000 AXPZ20 KNHC 180335 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC WED FEB 18 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 ALONG CENTERED 4N77W TO 1N90W TO 3N110W TO 3N125W TO 4N140W. NO SIGNIFICANT CONVECTION IS NOTED. ...DISCUSSION... BROAD MID/UPPER LEVEL TROUGH IS QUICKLY SWINGING SEWD INTO THE NW SECTION OF THE AREA AS A VERY PROGRESSIVE UPPER PATTERN TAKES SHAPE W OF THE AREA. THE UPPER LEVEL FLOW PATTERN COVERING MUCH OF THE AREA IS GENERALLY SWLY AS A STRONG JET STREAM BRANCH WITH MAXIMUM WINDS OF 90-100 KT AS SEEN ON WATER VAPOR IMAGERY ROUNDS THE BASE OF THE TROUGH FROM 20N140W NE TO 23N125W TO ACROSS NRN BAJA CALIFORNIA AND MEXICO WHERE IT CURVES UP OVER THE TOP OF A MID/UPPER LEVEL RIDGE OVER MEXICO. THIS JET CONTINUES TO ADVECT AMPLE UPPER LEVEL TROPICAL MOISTURE IN THE FORM OF SCATTERED TO BROKEN CIRRUS CLOUDS NE TOWARDS CENTRAL AND SRN BAJA CALIFORNIA AND TO ACROSS NRN MEXICO. DRY AIR AS MARKED BY MODERATE SUBSIDENCE ON WATER VAPOR IMAGERY EXISTS TO THE NW OF THE JET STREAM BRANCH. ONLY A FEW SMALL PATCHES OF STRATOCUMULUS CLOUDS MOVING WSW ARE VISIBLE FROM 8N-20N W OF 121W. TO THE S OF THE CLOUDINESS ASSOCIATED WITH THE ABOVE MENTIONED JET STREAM...THE ATMOSPHERE REMAINS VERY STABLE AS BROAD MID/UPPER RIDGING REMAINS ANCHORED HERE WITH THE ASSOCIATED ANTICYCLONE NEAR 6N94W. A RIDGE EXTENDS FROM THIS ANTICYCLONE NW TO 11N101W...THEN NWD TO ACROSS NRN AND CENTRAL MEXICO REACHING TO WELL N ACROSS THE CENTRAL U.S. STRONG SUBSIDENCE ALOFT HERE IS RESULTING IN A VERY DRY AND STABLE AIR MASS WITHIN THIS PORTION OF THE AREA...AND IS EVEN SUPPRESSING CONVECTION FROM DEVELOPING ALONG OR NEAR THE ITCZ. AN UPPER LEVEL CYCLONIC CIRCULATION OVER SE NICARAGUA HAS A TROUGH EXTENDING SSW TO 6N85W...BUT IS VOID OF ANY CONVECTIVE ACTIVITY DUE TO THE ABUNDANCE OF DRY AIR IN THE VICINITY FURTHER AIDED BY CONFLUENT FLOW PRESENT BETWEEN THE ABOVE RIDGE AND THE TROUGH. AT THE SURFACE... A 1015 MB LOW IS LOCATED JUST N OF THE AREA NEAR 32N135W WITH A COLD FRONT EXTENDING SW TO W OF THE AREA AT 27N140W. THE LOW IS FORECAST TRACK NE DURING THE NEXT 24 HOURS AS IT DISSIPATES. THE COLD FRONT WILL WEAKEN THROUGH THE NEXT 24 HOURS...BUT BE OVERTAKEN BY A STRONGER COLD FRONT WHICH WILL REACH FROM 30N138W TO 26N140W BY THEN. THIS FRONT IS THEN FORECAST TO REACH FROM 20N135W TO 24N140W IN 48 HOURS AS IT WEAKENS AS ITS UPPER LEVEL SUPPORT STAYS WELL N OF THE REGION. ELSEWHERE AT THE SURFACE...A 1021 MB HIGH IS ANALYZED NEAR 26N125W WITH A RIDGE SE TO 20N110W. HIGH PRES COVERS THE AREA N OF 18N AND TO THE SE OF THE COLD FRONT. A VERY TIGHT PRES GRADIENT BOTH E AND W OF THE FRONT SHOULD ALLOW FOR SW WINDS OF 25-30 KT WITH POSSIBLE HIGHER GUSTS WITHIN ABOUT 420 NM E OF FRONT IN 24 HOURS...WHILE NW WINDS OF 20-25 KT ARE EXPECTED BEHIND THE FRONT THEN DIMINISH TO 20 KT IN 48 HOURS. LARGE SWELLS ARE FORECAST TO BUILD UP TO 10-16 FT AND SPREAD SE IN THE WAKE OF THE FRONT NEAR 48 HOURS. THESE SWELLS WILL OVERSPREAD MUCH OF THE AREA N OF 5N AND W OF 110W THROUGH THE NEXT 48 HOURS AS THEY SLOWLY SUBSIDE. GAP WINDS... NE CARIBBEAN TRADES OF 20 TO AT TIMES 25 KT WILL CONTINUE TO SPILL THROUGH THE GULF OF PAPAGAYO BEYOND THE NEXT 48 HOURS AS A NEW AREA OF HIGH BUILDS SWD INTO THE SRN GULF OF MEXICO AND NRN CARIBBEAN. N-NE WINDS OF 20 KT FUNNELING THROUGH THE GULF PANAMA S TO 6N ARE EXPECTED TO DIMINISH IN ABOUT 36 HOURS AS WRN CARIBBEAN GRADIENT SLACKENS SOME. $$ AGUIRRE