000 AXNT20 KNHC 051756 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST TUE NOV 05 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. ...ITCZ/MONSOON TROUGH... THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM THE AFRICAN COAST NEAR 06N10W TO 10N21W TO 08N29W. ISOLATED MODERATE CONVECTION IS FROM 06N-13N BETWEEN 22W-29W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER THE WESTERN GULF NEAR 24N94W THAT EXTENDS AN UPPER LEVEL RIDGE AXIS NORTHEASTWARD TO BEYOND 33N78W PROVIDING AN OVERALL STABLE ENVIRONMENT ALOFT. THE UPPER LEVEL RIDGE SUPPORTS SURFACE RIDGING EXTENDING FROM THE MID-ATLC STATES SW OVER THE SE CONUS TO EASTERN MEXICO AND THE YUCATAN PENINSULA THIS AFTERNOON. A RELATIVELY STRONG PRESSURE GRADIENT EXISTS BETWEEN A FRONTAL TROUGH AND LOWER PRESSURE ACROSS THE NORTHERN CARIBBEAN SEA AND THE RIDGE PROVIDING FOR NE TO E WINDS IN THE RANGE OF 20 TO 30 KT E OF 90W. W OF 90W...E WINDS VEER SOUTHEASTERLY ACROSS THE FAR WESTERN PORTIONS AND REMAIN IN THE RANGE OF 10 TO 20 KT. RETURN FLOW NW OF THE SURFACE RIDGE AXIS EXTENDING FROM SE LOUISIANA TO TUXPAN MEXICO CONTINUES TO ADVECT LOW-LEVEL MOISTURE... CLOUDINESS...AND LOW-TOPPED ISOLATED SHOWERS NORTHWARD INTO AN AREA OF DEVELOPING LOW PRESSURE ACROSS THE CENTRAL AND SOUTHERN U.S. PLAINS. THIS ISOLATED SHOWER ACTIVITY IS NOT ONLY LIMITED TO THE WESTERN GULF...BUT IS ALSO NOTED ACROSS THE EASTERN GULF WATERS WITH A FEW ISOLATED TSTMS OCCURRING SW OF THE FLORIDA KEYS. BY LATE WEDNESDAY...THE PRESSURE GRADIENT ACROSS THE EASTERN GULF IS FORECAST TO RELAX SOMEWHAT WITH THE NEXT COLD FRONT EXPECTED TO EMERGE OFF THE TEXAS AND LOUISIANA COASTS BY LATE WEDNESDAY INTO EARLY THURSDAY. CARIBBEAN SEA... A LARGE PORTION OF THE CARIBBEAN BASIN IS UNDER THE INFLUENCE OF AN ANTICYCLONIC CIRCULATION CENTERED NEAR 16N78W. WATER VAPOR IMAGERY INDICATES MOISTURE WITH THIS UPPER LEVEL FEATURE REMAINS GENERALLY N OF 18N AND E OF 78W. AT THE SURFACE...A DISSIPATING STATIONARY FRONT IS ANALYZED ACROSS SOUTHEASTERN CUBA NEAR 20N76W TO SOUTH OF GRAND CAYMAN ISLAND NEAR 19N81W...AND A WEAK 1009 MB LOW IS CENTERED SOUTH OF JAMAICA NEAR 17N77W. SURFACE TROUGHING EXTENDS NE AND SE FROM THE LOW CENTER TO THE NORTHERN COLOMBIA COAST AND NORTHWESTERN HAITI RESPECTIVELY. ISOLATED SHOWERS AND TSTMS ARE OCCURRING OVER THE NW CARIBBEAN N OF 16N W OF 80W...AND S OF 20N BETWEEN 68W-80W. STRONGER CONVECTION IN THE FORM OF SCATTERED SHOWERS AND TSTMS REMAIN N OF 20N BETWEEN 68W-78W...PRIMARILY WITHIN THE SW NORTH ATLC REGION AND CONTINUE TO DRIFT MOISTURE SOUTHWARD ACROSS THE WINDWARD PASSAGE REGION AND HISPANIOLA. THE SURFACE LOW IS FORECAST TO REMAIN WEAK WITH TROUGHING CONTINUING TO DRIFT WESTWARD THROUGH FRIDAY. HISPANIOLA... CURRENTLY THE ISLAND IS UNDER THE INFLUENCE OF AN UPPER LEVEL ANTICYCLONE CENTERED NEAR 16N78W. AT THE SURFACE...A 1009 MB LOW IS CENTERED SW OF THE ISLAND NEAR 17N77W THAT REMAINS NEARLY STATIONARY WITH A SURFACE TROUGH ANALYZED NE ACROSS NORTHWESTERN PORTIONS OF HAITI TO 22N68W. WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE ONGOING ACROSS THE ISLAND AND ADJACENT COASTAL WATERS...INCLUDING THE WINDWARD PASSAGE. WITH AMPLE MIDDLE TO UPPER LEVEL DIFFLUENCE AND A WEAK CONVERGENT SURFACE BOUNDARY FOR THE ATMOSPHERE TO WORK WITH...SHOWERS AND TSTMS ARE EXPECTED TO CONTINUE THROUGH LATE WEDNESDAY UNTIL THE SURFACE LOW DRIFTS WESTWARD AND THE FRONTAL BOUNDARY TO THE NORTH ACROSS THE SW NORTH ATLC BECOMES MORE DIFFUSE. WITH MAXIMUM DAYTIME HEATING AND INSTABILITY OCCURRING DURING THE LATE AFTERNOON AND EARLY EVENING HOURS...CONVECTION IS FORECAST TO PEAK DURING THIS TIME EACH OF THE NEXT FEW DAYS. ATLANTIC OCEAN... AN UPPER LEVEL RIDGE AXIS EXTENDING FROM THE WESTERN GULF OF MEXICO NE TO BEYOND 35N73W IS WORKING IN TANDEM WITH A MID-LEVEL RIDGE CENTERED NEAR 30N77W TO SUPPORT OVERALL STABILITY ACROSS THE SW NORTH ATLC REGION N OF 24N W OF 68W. ALTHOUGH MOST OF THE STABILITY IS MANIFESTING ITSELF IN THE FORM OF A LACK OF DEEP CONVECTION...LOW-TOPPED ISOLATED SHOWERS CONTINUE TO ADVECT ON STRONG NE TO E WINDS DUE TO A STRONG PRESSURE GRADIENT BETWEEN A HIGH PRESSURE RIDGE ANCHORED OVER THE CAROLINAS AND SE U.S. AND A FRONTAL TROUGH NOTED ALONG 20N BETWEEN 68W-82W. MOST OF THE ACTIVE WEATHER ACROSS THE ATLC BASIN IS IN ASSOCIATION WITH A COLD FRONT ANALYZED FROM 32N54W TO 30N60W BECOMING STATIONARY INTO A 1011 MB LOW CENTERED NEAR 25N65W. THE STATIONARY BOUNDARY CONTINUES SW TO THE TURKS AND CAICOS ISLANDS NEAR 21N71W TO SE CUBA NEAR 20N76W. SCATTERED SHOWERS AND TSTMS ARE OCCURRING WITHIN 150 NM EITHER SIDE OF THE COLD FRONT AND FROM 18N-30N BETWEEN 54W-65W WITH THE LOW AND EASTERN PORTION OF THE STATIONARY BOUNDARY. DEEPER CONVECTION IS NOTED ALONG AND NORTH OF THE WESTERN PORTION OF THE STATIONARY BOUNDARY FROM 19N-24N BETWEEN 68W-80W. THIS FRONT IS SUPPORTED ALOFT BY AN UPPER LEVEL TROUGH AXIS EXTENDING FROM 33N57W TO 25N69W. FINALLY...OVER THE REMAINDER OF THE CENTRAL AND EASTERN ATLC...THE PRIMARY UPPER LEVEL FEATURE IS A BROAD UPPER LEVEL LOW CENTERED NEAR 25N47W. THE UPPER LEVEL TROUGH AXIS EXTENDS S-SW TO A BASE OVER THE DEEP TROPICS NEAR 07N58W. WHILE A FEW WEAK SURFACE TROUGHS ARE ANALYZED S OF 20N...THE MAIN AREA OF CONVECTION IS SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING FROM 12N-18N BETWEEN 38W- 44W AND LIKELY ASSOCIATED WITH MAXIMUM UPPER LEVEL DIFFLUENCE TO THE EAST OF THE UPPER LEVEL TROUGH AXIS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN