000 AXPZ20 KNHC 081519 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC THU APR 08 2010 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1500 UTC. ...ITCZ... AXIS IS CENTERED ALONG 05N77W TO 06N95W TO 05N120W TO 02N140W. SCATTERED MODERATE TO STRONG WITHIN 120 NM OF THE AXIS W OF 130W. SCATTERED MODERATE ISOLATED STRONG WITHIN 120-180 NM OF THE AXIS BETWEEN 107W AND 113W...AND WITHIN 60-90 NM OF THE AXIS BETWEEN 85W AND 94W. ...DISCUSSION... A MID/UPPER LEVEL TROUGH EXTENDS FROM SRN CALIFORNIA SW TO TO A WEAK ELONGATED CYCLONIC CIRCULATION NEAR 25N122W MOVING E 15 KT...THEN CONTINUES S TO 18N121W THEN CUTS SW TO 10N129W. A SHORTWAVE RIDGE LIES TO THE W TO THE W OF CYCLONIC CIRCULATION AND IS ACTING TO KICK THE CIRCULATION EWD. WESTERLIES ALOFT DOMINATE MUCH OF THE AREA S OF THESE FEATURES...WITH A TROPICAL JET STREAM BRANCH ENTERING THE AREA NEAR 24N140W THEN DIVING SE THROUGH 21N130W TO THE BASE OF THE TROUGH NOTED ABOVE...THEN CONTINUING NEWD THROUGH 16N120W TO 20N112W TO ACROSS CENTRAL MEXICO AND WELL TO THE ACROSS THE CENTRAL U.S. AHEAD OF A DEEP LAYER TROUGH. BROAD MID/UPPER LEVEL RIDGE AXIS COVERS THE P PORTION OF THE AREA TO 25N AND GENERALLY W OF 130W. THIS RIDGE IS BEING NUDGED EWD BY A BROAD LONG WAVE TROUGH WELL W OF THE REGION. ACROSS THE THE DEEP TROPICS...ACTIVE CONVECTION ALONG THE ITCZ IS OCCURRING WITHIN AN AREA DOMINATED BY UPPER LEVEL RIDGING ALIGNED ROUGHLY ALONG 7N WITH AN ASSOCIATED ANTICYCLONES NEAR 7N106W AND 06N135W. WITH UPPER LEVEL DIFFLUENCE IN PLACE AND SOME INSTABILITY PROVIDED BY TROUGHS PASSING TO THE N...EXPECT CONVECTION NEAR THE ITCZ TO REMAIN PRETTY ACTIVE W OF 95W THROUGH AT LEAST THE NEXT 48 HRS. OVER THE EASTERN PORTION OF THE AREA...A WEAK MID/UPPER LEVEL TROUGH EXTENDS FROM NEAR GUATEMALA SW TO NEAR 8N92W. THE TROUGH IS PROVIDING SOME ENHANCEMENT TO ITCZ CONVECTION BETWEEN 85W-94W. A WEAK MID/UPPER LEVEL CYCLONIC CIRCULATION DRIFTING W IS NEAR THE EQUATOR AT 93W...BUT NOT PRODUCING ANY CONVECTION DUE TO DRY AIR WRAPPED INTO ITS CIRCULATION. AT THE SURFACE...A RIDGE STRETCHES INTO THE AREA FROM 30N135W SE TO 22N120W TO 18N110W WITH THE PARENT HIGH CENTER OF 1040 MB WELL N OF THE AREA NEAR 41N144W. 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 LARGE AREA OF NE-E TRADES IN THE RANGE OF 20-25 KT N OF 8N AND W OF 122W. A TIGHT PRES GRADIENT BETWEEN THE AFOREMENTIONED RIDGE AND TROUGHING OVER THE SIERRA MADRE OCCIDENTALS IS RESULTING IN A SMALL AREA OF NW-N WINDS OF 20-25 KT THROUGH THE GULF OF CALIFORNIA FROM 25N TO 30N...WHERE SEAS ARE CLOSE TO 8 FT. THESE WINDS ARE FORECAST TO WEAKEN TO LESS THAN 20 KT BY LATE TONIGHT. THE HIGH CENTER NEAR 41N144W WILL SLIDE ESE OVER THE NEXT 24 HRS IN RESPONSE TO A STRONG FRONTAL SYSTEM MAKING HEADWAY TO THE E. THE RESULTANT TIGHTENING PRES GRADIENT IS EXPECTED N OF THE AREA E OF 130W DUE TO THE HIGH INTERACTING WITH LOW PRES OVER THE WRN U.S. WILL USHER IN ANOTHER BATCH OF N-NE 20-25 KT WINDS INTO THE NE PORTION TONIGHT. THE WINDS WILL DIMINISH SOME BETWEEN 36-48 HRS AS THE GRADIENT WEAKENS. THE 1200 UTC SEA STATE ANALYSIS INDICATED AN AREA OF MAXIMUM SEA HEIGHT OF 12 FT N OF 24N BETWEEN 118W AND 125W. THIS IS IN PRETTY GOOD AGREEMENT WITH MAJORITY OF THE WAVEWATCH GUIDANCE AND LATEST NWW3 ENSEMBLE MAX SIGNIFICANT WAVE HEIGHTS. THE GUIDANCE DEPICTS THE ENTIRE AREA W OF ABOUT 110W N OF 15N...AND W OF 93W S OF 15N WITH SEAS IN THE RANGE OF 8-11 FT IN NW TO N SWELLS. AT THE SAME TIME...IT APPEARS THAT LONG PERIOD SRN HEMISPHERIC SW SWELLS ARE MERGING WITH THE NW SWELLS OVER THE SRN SECTION OF THE AREA...AND WILL CONTINUE TO DO SO THROUGH AT LEAST THE NEXT 48 HRS. PRESENT INDICATIONS ARE THAT SEAS THROUGHOUT THE AFFECTED SWELL AREAS WILL SLOWLY SUBSIDE GOING INTO THE UPCOMING WEEKEND ...WITH HIGHEST SEAS (POSSIBLY UP TO 13 FT IN A N SWELL) LINGERING IN THE FAR NE SECTION. GAP WINDS... FRESH TO STRONG TRADES OVER THE CARIBBEAN SEA CONTINUE TO FUNNEL W ACROSS THE GULF OF PAPAGAYO RESULTING IN NE 20 KT WINDS. THESE WINDS WILL PULSATE DURING THE NEXT 48 HRS WITH MAXIMUM WINDS OCCURRING MAINLY IN THE EARLY MORNING HOURS DUE TO ENHANCED NOCTURNAL DRAINAGE FLOW. A COLD FRONT CURRENTLY SWEEPING THROUGH THE NORTHWESTERN GULF OF MEXICO WILL USHER IN N TO NE 20 KT WINDS INTO THE GULF OF TEHUANTEPEC LATE TONIGHT. THESE WINDS ARE FORECAST TO EXPAND IN AREAL COVERAGE TO 13N AND BETWEEN 94W-97W ON FRI WITH WINDS INCREASING TO 20 TO 30 KT AND SEAS BUILDING UP TO 10 FT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ COBB