000 AXNT20 KNHC 121800 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST TUE NOV 12 2013 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 1715 UTC. ...SPECIAL FEATURES... A COLD FRONT IS EXPECTED TO EMERGE INTO THE NW GULF WATERS TONIGHT. AS THE COLD FRONT PUSHES ACROSS THE GULF OF MEXICO... NORTHERLY-NORTHEASTERLY GALE FORCE WINDS/GUSTS ARE EXPECTED TO DEVELOP WEST OF THE FRONTAL BOUNDARY. SEE LATEST HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM THE WEST AFRICAN COAST NEAR 12N16W TO 10N20W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 09N21W TO 06N35W 04N49W. ASCAT DATA SHOW THERE IS A SURFACE TROUGH EMBEDDED WITHIN THE ITCZ AXIS...WHICH AT 1200 UTC IS ANALYZED FROM 13N40W TO 06N41W. SCATTERED RAINSHOWERS ARE MAINLY EAST OF THE TROUGH AXIS FROM 09N-12N BETWEEN 33W-40W. SCATTERED MODERATE CONVECTION AND TSTMS ARE FROM 04N-09N E OF 26W. ...DISCUSSION... GULF OF MEXICO... A BROAD UPPER-LEVEL RIDGE CENTERED OVER THE NW CARIBBEAN NEAR 18N78W CONTINUES TO PROVIDE SOUTHWEST TO WESTERLY FLOW ALOFT ACROSS THE GULF WATERS. UPPER-LEVEL DIFFLUENCE BETWEEN THE W-SW PERIPHERY OF THE RIDGE AND A TROUGH IN THE EAST PACIFIC WITH AXIS NEAR 110W CONTINUES TO ADVECT MOISTURE OVER GREAT PORTIONS OF MEXICO AS WELL AS NORTHEASTWARD ACROSS THE GULF. UPPER-LEVEL DIVERGENCE ALONG WITH LOW-LEVEL MOISTURE CONVERGENCE ALONG A SURFACE TROUGH ANALYZED FROM 24N93W TO 18N94W IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS MAINLY S OF 26N W OF 85W. SURFACE RIDGING DOMINATES N OF 26N AS WELL AS WEST OF THE TROUGH OVER THE BAY OF CAMPECHE WITH NW TO N WIND FLOW IN THE RANGE OF 20-25 KT S OF 25N W OF 95W. A COLD FRONT FOLLOWED BY REINFORCING SURFACE RIDGING WILL EMERGE TONIGHT INTO THE NW GULF WATERS. AS THE COLD FRONT PUSHES ACROSS THE GULF OF MEXICO... NORTHERLY- NORTHEASTERLY GALE FORCE WINDS/GUSTS ARE EXPECTED TO DEVELOP WEST OF THE FRONTAL BOUNDARY. NOTE SPECIAL FEATURES SECTION ABOVE...TO THE GULF TUESDAY THROUGH LATE THURSDAY. CARIBBEAN SEA... AN UPPER-LEVEL ANTICYCLONE CENTERED OVER THE NW CARIBBEAN NEAR 18N78W INFLUENCES THE NW AND NORTH-CENTRAL BASIN WITH DRY AIR SUBSIDENCE...THUS FAVORING FOR THE MOST PART FAIR WEATHER. IN THE FAR NW CARIBBEAN...LOW-LEVEL MOISTURE CONVERGENCE IS ENHANCING ISOLATED SHOWERS WITHIN 100 NM OF THE YUCATAN PENINSULA AND BELIZE COASTLINES. LOCALIZED MARGINAL UPPER-LEVEL DIVERGENCE S OF CENTRAL HISPANIOLA IS ENHANCING SIMILAR CONVECTION FROM 16N-18N BETWEEN 70W-73W. THE MONSOON TROUGH AXIS EXTENDS FROM THE E PACIFIC TO COSTA RICA AND PANAMA TO NORTHERN COLOMBIA. LOW-LEVEL MOISTURE CONVERGENCE ALONG WITH UPPER-LEVEL DIVERGENCE IS GENERATING SCATTERED MODERATE CONVECTION AND TSTMS S OF 11N W OF 76W. AN UPPER-LEVEL TROUGH EXTENDS FROM THE CENTRAL ATLC SW ACROSS THE LESSER ANTILLES TO A BASE OVER NORTHERN COLOMBIA SUPPORTING ISOLATED SHOWERS ACROSS THE EASTERN CARIBBEAN. A COLD FRONT IS EXPECTED TO ENTER THE FAR NW BASIN BY LATE WEDNESDAY TO EARLY THURSDAY. ...HISPANIOLA... CURRENTLY A FEW ISOLATED SHOWERS OCCURRING OFFSHORE THE SOUTHERN- CENTRAL ISLAND FROM 16N-18N BETWEEN 70W-73W. OTHERWISE...DRY AND OVERALL STABLE NORTHERLY FLOW ALOFT IS NOTED ON WATER VAPOR IMAGERY WHICH IS ANTICIPATED TO LIMIT ANY SIGNIFICANT DEEP CONVECTION OVER THE NEXT FEW DAYS. ATLANTIC OCEAN... WEAK UPPER LEVEL TROUGHING IS NOTED OVER THE CENTRAL ATLC SUPPORTING SURFACE TROUGHINESS GENERALLY N OF 25N BETWEEN 37W- 80W AS WELL AS A 1018 MB LOW CENTERED NEAR 30N58W. THE SURFACE TROUGHS ARE PROMOTING LOW-LEVEL MOISTURE CONVERGENCE WITH WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING N OF 25N BETWEEN 45W-70W. THE REMAINDER EASTERN ATLC IS UNDER THE INFLUENCE OF SURFACE RIDGING ANCHORED BY A 1037 MB HIGH CENTERED WELL NORTH OF THE DISCUSSION AREA NEAR 49N17W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR