000 AXNT20 KNHC 281745 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT FRI SEP 28 2012 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1645 UTC. ...SPECIAL FEATURES... HURRICANE NADINE IS LOCATED NEAR 29.6N 34.7W AT 28/1500 UTC. THIS POSITION IS LOCATED ABOUT 635 NM SW OF THE AZORES ISLANDS. NADINE IS MOVING NW NEAR 7 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 988 MB. MAXIMUM SUSTAINED WIND SPEED IS 65 KT WITH GUST TO 80 KT. PLEASE SEE LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS FROM 29N-32N BETWEEN 34W-37W. SCATTERED MODERATE CONVECTION IS FROM 29N-32N BETWEEN 32W-34W. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 17N32W TO 8N36W MOVING W NEAR 10 KT. IT LIES ON THE WEST SIDE OF A SURGE OF DEEP LAYER MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. ONLY A SMALL CLUSTER OF MODERATE CONVECTION IS FROM 14N-16N BETWEEN 33W-34W. TROPICAL WAVE IS IN THE WESTERN CARIBBEAN ALONG 19N81W TO 12N81W MOVING W AT 15-20 KT. THE WAVE LIES WITHIN A BROAD AREA OF DEEP LAYER MOISTURE PRESENT ACROSS THE CENTRAL AND WESTERN CARIBBEAN. THE WAVE ALSO CONTINUES TO LIE UNDERNEATH THE DIFFLUENT SIDE OF AN UPPER LEVEL TROUGH...WHICH IS HELPING ENHANCE CONVECTION NEAR IT. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 19N-21N BETWEEN 79W-82W. ACTIVITY IS PRESENT FARTHER E...BUT IS LIKELY MORE INFLUENCE BY THE UPPER LEVEL DYNAMICS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS WEST AFRICA TO THE COAST OF SENEGAL AT 13N16W CONTINUING SE ALONG 9N25W 7N36W. THE ITCZ CONTINUES FROM 7N36W ALONG 7N49W 7N58W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 5N-10N BETWEEN 15W-26W. SIMILAR ACTIVITY IS FROM 13N-16N BETWEEN 27W-29W. A SURFACE TROUGH IS ANALYZED NORTH OF THE ITCZ ALONG 17N46W TO 10N48W. THE TROUGH IS BEING ENHANCED BY AN UPPER LEVEL TROUGH TO THE WEST. THIS COMBINATION IS HELPING PRODUCE SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 7N-18N BETWEEN 43W-51W. ...DISCUSSION... GULF OF MEXICO... WEAK SURFACE RIDGING IS ACROSS THE GULF OF MEXICO EXTENDING FROM A HIGH CENTER OVER SOUTH CAROLINA. THE RIDGE ALONG WITH A SMALL AREA OF DRY AIR ALOFT IS HELPING PRODUCE FAIR WEATHER OVER A GOOD PORTION OF THE CENTRAL..EASTERN...AND SOUTHERN GULF INCLUDING FLORIDA AND THE YUCATAN PENINSULA. A SURFACE TROUGH IS PARALLEL TO THE TEXAS COAST SUPPORTING SCATTERED SHOWERS UP TO 150 NM OFFSHORE AND WELL AS OVER SOUTHERN LOUISIANA. ALOFT...MAINLY NORTHERLY FLOW COVERS THE BASIN BETWEEN AN UPPER LEVEL RIDGE EXTENDING UP MEXICO INTO TEXAS...AND AN UPPER LEVEL TROUGH EXTENDING DOWN THE EAST COAST OF FLORIDA. EXPECT SURFACE RIDGING TO REMAIN ACROSS THE BASIN WITH CONTINUED SHOWER ACTIVITY ALONG THE TEXAS COAST THROUGH THE MAJORITY OF THE WEEKEND. A SURFACE LOW AND ASSOCIATED FRONT WILL ENTER THE NW GULF ON SUNDAY. CARIBBEAN SEA... A TROPICAL WAVE IS MOVING THROUGH THE WESTERN CARIBBEAN ALONG 81W/82W. IT IS PRODUCING SHOWERS/THUNDERSTORMS NEAR THE NORTHERN EXTENT OF THE AXIS JUST SOUTH OF WESTERN CUBA. SHOWERS/THUNDERSTORMS CONTINUE TO THE E FROM COLOMBIA TO EASTERN CUBA BETWEEN 74W-79W...AS WELL AS ACROSS PORTIONS OF CENTRAL CUBA ASSOCIATED WITH DIFFLUENCE ALOFT AROUND AN UPPER LEVEL TROUGH EXTENDING WESTERN CUBA TO NICARAGUA. THE UPPER TROUGH IS LIKELY THE MAIN CAUSE OF ALL THE CONVECTION WITH A SMALLER INFLUENCE BY THE WAVE. SOME OF ACTIVITY SOUTH OF THE WAVE NEAR COLOMBIA AND ACROSS PANAMA IS ALSO INFLUENCED BY THE MONSOON TROUGH EXTENDING FROM THE E PACIFIC ACROSS NORTHERN COSTA RICA TO NORTHERN COLOMBIA. THE EASTERN CARIBBEAN IS EXPERIENCING MOSTLY FAIR WEATHER AT THIS TIME ASSOCIATED WITH DRY AIR ALOFT AROUND AN UPPER LEVEL RIDGE OVER THAT HALF OF THE BASIN. EXPECT THE TROPICAL WAVE TO CONTINUE TO MOVE WESTWARD AS THE UPPER LEVEL TROUGH REMAINS SOMEWHAT STATIONARY. THIS PATTERN WILL CONTINUE TO PRODUCE SHOWERS/THUNDERSTORMS ACROSS MUCH OF THE WESTERN CARIBBEAN. ATLANTIC OCEAN... ISOLATED SHOWERS/THUNDERSTORMS COVER THE EXTREME SW NORTH ATLC ASSOCIATED WITH AN UPPER LEVEL TROUGH EXTENDING DOWN THE EAST COAST OF FLORIDA INTO THE WESTERN CARIBBEAN. THE UPPER TROUGH SUPPORTS A WEAK SURFACE TROUGH ALONG 30N79W TO 25N79W. THE REMAINDER OF THE W ATLC IS EXPERIENCING FAIR CONDITIONS WITH AN UPPER LEVEL RIDGE COVERING THE AREA ALONG 66W. AN UPPER LEVEL TROUGH COVERS THE CENTRAL ATLC ALONG 27N49W ENHANCING CONVECTION NEAR A SURFACE TROUGH NORTH OF THE ITCZ REGION. A SECOND AND WEAKER SURFACE TROUGH IS ALONG 23N59W TO 20N61W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE E OF THE AXIS FROM 19N-24N BETWEEN 54W-57W. BROAD UPPER LEVEL RIDGING IS ACROSS THE REMAINDER OF THE BASIN PROVIDING MOSTLY FAIR CONDITIONS EXCEPT NEAR HURRICANE NADINE NEAR THE NORTHERN BOUNDARY OF THE DISCUSSION AREA. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON