000 AXPZ20 KNHC 302205 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC FRI JAN 30 2009 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2145 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 5N78W 5N90W 4N103W 3N115W 4N127W 3N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 45 NM OF 6N85W. ...DISCUSSION... A WEAKENING MID/UPPER LEVEL TROUGH EXTENDS FROM THE SWRN U.S. SW TO NEAR 32N123W. A JET STREAM BRANCH WITH MAXIMUM WINDS OF 60-90 KT ENTERS THE AREA THROUGH 19N140W...AND CONTINUES TO 22N130W THEN ESE TO 22N120W AND ACROSS SRN BAJA CALIFORNIA INTO WRN MEXICO. THIS JET CONTINUES TO ADVECT SCATTERED TO BROKEN HIGH LEVEL CLOUDS FROM THE DEEP CENTRAL TROPICAL PACIFIC REGION ENE TO NEAR 120W. GENERALLY ZONAL FLOW IS PRESENT OVER MOST OF THE AREA...EXCEPT FOR THE WRN PORTION OF THE AREA WHERE MID/UPPER LEVEL RIDGING IS NOTED AHEAD OF A LONGWAVE TROUGH W OF THE AREA. A 1033 MB HIGH CENTER WELL N OF THE AREA NEAR 39N135W EXTENDS A RIDGE S THROUGH 32N137W TO 28N128W TO 17N121W TO 12N113W. THE TROUGH W OF THE AREA IS FORECAST TO MOVE THROUGH THE NW PORTION ON SAT AND SUN. AN UPPER LEVEL CYCLONIC CIRCULATION IS THEN FORECAST TO ALONG THE FAR NORTHERN BOUNDARY AFTER 48 HOURS. THE ASSOCIATED SURFACE COLD FRONT IS FORECAST TO STAY N OF THE AREA THROUGH SAT. CLOUDS ARE CONCENTRATED OVER THE WRN SECTION FROM 15N-26N W OF 130W. EXPECT AN INCREASE OF SHOWERS AND TSTMS WITHIN THIS AREA SINCE IT LIES UNDER THE RIGHT ENTRANCE QUADRANT OF THE ABOVE MENTIONED JET STREAM...AND IN ADDITION THE UPPER LEVEL ENVIRONMENT HERE IS BECOMING DIFFLUENT WITH TIME AS MID/UPPER LEVEL RIDGING SHIFTS E AS THE LONGWAVE TROUGH APPROACHES 140W. A MID/UPPER LEVEL TROUGH EXTENDS FROM 17N128W SE TO 11N126W TO 5N121W TO NEAR THE EQUATOR AT 116W. TO THE E OF TROUGH... BROAD MID/UPPER LEVEL RIDGING DOMINATES THE AREA...NAMELY THE ERN PORTION WITH AN ASSOCIATED NEARLY STATIONARY ANTICYCLONE NEAR 7N95W. THIS PATTERN CONTINUES TO RESULT IN MODERATE TO STRONG SUBSIDENCE WITH VERY DRY STABLE AIR E OF ABOUT 120W WHERE...WITH THE EXCEPTION OF SCATTERED LOW CLOUDS WITH ISOLATED SHOWERS MOVING W...SKIES ARE MOSTLY CLEAR. THESE CONDITIONS ARE EXPECTED TO LAST OVER THE NEXT 48 HOURS AS MID/UPPER RIDGING HOLDS ACROSS THIS AREA. THE RESULTANT TIGHT PRES GRADIENT CREATED BY THE RIDGE MENTIONED IN THE FIRST PARAGRAPH AND LOWER PRES TO THE S OVER THE EQUATORIAL PACIFIC ZONE HAS BEEN BRINGING NE-E 20-25 KT TRADE WINDS TO MUCH OF THE NW PORTION OF THE AREA DURING THE PAST FEW DAYS. THESE WINDS ARE FORECAST TO TRANSLATE W OF THE AREA WITH A SWATH OF NE-E 20 KT WINDS REMAINING OVER A PORTION OF THE WRN PART OF THE AREA WITHIN THE NEXT 24 HOURS...AND CONTINUE THROUGH THE NEXT 48 HOURS AS THE RIDGE SLIDES EWD SOME. SEAS IN THIS AREA WILL BE IN THE 8-10 FT RANGE WITH A NE SWELL DIMINISHING TO 8 FT DURING THE NEXT 24 HOURS...AND TO LESS THAN 8 FT IN ABOUT 48 HOURS. GAP WINDS... GULF OF PAPAGAYO NE 20 KT WINDS ARE FORECAST TO CHANGE LITTLE THROUGH THE WEEKEND. NEXT GULF OF TEHUANTEPEC STORM EVENT IS FORECAST TO BEGIN IN ABOUT 12 HOURS AS STRONG HIGH PRES BUILDS SWD INTO THE FAR WRN GULF OF MEXICO AND ALONG THE ERN SLOPES OF THE SIERRA MADRE MOUNTAINS OF MEXICO IN THE WAKE OF A COLD FRONT CURRENTLY PRESSING SWD OVER SW MEXICO. WARM SSTS N THE GULF BASED ON LATEST SST ANALYSIS OF THE E PAC SHOULD PROVIDE FOR VERY GOOD INSTABILITY ALLOWING FOR THESE STRONG WINDS TO MIX DOWN TO THE SURFACE. MODEL RUNS OVER THE PAST FEW DAYS HAVE BEEN VERY CONSISTENT IN SUGGESTING THAT THIS WILL START OFF AS A GALE EVENT EARLY THIS EVENING REACHING STORM FORCE LATE TONIGHT INTO SAT MORNING BEFORE TAPERING OFF BACK TO GALE FORCE EARLY SAT AFTERNOON AND TO LESS THAN GALE FORCE BY SUN MORNING AS HIGH PRES OVER THE FAR WRN GULF AND MEXICO WEAKENS SUBSTANTIALLY. $$ AGUIRRE