000 AXNT20 KNHC 151149 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST WED DEC 15 2010 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 08N13W 06N28W 08N42W 05N52W. WIDELY SCATTERED MODERATE CONVECTION IS WITHIN 150 NM EITHER SIDE OF THE AXIS BETWEEN 12W-31W. A WEAK SURFACE TROUGH IS EMBEDDED WITHIN THE AXIS ANALYZED FROM 05N44W TO 11N38W. NO SIGNIFICANT DEEP CONVECTION IS ASSOCIATED WITH THE SURFACE TROUGH. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY INDICATES MOSTLY DRY AIR IS PRESENT ALOFT OVER THE GULF WITH CONFLUENT W-NW FLOW PROVIDING FOR AN OVERALL STABLE ATMOSPHERE THIS MORNING. AT THE SURFACE...A BROAD SURFACE RIDGE REMAINS IN CONTROL ANCHORED BY A 1023 MB HIGH CENTERED OVER SW GEORGIA. THE RIDGE IS FORECAST TO SLIDE E-SE AND INTO THE W ATLC BY THURSDAY. INCREASED S-SE WINDS WERE DEPICTED ON AN EARLIER 15/0248 UTC ASCAT PASS OVER PORTIONS OF THE NW GULF AND SOUTHERLY RETURN FLOW IS EXPECTED TO PERSIST THROUGHOUT THE DAY WEDNESDAY AHEAD OF THE NEXT FRONTAL BOUNDARY EXPECTED TO EMERGE OFF THE TEXAS COAST EARLY FRIDAY. CARIBBEAN SEA... VERY STRONG SUBSIDENCE AND DRY AIR ALOFT IS NOTED ACROSS THE NW CARIBBEAN THAT CONTINUES TO SUPPORT A SURFACE RIDGE THAT EXTENDS FROM THE SE CONUS AND GULF OF MEXICO OVER MUCH OF THE WESTERN CARIBBEAN W OF 78W. OVERALL STABLE CONDITIONS PERSIST AS A RESULT...WITH BROKEN TO OVERCAST STRATOCUMULUS CLOUDS NOTED ON SHORTWAVE INFRARED SATELLITE IMAGERY THIS MORNING. OVER THE EASTERN AND CENTRAL CARIBBEAN...A STATIONARY FRONT IS ANALYZED FROM EASTERN PUERTO RICO NEAR 18N66W TO 15N73W THEN BECOMES A SHEAR LINE TO THE NORTHERN COLOMBIA COAST NEAR 11N75W. LOW-LEVEL CONVERGENCE IN VICINITY OF THIS BOUNDARY CONTINUES TO PROVIDE FOCUS FOR ISOLATED SHOWERS WITHIN 150 NM EITHER SIDE OF THE BOUNDARY. POSSIBLE ISOLATED SHOWERS LINGER EAST OVER THE REMAINDER OF THE EASTERN CARIBBEAN AND LESSER ANTILLES DUE TO LIGHT E-NE TRADE WIND FLOW. A SWIFT MOVING SURFACE TROUGH IS ANALYZED EAST OF TRINIDAD...TOBAGO...AND THE FAR SE CARIBBEAN ALONG 59W THAT IS PROVIDING SCATTERED SHOWERS FROM 08N-13N BETWEEN 55W-62W. ATLANTIC OCEAN... BROAD UPPER LEVEL TROUGHING IS EVIDENT ON WATER VAPOR IMAGERY OVER THE W ATLC WATERS THIS MORNING REMAINING MAINLY N OF 25N AND W OF 55W THAT SUPPORTS A COLD FRONT ENTERING THE DISCUSSION AREA NEAR 32N54W AND EXTENDING SW ALONG 25N60W TO NE PUERTO RICO NEAR 18N66W AND INTO THE CENTRAL CARIBBEAN SEA. SCATTERED SHOWERS AND ISOLATED TSTMS ARE WITHIN 240 NM EAST OF THE FRONT N OF 26N AND LIKELY ENHANCED DUE TO DIFFLUENCE BETWEEN THE TROUGH AND AN UPPER LEVEL RIDGE WITH AXIS ALONG 50W. ISOLATED SHOWERS ARE ALSO OCCURRING WITHIN FROM 18N-26N BETWEEN THE FRONT AND 52W. FARTHER EAST...AN UPPER LEVEL TROUGH CONTINUES TO IMPACT MUCH OF THE EASTERN ATLC E OF 35W DRIVING A COMPLEX AREA OF LOW PRESSURE NORTH OF THE DISCUSSION AREA THAT EXTENDS A COLD FRONT ALONG 31N24W 25N23W TO 17N28W. SCATTERED SHOWERS ARE ISOLATED TSTMS ARE FROM 24N-32N BETWEEN 19W-25W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN