000 AXPZ20 KNHC 262205 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SAT DEC 26 2009 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2145 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 5N78W TO 5N92W 4N105W 8N117W 5N140W. SCATTERED MODERATE CONVECTION IS WITHIN 180 NM S OF THE AXIS E OF 80W AND BETWEEN 82W AND 86W. ...DISCUSSION... AN UPPER LEVEL TROUGH EXTENDS NE TO SW FROM SW TEXAS AND NORTHERN MEXICO SW TO 19N112W TO 12N119W WHERE IT BECOMES ILL-DEFINED. TO THE OF THE TROUGH THE UPPER LEVEL FLOW IS ZONAL N OF 19N AND VERY MOIST CONSISTING OF BROKEN HIGH CLOUDS STREAMING EASTWARD MAINLY TO THE N OF 24N. A STRONG JET STREAM EXTENDS INTO THE AREA THROUGH 25N140W TO 28N127W AND TO ACROSS CENTRAL BAJA CALIFORNIA. MAXIMUM JET CORE WIND SPEEDS AS NOTED BY SATELLITE DERIVED WIND DATA ARE IN THE RANGE OF 70-1200 KT IN THE JET STREAM CORE FROM 25N TO 29N BETWEEN 122W AND 131W...AND ALSO WITHIN THE REAR ENTRANCE REGION N OF 23N W OF 136W. THE SOUTHERN EXTENSION OF A NARROW UPPER TROUGH THAT EXTENDS FROM THE CENTRAL ATLANTIC SW TO THROUGH THE EASTERN CARIBBEAN SEA AND SW TO ACROSS PANAMA TO NEAR 5N80W. THE COMBINATION OF LOW LEVEL CONVERGENCE AND UPPER DIFFLUENCE E OF THE UPPER TROUGH CONTINUES TO SUPPORT THE CONVECTION ALONG AND NEAR THE ITCZ E OF E OF 80W. ELSEWHERE ACROSS THE SE PORTION OF THE AREA...THE ATMOSPHERIC ENVIRONMENT REMAINS UNDER MODERATE SUBSIDENCE AS NOTED ON SATELLITE WATER VAPOR IMAGERY ALLOWING FOR MOSTLY STABLE CONDITIONS TO PREVAIL THERE OUTSIDE THE ITCZ CONVECTION MENTIONED ABOVE. MODERATE SUBSIDENCE AND ASSOCIATED STABLE ATMOSPHERIC CONDITIONS ARE ALSO EVIDENT W OF THE UPPER TROUGH S OF 24N. ONLY SCATTERED TO OCCASIONALLY BROKEN LOW CLOUDS MOVING W TO SW WITH POSSIBLE ISOLATED SHOWERS ARE NOTED FROM 10N TO 24N W OF 119W. THE UPPER FLOW PATTERN BETWEEN THE TROUGH AND THE WESTERN EXTENSION OF MID/UPPER LEVEL RIDGING THAT EXTENDS OVER S AMERICA ALONG 5N IS ADVECTING UPPER LEVEL MOISTURE ALONG THE COAST OF COLOMBIA NE ACROSS SRN PANAMA...BEFORE IT QUICKLY EVAPORATES IN THE DRY AIR UNDER THE MODERATE SUBSIDENCE. AN UPPER ANTICYCLONE IS CENTERED OVER EASTERN HONDURAS WITH A RIDGE EXTENDING SW TO A SHARP CREST NEAR 2N111W. A RIDGE ALSO EXTENDS NE TO A CREST OVER CENTRAL CUBA. CONVECTION PREVIOUSLY MENTIONED IS ENHANCED ALONG THE SOUTHERN PERIPHERY OF THE RIDGE NEAR 04N90W...BUT THE DEBRIS MOISTURE REMAINS IN THE SAME AREA. DEBRIS MOISTURE FROM FORMER ITCZ CONVECTION IS CONFINED IN A TROPICAL PLUME ALONG THE NW PERIPHERY OF THIS UPPER RIDGE...ROUGHLY WITHIN 180 NM OF LINE 10N120W TO 20N105W. THE MOISTURE FANS OUT OVER THE UPPER LEVELS OF THE GULF OF MEXICO AND FLORIDA. OTHERWISE DRY UPPER AIR IS INDICATED OVER THE DISCUSSION AREA S OF 18N E OF 105W. AT THE SURFACE...A 1018 MB HIGH PRES CENTERED NEAR 26N123W IS BEGINNING TO BLOCK THE EASTWARD PROGRESSION OF A COLD FRONT CURRENTLY EXTENDING FROM 32N128W TO 21N140W. EASTERLY TRADES OF 20 KT CONTINUE ALONG THE SOUTHERN PERIPHERY OF THE RIDGE. SUBSIDING NW SWELLS ALREADY PROPAGATING OVER MOST OF THE AREA W OF 112W ARE ALREADY BEING REINFORCED BY ANOTHER TRAIN OF LARGE NW SWELLS IN THE WAKE OF THIS COLD FRONT AND A SECONDARY SURGE EXPECTED TO MOVE INTO THE NW PORTION ON SUN. A LOW PRES IS EXPECTED TO MOVE SE INTO THE N CENTRAL WATERS LATE SUN AND DEEPEN TO A MINIMAL GALE CENTER EARLY MON. GULF OF TEHUANTEPEC...NORTHERLY WINDS ARE EXPECTED TO INCREASE TO 20 TO 25 KT IN THE GULF OF TEHUANTEPEC SUN AFTERNOON... AND CONTINUE TO GRADUALLY INCREASE INTO EARLY NEXT WEAK. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ AGUIRRE