000 AXPZ20 KNHC 092203 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC FRI APR 09 2010 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 2100 UTC. ...ITCZ... AXIS IS CENTERED ALONG 05N76W TO 03N82W TO 05N87W TO 05N97W TO 02N102W TO 047N117W TO 02N130W TO 04N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 90 NM S AND 150 NM N OF THE AXIS E OF 101W. SCATTERED MODERATE TO STRONG CONVECTION WITHIN 180-210 NM OF THE AXIS BETWEEN 112W AND 134W. ...DISCUSSION... A MID/UPPER LEVEL SHORTWAVE TROUGH EXTENDS FROM ERN MEXICO SW TO 24N113W. A BROAD FLAT MID/UPPER LEVEL RIDGE IS PRESENT S AND W OF THE TROUGH S OF 22N WITH THE ASSOCIATED ANTICYCLONE NEAR 08N126W. MODEST RIDGING IS ELSEWHERE W OF THE TROUGH. THE TROPICAL JET STREAM BRANCH ENTERS THE AREA THROUGH 19N140W AND CONTINUES ALONG 21N125W THROUGH THE BASE OF THE TROUGH NOTED ABOVE BEFORE CURVING NE ACROSS THE SRN TIP OF BAJA AND THEN NE INTO CENTRAL MEXICO. THIS JET IS TRANSPORTING UPPER LEVEL MOISTURE IN THE FORM OF SCATTERED TO BROKEN CIRRUS CLOUDS EWD TO NEAR 110W AND ACROSS MEXICO. AN AREA OF MODERATE SUBSIDENCE AND ASSOCIATED DRY AND STABLE CONDITIONS IS W OF THE TROUGH FROM 20N TO 30N BETWEEN 110W AND 130W. THE AREA OF MID/UPPER LEVEL RIDGING IS BEING NUDGED EWD BY A LONG WAVE TROUGH WELL W OF THE REGION. ACROSS THE DEEP TROPICS...CONVECTION REMAINS ACTIVE ALONG THE ITCZ W OF 115W AND IS HELPING TO MAINTAIN THE BROAD MID/UPPER LEVEL RIDGING. WITH UPPER LEVEL DIFFLUENCE S OF THE RIDGE IN PLACE...EXPECT CONVECTION NEAR THE ITCZ TO REMAIN FAIRLY ACTIVE W OF ABOUT 110W THROUGH THE NEXT 48 HRS. AT THE SURFACE...A RIDGE STRETCHES INTO THE AREA FROM A 1030 MB HIGH CENTERED N OF THE AREA 37N135W SE TO NEAR 23N117W. HIGH PRES COVERED THE AREA N OF 14N AND W OF 115W. THE PRES GRADIENT BETWEEN THE RIDGE AND LOWER PRES ASSOCIATED WITH THE ITCZ WAS MAINTAINING A SHRINKING AREA OF N-NE WINDS OF 20 KT W OF A LINE FROM 30N122W TO 26N130W. SIMILAR PRES GRADIENT BETWEEN THE AFOREMENTIONED RIDGE AND LOWER PRES OVER THE SW U.S. IS RESULTING IN A LARGE AREA OF NW 20-30 KT WINDS JUST N OF THE AREA E OF 125W. AS THE HIGH CENTER SLIDES SE AND WEAKENS THROUGH THE NEXT 24 HRS...THESE WINDS WILL DECREASE. THE HIGH WILL MOVE SE IN RESPONSE TO A RATHER VIGOROUS FRONTAL SYSTEM WHICH IS QUICKLY ADVANCING EWD. THIS SYSTEM WILL SWING A COLD FRONT INTO THE FAR NW WATERS SAT NIGHT AND THROUGH THE FAR NRN AND NE WATERS THROUGH THE REMAINDER OF THE WEEKEND INTO MON WHILE WEAKENING. WINDS AHEAD AND BEHIND THE FRONT WILL INCREASE TO ABOUT 30 KT WITH GALE CONDITIONS JUST N OF THE AREA. WINDS DIMINISH LATE SUN INTO MON AS HIGH PRES BUILDS IN ACROSS THE NRN AND CENTRAL WATERS BEHIND THE FRONT WITH A MUCH WEAKER GRADIENT. THE 12 UTC SEAS STATE ANALYSIS INDICATED MAXIMUM SEA HEIGHTS OF 12 FT JUST N OF 30N E OF 130W...WITH SEAS 9 TO 11 FT ACROSS MOST OF THE REMAINDER OF THE AREA W OF 110W TO THE EQUATOR IN MERGING NW AND SW SWELL. WAVE MODEL GUIDANCE SUGGESTS THAT THESE SEAS WILL SLOWLY SUBSIDE THROUGH SAT AFTERNOON...HOWEVER ANOTHER PULSE OF LONG PERIOD SWELLS ORIGINATING FROM THE NW WILL PROPAGATE INTO THE NRN WATERS LATER SAT AFTERNOON AND EVENING DUE TO THE APPROACHING FRONTAL SYSTEM. PRESENT INDICATIONS ARE THAT MAX SEAS WITH THIS SWELL TRAIN SHOULD REACH 14 TO 16 FT ALONG OR NEAR 30N LATE SUN INTO MON. GAP WINDS... FRESH TO STRONG TRADES OVER THE CARIBBEAN SEA CONTINUE TO FUNNEL W ACROSS THE GULF OF PAPAGAYO RESULTING IN PULSES OF NE 20 KT WINDS. THESE WINDS ARE FORECAST TO INCREASE TO 20-25 KT LATE TONIGHT...AND TO 30 KT BY LATE SAT NIGHT...BUT SHOULD BE A BRIEF OCCURRENCE. A RATHER STRONG COLD FRONT FOR EARLY IN APRIL HAS MOVED THROUGH THE ISTHMUS OF TEHUANTEPEC. AS A RESULT OF THE TIGHT PRES GRADIENT BEHIND IT OVER SE MEXICO...N WINDS IN THE RANGE OF 20-30 KT CONTINUE TO FILTER SWD THROUGH THE GULF OF TEHUANTEPEC WITHIN 60 NM EITHER SIDE OF A LINE FROM 6N94.5W TO 15N95W TO 12N96.5W. NWP MODEL GUIDANCE INDICATES THAT THESE WINDS SHOULD VARY LITTLE THROUGH THE NEXT 12 HRS...THEN DIMINISH TO 20-25 KT BY 24 HRS. SEAS ARE FORECAST TO REMAIN UP TO 11 FT THROUGH 24 HRS...THEN SUBSIDE TO 8 FT BY 48 HRS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ STRIPLING