000 AXNT20 KNHC 160004 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2345 UTC. ...SPECIAL FEATURES... TROPICAL STORM KARL IS CENTERED NEAR 19.2N 90.1W AT 16/0000 UTC OR ABOUT 50 NM SE OF CAMPECHE MEXICO MOVING WNW AT 12 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. SEE THE 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. KARL CONTINUES TO BE LOCATED INLAND OVER THE YUCATAN PENINSULA AND THEREFORE HAS WEAKENED OVER THE LAST SEVERAL HOURS. HOWEVER...IT CONTINUES TO GENERATE STRONG CONVECTION WITHIN 90 NM OF THE CENTER IN THE ALL QUADRANTS. THESE RAINS COULD CAUSE LIFE-THREATENING FLASH FLOODS AND MUD SLIDES...ESPECIALLY IN AREAS OF MOUNTAINOUS TERRAIN. THE OUTER BANDS OF MODERATE TO STRONG CONVECTION COVER THE REMAINDER OF THE AREA INCLUDING THE CENTRAL AND SE GULF OF MEXICO AND THE NW CARIBBEAN. RE-INTENSIFICATION IS EXPECTED ON THURSDAY OR FRIDAY AFTER THE CENTER EMERGES INTO THE BAY OF CAMPECHE. HURRICANE IGOR IS CENTERED NEAR 20.1N 55.6W AT 15/2100 UTC OR ABOUT 505 NM ENE OF THE NORTHERN LEEWARD ISLANDS AND ABOUT 1015 NM SE OF BERMUDA MOVING W-NW AT 7 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 942 MB. MAXIMUM SUSTAINED WIND SPEED IS 115 KT WITH GUSTS TO 140 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. NUMEROUS STRONG CONVECTION IS WITHIN 130 NM FROM THE CENTER IN THE SW AND SE QUADRANTS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION COVERING THE REMAINDER OF THE AREA WITHIN 140 NM FROM THE CENTER IN THE NW AND NE SEMICIRCLE. SOME FLUCTUATIONS IN STRENGTH ARE POSSIBLE DURING THE NEXT OR TWO...BUT IGOR IS EXPECTED TO REMAIN A DANGEROUS HURRICANE. HURRICANE JULIA IS CENTERED NEAR 19.2N 33.5W AT 15/2100 UTC OR ABOUT 665 NM WNW OF THE CAPE VERDE ISLANDS MOVING NW AT 15 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 953 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. NUMEROUS STRONG CONVECTION IS WITHIN 90 NM FROM THE CENTER IN THE SW SEMICIRCLE AND 60 NM FROM THE CENTER IN THE NE SEMICIRCLE. SCATTERED MODERATE/ ISOLATED STRONG CONVECTION COVERING THE REMAINDER OF THE AREA WITHIN 120 NM FROM THE CENTER. JULIA IS EXPECTED TO MAINTAIN ITS INTENSITY TODAY BEFORE SLOWLY WEAKENING LATER ON THURSDAY. ...ITCZ... THE ITCZ...OR PERHAPS BETTER DESCRIBED AS A MONSOONAL TROUGH BECAUSE OF THE CONVERGENCE OF NE AND SW SURFACE WINDS...REMAINS DISCONTINUOUS ACROSS THE ATLANTIC DUE TO HURRICANES IGOR AND JULIA. THE AXIS EXTENDS ALONG 9N13W 8N19W 11N25...RESUMING NEAR 10N35N TO 11N44W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 6N TO 12N BETWEEN 13W AND 28W. SIMILAR CONVECTION IS FROM 6N TO 10N BETWEEN 34W AND 43W. ...DISCUSSION... GULF OF MEXICO... THE OUTER BANDS FROM TROPICAL STORM KARL SPREAD ACROSS THE GULF AFFECTING MOST OF THE CENTRAL AND SE BASIN S OF 28N E OF 94W PRODUCING SCATTERED SHOWERS AND THUNDERSTORMS WITH WINDS UP TO 25 KT. THE ACTIVITY IS ENHANCED BY UPPER LEVEL DIFFLUENCE NOTED IN THE NORTH CENTRAL GULF...BETWEEN THE OUTFLOW GENERATED BY KARL AND A BROAD UPPER LEVEL RIDGE OF HIGH PRESSURE WITH UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER SOUTHERN LOUISIANA. FAIR WEATHER CONDITIONS ARE ELSEWHERE W OF 94W AND OVER THE FAR NE BASIN THIS EVENING. SHORT RANGE COMPUTER MODELS INDICATE THE CONVECTION ASSOCIATED WITH KARL WILL CONTINUE TO SPREAD ACROSS THE CENTRAL AND WESTERN BASIN THROUGHOUT THE NEXT FEW DAYS AND OVER THE WEEKEND. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS REGARDING THIS SYSTEM. CARIBBEAN SEA... THE OUTER BANDS FROM TROPICAL STORM KARL CONTINUE TO SPREAD ACROSS THE NW CARIBBEAN SEA N OF 15N W OF 76W PRODUCING SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE AREA. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS REGARDING THIS SYSTEM. AWAY FROM THIS AREA OF CONVECTION...FAIR WEATHER CONDITIONS ARE ELSEWHERE ACROSS THE BASIN WITH A FEW ISOLATED SHOWERS EMBEDDED IN THE EASTERLY SFC FLOW...ESPECIALLY E OF 75W...DUE TO DRY AIR AND STRONG SUBSIDENCE ALOFT NOTED ON WATER VAPOR IMAGERY. ATLANTIC OCEAN... SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE ACROSS THE FAR WESTERN ATLC AREA OF DISCUSSION S OF 26N W OF 75W...INCLUDING THE FLORIDA STRAITS AND PORTIONS OF THE BAHAMAS AND THE NORTHERN COASTAL WATERS OF CUBA. THIS AREA OF CONVECTION IS ASSOCIATED WITH TROPICAL STORM KARL DISCUSSED ABOVE IN THE SPECIAL FEATURES SECTION. THE ONLY MINOR SYNOPTIC FEATURE OF NOTE IS THE TAIL END OF A WEAK STATIONARY FRONTAL BOUNDARY FROM 28N74W TO 32N65W CONTINUING NORTHEASTWARD FROM THERE. NO DEEP CONVECTION IS FOUND IN ASSOCIATION WITH THIS BOUNDARY...THOUGH THERE MAY BE SOME LOW-TOPPED SHOWERS PRESENT WITHIN 20 NM OF THE AXIS. ASIDE HURRICANES IGOR AND JULIA...THE REMAINDER OF THE ATLC N OF 22N IS UNDER THE INFLUENCE OF DRY AND STABLE AIR ALOFT AROUND AN UPPER LEVEL RIDGE SUPPORTING A 1028 MB HIGH LOCATED NORTH OF THE DISCUSSION AREA NEAR 41N30W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA