000 AXNT20 KNHC 171200 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT FRI SEP 17 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...SPECIAL FEATURES... HURRICANE KARL IS CENTERED NEAR 19.6N 95.6W AT 17/1200 UTC OR ABOUT 50 NM NE OF VERACRUZ MEXICO AND ABOUT 150 NM SE OF TUXPAN MEXICO MOVING W AT 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 956 MB. MAXIMUM SUSTAINED WIND SPEED IS 105 KT WITH GUSTS TO 130 KT. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT3/WTNT33 AND THE FULL FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. SCATTERED/NUMEROUS STRONG CONVECTION IS WITHIN 45 NM OF THE CENTER OVER THE N SEMICIRCLE AND WITHIN 60 NM OF THE CENTER IN OVER THE S SEMICIRCLE. SCATTERED MODERATE/STRONG CONVECTION COVERS THE REMAINDER OF THE AREA FROM S OF 21N W OF 93W TO INLAND OVER THE S MEXICO. KARL IS EXPECTED TO MAKE LANDFALL LATER TODAY. HURRICANE IGOR IS CENTERED NEAR 22.7N 59.8W AT 17/1200 UTC OR ABOUT 730 NM SSE OF BERMUDA MOVING NW AT 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 935 MB. MAXIMUM SUSTAINED WIND SPEED IS 110 KT WITH GUSTS TO 135 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. SCATTERED/NUMEROUS STRONG CONVECTION IS FROM 21N-23N BETWEEN 59W-61W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION COVERS THE REMAINDER OF THE AREA WITHIN 150 NM OF LINE FROM 20N55W TO 23N61W. OUTER RAINBANDS OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE WITHIN 120 NM OF LINE FROM 15N55W 23N52W 27N56W 26N60W TO 22N61W. HURRICANE JULIA IS CENTERED NEAR 23.8N 45.1W AT 17/0900 UTC OR ABOUT 1260 NM SW OF THE AZORES MOVING WNW AT 21 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 981 MB. MAXIMUM SUSTAINED WIND SPEED IS 75 KT WITH GUSTS TO 90 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. SCATTERED STRONG CONVECTION IS WITHIN 45 NM OF THE CENTER OVER THE NW QUADRANT. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS COVERS THE REMAINDER OF THE AREA FROM 22N-25N BETWEEN 43W-46W. ...TROPICAL WAVES... TROPICAL WAVE IS APPROACHING THE CAPE VERDE ISLANDS ALONG 20W/21W S OF 17N MOVING W 10-15 KT. SATELLITE IMAGERY SHOWS BROAD CYCLONIC TURNING NEAR AND TO THE WEST OF THE WAVE AXIS ALONG 13N. NO ASSOCIATED SHOWER ACTIVITY/CONVECTION. ...ITCZ... THE ITCZ/MONSOONAL TROUGH REMAINS ACROSS THE ATLC BASIN FROM 10N23W 13N33W TO 11N46W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 10N-15N BETWEEN 22W-38W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 7N-11N BETWEEN 43W-47W. ...DISCUSSION... GULF OF MEXICO... THE PRIMARY CONCERN FOR THE S GULF OF MEXICO IS HURRICANE KARL THAT COULD BECOME A MAJOR HURRICANE BEFORE MAKING LANDFALL LATER TODAY OVER MEXICO...SEE SPECIAL FEATURES ABOVE. THE BROAD UPPER RIDGE ASSOCIATED WITH KARL COVERS THE GULF PROVIDING DIFFLUENCE ALOFT TO SUPPORT OUTER RAINBANDS WITH CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS COVERING MOST OF THE GULF WATERS TO GULF COAST FROM LOUISIANA TO FLORIDA INCLUDING THE FLORIDA KEYS AND TO INLAND OVER NE MEXICO. EMBEDDED WITHIN THIS UPPER FLOW IS A WEAK SURFACE TROUGH THAT EXTENDS FROM ALONG 84W FROM 27N TO OVER TALLAHASSEE. A SHORTWAVE UPPER TROUGH REMAINS OVER E TEXAS FROM SAN ANTONIO TO NEAR BROWNSVILLE GENERATING SCATTERED SHOWERS/THUNDERSTORMS N OF 25N TO THE COAST OF LOUISIANA AND W OF 89W TO INLAND OVER TEXAS. CARIBBEAN SEA... THE BROAD UPPER RIDGE ASSOCIATED WITH KARL REMAINS OVER THE W CARIBBEAN W OF 80W BRINGING MOSTLY HIGH CLOUDS TO THE AREA WITH SOME ISOLATED SHOWERS/THUNDERSTORMS DOTTING THE AREA N OF 16N W OF 90W. AN UPPER RIDGE ANCHORED S OF HURRICANE IGOR IN THE W TROPICAL ATLC IS GIVING THE E CARIBBEAN S TO SW FLOW ALOFT INDUCING AN INVERTED UPPER TROUGH THAT EXTENDS FROM W COLOMBIA NEAR 9N76W TO HAITI NEAR 18N72W. THE INVERTED TROUGH COUPLED WITH THE CONVERGING SURFACE FLOW OVER THE SW CARIBBEAN IS GENERATING ISOLATED SHOWERS/ISOLATED THUNDERSTORMS S OF 13N BETWEEN 71W-83W. STRONG SUBSIDENCE WITH DRY STABLE AIR COVERS THE CARIBBEAN N OF 13N BETWEEN 66W-80W GIVING THE AREA MOSTLY CLEAR SKIES THIS MORNING. ATLANTIC OCEAN... HURRICANE IGOR REMAINS A CONCERN FOR THE ATLC WATERS THIS MORNING WHILE BERMUDA BRACES FOR THIS LARGE AND DANGEROUS HURRICANE...SEE SPECIAL FEATURES ABOVE. A SURFACE RIDGE REMAINS OVER THE W ATLC. STRONG SUBSIDENCE AND DRY AIR ALOFT COVERS THE W ATLC FROM 66W-80W GIVING THE AREA FAIR WEATHER THIS MORNING. THE UPPER RIDGE ASSOCIATED WITH HURRICANE IGOR COVERS THE CENTRAL ATLC FROM 16N-30N BETWEEN 50W-65W. HURRICANE JULIA IS ABOUT TO ENCOUNTER AN UPPER LEVEL JET WHICH IS PART OF THE OUTFLOW FROM IGOR AND SHOULD INDUCE SIGNIFICANT SHEAR THUS WEAKENING JULIA. AN E/W UPPER RIDGE HAS ONCE AGAIN DOMINATED THE E TROPICAL ATLC ALONG 20N TO 36W. THE FIRST VISIBLE SATELLITE IMAGES SHOWS DRY SAHARAN AIR AND DUST COVERING THE E ATLC FROM 16N-26N E TO 38W WHICH IS JUST E OF HURRICANE JULIA. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW