000 AXNT20 KNHC 150559 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT WED SEP 15 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0445 UTC. ...SPECIAL FEATURES... TROPICAL STORM KARL IS CENTERED NEAR 18.6N 86.0W AT 15/0600 UTC OR ABOUT 130 NM E OF CHETUMAL MEXICO MOVING W-NW AT 13 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 999 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 AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. NUMEROUS STRONG CONVECTION IS WITHIN 60 NM IN THE SW QUADRANT WITH SCATTERED MODERATE/STRONG CONVECTION COVERING THE REMAINDER OF THE AREA WITHIN 60 NM OF LINE FROM 18N86W TO THE COAST OF THE YUCATAN NEAR 19N88W. HURRICANE IGOR IS CENTERED NEAR 19.0N 53.9W AT 15/0300 UTC OR ABOUT 525 NM E OF THE NORTHERN LEEWARD ISLANDS AND ABOUT 990 NM KM SE OF BERMUDA MOVING W-NW AT 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 925 MB. MAXIMUM SUSTAINED WIND SPEED IS 135 KT WITH GUSTS TO 165 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. SCATTERED/NUMEROUS STRONG CONVECTION IS WITHIN 120 NM OVER THE SE SEMICIRCLE WITH SCATTERED MODERATE/ISOLATED STRONG CONVECTION COVERING THE REMAINDER OF THE AREA FROM 13N-23N BETWEEN 48W-57W. HURRICANE JULIA IS CENTERED NEAR 16.9N 31.3W AT 15/0530 UTC OR ABOUT 425 NM W OF THE CAPE VERDE ISLANDS MOVING W-NW AT 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 955 MB. MAXIMUM SUSTAINED WIND SPEED IS 110 KT WITH GUSTS TO 135 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. A SPECIAL ADVISORY AS ISSUED AT 15/0530 UTC DUE TO A RAID INTENSITY INCREASE. SCATTERED/NUMEROUS STRONG CONVECTION IS WITHIN 90 NM OVER THE W SEMICIRCLE WITH SCATTERED MODERATE/ISOLATED STRONG CONVECTION COVERING THE REMAINDER OF THE AREA FROM 13N-20N BETWEEN 28W-33W. ...ITCZ... THE MONSOONAL TROUGH REMAINS ACROSS THE ATLC BASIN BEING DISTORTED BY HURRICANES IGOR AND JULIA. CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE FROM 4N-11N BETWEEN 10W-44W. ...DISCUSSION... GULF OF MEXICO... A BROAD UPPER LEVEL RIDGE COVERS THE GULF N OF 24N TO OVER THE SE U.S. EXTENDING E INTO THE W ATLC ANCHORED OFF THE SE LOUISIANA COAST NEAR 28N88W. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 75 NM OF LINE FROM 26N90W TO THE COAST OF THE FLORIDA PENINSULA NEAR 29N83W. A BROAD UPPER RIDGE ASSOCIATED WITH T.S. KARL COVERS THE SE GULF S OF 24N E OF 88W PROVIDING DENSE CLOUD COVER WITH SCATTERED SHOWERS OVER THE AREA AND POSSIBLE ISOLATED THUNDERSTORMS IN THE FLORIDA STRAITS. A WEAK UPPER INVERTED TROUGH IS IN THE SW GULF OVER THE BAY OF CAMPECHE EXTENDING FROM NEAR 19N92W TO 24N97W SUPPORTING A WEAK SURFACE TROUGH THAT EXTENDS FROM 22N96W TO S MEXICO COAST NEAR 18N94W BUT NOT GENERATING ANY SIGNIFICANT WEATHER. OTHERWISE... MOSTLY DRY STABLE AIR ALOFT DOMINATES THE REMAINDER OF THE GULF TONIGHT WITH MOSTLY CLEAR SKIES. CARIBBEAN SEA... THE PRIMARY FOCUS FOR THE CARIBBEAN TONIGHT IS TROPICAL STORM KARL THAT DEVELOPED EARLIER ON TUE...SEE SPECIAL FEATURES ABOVE. THE UPPER LEVELS OF THE CARIBBEAN ARE DOMINATED BY A BROAD UPPER RIDGE THAT IS ASSOCIATED WITH T.S. KARL EXTENDING AN AXIS SE FROM 20N80W TO 13N69W PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS NE OF A LINE FROM 16N77W TO 22N84W TO OVER CUBA. ISOLATED SHOWERS ARE POSSIBLE OVER THE REMAINDER OF THE NW CARIBBEAN N OF 14N W OF 72W. AN UPPER LOW IS OVER THE LEEWARD/VIRGIN ISLANDS NEAR 17N63W COVERING THE REMAINDER OF THE CARIBBEAN INTO THE W TROPICAL ATLC. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE IN THE E CARIBBEAN WITHIN 45 NM OF A LINE FROM 14N64W TO 15N72W LEAVING THE THE REMAINDER OF THE E CARIBBEAN E OF 70W REMARKABLY CLEAR TONIGHT. ATLANTIC OCEAN... HURRICANES IGOR AND JULIA ARE THE PRIMARY FOCUS FOR THE ATLC AGAIN TONIGHT. THE UPPER RIDGE ASSOCIATED WITH T.S. KARL IS PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS FROM OVER THE BAHAMA ISLANDS TO ACROSS CUBA W OF 75W INTO THE FLORIDA STRAITS. THE UPPER RIDGE OVER THE GULF OF MEXICO AND THE ABOVE MENTIONED UPPER RIDGE IS GIVING THE W ATLC NW TO N FLOW ALOFT WITH A WEAK SURFACE TROUGH EXTENDING FROM 30N66W ALONG 26N72W ACROSS THE N BAHAMA ISLANDS TO 25N79W AND NO SIGNIFICANT WEATHER. AN UPPER LOW IS OVER THE LEEWARD AND VIRGIN ISLANDS NEAR 17N63W COVERING THE AREA FROM 11N-23N E OF HURRICANE IGOR TO 67W AND IS EMBEDDED WITHIN SOME VERY DRY AIR AND SUCH IS EXPERIENCING REMARKABLY CLEAR SKIES TONIGHT. THE UPPER RIDGE ASSOCIATED WITH IGOR COVERS A LARGE NEARLY UNIFORMED IN AREA WHILE THE UPPER RIDGE ASSOCIATED WITH JULIA IS NARROW AND ELONGATED N-NE TO S-SW AND AN UPPER TROUGH BETWEEN. STRONG SUBSIDENCE AND DRY STABLE AIR DOMINATE THE REMAINDER OF THE W AND CENTRAL ATLC BETWEEN IGOR AND JULIA. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW