000 AXPZ20 KNHC 081532 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC TUE DEC 08 2009 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1500 UTC. ...ITCZ... AXIS ANALYZED ALONG 04N78W TO 04N93W TO 08N115W TO 09N126W TO 06N140W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION WAS NOTED WITHIN 210 NM N OF THE AXIS BETWEEN 118W AND 121W...AND BETWEEN 125W AND 130W...AND WITHIN 150 NM N OF THE AXIS W OF 135W. SCATTERED MODERATE CONVECTION WAS NOTED WITHIN 60 NM S OF THE AXIS BETWEEN 103W AND 105W...AND WITHIN 150 NM S OF THE AXIS BETWEEN 121W AND 124W. ...DISCUSSION... A BROAD AND EXPANSIVE UPPER LEVEL RIDGE REMAINS POSITIONED ACROSS A LARGE PORTION OF THE DISCUSSION AREA EXTENDING FROM THE W CARIBBEAN ACROSS CENTRAL AMERICA AND SOUTHERN MEXICO INTO THE E PACIFIC BASIN TO NEAR 19N128W...ANCHORED BY AN UPPER LEVEL ANTICYCLONIC CENTERED NEAR 16N106W. DRY AND STABLE AIR EXISTS S OF 18N E OF 110W WITH STRONG SUBSIDENCE IN PLACE AS INDICATED ON WATER VAPOR SATELLITE IMAGERY. W OF THE RIDGE...MIDDLE TO UPPER LEVEL MOISTURE IS ADVECTING FROM THE ITCZ TO THE N AND NE AROUND THE NW PORTION OF THE ANTICYCLONE...WITH A BROAD AREA OF MID AND HIGH LAYERED CLOUDS IN PLACE. STRONG SOUTHWESTERLY WINDS ALOFT N OF 15N BETWEEN 110W AND 135W ARE LIMITING CONVECTIVE DEVELOPMENT AT THE SURFACE. N OF THIS RIDGE...TWO FLATTENING LONGWAVE TROUGHS ARE IN PLACE...ONE EXTENDING FROM THE CENTRAL GULF OF MEXICO TO THE SOUTHERN BAJA PENINSULA...AND ANOTHER TO THE NORTH EXTENDING FROM THE TEXAS PANHANDLE ALONG THE U.S./MEXICO BORDER TO NEAR 32N121W. A WEAKENING COLD FRONT ASSOCIATED WITH THE NORTHERLY TROUGH IS PUSHING ACROSS THE BAJA FROM NEAR 30N112W TO 23N120W. SW WINDS IN THE 20 TO 30 KT RANGE ARE OCCURRING AHEAD OF THIS FRONT IN THE N GULF OF CALIFORNIA N OF 28N...AND ALSO W OF THE BAJA N OF 27N...AS CAPTURED BY AN EARLIER 0430 UTC ASCAT PASS. NORTHERLY WINDS BEHIND THE FRONT IN THE PACIFIC REMAIN IN THE 20 TO 25 KT RANGE...HOWEVER DO NOT EXPECT THESE STRONGER NORTHERLY WINDS TO TRANSLATE TO THE E INTO THE N GULF OF CALIFORNIA AS THE FRONT PROGRESSES THERE DUE TO THE BLOCKING OF THE HIGHER TERRAIN IN INTERIOR BAJA. MEANWHILE A SURFACE RIDGE EXTENDING SOUTH OF THIS FRONT WILL PREVENT A MORE S-SE PROGRESSION. THE FRONT WILL CONTINUE TO WEAKEN AND EVENTUALLY DISSIPATE BY THIS AFTERNOON AS IT MOVES TO THE E OVER THE MOUNTAINOUS TERRAIN OF NORTHERN MEXICO. ALSO...NW SWELL OF 8 TO 13 FT IS PROPAGATING INTO THE FAR N WATERS BEHIND THIS FRONT. A STRONGER AND DEEPER UPPER LEVEL TROUGH EXTENDS FROM 42N141W TO 19N147W...WITH A DEVELOPING UPPER LEVEL LOW POSITIONED OUT AHEAD OF THE TROUGH NEAR 18N137W. AN ASSOCIATED SURFACE COLD FRONT IS JUST E OF THE TROUGH AXIS...EXTENDING FROM 32N138W TO 25N143W TO 20N150W. THIS FRONT IS MOVING INTO THE NW PORTION OF THE DISCUSSION AREA... WITH 20 TO 25 KT SW WINDS OCCURRING AHEAD OF IT AS INDICATED BY AN EARLIER 0610 UTC ASCAT PASS...WITH NW WINDS TO 20 KT BEHIND THE FRONT. THE FRONT WILL TRACK ACROSS THE FAR NORTHERN WATERS REACHING TO NEAR 30N134W TO 26N136W TO 22N140W BY EARLY WED WHERE IT WILL BEGIN TO DISSIPATE AS IT ENCOUNTERS SURFACE HIGH PRES W OF THE BAJA PENINSULA. A LARGE AREA OF LONG PERIOD NW SWELL WILL ARRIVE BEHIND THE FRONT...AND AN EARLIER 0915 UTC JASON ALTIMETER PASS CAPTURED SEA HEIGHTS OF AROUND 22 FT W OF OUR AREA NEAR 30N143W. MAXIMUM SEAS WILL REACH 20 FT JUST SE OF 30N140W BY THIS AFTERNOON. THIS SWELL WILL THEN PROPAGATE THROUGH THE MAJORITY OF THE DISCUSSION AREA THROUGH THE END OF THE WEEK...REACHING TO THE EQUATOR AND BEYOND. S OF 20N...A 1010 MB LOW PRESSURE SYSTEM IS EMBEDDED WITHIN THE ITCZ...POSITIONED NEAR 11N116W...ALONG A SURFACE TROUGH EXTENDING FROM 15N114W TO 07N117W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS OCCURRING WITHIN 150 NM OF THE LOW IN THE NW QUADRANT. THIS LOW IS MOVING INTO A REGION OF STRONG SW UPPER WINDS WHICH WILL INHIBIT ANY FURTHER DEVELOPMENT OF THE LOW. TO THE E...A WEAK SURFACE TROUGH EXTENDS FROM 03N95W TO 06N95W...ALTHOUGH INFRARED SATELLITE IMAGERY IS NOT INDICATING ANY CONVECTION WITH THIS FEATURE AS IT IS MOVING THROUGH A VERY HOSTILE ENVIRONMENT... AND AS SUCH...IS EXPECTED TO DISSIPATE WITHIN THE NEXT 24 HOURS. GAP WINDS... GULF OF PAPAGAYO...EASTERLY TRADES IN THE W CARIBBEAN WILL CONTINUE TO PASS OVER NICARAGUA AND COSTA RICA LEADING TO NE-E WINDS TO 20 KT IN THE GULF OF PAPAGAYO AND DOWNSTREAM TO 89W THROUGH LATE TONIGHT. EVIDENCE OF THESE WINDS WERE CAPTURED BY A SHIP WITH CALL SIGN 3FMH7 AT 1200 UTC. THE WINDS WILL BE STRONGEST DURING THE MORNING HOURS WITH THE AID OF DRAINAGE FLOW OFF THE LANDMASS. $$ LEWITSKY