000 AXPZ20 KNHC 270344 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC SUN DEC 27 2009 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0315 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 4N78W TO 5N90W 4N100W 8N119W 6N140W. SCATTERED MODERATE TO STRONG CONVECTION IS N OF THE AXIS WITHIN 45 NM OF 7N78W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM S OF THE AXIS BETWEEN 84W-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 70-120 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 ATMOSPHERE 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 1019 MB HIGH PRES IS CENTERED NEAR 26N121W WITH A RIDGE SE TO NEAR 21N114W. TO ITS NW...A DISSIPATING FRONTAL TROUGH EXTENDS FROM 30N126W TO 22N138W. NE 20 KT WINDS ARE OBSERVED WITHIN AN AREA FROM 9N TO 19N W OF 128W AND FROM 12N TO 19N BETWEEN 122W AND 128W WITH SEAS OF 10 TO 15 FT IN NW SWELL. THESE WINDS ARE FOUND OVER THE SW PERIPHERY OF THE RIDGE. SUBSIDING LARGE NW SWELLS MIGRATING SE AND S OVER JUST ABOUT THE ENTIRE AREA W OF A LINE FROM 30N117W TO 13N117W TO 00N120W ARE 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 TONIGHT. A WEAK LOW PRES CENTER OF 1018 MB IS FORECAST TO BE NEAR 31N129W BY SUN EVENING...THEN QUICKLY DROP SE TO NEAR 29N126W AS 1014 MB BY MON MORNING...AND TO NEAR 28N119W AS 1016 MB BY MON EVENING WITH A FRONTAL TROUGH EXTENDING FROM ITS CENTER SW TO NEAR 21N124W. NW-N 20-25 KT WINDS CAN BE EXPECTED WITHIN 270 NM IN THE W AND NW QUADRANTS OF THE LOW BY MON MORNING WITH SOME POSSIBLE GUSTS TO 30 KT. SEAS UP TO 16 FT IN NW SWELL ARE EXPECTED WITHIN THESE QUADRANTS OF THE LOW. GAP WINDS... GULF OF TEHUANTEPEC...N WINDS ARE EXPECTED TO INCREASE TO 20 TO 25 KT IN THE GULF OF TEHUANTEPEC SUN NIGHT...AND INCREASE TO 20 TO 30 KT BY MON EVENING WITH POSSIBLE GUSTS TO GALE FORCE SOON THEREAFTER. A HIGH RESOLUTION ASCAT PASS FROM SAT MORNING INDICATED NE WINDS OF 20 KT THROUGH THE GULF OF PAPAGAYO. ALTHOUGH IT APPEARS THAT THE GFS MODEL GUIDANCE WAS UNDER DONE IN CAPTURING THESE WINDS...THE NAM 10M WINDS HINTS AT THEM RETURNING SUN MORNING WHILE THE GFS DOES NOT START THEN AGAIN UNTIL SUN NIGHT. SO WILL FOR THIS FORECAST WILL INTRODUCE NE TO 20 KT PAPAGAYO WINDS TO BEGIN SUN MORNING...WITH LITTLE CHANGE THROUGH MON EVENING. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ AGUIRRE