000 AXNT20 KNHC 290552 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST TUE DEC 28 2009 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 THE 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0530 UTC. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED FROM THE CENTRAL COAST OF LIBERIA AND CONTINUES ALONG 5N20W 3.5N30W 2N40W TO NORTHEASTERN BRAZIL NEAR THE CITY OF MACAPA. WEAK TO MODERATE CONVECTION IS DEVELOPING ALONG THE ITCZ BETWEEN 25W AND 40W. ...DISCUSSION... THE GULF OF MEXICO... AN UPPER LEVEL RIDGE OF HIGH PRESSURE IS PASSING OVER THE REGION BRINGING LIGHT SOUTHWEST FLOW ALOFT. STRONG SURFACE HIGH PRESSURE OVER EAST TEXAS HAS BROUGHT DRY AND COOLER AIR TO THE BASIN. SHIP AND BUOY OBSERVATIONS ARE SHOWING NNE WINDS 15 TO 25 KT ACROSS THE BASIN. A TIGHT GRADIENT OF TEMPERATURE BETWEEN LAND AND SEA CONTINUES TO CREATE A TROUGH ALONG THE MEXICO COAST FROM 25N97W NEAR MATAMOROS TO 18N93W NEAR CIUDAD DEL CARMEN. INFRA-RED IMAGERY SHOWS MULTI LAYER CLOUDS OVER THIS REGION...WITH POSSIBLE LIGHT SHORT LIVE SHOWERS DEVELOPING ON EITHER SIDE OF THE TROUGH. COMPUTER MODELS SUGGEST THIS TROUGH SHIFTING NORTH TO THE TEXAS COAST AND DEVELOPING INTO A SURFACE LOW PRESSURE SYSTEM OVER THE NEXT 24 TO 48 HOURS. ELSEWHERE ACROSS THE REGION...WEATHER CONDITIONS WILL REMAIN FAIR OVER THE NEXT 24 HOURS. THE CARIBBEAN SEA... UPPER LEVEL RIDGE OF HIGH PRESSURE COVERS THE ENTIRE CARIBBEAN SEA...SUPPRESSING DEEP CONVECTION IN THIS REGION. WATER VAPOR IMAGERY SHOWS LITTLE MOISTURE MOVING OVER THE WESTERN BASIN...ESPECIALLY OVER THE SOUTHWESTERN TIP OF THE BASIN NEAR THE BORDER BETWEEN PANAMA AND COSTA RICA. A FEW LIGHT SHOWERS MAY DEVELOP IN THIS AREA. SHIP AND BUOY OBSERVATIONS SHOW EASTERLY WINDS 10 TO 15 KT ACROSS THE BASIN...EXCEPT FOR THE NW CORNER OF THE BASIN WHERE OBSERVATIONS SHOW NORTH-NORTHEAST WINDS 10 TO 15 KT. HIGH PRESSURE WEATHER WILL CONTINUE TO DOMINATE OVER THE ENTIRE BASIN. THE ATLANTIC OCEAN... A COLD FRONT IS ANALYZED OVER THE WESTERN ATLANTIC PASSING THROUGH 32N64W TO 27N67W TO THE SOUTHERN BAHAMAS NEAR 22N72W. WEAK CONVECTION IS SEEN 50 NM EAST OF THE FRONT COVERING AN AREA FROM 25N TO 32N BETWEEN 61W AND 67W. AS THIS FRONT MOVES EASTWARD...EXPECT GALE FORCE WINDS TO DEVELOP OVER THE NEXT 24 HOURS AHEAD OF THE FRONT NORTH OF 27N BETWEEN 63W AND 59W. A 1026 MB HIGH IS FOUND NEAR 32N47W. THIS HIGH PRESSURE IS BRINGING LITTLE ACTIVITY TO THE CENTRAL ATLANTIC REGION AND WILL MOVE EAST TO NEAR 32N37W AS UPPER LEVEL TROUGH PUSHES INTO THE CENTRAL ATLANTIC REGION IN THE NEXT 24 HOURS. WATER VAPOR IMAGERY SHOWS AN TROUGH OVER THE EASTERN ATLANTIC PASSING THROUGH THE 25W LINE BETWEEN 22N AND 32N. THIS TROUGH SUPPORTS THE COLD FRONT THAT PASSES THROUGH 31N17W TO 25N22W 20N31W AND 16N40W. A STATIONARY FRONT CONTINUES FROM 16N40W TO 17N55W. ALTHOUGH THIS FRONTAL SYSTEM IS STARTING TO DISSIPATE...SHOWERS ARE POSSIBLE WITHIN 60 NM TO 90 NM ON EITHER SIDE OF THE FRONTAL BOUNDARY. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE. $$ GARCIA