000 AXNT20 KNHC 171750 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST FRI DEC 17 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 05N07W 06N25W TO THE EQUATOR NEAR 50W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 01N-07N BETWEEN 34W AND 44W. A SHEAR LINE IS ANALYZED N OF THE AXIS ALONG 05N37W 08N43W 08N49W. THE EASTERN PORTION OF THIS SPEED CONVERGENCE AXIS IS ENHANCING CONVECTION ALONG THE ITCZ. ...DISCUSSION... GULF OF MEXICO... AS OF 1500 UTC...A COLD FRONT EXTENDS FROM A LOW PRESSURE SYSTEM OVER SOUTH CAROLINA CROSSING THROUGH THE FLORIDA PANHANDLE NEAR 31N85W TO S OF MISSISSIPPI NEAR 29N89W WHERE IT BECOMES STATIONARY ALONG 28N94W 24N98W CONTINUING NW INTO NORTHERN MEXICO. SCATTERED SHOWERS ARE WITHING 45 NM EITHER SIDE OF THE COLD FRONT. POSSIBLE SHOWERS ARE ALONG THE STATIONARY BOUNDARY. THIS SYSTEM IS SUPPORTED BY AN UPPER LEVEL TROUGH MOVING TOWARDS THE AREA FROM THE SOUTHERN ROCKIES AND SOUTHERN PLAINS. THE REMAINDER OF THE AREA IS UNDER DRY AIR AND SUBSIDENCE AROUND A BROAD UPPER RIDGE SUPPORTING MOSTLY FAIR WEATHER ACROSS THE BASIN. A WEAK SURFACE TROUGH PARALLELS THE NE MEXICAN COASTLINE ALONG 24N98W TO A WEAK 1010 MB LOW NEAR 20N96W WITH NO ASSOCIATED SHOWERS. ISOLATED SHOWERS ARE ALSO NOTED IN THE CENTRAL GULF FROM 24N-27N BETWEEN 86W AND 91W. EXPECT THE FRONT TO REMAIN RELATIVELY STATIONARY OVER THE NEXT SEVERAL HOURS UNTIL BEGINNING TO MOVE SE EARLY SATURDAY. CARIBBEAN SEA... VERY STRONG SUBSIDENCE AND DRY AIR ALOFT IS NOTED ACROSS THE NW CARIBBEAN AROUND A BROAD UPPER RIDGE THAT CONTINUES TO SUPPORT A SURFACE RIDGE EXTENDING FROM THE W ATLC AND CUBA TO THE GULF OF HONDURAS N OF 17N AND W OF 80W ALLOWING MOSTLY FAIR WEATHER. A SURFACE TROUGH IS ANALYZED FROM THE COAST OF COLOMBIA NEAR 09N77W ALONG 13N78W TO S OF JAMAICA NEAR 17N77W. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE ASSOCIATED WITH THE TROUGH N OF 15N BETWEEN 73W AND 80W. A WEAK SHEAR LINE IS ANALYZED FROM THE MARTINIQUE PASSAGE NEAR 15N61W ALONG 14N67W TO 15N74W ENHANCED BY STRONG TRADE WINDS ACROSS THE BASIN SUPPORTED BY THE STRONG PRESSURE GRADIENT BETWEEN THE SURFACE RIDGE OVER THE W ATLANTIC AND THE GENERAL LOW PRESSURE OVER SOUTH AMERICA. THE WEAK SHEAR LINE DELINEATES THE SLIGHTLY WEAKER E-NE WINDS IN THE SE CARIBBEAN FROM THE STRONGER E-NE WINDS IN THE NE CARIBBEAN. THESE WINDS ARE ENHANCING CONVECTION N OF 14N BETWEEN 68W AND 73W. IT ALSO IS SUPPORTING THE CONVECTION ASSOCIATED WITH THE SURFACE TROUGH. EXPECT LITTLE CHANGE OVER THE NEXT 24 HOURS. ATLANTIC OCEAN... MOSTLY DRY AIR AND STRONG SUBSIDENCE RESIDES WITHIN WESTERLY ZONAL UPPER LEVEL FLOW ACROSS THE W ATLC W OF 50W THAT CONTINUES TO SUPPORT A BROAD SURFACE RIDGE ANCHORED BY A 1021 MB HIGH CENTERED NEAR 26N67W. MOSTLY FAIR CONDITIONS ARE FOUND WITHIN THE INFLUENCE OF THIS FEATURE THIS MORNING. OVER THE CENTRAL ATLC...AN UPPER LEVEL TROUGH NORTH OF THE DISCUSSION AREA IN THE VICINITY OF 37N47W SUPPORTS A COLD FRONT ENTERING THE REGION NEAR 32N42W THEN EXTENDING SW TO 24N47W AND CONTINUES AS A SURFACE TROUGH TO 18N49W. ISOLATED SHOWERS REMAIN WITHIN 75 NM EAST OF THE COLD FRONT S OF 31N. FARTHER EAST...AN UPPER LEVEL LOW CENTERED NEAR 35N18W CONTINUES TO IMPACT MUCH OF THE EASTERN ATLC E OF 35W SUPPORTING A 988 MB OCCLUDED LOW CENTERED WEST OF THE MADEIRA ISLANDS NEAR 33N19W. A COLD FRONT EXTENDS INTO THE AREA ALONG 32N13W ACROSS THE EASTERNMOST CANARY ISLANDS NEAR 28N14W THEN BECOMING DISSIPATING ALONG 26N16W TO 19N26W. ISOLATED SHOWERS ARE MAINLY OCCURRING WITHIN 75 NM AHEAD OF THE FRONT. WEAK SURFACE RIDGING AROUND A 1015 MB HIGH NEAR 24N41W IS BETWEEN THE TWO FRONTAL SYSTEMS PROVIDING FAIR WEATHER BETWEEN 27W AND 42W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MONTALVO/WALTON