000 AXPZ20 KNHC 090339 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC THU APR 09 2009 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... ITCZ AXIS IS CENTERED 08N84W TO 04N92W TO 04N100W TO 03N110W TO 01N121W 01N130W TO 21N140W. NO SIGNIFICANT CONVECTION IS NOTED. ...DISCUSSION... THE CLOSED UPPER LEVEL LOW THAT WAS N OF THE AREA 24-30 HRS AGO HAS SINCE MOVED WELL INLAND THE U.S. W COAST. A TROUGH TRAILS SW FROM IT INTO THE AREA AT 32N119W AND REACHES TO 29N120W. CONFLUENT FLOW LEFT BEHIND IN THE WAKE OF THE TROUGH IS RESULTING IN A SWATH OF MODERATE SUBSIDENCE FROM 29N-32N...AND IS NUDGING NE ACROSS SRN CALIFORNIA. A WEAK MID/UPPER LEVEL RIDGE ALONG 128W N OF 31N WILL QUICKLY MOVE INLAND THE WRN U.S. TONIGHT IN ADVANCE OF A STRONG SHORTWAVE TROUGH TAKING PLACE WELL N OF THE DISCUSSION AREA...MORE ON THIS LATER IN THE DISCUSSION. A JET STREAM BRANCH WITH MAXIMUM WINDS OF 60-70 KT ENTERS THE REGION THROUGH 25N140W...AND EXTENDS ALONG 26N130W ROUNDING THE BASE OF THE UPPER TROUGH NE TO ACROSS NRN BAJA CALIFORNIA AND TO ACROSS THE SW U.S. THE JET CONTINUES TO TRANSPORT AMPLE HIGH LEVEL BROKEN CLOUDS ENE TO ACROSS NRN AND CENTRAL BAJA CALIFORNIA. TO ITS S...BROAD ANTICYCLONIC FLOW IS OBSERVED WITH AN ANTICYLONE LOCATED NEAR 4N105W. THE FLOW IS INTERRUPTED BY A MID/UPPER LEVEL TROUGH THAT EXTENDS FROM 15N124W TO 10N124W TO 4N123W. AT THE SURFACE...A WEAK TROUGH MOVING W 17 KT IS ALONG 119W S OF 10N. BROKEN LOW CLOUDS WITH WEAK ISOLATED SHOWERS ARE WITHIN 60 NM EITHER SIDE OF THE TROUGH FROM 6N-10N. ANOTHER WEAK SURFACE MOVING W ABOUT 15 KT IS ALONG 111W FROM 9N-13N. A VORTICITY MAXIMUM ON THE TROUGH NEAR 10N IS PRODUCING WEAKENING TSTMS WITHIN 30 NM OF 10N111W. YET ANOTHER SURFACE TROUGH...ALSO RATHER WEAK MOVING W 15 KT...IS ALONG 129W FROM 8N-13N. BROKEN LOW CLOUDS WITH ISOLATED SHOWERS ARE ALONG AND WITHIN 120 NM E OF THE TROUGH. ABUNDANT MODERATE TO STRONG SUBSIDENCE ASSOCIATED WITH UPPER LEVEL RIDGING RESULTING IN RATHER DRY AND STABLE CONDITIONS REMAINS ENTRENCHED THROUGHOUT ALL LEVELS OF THE ATMOSPHERE S OF 18N AND E OF 108W...AND ALSO S OF 16N W OF 115W. SMALL PATCHES OF SCATTERED TO BROKEN STRATOCUMULUS CLOUDS MOVING SW WITH POSSIBLE ISOLATED SHOWERS ARE N OF 20N W OF 124W...AND ARE BEING STEERED BY THE NE-E FLOW AROUND THE SRN PERIPHERY OF SURFACE RIDGING THAT EXTENDS SEWD INTO THE AREA THROUGH 28N140W TO 23N120W TO NEAR 18N113W. THE FLOW IS CHARACTERIZED BY NE WINDS OF 20 KT FROM 8N-19N W OF 124W WITH SEAS IN THE 8 TO 10 FT RANGE IN NE SWELL. THESE WINDS WILL COVER FROM 7N-20N W OF ABOUT 127W IN 48 HRS. SEAS WILL CONTINUE IN THE 8-10 FT IN A NW SWELL...WITH SEAS TO 9 FT IN SUBSIDING NW SWELL ELSEWHERE N OF 8N W OF 114W. LATEST NWP MODEL GUIDANCE SUGGESTS THAT THE AFOREMENTIONED TROUGH WELL N OF THE AREA WILL DIVE SWD WHILE DEEPENING DUE TO A VIGOROUS MID/UPPER LEVEL JET. THE MODELS REMAIN IN GOOD AGREEMENT THAT ITS ASSOCIATED SURFACE COLD FRONT WILL SWEEP THROUGH THE NE WATERS LATE THU THROUGH FRIDAY PRECEDED AND FOLLOWED BY STRONG WINDS. GUIDANCE ALSO INDICATES THAT A SURFACE LOW WILL DEVELOP NEAR THE CALIFORNIA COAST LATE THU AND MOVE SE THROUGH FRI BEFORE MOVING INLAND SRN CALIFORNIA FRI NIGHT. THIS WILL SERVE TO STRENGTHEN THE SURFACE PRESSURE GRADIENT NEAR THE FRONT WITH THE POTENTIAL FOR GALE FORCE WINDS NW OF THE COLD FRONT WHERE LOW LEVEL INSTABILITY WILL INCREASE...BUT THESE WINDS SHOULD STAY N OF THE AREA. LATEST WAVEWATCH GUIDANCE INDICATES SEAS BUILDING TO 14 FT OVER THE FAR NE WATERS BY FRI NIGHT IN THE WAKE OF THE FRONT. GAP WINDS... A HIGH RESOLUTION QUIKSCAT PASS FROM 1248 UTC INDICATED THAT THE STRONG GAP WIND EVENT CONTINUES TO RAPIDLY WEAKEN IN THE GULF OF TEHUANTEPEC WITH THE GALE FORCE WINDS NOTED EARLIER NOW REDUCED TO 20-30 KT SO THE GALE WARNING HAS BEEN ALLOWED TO EXPIRE. SATELLITE IMAGERY CONTINUES TO INDICATE COOLING SEA SURFACE TEMPERATURES DUE TO UPWELLING AND THIS HAS STABILIZED LOW LEVEL LAPSE RATES ALLOWING FOR THE WINDS TO DROP OFF TO BELOW GALE FORCE. WINDS WILL CONTINUE ON THE DOWNWARD TREND THROUGH THE NEXT 24 HRS...REACHING TO LESS THAN 20 KT IN 48 HRS WITH SEAS LESS THAN 8 FT IN THE GULF. THE SWELLS PRODUCED BY THIS EVENT WILL...HOWEVER...PROPAGATE S AND SW INTO THE FAR EQUATORIAL EAST PACIFIC. INCREASING TRADE WINDS OVER THE WRN CARIBBEAN ARE FILTERING THROUGH INTO THE ERN PACIFIC AND FUNNELING OUT THROUGH THE GULF OF PAPAGAYO AS NE-E 20-25 KT WINDS. THESE WINDS ARE FORECAST TO SUBSIDE IN ABOUT 36 HRS. N WINDS OF 20-25 KT THROUGH THE GULF OF PANAMA ARE EXPECTED TO ALSO DIMINISH IN 36 HRS. ALSO...SW TO W 20 KT WINDS OVER THE NRN GULF OF CALIFORNIA N OF 29N ARE EXPECTED TO DIMINISH TO LESS THAN 20 KT IN 24 HRS...THEN INCREASE AGAIN TO SW 20 KT N OF 29N IN 48 HRS. NW WINDS OF 20 KT WITHIN 60 NM OF THE BAJA CALIFORNIA COAST N OF 25 WILL CONTINUE THROUGH THE NEXT 34 HRS. $$ AGUIRRE