000 AXNT20 KNHC 141758 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT TUE SEP 14 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 IGOR IS CENTERED NEAR 18.3N 52.3W AT 14/1500 UTC OR ABOUT 615 NM E OF THE NORTHERN LEEWARD ISLANDS MOVING WNW AT 6 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 945 MB. MAXIMUM SUSTAINED WIND SPEED IS 115 KT WITH GUSTS TO 140 KT. VISIBLE SATELLITE PRESENTATION SHOWS IGOR HAS MAINTAINED A WELL-DEFINED EYE AND VERY GOOD CIRRUS OUTFLOW IN ALL DIRECTIONS. NUMEROUS STRONG CONVECTION IS WITHIN 90 NM OF THE CENTER WHILE NUMEROUS MODERATE AND SCATTERED STRONG CONVECTION IS ELSEWHERE FROM 15N-21N BETWEEN 48W-55W. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. HURRICANE JULIA IS CENTERED NEAR 16.2N 29.5W AT 14/1500 UTC OR ABOUT 305 NM WNW OF THE SOUTHERNMOST CAPE VERDE ISLANDS MOVING WNW AT 9 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 984 MB. MAXIMUM SUSTAINED WIND SPEED IS 75 KT WITH GUSTS TO 90 KT. ADDITIONAL STRENGTHENING IS POSSIBLE OVER THE NEXT 12-24 HOURS BEFORE JULIA COMES UNDER INCREASED WESTERLY SHEAR THAT WILL IMPACT THE CYCLONE. NUMEROUS MODERATE AND SCATTERED STRONG CONVECTION IS WITHIN 120 NM OF THE CENTER WHILE SCATTERED MODERATE AND ISOLATED STRONG IS ELSEWHERE FROM 13N-20N BETWEEN 26W-33W. 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. A BROAD LOW PRESSURE AREA IS LOCATED IN THE WESTERN CARIBBEAN SEA FOCUSED ON A 1006 MB LOW CENTERED NEAR 18N82W. A SURFACE TROUGH EXTENDS FROM THE LOW CENTERED SOUTHWARD TO NEAR 11N83W MOVING WNW NEAR 10-15 KT. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION LOCATED FROM 18N-21N BETWEEN 76W-82W AND WITHIN 240 NM OF THE NW QUADRANT. THIS CONVECTIVE ACTIVITY IS ALSO LIKELY ENHANCED BY AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER CENTRAL CUBA NEAR 22N80W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS ALSO NORTH OF CUBA FROM 20N-24N BETWEEN 72W-81W AND OVER THE SW CARIBBEAN SEA FROM 09N-12N BETWEEN 77W-85W. ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE FOR DEVELOPMENT OF A TROPICAL CYCLONE OVER THE NEXT 48 HOURS. ...ITCZ... A MONSOONAL TROUGH REMAINS ACROSS THE ATLC BASIN BETWEEN HURRICANES IGOR AND JULIA ANALYZED AS A SURFACE TROUGH ALONG 12N33W TO 12N39W TO 14N42W. S-SW LOW-LEVEL FLOW EXTENDS EAST OF 33W TO THE AFRICAN COAST NEAR 08N13W. SCATTERED MODERATE CONVECTION IS FROM 02N-09N BETWEEN 06W-28W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE NW GULF NEAR 29N92W AND IS PROVIDING THE FLORIDA PENINSULA AND MUCH OF THE GULF N OF 22N WITH NORTHWESTERLY UPPER LEVEL FLOW OVER THE NE GULF AND FLORIDA PENINSULA AND EASTERLY UPPER LEVEL FLOW S OF 29N W OF 85W. WATER VAPOR IMAGERY ALSO INDICATES THIS IS USHERING IN MODERATELY DRY AIR OVER THE NORTH CENTRAL GULF AND EASTERN GULF E OF 90W. HOWEVER...WHILE DRY AIR EXISTS IN THE MIDDLE TO UPPER LEVELS...A LINGERING