000 AXPZ20 KNHC 100355 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC SAT APR 10 2010 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 0200 UTC. ...ITCZ... AXIS ALONG 05N77W TO 06N85W TO 05N108W TO 03N117W TO 06N124W TO 01N130W TO 02N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WAS WITHIN 90 NM OF AXIS BETWEEN 87W AND 102W. SCATTERED TO LOCALLY NUMEROUS MODERATE TO STRONG CONVECTION WAS WITHIN 180-240 NM OF AXIS BETWEEN 112W AND 136W. ...DISCUSSION... A MID/UPPER LEVEL SHORTWAVE TROUGH EXTENDS FROM CENTRAL ARIZONA S-SW TO 22N112W AND WAS PROGRESSING EWD...EMBEDDED IN THE WLY FLOW ALOFT DOMINATING MOST OF THE AREA. A BROAD FLAT MID/UPPER LEVEL RIDGE PREVAILED S OF THE WLYS...ALONG 6-8N BETWEEN 108W AND 150W WITH AN ASSOCIATED ANTICYCLONE NEAR 07N126W. THE TROPICAL JET STREAM BRANCH ENTERS THE AREA THROUGH 18N140W AND CONTINUES NEARLY E ACROSS THE AREA THROUGH THE BASE OF THE TROUGH NOTED ABOVE BEFORE CURVING NE JUST S OF 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 S OF THE JET TO THE BASE OF THE TROUGH AND AND ACROSS MEXICO. AN AREA OF MODERATE SUBSIDENCE AND ASSOCIATED DRY AND STABLE CONDITIONS IS W OF THE TROUGH FROM 20N TO 25N BETWEEN 110W AND 140W. ACROSS THE DEEP TROPICS...CONVECTION REMAINS VERY ACTIVE ALONG THE ITCZ W OF 110W AND IS HELPING TO MAINTAIN THE BROAD MID/UPPER LEVEL RIDGING. WITH UPPER LEVEL GOOD DIFFLUENCE S OF THE RIDGE IN PLACE...EXPECT CONVECTION NEAR THE ITCZ TO REMAIN ACTIVE W OF ABOUT 110W THROUGH THE NEXT 48 HRS. AT THE SURFACE...A RIDGE STRETCHES INTO THE AREA FROM A 1025 MB HIGH CENTERED N OF THE AREA 36N134W SE TO NEAR 22N114W. HIGH PRES COVERED THE AREA N OF 12N AND W OF 120W. THE PRES GRADIENT BETWEEN THE RIDGE AND LOWER PRES ASSOCIATED WITH THE ITCZ HAS WEAKENING DURING THE PAST 24-36 HOURS...WITH ONLY A SMALL AREA OF NE WINDS NEAR 20 KT REMAINING S OF 10N W OF 132W. A TIGHT PRES GRADIENT REMAINS BETWEEN THE AFOREMENTIONED RIDGE AND LOWER PRES OVER THE SW U.S. RESULTING IN A LARGE AREA OF NW 20-30 KT WINDS JUST N OF THE AREA E OF 128W. AS THE HIGH CENTER SLIDES SE AND WEAKENS THROUGH THE NEXT 24 HRS...THESE WINDS WILL ALSO 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 LARGE SURFACE RIDGE AND SEVERAL WEAK PERTURBATIONS RIDING OVER THE RIDGE AND INTO BAJA CALIFORNIA THE PAST FEW WEEKS HAVE CREATED AN INDUCED TROUGH EXTENDING FROM JUST S OF THE SRN TIP OF BAJA TO THE ITCZ ALONG ABOUT 120W. ABUNDANT TROPICAL MOISTURE CONTINUES TO CONVERGE ON THE E SIDE OF THIS TROUGH E TO 110W AIDING IN THE ACTIVE CONVECTIVE ZONE. 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 20-25 KT CONTINUE TO FILTER SWD THROUGH THE GULF OF TEHUANTEPEC WITHIN 60 NM EITHER SIDE OF A LINE FROM 16N94.5W TO 15N95W TO 12N96.5W. NWP MODEL GUIDANCE INDICATES THAT THESE WINDS SHOULD VARY LITTLE THROUGH THE NEXT 12 HRS...THEN DIMINISH IN AREAL COVERAGE BY 24 HRS. SEAS ARE FORECAST TO REMAIN UP 9 TO 10 FT THROUGH 24 HRS...THEN SUBSIDE TO LESS THAN 8 FT BY 48 HRS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ STRIPLING