000 AXPZ20 KNHC 180349 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC MON JAN 18 2010 UPDATED FOR LATEST WIND FORECASTS TO AFFECT GAP WIND AREA AND FOR GULF OF CALIFORNIA 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... AXIS WAS ANALYZED ALONG 4N77W TO 5N90W TO 5N100W 7N110W 6N121W 7N130W 6N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60 NM S OF THE AXIS BETWEEN 131W-133W. SCATTERED MODERATE CONVECTION IS WITHIN 30 NM OF AXIS BETWEEN 124W-127W. ...DISCUSSION... THE PREVAILING UPPER PATTERN WAS OBSERVED TO CONSIST OF STRONG DEEP WESTERLY FLOW PRIMARILY TO THE N OF 25N OVER THE THE NORTHERN PERIPHERY OF LARGE SCALE RIDGING CENTERED WELL W OF THE AREA TO THE SW OF THE HAWAIIAN ISLANDS. A SERIES OF SHORTWAVE TROUGHS EMBEDDED WITHIN THE WESTERLY FLOW WERE QUICKLY MOVING EASTWARD TOWARDS THE WESTERN U.S. AND NORTHERN BAJA CALIFORNIA REGIONS. THE EASTERN MOST TROUGH EXTENDS FROM THE SW U.S. SSW TO THE SOUTHERN GULF OF CALIFORNIA...THEN SW TO NEAR 11N121W WHERE IT IS BEST DESCRIBED AS A SHEAR AXIS SW TO W OF THE REGION AT 7N140W. THE BULK OF DEEP LEVEL MOISTURE ASSOCIATED WITH FAST WESTERLY FLOW WAS N OF THE AREA...BUT A BATCH HAS MADE IT INTO THE NE PORTION OF THE AREA TO THE N OF 23N AND WAS SPREADING E TOWARDS SOUTHERN CALIFORNIA AND THE BAJA PENINSULA. LATEST SATELLITE IMAGERY SHOWED THAT CONVECTION HAD INCREASED SOME ALONG THE ITCZ W OF ABOUT 124W. MID/UPPER LEVEL FORCING DUE TO THE SHORTWAVE TROUGHS WILL RESULT IN ABUNDANT PRECIPITATION JUST SKIRTING THE NE PORTION OF THE AREA AND AFFECTING THE WESTERN U.S OVER THE NEXT 48 HRS. WATER VAPOR IMAGERY SHOWED ABUNDANT MODERATE SUBSIDENCE WITH ASSOCIATED STABLE ENVIRONMENT CONDITIONS COVERING THE JUST ABOUT THE ENTIRE AREA SW OF A LINE FROM 32N140W TO 26N130W TO 23N119W. A SURFACE COLD FRONT RELATED TO A RATHER VIGOROUS SHORTWAVE N OF THE AREA NEAR 139W HAD APPROACHED 32N141W. SW TO W WINDS OF 20 TO 25 KT ARE OCCURRING AHEAD OF THE FRONT N OF 28N AND 130W. AS THE TIGHT PRES GRADIENT E OF THE COLD FRONT SHIFTS E IN TANDEM WITH THE FRONT AND LOW PRES REMAINS OVER SOUTHERN CALIFORNIA...EXPECT THESE WINDS TO BEGIN TO IMPACT THE FAR NORTHERN WATERS OF THE GULF OF CALIFORNIA N OF ABOUT 29N BEGINNING MON NIGHT WITH LITTLE CHANGE THROUGH TUE. ALTHOUGH UPPER LEVEL IMPULSES WILL MAINLY STAY TO THE N INTO MON...ENOUGH OF THAT ENERGY WILL MAKE IT JUST S OF 32N TO PROVIDE ENOUGH IMPETUS TO W TO NW FLOW BEHIND THE FRONT ON MON SUPPORTING WINDS OF 25 TO 30 KT WITH POSSIBLE HIGHER GUSTS TO NEAR GALE FORCE MON INTO TUE MORNING AS A SECOND AND STRONGER COLD FRONT FOLLOWS IN BEHIND THIS INITIAL COLD FRONT. HOWEVER...THE MAIN ISSUE WILL BE MARINE RELATED WITH SURGES OF VERY LARGE LONG PERIOD NW SWELLS MIGRATING INTO MUCH OF THE WESTERN AND CENTRAL PORTIONS OF THE AREA THROUGH TUE WITH SEAS POSSIBLY BUILDING TO AS HIGH AS 25 FT OVER THE FAR NORTHERN WATERS W OF THE SECOND COLD FRONT. YET A THIRD COLD FRONT IS FORECAST TO MOVE INTO THE FAR NW CORNER TUE EVENING PRECEDED BY SW WINDS TO 30 KT...BUT MAY EASILY REACH UP TO GALE FORCE. THE PRES DIFFERENCE BETWEEN WEAK HIGH PRES AND RELATIVELY LOWER PRES NEAR THE ITCZ SHOULD MAINTAIN AN AREA OF NE TO E 20 TO 25 KT TRADES FROM 7N TO 16N W OF 120W THROUGH TUE WITH SEAS UP 11 FT IN NW SWELL TO POSSIBLY 13 FT BY TUE AFTERNOON. TO THE S AND SE OF THE ABOVE DESCRIBED TROUGHS...DEEP TROPICAL MOSITURE REMAINS LIMITED EVEN ALONG THE ITCZ AS MODERATE SUBSIDENCE NOTED IN THE WAKE OF THE TROUGH HAS IMPINGED UPON THE ITCZ. A WEAK SURFACE TROUGH MOVING W ABOUT 10 KT EXTENDED FROM 6N108W TO 13N107W. ONLY ISOLATED SHOWERS WERE SEEN WITHIN 30 NM OF 8N104W. LARGE SCALE UPPER LEVEL RIDGING WAS OBSERVED OVER THE FAR EASTERN PORTION OF THE AREA E OF ABOUT 100W FURTHER SUPPORTING THE DRY AND STABLE ENVIRONMENTAL CONDITIONS SE OF THE TROUGH. ONLY SOME UPPER LEVEL MOSITURE WAS BEING SQUEEZED OUT OF THE ITCZ AND WITH PREVIOUS CONVECTION TIED TO THE SURFACE TROUGH. THIS MOSITURE WAS BEING ADVECTED NE TOWARDS SE MEXICO IN A 300 NM WIDE LINE BETWEEN RIDGE AND AND TROUGH. WIDELY SCATTERED SHOWERS AND ISOLATED WEAK TSTMS WERE ALONG THE ITCZ BETWEEN 81W-85W. GAP WINDS... A PARTIAL HIGH RESOLUTION ASCAT PASS FROM THIS MORNING SHOWED N WINDS OF 20 TO 30 KT OVER THE MIDDLE SECTION OF THE GULF OF TEHUANTEPEC. THESE WINDS ARE FORECAST TO DIMINISH TO 20 KT WITHIN 90 NM FROM THE COAST IN 24 HRS...AND TO LESS THAN 20 KT AT OR NEAR 48 HRS AS HIGH PRES OVER THE WESTERN GULF OF MEXICO WEAKENS WHILE MOVING E...AND RELAXES THE GRADIENT ALONG THE SE MEXICAN COAST. GULF OF PAPAGAYO... A WINDSAT PASS FROM SUN MORNING SHOWED NE 20 TO 25 KT WINDS OVER A SWATH DESCRIBED ROUGHLY AS WITHIN 75 NM EITHER SIDE OF A LINE FROM 11N86 TO 10N89W. LATEST MODEL GUIDANCE SUGGEST THIS AREA OF WINDS MAY EXPAND SOME ON MON WITH WINDS INCREASING UP TO 30 KT...THEN DIMINISH SOME ON TUE. SEAS SHOULD BUILD UP TO 10 FT ON MON BEFORE SUBSIDING LATE MON THROUGH TUE. GULF OF PANAMA... N WINDS OF 20 KT THROUGH THE GULF HAVE REACHED AS FAR S AS 6N BETWEEN 79W AND 81W. THESE WINDS ARE FORECAST TO CHANGE VERY LITTLE THROUGH TUE. LATEST MODEL GUIDANCE HINTED THAT THESE WINDS MAY LAST WELL INTO NEXT WEEK. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ AGUIRRE