000 AXNT20 KNHC 092342 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST FRI NOV 09 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N16W TO 10N19W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 10N19W TO 11N36W TO 06N57W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 05N-13N BETWEEN 18W-47W. MUCH OF THIS CONVECTION IS LIKELY ENHANCED DUE TO UPPER LEVEL SOUTHWESTERLY DIFFLUENT FLOW ALOFT. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY INDICATES A MIDDLE TO UPPER LEVEL RIDGE IS OVER MUCH OF THE GULF THIS EVENING WHICH IS SUPPORTING A BROAD SURFACE RIDGE ANCHORED BY A 1026 MB HIGH CENTERED OVER CENTRAL ALABAMA NEAR 33N86W. MOSTLY SCATTERED STRATOCUMULUS CLOUDINESS IS ACROSS THE GULF WITH FAIR CONDITIONS AND MODERATE TO FRESH EAST-SOUTHEAST WINDS EXPECTED TO PERSIST THROUGH SATURDAY. BY SUNDAY...THE PRESSURE GRADIENT BETWEEN THE RIDGING AND DEVELOPING LOW PRESSURE OVER THE CENTRAL AND SOUTHERN PLAINS WILL INCREASE THE EAST-SOUTHEASTERLY WINDS OVER MUCH OF THE BASIN WITH THE NEXT COLD FRONT EMERGING OFF THE TEXAS GULF COAST AND INTO THE NW GULF WATERS EARLY MONDAY. CARIBBEAN SEA... NORTHWESTERLY TO WESTERLY UPPER LEVEL FLOW DOMINATE ACROSS MUCH OF THE CARIBBEAN BASIN WITH WATER VAPOR IMAGERY INDICATING MOSTLY DRY AND SUBSIDENT CONDITIONS PREVAILING ALOFT. A MIDDLE TO UPPER LEVEL TROUGH IS OVER THE MUCH OF THE SW NORTH ATLC REGION WITH THE TROUGH BASE LOCATED OVER CUBA THIS EVENING. WHILE THE UPPER LEVEL TROUGH SUPPORTS A COLD FRONT IN THE ATLC...A SHEAR LINE IS ANALYZED FROM WESTERN HISPANIOLA NEAR 19N73W TO JAMAICA NEAR 18N77W THEN SOUTHWEST TO 12N82W. AS TYPICAL WITH SHEAR LINES...AN EARLIER ASCAT PASS AROUND 09/1536 UTC SHOWS STRONGER N-NE WINDS NORTH OF THE SHEAR LINE ACROSS THE NW CARIBBEAN. LOW-LEVEL MOISTURE CONVERGENCE IN THE VICINITY OF THE SHEAR LINE IS ALSO GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 120 NM EITHER SIDE OF THE BOUNDARY AND FROM 10N-12N BETWEEN 80W-84W. THE CLOSE PROXIMITY OF THE MONSOON TROUGH AXIS ALONG 10N IN THIS AREA IS ALSO PROVIDING FOCUS FOR ISOLATED SHOWERS AND TSTMS S OF 10N...INCLUDING PORTIONS OF INLAND PANAMA. ELSEWHERE ACROSS THE REMAINDER OF THE CENTRAL AND EASTERN CARIBBEAN...CONDITIONS REMAIN FAIRLY TRANQUIL WITH ONLY AN APPROACHING WEAK TROUGH ALONG 60W INTRODUCING SCATTERED SHOWERS AND ISOLATED TSTMS FOR THE LESSER ANTILLES AS THE FEATURE MOVES WESTWARD. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY N OF 32N BETWEEN 70W-80W THAT DIPS SOUTHWARD INTO THE DISCUSSION AREA WITH AN AXIS ALONG 32N69W TO OVER WESTERN CUBA NEAR 23N80W. THIS TROUGH SUPPORTS A COLD FRONT ANALYZED FROM 32N58W TO 25N64W TO NORTHERN HISPANIOLA NEAR 20N72W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING WITHIN 360 NM EAST OF THE COLD FRONT N OF 27N...WITHIN 240 NM EAST OF THE COLD FRONT S OF 27N...AND WITHIN 120 NM WEST OF THE COLD FRONT. ELSEWHERE WEST OF THE FRONT...HIGH PRESSURE CONTINUES TO BUILD EASTWARD FROM THE SE CONUS INTO THE SW NORTH ATLC AND IS ANCHORED BY A 1026 MB HIGH CENTERED OVER CENTRAL ALABAMA NEAR 33N86W. EAST OF THE COLD FRONT OVER THE REMAINDER OF THE CENTRAL AND EASTERN ATLC... SURFACE RIDGING DOMINATES ANCHORED BY A 1031 MB HIGH CENTERED WEST OF THE AZORES NEAR 38N36W. A MIDDLE TO UPPER LEVEL LOW IS CENTERED WITHIN THE SOUTHEASTERN PERIPHERY OF THE RIDGE NEAR 20N35W AND SUPPORTS A SURFACE TROUGH FROM 16N-21N ALONG 38W. SATELLITE IMAGERY SUGGESTS A WEAK WESTWARD MOVING LOW PRESSURE CENTER IS NEAR 19N38W...HOWEVER STRONG SOUTHWESTERLY MIDDLE TO UPPER LEVEL SHEAR IS KEEPING CONVECTION TO A MINIMUM NEAR THE LOW-LEVEL CENTER. SCATTERED SHOWERS AND TSTMS ARE OCCURRING FROM 13N-25N BETWEEN 19W-36W DUE TO MAXIMUM DIFFLUENCE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN