MODERATE AND SCATTERED STRONG CONVECTION IS WITHIN 150 NM OF CENTER IN THE NE SEMICIRCLE. ELSEWHERE SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 29N-36N BETWEEN 71W-79W. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT2/WTNT32 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. TROPICAL STORM FIONA IS NEAR 26.4N 66.7W AT 03/0000 UTC OR ABOUT 370 NM SSW OF BERMUDA MOVING NNW AT 15 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1002 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. NUMEROUS MODERATE AND SCATTERED STRONG CONVECTION IS WITHIN 150 NM OF CENTER IN THE SW AND W QUADRANTS. ELSEWHERE SCATTERED MODERATE CONVECTION IS WITHIN 210 NM SW OF A LINE FROM 26N67W TO 19N62W. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT3/WTNT33 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. REMNANT LOW GASTON IS NEAR 13.5N 39.5W AT 02/2100 UTC OR ABOUT 880 NM W OF THE SOUTHERNMOST CAPE VERDE ISLANDS AND 1270 NM E OF THE LESSER ANTILLES MOVING W AT 4 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1009 MB. MAXIMUM SUSTAINED WIND SPEED IS 25 KT WITH GUSTS TO 35 KT. GASTON HAS DEGENERATED INTO A REMNANT LOW PRESSURE AREA OVER THE CENTRAL TROPICAL ATLC...LEAVING A LOW-LEVEL CIRCULATION CENTER WITHOUT ANY DEEP CONVECTION. HOWEVER...SCATTERED SHOWERS STILL PERSIST WITHIN 300 NM OF THE LOW CENTER. GIVEN A MARGINALLY FAVORABLE ENVIRONMENT ALOFT AND BROAD LOW-LEVEL CYCLONIC TURNING EVIDENT ON SATELLITE IMAGERY... THERE IS A CHANCE THAT GASTON COULD REGENERATE OVER THE NEXT COUPLE OF DAYS AS IT MOVES WESTWARD. ...TROPICAL WAVES... A TROPICAL WAVE IS FROM 07N TO 17N ALONG 17W MOVING W AT 10-15 KT. A BROAD LOW-LEVEL MONSOONAL TROUGH EXISTS OVER THE TROPICAL EASTERN ATLC E OF 30W AND THIS TROPICAL WAVE IS EXPECTED TO ENHANCE ONGOING CONVECTION ALONG AND NORTH OF THE ITCZ AXIS. CIMSS WAVETRAK MODEL GUIDANCE INDICATES A FAIRLY LARGE AREA OF 850 MB RELATIVE VORTICITY FROM 08N-16N BETWEEN 13W-26W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION COVERS THE AREA IN THE VICINITY OF THE WAVE FROM 11N-15N BETWEEN 12W-22W. ...ITCZ... ITCZ AXIS IS ALONG 09N20W 08N27W 09N34W 08N47W 08N60W. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 04N-11N BETWEEN 19W-29W. SIMILAR CONVECTION IS WITHIN 120 NM OF THE AXIS BETWEEN 34W-48W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL TROUGH AXIS EXTENDS FROM THE NORTH-CENTRAL GULF NEAR THE LOUISIANA COAST S-SW INTO AN UPPER LEVEL LOW CENTERED IN THE WESTERN GULF NEAR 23N93W. THIS UPPER LEVEL LOW SUPPORTS A SURFACE TROUGH ANALYZED FROM 24N94W TO THE WESTERN YUCATAN PENINSULA COAST NEAR 20N90W. WHILE ONLY A WEAK WIND SHIFT IS NOTED WITH THE SURFACE TROUGH FEATURE...MIDDLE TO UPPER LEVEL MOISTURE IS BEING ADVECTED NORTH-NORTHEASTWARD OVER MUCH OF THE EASTERN GULF ON SSW WINDS GENERATING WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE YUCATAN PENINSULA AND MOST OF THE EASTERN GULF S OF 29N E OF 90W. OTHERWISE...THE REMAINDER OF THE GULF IS UNDER A RELATIVELY WEAK RIDGE AXIS THAT EXTENDS FROM THE FLORIDA STRAITS NW TO A WEAK 1015 MB HIGH CENTERED NEAR 29N87W. LIGHT EASTERLY WINDS UP TO 15 KT ARE FORECAST THROUGH FRIDAY MORNING UNTIL A WEAK COLD FRONT STALLS OVER THE NORTHERN WATERS FRIDAY AND DISSIPATES BY LATE SATURDAY. CARIBBEAN SEA... AN UPPER LEVEL ANTICYCLONIC CIRCULATION LOCATED OVER THE SW NORTH ATLC CENTERED NEAR 30N66W EXTENDS AN UPPER LEVEL RIDGE OVER MUCH OF THE CARIBBEAN BASIN THIS EVENING. THIS IS PROVIDING FOR MOSTLY EAST TO SOUTHEASTERLY UPPER LEVEL FLOW AND A FAIRLY PROGRESSIVE PATTERN FOR AVAILABLE MID-LEVEL MOISTURE WESTWARD. EXAMINING AN EXTENDED LOOP OF TOTAL PRECIPITABLE WATER IMAGERY...TWO DISTINCT AREAS OF MOISTURE ARE OBSERVED. THE FIRST IS LOCATED BETWEEN 72W-83W AND ALONG WITH THE UPPER LEVEL DIFFLUENT PATTERN IN PLACE ALOFT DUE TO THE UPPER LEVEL RIDGE... WIDELY SCATTERED SHOWERS AND POSSIBLE ISOLATED TSTMS ARE OVER MUCH OF THE WESTERN CARIBBEAN. THIS ACTIVITY EXTENDS OVER INTERIOR PORTIONS OF CENTRAL AMERICA FROM WESTERN PANAMA NW TO THE GULF OF HONDURAS AND GUATEMALA. THE OTHER AREA OF LOW-LEVEL MOISTURE NOTED ON TPW IMAGERY IS MOST LIKELY WESTWARD MOVING ENERGY LEFT BEHIND BY TROPICAL STORM FIONA AS IT SKIRTED NE OF THE BASIN A FEW DAYS AGO. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING FROM 12N-19N BETWEEN 64W-72W...INCLUDING PUERTO RICO AND THE MONA PASSAGE. LINGERING ISOLATED SHOWERS ARE ALSO OVER THE LEEWARD ISLANDS DUE TO AN UPPER LEVEL LOW CENTERED NEAR 22N51W AND A TROUGH AXIS EXTENDING FROM THE LOW TO 20N60W. ATLANTIC OCEAN... HURRICANE EARL REMAINS THE MAIN FEATURE OF CONCERN OVER THE FAR WESTERN ATLC AFFECTING THE COASTAL AND OFFSHORE WATERS OF U.S. N OF 32N. TROPICAL STORM FIONA IS TO THE SE OF EARL OVER OPEN WATERS AND IS FORECAST TO TRACK N-NW POSSIBLY IMPACTING BERMUDA BY LATE FRIDAY. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS REGARDING THESE TWO SYSTEMS. SURFACE ANTICYCLONIC FLOW IS ELSEWHERE ACROSS THE ATLC E OF 64W N OF 20N...ANCHORED BY A 1023 MB HIGH CENTERED NEAR 32N59W AND ANOTHER 1019 MB HIGH CENTERED NEAR 36N20W. DRY SAHARAN AIR ALOFT IS ALSO NOTED ON SATELLITE VISIBLE N OF 20N E OF 40W. A WEAK SURFACE TROUGH EXTENDS IN BETWEEN THESE TWO REGIONS OF HIGH PRESSURE ACROSS THE CENTRAL ATLANTIC ENTERING THE DISCUSSION AREA THROUGH 32N34W TO 25N50W THEN AS A SHEAR LINE TO 27N57W. ISOLATED SHOWERS ARE WITHIN 60 NM EITHER SIDE OF THE BOUNDARY. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN