000 AXNT20 KNHC 242344 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST THU NOV 24 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 11N16W TO 08N19W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 08N19W TO 05N35W TO 07N50W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 02N-09N BETWEEN 15W-29W...AND WITHIN 180 NM EITHER SIDE OF A LINE FROM 03N35W TO 13N48W. A SURFACE TROUGH REMAINS NEAR THE WESTERN EXTENT OF THE ITCZ ANALYZED FROM 05N52W TO 15N50W WITH NO SIGNIFICANT DEEP CONVECTION NOTED ON SATELLITE IMAGERY...HOWEVER...SCATTERED SHOWERS ARE OCCURRING WITHIN 150 NM EITHER SIDE OF THE SURFACE TROUGH AXIS. ...DISCUSSION... GULF OF MEXICO... MOSTLY WESTERLY UPPER LEVEL FLOW IS NOTED ALOFT WITH VERY DRY AIR AND STRONG SUBSIDENCE EVIDENT ON WATER VAPOR IMAGERY ACROSS THE GULF BASIN THIS EVENING. AN UPPER LEVEL TROUGH CONTINUES TO IMPACT THE WESTERN NORTH ATLC WITH A COLD FRONT TRAILING WESTWARD FROM THE CENTRAL BAHAMAS INTO THE STRAITS OF FLORIDA ALONG 24N AND INTO THE SE GULF WATERS. FROM 24N85W THE FRONT BECOMES STATIONARY ALONG 24N90W TO 18N94W. SINCE THE UPPER LEVEL LEVELS ARE VERY STABLE...ONLY LOW-TOPPED ISOLATED SHOWERS ARE OCCURRING WITHIN 60 NM EITHER SIDE OF THE FRONT. ELSEWHERE NORTH OF THE FRONT THE REMAINDER OF THE GULF IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1029 MB HIGH CENTERED OVER NW MISSISSIPPI. NE TO E WINDS PREVAIL ON THE SOUTHERN PERIPHERY OF THE RIDGE IN THE RANGE OF 10 TO 20 KT. THESE WINDS ARE EXPECTED TO REMAIN EASTERLY AND BRISK OVER PORTIONS OF THE EASTERN GULF THROUGH FRIDAY...AND VEER SOUTHEASTERLY AHEAD OF THE NEXT COLD FRONT FORECAST TO EMERGE OFF THE TEXAS GULF COAST LATE SATURDAY. CARIBBEAN SEA... A WEAK UPPER LEVEL RIDGE IS LOCATED OVER THE NW CARIBBEAN WITH DRY AIR AND STRONG SUBSIDENCE ALOFT NOTED ON WATER VAPOR IMAGERY N OF 16N W OF 65W. N-NE WINDS AND MOSTLY FAIR CONDITIONS ARE NOTED ON SATELLITE IMAGERY THIS EVENING N OF 18N E OF 83W AND N OF 16N W OF 83W. THE REMAINDER OF THE CARIBBEAN BASIN REMAINS UNDER THE INFLUENCE OF WEAK DIFFLUENCE ALOFT AND MOIST SW FLOW ALOFT. WINDS AT THE SURFACE REMAIN E-NE WITH SCATTERED SHOWERS AND TSTMS OCCURRING S OF 16N. THE MOST ACTIVE AREA OF CONVECTION IS LOCATED IN THE SW CARIBBEAN S OF 16N BETWEEN 76W-84W DUE TO LOW-LEVEL CONVERGENCE AND CLOSE PROXIMITY OF THE MONSOON TROUGH AXIS ALONG 11N. FARTHER EAST...A SURFACE TROUGH IS ANALYZED FROM 10N62W TO 15N61W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING S OF 16N BETWEEN 58W-70W. ATLANTIC OCEAN... AN UPPER LEVEL TROUGH IS LOCATED OVER THE WESTERN NORTH ATLC WITH AXIS FROM 40N63W TO A BASE NEAR 32N81W. THIS TROUGHING SUPPORTS A COLD FRONT ANALYZED INTO THE DISCUSSION AREA NEAR 32N65W THEN SW TO 27N70W TO THE CENTRAL BAHAMAS NEAR 25N77W THEN WESTWARD ALONG 24N INTO THE STRAITS OF FLORIDA AND SE GULF OF MEXICO. WHILE MOSTLY DRY AIR AND STABLE CONDITIONS ARE NOTED ON WATER VAPOR IMAGERY OVER THE SW NORTH ATLC...ONLY ISOLATED SHOWERS ARE OCCURRING WITHIN 60 NM EITHER SIDE OF THE FRONT. WEST OF THE FRONT...STRONG N-NE WINDS PERSIST ON THE SE PERIPHERY OF A RIDGE ANCHORED OVER EASTERN TENNESSEE. EAST OF THE FRONT...WEAK PRE-FRONTAL TROUGHING AND LOW-LEVEL CONVERGENCE IS GENERATING POSSIBLE ISOLATED SHOWERS N OF 23N BETWEEN 53W AND THE COLD FRONT. FARTHER EAST...AN UPPER LEVEL LOW IS CENTERED NEAR 32N32W AND SUPPORTS A STORM FORCE 1002 MB LOW CENTERED NEAR 34N31W. A STATIONARY FRONTAL BOUNDARY EXTENDS EAST OF THE LOW NEAR 32N28W SW TO 21N39W WITH WIDELY SCATTERED SHOWERS COVERING A LARGE PORTION OF THE EASTERN ATLC FROM 20N-32N BETWEEN 20W-32W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN