000 AXNT20 KNHC 202351 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST MON DEC 20 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2345 UTC. ...SPECIAL FEATURE... A 1008 MB LOW IS LOCATED ABOUT 275 MILES EAST-SOUTHEAST OF BARBADOS NEAR 11N56W. THIS LOW IS EMBEDDED IN A SURFACE TROUGH ANALYZED FROM 13N53W TO 7N59W. THIS SYSTEM IS PRODUCING SCATTERED SHOWERS OVER THE SOUTHWESTERN TROPICAL ATLANTIC FROM 7N TO 15N BETWEEN 48W AND 57W. ENVIRONMENTAL CONDITIONS ARE NOT CONDUCIVE FOR DEVELOPMENT AT THIS TIME. HOWEVER...CONDITIONS COULD BECOME A LITTLE MORE FAVORABLE ON TUESDAY...RESULTING IN A BRIEF WINDOW OF OPPORTUNITY FOR SOME DEVELOPMENT AS THE LOW PASSES NEAR THE SOUTHERN AND CENTRAL LESSER ANTILLES. THERE IS A MEDIUM CHANCE OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES TOWARD THE WEST-NORTHWEST AT ABOUT 10 KT. REGARDLESS OF DEVELOPMENT...THIS SYSTEM WILL BRING LOCALLY HEAVY RAINFALL AND GUSTY WINDS TO MUCH OF THE LESSER ANTILLES DURING THE NEXT DAY OR SO. ...ITCZ... THE ITCZ AXIS IS ANALYZED FROM WEST AFRICA OVER THE COAST OF GUINEA NEAR 5N9W CONTINUING WEST ALONG 3N16W 4N26W 2N35W 1N43W TO BRAZIL NEAR EQ50. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 2N TO 12N BETWEEN 25W AND 32W. SIMILAR CONVECTION IS WITHIN 110 NM ON EITHER SIDE OF THE ITCZ BETWEEN 15W AND 21W. ...DISCUSSION... GULF OF MEXICO... A 1021 MB HIGH IS OVER THE FLORIDA PANHANDLE PROVIDING A RELAX PRESSURE GRADIENT WITH LIGHT SURFACE ANTICYCLONIC FLOW ACROSS THE GULF. DRY AND STABLE AIR IS NOTED ON WATER VAPOR IMAGERY AS AN UPPER LEVEL RIDGE OF HIGH PRESSURE SETTLES OVER THE REGION. IN THE MEANTIME...A COLD AIRMASS IS IN PLACE ACROSS THE GULF WITH LOW LEVEL STRATOCUMULUS CLOUDS CONCENTRATED OVER THE CENTRAL BASIN. A WEAK SURFACE TROUGH IS WHITING 50 NM ALONG THE COAST OF MEXICO FROM MATAMOROS NEAR 26N96W TO SE OF VERACRUZ NEAR 19N95W GENERATING SCATTERED SHOWERS WITHIN 20 NM OF THE AXIS. FAIR WEATHER CONDITIONS ARE EXPECTED TO CONTINUE ELSEWHERE ACROSS THE REGION OVER THE NEXT 24 HOURS. CARIBBEAN SEA... MOST OF THE CARIBBEAN IS DOMINATED BY AN UPPER RIDGE PROVIDING FAIR WEATHER TO THE CENTRAL AND WESTERN BASIN W OF 72W. HOWEVER A DEEP LAYERED TROUGH OVER THE WESTERN ATLC SUPPORTS A COLD FRONT THAT ENTERS THE NE CARIBBEAN ACROSS THE MONA PASSAGE TO NEAR 17N72W BECOMING DISSIPATING TO NEAR 17N86W. A SURFACE TROUGH IS ANALYZED FROM 17N69W CONTINUING SOUTH TO THE COAST OF VENEZUELA NEAR THE PARAGUANA PENINSULA. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE WITHIN 70 NM ON EITHER SIDE OF THE COLD FRONT AND SURFACE TROUGH AXIS. THE CONVECTION ALONG THE DISSIPATING FRONT IS VERY LIMITED DUE TO THE DRY UPPER LEVEL RIDGE. SCATTERED SHOWERS ARE WITHIN 30 NM OFF THE COAST OF HONDURAS. SIMILAR ACTIVITY IS OCCURRING OVER PANAMA AND COSTA RICA BETWEEN 81W AND 84W...SUPPORTED BY THE SURFACE NORTHERLY FLOW BANKING UP LOW LEVEL MOISTURE IN THIS AREA. 10-15 KT SE WINDS ARE OVER THE EASTERN BASIN E OF 67W WITH ISOLATED SHOWERS EMBEDDED IN THE FLOW. EXPECT THE SURFACE TROUGH AND COLD FRONT TO CONTINUE TO MOVE EASTWARD SUPPORTING SHOWER ACTIVITY OVER THE NE CARIBBEAN OVER THE NEXT 24 HOURS. ATLANTIC OCEAN... A DEEP LAYERED TROUGH IS OVER THE NW ATLC SUPPORTING A COLD FRONT THAT EXTENDS FROM 32N56W ALONG 25N59W INTO THE NE CARIBBEAN ACROSS THE US/UK VIRGIN ISLANDS. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE OCCURRING FROM 21N TO BEYOND 32N BETWEEN 52W AND THE FRONT. THIS AREA OF CONVECTION/TROUGHINESS IS UNDER STRONG DIFFLUENCE ALOFT BETWEEN THE UPPER TROUGH ACROSS THE WESTERN ATLC AND AN UPPER LEVEL RIDGE ACROSS THE CENTRAL ATLC. THIS UPPER LEVEL RIDGE IS SUPPORTING SURFACE RIDGING ACROSS THE REMAINDER OF THE CENTRAL ATLC ANCHORED BY A 1020 MB HIGH NEAR 25N41W PROVIDING MOSTLY FAIR WEATHER CONDITIONS BETWEEN 25W AND 52W. A WEAK SURFACE TROUGH ENTERS THE FAR EASTERN ATLC NEAR 32N11W CONTINUING SW ALONG 24N18W TO 20N25W. ISOLATED SHOWERS ARE WITHIN 20 NM ON EITHER SIDE OF THE FRONT. THE SYSTEM IS SUPPORTED BY AN UPPER LEVEL LOW/TROUGH CENTERED AROUND 36N13W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA