000 AXPZ20 KNHC 060325 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC SAT DEC 06 2008 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... THE INTERTROPICAL CONVERGENCE ZONE IS CENTERED ALONG 6N78W 6N89W 7N100W 7N115W 10N125W 7N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60 NM N OF THE AXIS BETWEEN 103W-105W... AND WITHIN 120 NM S OF THE AXIS BETWEEN 124W-129W. ...DISCUSSION... A LARGE UPPER TROUGH CONTINUES TO EXTEND FROM THE SW UNITED STATES WSW FROM CALIFORNIA TO 28N129W TO SW OF THE AREA AT 19N140W. WATER VAPOR IMAGERY SHOWS A COUPLE OF UPPER LEVEL LOWS EMBEDDED WITHIN THE TROUGH. THE FIRST BEING RATHER WEAK AND ELONGATED IS LOCATED NEAR 32N121W AND THE SECOND...ABOUT 6 DEG IN DIAMETER...IS MOVING W 20 KT NEAR 28N135W. THE TROUGH CONTINUES SW FROM THIS LOW TO SW OF THE AREA AT 15N140W. THE TROUGH WILL QUICKLY SHIFT E TO THE EASTERN UNITED STATES ON SAT AS A HIGHLY AMPLIFIED RIDGE TO THE NW OF THE TROUGH SPILLS EASTWARD. THE FIRST OF THE UPPER LOWS WILL MEANDER OFF THE SOUTHERN CALIFORNIA COAST THROUGH SAT...THEN MOVE SE ACROSS FAR SOUTHERN CALIFORNIA AND NORTHERN BAJA CALIFORNIA LATE SUN NIGHT THROUGH MON BEFORE BECOMING ABSORBED INTO A MID/UPPER TROUGH THAT IS FORECAST TO CARVE SWD OVER THE WESTERN INTER-MOUNTAIN REGION OF THE UNITED STATES. THE SECOND UPPER LEVEL LOW WILL DROP SW TO JUST W OF THE AREA DISCUSSION AREA NEAR 21N141W BY SUN AFTERNOON...THEN MOVE A LITTLE WESTWARD BEFORE MOVING BACK EAST AND ENTERING THE AREA ONCE AGAIN LATE MON NIGHT NEAR 20N140W. THE LOW WILL REMAIN CUT-OFF OVER THE FAR WESTERN SECTION OF THE AREA WELL INTO NEXT WEEK. A LOW LEVEL STREAMLINE ANALYSIS SHOWS WHAT APPEARS TO BE THE BEGINNINGS OF A WEAK SURFACE TROUGH...A REFLECTION OF THE UPPER LOW THAT IS NEAR 28N135W...EXTENDING FROM 26N135W NW TO 29N137W. GLOBAL MODEL GUIDANCE SUGGESTS THAT THIS TROUGH WILL LINGER OVER THE NW PORTION OF THE AREA THROUGH EARLY NEXT WEEK RESULTING IN AN AREA OF TIGHT PRES GRADIENT OVER THAT PORTION OF THE AREA AS IT INTERACTS WITH HIGH PRES RIDGING THAT STRENGTHENS WHILE BUILDING SE INTO THE NORTHERN AND CENTRAL PORTIONS OF THE AREA. TO THE SE OF THE TROUGH AND LOW NEAR 28N135W...A SPLIT JET STREAM BRANCH ENTERS THE AREA THROUGH 12N140W...AND REACHES TO 22N130W TO 27N120W AND EASTWARD TO ACROSS NORTHERN MEXICO AND ENE TO WELL OVER CENTRAL TEXAS...WHILE THE SECOND ONE DIVES SE THROUGH 16N119W TO 10N112W TO 00N105W. THESE JET STREAM BRANCHES ARE RIDING OVER AND ACROSS BROAD MID/UPPER LEVEL RIDGING THAT PRETTY MUCH COVERS THE AREA S OF THE TROUGH BETWEEN 100W AND 132W. WHERE THE JETS SPLIT...A DIFFLUENT POCKET OF UPPER LEVEL WIND FLOW HAS BEEN CREATED FROM ABOUT 8N TO 18N BETWEEN 117W AND 127W. THIS IS SUPPORTING PATCHES OF RAIN WITH EMBEDDED SCATTERED MODERATE TO ISOLATED STRONG TSTMS FROM 9N TO 18N BETWEEN 123W AND 129W. UPPER LEVEL MODEL GUIDANCE INDICATES THAT THIS ACTIVE AREA OF PRECIPITATION SHOULD LAST UNTIL THE UPPER LOW NEAR 28N135W WEAKENS OVER THE WESTERN PART OF THE AREA IN A DEVELOPING SURROUNDING UPPER RIDGE PATTERN DURING THE MIDDLE OF NEXT WEEK. PRESENT GULF OF TEHUANTEPEC GALE EVENT OF WINDS OF 25-35 KT IS FORECAST TO END SAT AFTERNOON AS HIGH PRES OVER MEXICO WEAKENS RELAXING THE PRES GRADIENT ALONG SE MEXICO AND THE GULF. ACROSS THE GULF OF PAPAGAYO...NE WINDS TO 20 KT WERE NOTED BY A QUIKSCAT PASS FROM NEAR 0000 UTC THIS EVENING. THESE WINDS ARE EXPECTED TO LAST THROUGH EARLY ON WED OF NEXT WEEK WHILE REACHING THEIR MAXIMUM INTENSITY IN THE MORNINGS. DOWNWIND OF THE GULF OF PAPAGAYO...THE SAME QUIKSCAT PASS CONFIRMED THE PRESENCE OF A SWATH OF NE 20 KT WINDS FROM 8N-11N BETWEEN 93W-109W. SURFACE RIDGING ACROSS THE CENTRAL AMERICA WILL BE ENHANCED SOME OVER THE NEXT 24-48 HOURS BY THE SAME HIGH PRES THAT INITIATED THE GULF OF TEHUANTEPEC GALE WINDS. THIS WILL ALLOW FOR THIS AREA OF WINDS TO TRANSLATE WESTWARD TO NEAR 128W IN ABOUT 48 HOURS. LATEST NOAA WAVEWATCH GUIDANCE SUGGESTS THAT SEAS WILL PEAK UP TO 10 FT IN THE GULF OF TEHUANTEPEC DURING THE SHORT ONGOING GALE EPISODE. NE SWELL OF POSSIBLY UP TO 9 FT WILL LIKELY CONTINUE TO SPREAD W FROM THE GULF OVER THE NEXT DAY BEFORE DECAYING FURTHER. FNMOC...NPH AND UKMET WAVE GUIDANCE FOR THE MOST PART LOOKS REASONABLE FOR AREAS OUTSIDE THE GULF. LATEST RUNS OF THE REGULAR NOAA WAVEWATCH HAS COME MORE IN TUNE WITH SEA HEIGHTS OVER THE REGION...WITH THE EXCEPTION OF THE FAR NW CORNER WHERE IT IS OVERDONE BY ABOUT 3 FT...SHOWING 10 FT SEAS WHILE A FEW RECENT SHIP OBSERVATIONS SHOW 6 TO 7 FT. SEAS ARE EXPECTED TO INCREASE TO 8-11 FT IN NW SWELL OVER THE NEXT 24 HOURS OVER THE NW PORTION NEAR THE SURFACE TROUGH ALONG 26N135W 29N137W...THEN SUBSIDE TO 8-9 FT MON AS TROUGH WEAKENS AS IT MOVES W OF THE RIDGE AXIS THAT WILL EXTEND SE THROUGH NORTHERN AND CENTRAL PORTIONS OF THE AREA. ELSEWHERE...QUIKSCAT DATA FROM THIS MORNING SHOWED NUMEROUS RAIN FLAGGED WIND VECTORS IN EXCESS OF 20 KT WITHIN THE AREA OF PRECIPITATION AIDED BY UPPER LEVEL DIFFLUENCE AS MENTIONED EARLIER IN THE DISCUSSION. GLOBAL MODELS EVENTUALLY LOCK INTO A SURFACE TROUGH OR LOW FEATURE IN THIS AREA OVER THE NEXT FEW DAYS AND MOVE IT WNW. PRESENTLY...A SURFACE TROUGH IS ANALYZED FROM 16N129W TO 9N130W. WILL KEEP REFERENCE OF TROUGH IN FUTURE DISCUSSIONS AND FORECASTS UNTIL THERE IS EVIDENCE OF A LOW FORMING EITHER ON SATELLITE IMAGERY AND/OR SHIP SCATTEROMETER OBSERVATIONS. FOR WINDS NEAR THE TROUGH NE 20 KT IS MORE REALISTIC FOR TIME BEING. $$ AGUIRRE