STATIONARY FRONTAL BOUNDARY IS ANALYZED IN THE W ATLC TO THE FLORIDA COAST NEAR KEY BISCAYNE. AS THIS BOUNDARY BECOMES MORE DIFFUSE TO THE WEST OVER THE EASTERN GULF...ISOLATED SHOWERS ARE S OF 26N E OF 85W. ELSEWHERE N OF 22N...PRIMARILY E WINDS ARE OBSERVED UP TO 15 KT. FINALLY...A SURFACE TROUGH IS ANALYZED FROM 18N93W TO 22N95W AND IS PROVIDING FOCUS FOR SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE BAY OF CAMPECHE S OF 22N W OF 93W. CARIBBEAN SEA... AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER CENTRAL CUBA NEAR 22N80W AND CONTINUES TO PROVIDE MUCH OF THE BASIN WITH UPPER LEVEL EASTERLY FLOW W OF 68W. A WEAKNESS ON THE WESTERN PERIPHERY OF THE RIDGE IS ASSOCIATED WITH THE 1006 MB SPECIAL FEATURES LOW CENTER AND SURFACE TROUGHING ACROSS THE WESTERN CARIBBEAN. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS LOCATED FROM 18N-21N BETWEEN 76W-82W AND WITHIN 240 NM OF THE NW QUADRANT OF THE LOW CENTER. ALSO FARTHER SOUTH OVER THE SW CARIBBEAN...SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 09N-12N BETWEEN 77W-85W. WATER VAPOR IMAGERY INDICATES THAT MOSTLY DRY AIR AND STRONG SUBSIDENCE IS OVER THE EASTERN CARIBBEAN AND LEEWARD ISLANDS PROVIDING OVERALL FAIR CONDITIONS AND CLEAR SKIES THIS AFTERNOON. ATLANTIC OCEAN... DRY NORTHWESTERLY UPPER LEVEL FLOW RESIDES W OF 63W OVER THE SW NORTH ATLC DUE TO AN UPPER LEVEL ANTICYCLONE CENTERED IN THE NW GULF OF MEXICO NEAR 29N92W. THIS UPPER LEVEL ENVIRONMENT IS SUPPORTING A 1022 MB HIGH CENTERED OVER EASTERN NORTH CAROLINA NEAR 35N83W. FARTHER EAST...AN UPPER LEVEL TROUGH AXIS EXTENDS FROM 32N61W TO 24N70W AND SUPPORTS A 1010 MB LOW CENTERED NEAR 37N66W AND A COLD FRONT THAT EXTENDS FROM THE LOW TO 31N68W THEN CONTINUES AS A STATIONARY FRONT ALONG 27N73W TO THE FLORIDA COAST NEAR BISCAYNE BAY. WHILE THE FRONT LACKS ANY SIGNIFICANT DEEP CONVECTION...ISOLATED SHOWERS ARE WITHIN 30 NM EITHER SIDE OF THE BOUNDARY. FARTHER SOUTH...WHILE THE UPPER LEVEL TROUGH AXIS WEAKENS NE OF CUBA...UPPER LEVEL DIFFLUENCE IS OVER FAR SW PORTION OF THE SW NORTH ATLC. THIS ALONG WITH THE BROAD AREA OF LOWER PRESSURE OVER THE NW CARIBBEAN SEA...EXTENDING FROM THE SPECIAL FEATURES LOW...IS GENERATING SCATTERED SHOWERS AND TSTMS FROM 20N-23N BETWEEN 69W-78W...INCLUDING THE SE BAHAMAS...TURKS AND CAICOS ISLANDS...AND THE NORTHERN COAST OF CUBA. OVER THE CENTRAL ATLC...ANOTHER REMNANT FRONTAL BOUNDARY ANALYZED AS A SURFACE TROUGH IS POSITIONED FROM 31N56W TO 27N61W. ISOLATED SHOWERS ARE WITHIN 90 NM EITHER SIDE OF THE TROUGH AXIS. THE REMAINDER OF THE EASTERN ATLC IS DOMINATED BY SURFACE RIDGING ANCHORED BY A 1030 MB HIGH CENTERED N OF THE AZORES NEAR 44N28W. AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER W AFRICA NEAR 23N13W WITH AN UPPER LEVEL RIDGE AXIS EXTENDING SW TO THE CAPE VERDE ISLANDS NEAR 15N26W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN