000 AXNT20 KNHC 271756 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT TUE SEP 27 2011 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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURES... TROPICAL STORM PHILIPPE IS CENTERED NEAR 15.8N 35.3W AT 27/1500 UTC OR ABOUT 650 NM W OF THE CAPE VERDE ISLANDS MOVING NW AT 4 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1003 MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. SCATTERED MODERATE CONVECTION REMAINS SHEARED TO THE EAST OF PHILIPPE FROM 15N-18N BETWEEN 31W-34W. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. THE REMNANTS OF OPHELIA ARE ANALYZED AS A 1010 MB LOW CENTERED E-NE OF THE LEEWARD ISLANDS NEAR 18N60W. DEEP CONVECTION CONTINUES TO SUSTAIN ITSELF SOUTH AND SOUTHEAST OF THE LOW CENTER BENEATH A MIDDLE TO UPPER LEVEL RIDGE CENTERED NEAR 18N58W. SCATTERED TO NUMEROUS MODERATE AND ISOLATED STRONG CONVECTION IS FROM 14N-20N BETWEEN 56W-62W. THE LOW IS FORECAST TO LINGER NE OF THE LEEWARD ISLANDS AND SLOWLY DRIFT W-NW OVER THE NEXT FEW DAYS. LOCALLY HEAVY RAINFALL IS EXPECTED OVER PORTIONS OF THE NORTHERN LEEWARD ISLANDS THROUGH WEDNESDAY. ...TROPICAL WAVES... TROPICAL WAVE IS ANALYZED FROM 03N22W TO 10N21W MOVING W AT 10 KT. EXAMINING A METEOSAT-9 HOVMOLLER DIAGRAM FROM THE PAST FEW DAYS AND LOW-LEVEL STREAMLINE MODEL DATA...ENERGY ASSOCIATED WITH THE WAVE CONTINUES TO SHOW CYCLONIC TURNING OF THE LOW-LEVEL CLOUD FIELD BETWEEN 19W-24W. NO SIGNIFICANT DEEP CONVECTION IS OBSERVED ON SATELLITE IMAGERY IN THE VICINITY OF THE WAVE AXIS. TROPICAL WAVE PREVIOUSLY ANALYZED ALONG 48W HAS SHOWED SIGNIFICANT WEAKENING OVER THE PAST 24-48 HOURS AND ANY REMNANT ENERGY CONTINUES TO DRIFT SLOWLY WESTWARD. A SURFACE TROUGH REMAINS ANALYZED FROM 14N46W TO 10N51W INDICATING CONVERGENCE OF LOW-LEVEL MOISTURE GENERATING ISOLATED SHOWERS FROM 12N-15N BETWEEN 44W-49W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 13N17W TO 10N19W. NO SIGNIFICANT CONVECTION IS NOTED ALONG THIS FEATURE. ...DISCUSSION... GULF OF MEXICO... UPPER LEVEL WESTERLY FLOW DOMINATES ACROSS THE GULF THIS AFTERNOON BETWEEN AN UPPER LEVEL LOW CENTERED OVER THE GREAT LAKES REGION AND AN ANTICYCLONIC CIRCULATION CENTERED OVER SOUTHERN MEXICO NEAR 18N91W. WATER VAPOR IMAGERY INDICATES A MODERATELY DRY AIRMASS IS IN PLACE ACROSS MUCH OF THE GULF N OF 23N. AT THE SURFACE...A RIDGE EXTENDS FROM THE SW NORTH ATLC WATERS TO A 1015 MB HIGH CENTERED NEAR 25N87W. A WEAKNESS WITHIN THE RIDGE...ANALYZED AS A SURFACE TROUGH FROM 25N82W TO 30N83W...IS PROVIDING A SUBTLE WIND SHIFT NOTED IN AN EARLY MORNING WINDSAT PASS WHERE WINDS REMAIN GENERALLY LIGHT. FARTHER SW OVER THE SW GULF WATERS...A SURFACE TROUGH EXTENDS ALONG 22N91W TO 19N94W AND ALONG WITH AN UPPER LEVEL DIFFLUENT ENVIRONMENT ALOFT IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS S OF 22N BETWEEN 90W-95W. THE REMAINDER OF THE GULF IS EXPERIENCING CLEAR SKIES AND FAIR WEATHER CONDITIONS AS THE HIGH AND ASSOCIATED RIDGE IS FORECAST TO REMAIN QUASI-STATIONARY OVER THE CENTRAL GULF THROUGH THURSDAY. CARIBBEAN SEA... AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER SOUTHERN MEXICO NEAR 18N91W AND IS PROVIDING MUCH OF THE WESTERN AND CENTRAL CARIBBEAN W OF 67W WITH NORTHEAST TO EASTERLY FLOW ALOFT. THIS IN TURN IS MAINTAINING MOSTLY FAIR WEATHER CONDITIONS AND CLEAR SKIES...HOWEVER...GIVEN AN UPPER LEVEL DIFFLUENT ENVIRONMENT AND AREAS OF TRADEWIND CONVERGENCE... ISOLATED SHOWERS ARE OCCURRING FROM 14N-18N BETWEEN 71W-84W. ALSO...THE MONSOON TROUGH AXIS EXTENDS FROM CENTRAL NICARAGUA NEAR 13N85W TO 13N77W. LOW-LEVEL CYCLONIC FLOW AND MIDDLE TO UPPER LEVEL LIFT PROVIDED BY A WEAK UPPER LEVEL LOW CENTERED NEAR 12N84W ARE GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS FROM 08N-14N BETWEEN 80W-84W. THE REMAINDER OF THE EASTERN CARIBBEAN FALLS UNDER THE INFLUENCE OF THE REMNANTS OF OPHELIA WHICH ARE ANALYZED AS A 1010 MB LOW CENTERED E-NE OF THE LEEWARD ISLANDS NEAR 18N60W AND IS NOTED ABOVE IN THE SPECIAL FEATURES SECTION. RADAR IMAGERY FROM GUADELOUPE INDICATES THAT PRECIPITATION REMAINS WITHIN 60-90 NM TO THE EAST OF THE LESSER ANTILLES...AND GIVEN THE SLOW MOVEMENT W-NW OVER THE NEXT 24-36 HOURS...LOCALLY HEAVY RAINFALL IS EXPECTED OVER THE LEEWARD ISLANDS THROUGH WEDNESDAY. ATLANTIC OCEAN... A NARROW UPPER LEVEL RIDGE EXTENDS FROM EASTERN CUBA OVER THE SE BAHAMAS TO 34N72W. THIS RIDGE AXIS LIES EAST OF AN UPPER LEVEL LOW CENTERED OVER THE GREAT LAKES REGION. SOUTHWESTERLY UPPER LEVEL FLOW BETWEEN THESE TWO UPPER LEVEL FEATURES IS PROVIDING FOR AN UPPER LEVEL DIFFLUENT ENVIRONMENT WHICH IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN A NARROW CORRIDOR OF THE SW NORTH ATLC WATERS FROM 22N TO BEYOND 32N BETWEEN 74W-80W. EAST OF THE UPPER LEVEL RIDGE...AN UPPER LEVEL TROUGH AXIS IS FROM 29N69W TO 18N65W AND EVEN THOUGH A RIDGE DOMINATES AT THE SURFACE...MIDDLE TO UPPER LEVEL DYNAMICS EAST OF THE UPPER LEVEL TROUGH AXIS IS GENERATING ISOLATED SHOWERS AND TSTMS FROM 20N-29N BETWEEN 65W-69W. THE ONLY REMAINING AREA OF ACTIVE WEATHER WITHIN THE OFFSHORE ZONES IS THE REMNANTS OF OPHELIA FOCUSED AROUND A 1010 MB LOW CENTERED NEAR 18N60W. SCATTERED TO NUMEROUS SHOWERS AND SCATTERED STRONG TSTMS ARE OCCURRING 14N-20N BETWEEN 56W-62W. FINALLY...AN UPPER LEVEL TROUGH AXIS DIPS INTO THE DISCUSSION AREA ALONG 32N30W TO 23N36W TO 17N49W ACROSS THE EASTERN AND CENTRAL ATLC THAT SUPPORTS WEAK SURFACE TROUGHING N OF 22N BETWEEN 40W-50W. ISOLATED SHOWERS ARE OCCURRING EAST OF THIS AREA N OF 27N BETWEEN 25W-37W. THE REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE AXIS EXTENDING FROM A WESTERN EUROPEAN HIGH ACROSS THE IBERIAN PENINSULA TO THE CANARY AND MADEIRA ISLANDS TO THE CAPE VERDE ISLANDS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN