000 AXNT20 KNHC 031803 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT FRI SEP 03 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURES... HURRICANE EARL IS CENTERED NEAR 37.5N 72.5W AT 03/1800 UTC ABOUT 250 NM S-SW OF NANTUCKET MASSACHUSETTS MOVING N-NE AT 18 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 961 MB. MAXIMUM SUSTAINED WIND SPEED IS 75 KT WITH GUSTS TO 90 KT. 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. SCATTERED MODERATE CONVECTION IS WITHIN A 60 NM RADIUS OF 37.5N72.5W. HOWEVER...RAIN AND POSSIBLE THUNDERSTORMS COVER A LARGER AREA FROM 34N-43N W OF 67W TO INLAND ALONG THE COAST FROM CAPE HATTERAS NORTH CAROLINA TO BOSTON MASSACHUSETTS. TROPICAL STORM FIONA IS CENTERED NEAR 29.5N 65.9 AT 03/1800 UTC OR ABOUT 175 NM S-SW OF BERMUDA MOVING N-NE AT 11 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1010 MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. 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. THE LOW LEVEL CENTER IS PARTIALLY EXPOSED ON FIONA WITH SCATTERED MODERATE/STRONG CONVECTION IS FROM 27N-29N BETWEEN 65W-67W. THE REMNANT LOW GASTON IS NEAR 14N45W AT 03/1200 UTC IS LOCATED ABOUT HALFWAY BETWEEN THE CAPE VERDE ISLANDS AND THE LESSER ANTILLES. ENVIRONMENTAL CONDITIONS FAVOR SLOW DEVELOPMENT AND A TROPICAL DEPRESSION COULD RE-FORM AS IT MOVES WESTWARD AT 9 KT DURING THE NEXT COUPLE OF DAYS. THERE IS A MEDIUM CHANCE OF THIS SYSTEM BECOMING A TROPICAL CYCLONE AGAIN DURING THE NEXT 48 HOURS. CLUSTERS OF SCATTERED MODERATE/ ISOLATED STRONG CONVECTION ARE FROM 13N-18N BETWEEN 39W-45W. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 19N17W THROUGH A 1008 MB LOW NEAR 14N19W TO 8N22W MOVING NW NEAR 10 KT. BROAD LOW LEVEL MONSOONAL TROUGH EXISTS OVER THE TROPICAL E ATLC E OF 30W COVERING THIS WAVE AND ENHANCING CONVECTION. SCATTERED MODERATE WITH EMBEDDED CLUSTERS OF SCATTERED STRONG CONVECTION COVERS THE AREA W OF THE WAVE FROM 13N-17N BETWEEN 19W-22W WITH SCATTERED MODERATE/ ISOLATED STRONG CONVECTION FROM 13N-15N BETWEEN 22W-25W. ...ITCZ... ITCZ AXIS IS ALONG 10N22W 8N27W 10N40W 8N53W TO 5N59W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 5N-10N BETWEEN 24W-31W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM EITHER SIDE OF THE ITCZ AXIS BETWEEN 41W-53W. ...DISCUSSION... GULF OF MEXICO... AN ELONGATED UPPER LOW IS ROUGHLY CENTERED OVER THE W GULF NEAR 25N92W EXTENDING AN AXIS FROM NEAR NEW ORLEANS LOUISIANA TO THE BAY OF CAMPECHE NEAR 20N94W SUPPORTING A SURFACE TROUGH ANALYZED FROM 22N95W TO THE COAST OF MEXICO NEAR 19N94W. WHILE ONLY A WEAK WIND SHIFT IS NOTED WITH THIS SURFACE TROUGH FEATURE MID/UPPER LEVEL MOISTURE IS BEING ADVECTED N-NE TO OVER MUCH OF THE GULF GENERATING CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 24N-28N BETWEEN 84W-89W AND W OF 28N W OF 89W. A BROAD UPPER RIDGE DOMINATES THE REMAINDER OF THE GULF ANCHORED OVER THE BAHAMAS. OTHERWISE...THE N GULF IS UNDER A RELATIVELY WEAK RIDGE AXIS THAT EXTENDS FROM THE W ATLC ACROSS S FLORIDA TO ALONG THE N GULF COAST TO OVER S LOUISIANA WITH A 1016 MB HIGH IN THE E GULF NEAR 28N85W. LIGHT ELY WINDS ARE FORECAST THROUGH TODAY UNTIL A WEAK COLD FRONT STALLS OVER THE NE GULF WATERS SAT THROUGH SUN. CARIBBEAN SEA... A BROAD UPPER RIDGE ANCHORED OVER THE BAHAMAS COVERS MOST OF THE CARIBBEAN W OF 70W AND EXTENDS TO OVER THE E GULF OF MEXICO PROVIDING MOSTLY E TO SE UPPER LEVEL FLOW. ABUNDANCE OF TROPICAL MOISTURE IN THE UPPER LEVELS COMBINED WITH DIFFLUENCE ALOFT ARE GENERATING AN AREA OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 12N-17N BETWEEN 72W-77W AND IN THE SW CARIBBEAN FROM 10N-13N W OF 82W TO INLAND OVER COSTA RICA AND NICARAGUA. THE REMAINDER OF THE W CARIBBEAN IS UNDER CLEAR SKIES. A BROAD UPPER TROUGH EXTENDING ACROSS THE CENTRAL ATLC COVERS THE E CARIBBEAN E 70W TO THE COAST OF VENEZUELA. THIS IS FUNNELING IN DRY STABLE AIR ALOFT N OF 14N E OF 62W LEAVING THE LEEWARD/VIRGIN ISLANDS AND PUERTO RICO REMARKABLY CLEAR THIS AFTERNOON. DIFFLUENCE TO THE SW OF THE UPPER TROUGH ARE GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM 11N-15N BETWEEN 67W-69W. THE SURFACE RIDGE THAT COVERS THE W ATLC EXTENDS OVER THE N CARIBBEAN N OF 15N E OF JAMAICA. ATLANTIC OCEAN... HURRICANE EARL REMAINS THE MAIN FEATURE OF CONCERN OVER THE NW ATLC AND NEW ENGLAND STATES THIS AFTERNOON. TROPICAL STORM FIONA IS TO THE SE OF EARL OVER THE OPEN WATERS AND IS FORECAST TO TRACK ACROSS BERMUDA SAT MORNING. SEE SPECIAL FEATURES ABOVE. BROAD UPPER RIDGE THAT COVERS THE E GULF OF MEXICO AND THE W CARIBBEAN IS ANCHORED OVER THE BAHAMAS NEAR 25N77W AND COVERS THE W ATLC W OF 70W. A BROAD E/W UPPER RIDGE COVERS THE REMAINDER OF ATLC S OF 30N E OF 50W ANCHORED NEAR 24N27W. A SURFACE RIDGE DOMINATES MOST OF THE ATLC WITH A WEAK REMNANT SURFACE TROUGH SPLITTING THE AREA EXTENDING FROM 31N33W TO 25N41W AND ISOLATED SHOWERS WITHIN 60 NM EITHER SIDE OF THE SURFACE TROUGH. THE SURFACE RIDGE IS S OF FIONA COVER THE W ATLC S OF 26N TO ACROSS THE S FLORIDA PENINSULA INTO THE GULF OF MEXICO. A NARROW SWATH OF DRY SAHARAN AIR ALOFT IS NOTED ON VISIBLE SATELLITE IMAGERY TO THE E OF FIONA AND OVER THE FAR NE CARIBBEAN FROM 14N TO BEYOND 32N BETWEEN 60W-65W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW