000 AXNT20 KNHC 301749 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SAT SEP 29 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 37.1N 38.6W AT 30/1500 UTC. THIS POSITION IS LOCATED ABOUT 555 NM W OF THE AZORES ISLANDS. NADINE IS MOVING NW NEAR 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 979 MB. MAXIMUM SUSTAINED WIND SPEED IS 80 KT WITH GUST TO 100 KT. PLEASE SEE LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. SCATTERED MODERATE CONVECTION IS FROM 36N-38N BETWEEN 38W-42W. ...TROPICAL WAVES... TROPICAL WAVE IS MOVING THROUGH THE CAPE VERDE ISLANDS ALONG 18N24W TO 10N27W. THE WAVE IS FINALLY GAINING SOME WESTWARD MOTION AT NEAR 10 KT. THE WAVE IS EMBEDDED WITHIN A BROAD AREA OF MOISTURE COVERING THE EASTERN TROPICAL ATLC. MAXIMUM MOISTURE VALUES ARE NOTED NEAR THE WAVE AXIS. THE LOW LEVEL CYCLONIC FLOW AROUND THE WAVE REMAINS LOW AMPLITUDE AND BROAD AS THE WAVE MOVES THROUGH THE MONSOON TROUGH. THIS EXPLAINS THE LARGE AREA OF CONVECTION ASSOCIATED WITH THE WAVE. CURRENTLY...SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 14N-17N BETWEEN 21W-27W...FROM 7N-9N BETWEEN 28W-35W...AND FROM 11N-15N BETWEEN 27W-35W. TROPICAL WAVE IS ALONG 20N38W TO 10N43W MOVING W NEAR 10 KT. IT LIES ON THE WEST SIDE OF A SURGE OF DEEP LAYER MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 15N-21N BETWEEN 35W-41W. SIMILAR ACTIVITY IS FROM 8N-15N BETWEEN 41W-44W. TROPICAL WAVE PREVIOUSLY IN THE WESTERN CARIBBEAN HAS BEEN ANALYZED AS A SURFACE TROUGH DUE TO ITS STATIONARY POSITION OVER THE PAST 24 HOURS. IT WILL BE DISCUSSED IN THE CARIBBEAN SECTION. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS WEST AFRICA TO THE COAST OF SENEGAL AT 16N16W CONTINUING ACROSS ATLC WATERS ALONG 10N27W 8N44W. THE ITCZ BEGINS AT 8N44W CONTINUING TO 9N61W. CONVECTION NEAR THE MONSOON TROUGH HAS BEEN ASSOCIATED WITH THE TROPICAL WAVES. SEE ABOVE. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS N OF THE ITCZ FROM 9N-12N BETWEEN 50W-58W. ...DISCUSSION... GULF OF MEXICO... AS OF 1500 UTC...A COLD FRONT IS MOVING THROUGH THE NW GULF OF MEXICO FROM A 1003 MB SURFACE LOW OVER SE TEXAS AT 31N94W CONTINUING ALONG 24N95W 22N98W AND INTO MEXICO TO 23N 100W WHERE IT BECOMES STATIONARY TO 26N102W. A LINE OF SHOWERS/THUNDERSTORMS EXTENDS 90 NM EAST OF THE FRONT TO THE NORTH OF 27N WITH SCATTERED SHOWERS CONTINUING TO 87W AND FARTHER E INLAND OVER THE FLORIDA PANHANDLE. STRONG WINDS ARE BOTH AHEAD AND BEHIND THE NORTHERN PORTIONS OF THE AXIS REACHING UP TO 30 KT. SHOWERS/THUNDERSTORMS ARE ALSO NEAR THE SOUTHERN EXTENT OF THE FRONT NEAR THE MEXICAN COAST FROM 20N-23N BETWEEN 94W-100W. THE REMAINDER OF THE BASIN IS EXPERIENCING FAIR WEATHER DUE TO DRY AIR ALOFT AROUND AN UPPER LEVEL RIDGE ACROSS THE SW NORTH ATLC. AN UPPER LEVEL TROUGH MOVING THROUGH THE CENTRAL CONUS SUPPORTS THE FRONTAL BOUNDARY AND WILL ALSO BRING STRONG DRY AIR AND SUBSIDENCE BEHIND THE FRONT AS IT PUSHES EASTWARD. EXPECT THE FRONT TO CONTINUE EAST WITH SHOWERS/THUNDERSTORMS NEAR THE AXIS. CARIBBEAN SEA... THE TROPICAL WAVE PREVIOUSLY IN THE WESTERN CARIBBEAN IS NOW BEING ANALYZED AS A SURFACE TROUGH DUE TO THE LACK OF WESTWARD MOTION FOR THE PAST 24-48 HOURS. THE TROUGH EXTENDS FROM WESTERN CUBA NEAR 23N81W TO 16N84W. THE TROUGH ALSO LIES UNDER AN UPPER LEVEL LOW SPINNING NEAR 17N85W. ACTIVITY NEAR THE SURFACE TROUGH IS LIKELY MORE ASSOCIATED WITH THE UPPER LEVEL TROUGH. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE MAINLY E OF THE SURFACE TROUGH FROM 14N-22N BETWEEN 75W-83W. A FEW ISOLATED SHOWERS/THUNDERSTORMS HAVE ALSO POPPED UP ACROSS PORTIONS OF PANAMA ASSOCIATED WITH THE MONSOON TROUGH THAT EXTENDS THROUGH COSTA RICA AND PANAMA TO NORTHERN COLOMBIA. A FEW ISOLATED SHOWERS ARE ALSO ACROSS HISPANIOLA DUE TO AN EXTENSION OF THE UPPER LOW IN THE NW CARIBBEAN THAT EXTENDS INTO THE W ATLC. THE REMAINDER OF THE BASIN IS EXPERIENCING MOSTLY FAIR CONDITIONS DUE TO DRY AIR ALOFT AROUND AN UPPER LEVEL RIDGE ACROSS THE EASTERN HALF OF THE AREA. TRADEWIND FLOW OF 15-20 KT IS ACROSS MUCH OF THE AREA WITH LIGHTER WINDS IN THE SW CORNER. EXPECT MOIST CONDITIONS TO REMAIN OVER THE WESTERN CARIBBEAN FOR AT LEAST THE NEXT 24 HOURS. ATLANTIC OCEAN... A WEAK UPPER RIDGE COVERS THE EXTREME SW NORTH ATLC CENTERED NEAR 27N76W PROVIDING WEAK RIDGING OVER FLORIDA AND THE NW BAHAMAS. HOWEVER...AN UPPER LEVEL TROUGH EXTENDING FROM CENTRAL CUBA ACROSS THE CENTRAL BAHAMAS TO NEAR 31N62W IS SUPPORTING A LARGE AREA OF SHOWERS/THUNDERSTORMS FROM 21N-25N BETWEEN 66W-77W...AND FROM 23N-29N BETWEEN 63W-68W. THIS ACTIVITY HAS INDUCED A WEAK SURFACE TROUGH ALONG 23N71W TO 20N73W. WEAK UPPER RIDGING IS EAST OF THE UPPER TROUGH FROM HISPANIOLA TO NEAR 32N58W. THE UPPER RIDGE SUPPORTS BROAD SURFACE RIDGING EXTENDING FROM A 1022 MB HIGH NORTH OF THE AREA NEAR 35N49W. A LONGWAVE UPPER TROUGH CONTINUES TO COVE THE CENTRAL ATLC EXTENDING FROM WEST OF NADINE TO THE ITCZ REGION NEAR 10N54W. UPPER LEVEL RIDGING COVERS THE REMAINDER OF DISCUSSION AREA CENTERED NEAR 18N33W AND IS PROVIDING FAIR CONDITIONS ACROSS THE EASTERN ATLC. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON/DELGADO