000 AXPZ20 KNHC 172330 AAA TWDEP TROPICAL WEATHER DISCUSSION...UPDATED NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2330 UTC TUE FEB 17 2009 UPDATED ITCZ SECTION 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 2300 UTC. ...ITCZ...UPDATED ITCZ AXIS IS CENTERED ALONG CENTERED 04N77W TO 01N90W TO 02N120W TO 03130W TO 03N140W. SCATTERED MODERATE CONVECTION IS WITHIN 30 NM OF THE AXIS BETWEEN 121W-125W. ...DISCUSSION... BROAD MID/UPPER LEVEL TROUGH IS QUICKLY ADVANCING INTO THE FAR NW CORNER OF THE AREA AS A HIGHLY AMPLIFIED FLOW PATTERN TAKES FORM TO THE W OF THE AREA. SW UPPER LEVEL FLOW COVERS JUST ABOUT THE ENTIRE AREA TO THE SE OF THE TROUGH AS A STRONG JET STREAM BRANCH WITH MAXIMUM WINDS OF 90-100 KT AS SEEN ON WATER VAPOR IMAGERY ENTERS THE AREA TO THE S OF THE BASE OF THE TROUGH AT 16N140W AND EXTENDS NE TO 20N128W TO ACROSS CENTRAL BAJA CALIFORNIA AND NW MEXICO AND TO ACROSS 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 SCATTERED TO BROKEN STRATOCUMULUS CLOUDS MOVING WSW ARE VISIBLE FROM 16N-28N W OF 123W. TO THE S OF THE CLOUDINESS ASSOCIATED WITH THE ABOVE MENTIONED JET STREAM...THE ATMOSPHERE REMAINS VERY STABLE AS BROAD MID/UPPER RIDGING STAYS STRONG HERE WITH THE ASSOCIATED ANTICYCLONE NEAR 6N94W. A RIDGE EXTENDS FROM THIS ANTICYCLONE NW TO 13N101W...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 ABUNDANCE OF DRY AIR IN THE VICINITY. AT THE SURFACE... A 1015 MB LOW IS LOCATED JUST N OF THE AREA NEAR 32N137W WITH A COLD FRONT EXTENDING SW TO OUT OF THE AREA AT 27N140W. THE LOW IS FORECAST TO MOVE NE PUSHING THE COLD FRONT INTO THE NW WATERS TO A POSITION ROUGHLY ALONG 30N135W 24N140W IN ABOUT 48 HOURS. VERY TIGHT PRES GRADIENT BOTH E AND W OF THE FRONT SHOULD ALLOW FOR S-SW WINDS OF 20-25 KT WITH HIGHER GUSTS NEAR 30N AND GUSTS TO GALE FORCE N OF 30N WITHIN ABOUT 300-420 NM AHEAD OF THE FRONT IN 36-48 HOURS...WHILE NW WINDS OF 20-30 KT ARE EXPECTED BEHIND THE FRONT IN 24 HOURS THEN DIMINISHING TO 20 KT IN 48 HOURS. LARGE SWELLS OF 11-17 FT WILL SPREAD SE IN THE WAKE OF THE FRONT NEAR 48 HOURS. THESE SWELLS WILL OVERSPREAD MUCH OF THE AREA W OF 110W THROUGH THE NEXT 48 HOURS AS THEY SLOWLY SUBSIDE. GAP WINDS... NE CARIBBEAN TRADES OF 20-25 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 SW CARIBBEAN TRADES DIMINISH SOME. $$ AGUIRRE