000 AXPZ20 KNHC 060954 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SUN DEC 06 2009 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0800 UTC. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE CAN BE FOUND ALONG A LINE FROM 05N77W TO 08N85W TO 11N114W TO 08N123W TO 09N140W. SCATTERED MODERATE CONVECTION LIES WITHIN 75 NM N AND 120 NM S OF AXIS BETWEEN 97W AND 107W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION LIES WITHIN 180 NM S OF AXIS BETWEEN 117W AND 128W. ...DISCUSSION... THE AMPLIFIED UPPER PATTERN THAT HAD BEEN IN PLACE THE LAST FEW DAYS OVER THE FORECAST AREA N OF 20N IS BEGINNING TO BREAK DOWN. CURRENTLY...A TROUGH LIES OVER MEXICO ALONG 105W N OF 22N AND THEN EXTENDS SW TO A WEAK UPPER LOW NEAR 17N125W. AN UPPER RIDGE LIES N OF THIS LOW ALONG 125W AND A SECOND UPPER TROUGH IS BEGINNING TO ENCROACH UPON NW WATERS. THIS SECOND TROUGH IS TURNING NEGATIVE TILT ON THE LEADING EDGE OF A BROAD TROUGH OVER THE CENTRAL N PACIFIC. THE SHORTWAVE ENERGY ASSOCIATED WITH THIS TROUGH WILL PASS THROUGH THE MEAN RIDGE AXIS TODAY AND INTO THE MEAN TROUGH OVER NORTH AMERICA. THE PASSAGE OF THIS SHORTWAVE ENERGY THROUGH THE UPPER RIDGE WILL HELP WEAKEN THE DEEP LAYER RIDGING AND KEEP THE SURFACE HIGH WEAK OVER NORTH WATERS...REDUCING THE EASTERLY TRADE WINDS TO 20 KT OR LESS THE NEXT FEW DAYS. THE COLD FRONT ASSOCIATED WITH THE UPPER TROUGH OVER NW WATERS CAN BE FOUND FROM 30N137W TO 27N140W. THE 0652 UTC ASCAT PASS SHOWS SOUTHERLY WINDS OF 20 KT JUST AHEAD OF THE COLD FRONT. THESE WINDS WILL QUICKLY SHIFT N OF THE AREA THIS MORNING...BUT NW SWELL IN THE 8 TO 12 FT RANGE WILL CONTINUE TO MOVE SE INTO THE AREA AHEAD OF THE FRONT. MEANWHILE...A NEW FRONT WILL APPROACH NW WATERS BY THIS TIME TUE AND BRING A NEW BATCH OF NW SWELL WITH SEAS RISING TO 18 FT. S OF 20N...TWO LOW PRES SYSTEMS ARE EMBEDDED WITHIN THE ITCZ. THE 1012 MB SURFACE LOW NEAR 09N132W HAS SCATTERED MODERATE CONVECTION FOUND WITHIN 150 NM W SEMICIRCLE OF THE LOW. THIS LOW IS MOVING INTO A REGION OF STRONGER UPPER WINDS FROM THE SW THAT WILL LIMIT ANY FURTHER DEVELOPMENT OF THE LOW. A SECOND SURFACE LOW LIES NEAR 10N111W. THIS 1010 MB LOW HAS SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WITHIN 150 NM IN ITS W SEMICIRCLE. THIS LOW LIES UNDER A RIDGE AXIS EXTENDING W FROM AN ANTICYCLONE CENTERED NEAR 13N92W TO 05N115W. THIS SYSTEM IS MORE LIKELY TO SURVIVE THE NEXT FEW DAYS AS IT REMAINS IN A REGION OF UPPER LEVEL DIFFLUENCE ASSOCIATED WITH THIS STATIONARY UPPER RIDGE AXIS. BETWEEN THESE TWO LOWS LIES A CONVECTIVELY ACTIVE REGION ALONG THE ITCZ BETWEEN 117W AND 128W ASSOCIATED WITH THE REAR RIGHT QUADRANT OF THE AFOREMENTIONED SOUTHWESTERLY UPPER JET. EXPECT SHOWERS AND THUNDERSTORMS TO CONTINUE IN THIS REGION THE NEXT DAY OR TWO AS THE UPPER JET REMAINS RELATIVELY STATIONARY HERE. GULF OF CALIFORNIA...SW WINDS IN THE 20 TO 25 KT RANGE CAN BE FOUND IN THE NORTHERN GULF OF CALIFORNIA ADVANCE OF A NEW COLD FRONT DIVING THROUGH THE GREAT BASIN. THE 0510 UTC ASCAT PASS CONFIRMS THESE CONDITIONS WHICH ARE EXPECTED TO CONTINUE THE NEXT FEW DAYS AS THE TROUGHING IN THE GREAT BASIN IS RELOADED WITH NORTHERN STREAM ENERGY...ALLOWING THE PRES GRADIENT BETWEEN THE LOWER PRES TO THE NORTH AND HIGHER PRES TO THE S OVER N CENTRAL WATERS AS WELL AS OVER THE GULF OF MEXICO TO REMAIN STRONG. GAP WINDS... GULF OF TEHUANTEPEC...THE 0324 UTC ASCAT PASS SHOWED WINDS TO GALE FORCE CONTINUING IN THE REGION. THESE GALE FORCE NORTHERLY WINDS ARE EXPECTED TO DIMINISH LATER THIS MORNING AS THE HIGH PRES OVER THE GULF OF MEXICO SHIFTS NORTHEASTWARD AWAY FROM THE AREA. GULF OF PAPAGAYO...EXPECT ELY WINDS TO PULSE UP AND DOWN THROUGH THE GULF OF PAPAGAYO AND THEN DOWNSTREAM TO NEAR 89W DURING THE NEXT FEW DAYS. THESE WINDS WILL BE STRONGEST...20 TO 25 KT...IN THE MORNING HOURS WITH THE AID OF DRAINAGE FLOW. $$ SCHAUER