000 AXPZ20 KNHC 120334 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC FRI MAR 12 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 0145 UTC. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE WAS ANALYZED ALONG A LINE FROM 04N77W TO 06N90W TO 05N105W TO 07N115W TO 02N140W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS WITHIN 180 NM S OF THE ITCZ AXIS BETWEEN 84W AND 96W AND WITHIN 90 NM N OF AXIS THE ITCZ AXIS BETWEEN 83W AND 89W. SCATTERED MODERATE CONVECTION WAS WITHIN 300 NM SW OF THE ITCZ AXIS BETWEEN 109W AND 118W. ...DISCUSSION... A PROGRESSIVE PATTERN OVER N WATERS WILL SEE THE BROAD UPPER TROUGH OVER NW MEXICO FINALLY PUSH EASTWARD AS THE NEXT DEEP LAYERED TROUGH MOVES INTO NW WATERS OVERNIGHT TONIGHT. A W-SW UPPER JET IN EXCESS OF 130 KT WILL REMAIN CENTERED ALONG 25N E OF 120W THROUGH FRI NIGHT WHEN THE JET WILL PUSH E ALONG THE LEADING EDGE OF THE DEEP LAYERED TROUGH. THE W-SW UPPER LEVEL WINDS FEEDING INTO THE JET ARE BEGINNING TO LOSE THEIR CONNECTION TO TROPICAL MOISTURE. THIS IS EVIDENT BY THE DISSIPATING BAND OF CIRRUS CLOUDS FOUND WITHIN 180 NM OF A LINE FROM 23N100W TO 16N117W. THE UPPER TROUGH OVER NW MEXICO FROM 30N104W TO 23N110W WILL MOVE E TO MAKE WAY FOR THE DEEP LAYERED TROUGH BY FRI WITH THE COLD FRONT ASSOCIATED WITH THIS NEW TROUGH EXPECTED TO BE WEAK INITIALLY. THE LARGEST IMPACT FROM THIS COLD FRONT OVERNIGHT TONIGHT AND ON FRI WILL BE A NEW SURGE OF NW SWELL PUSHING INTO THE AREA WITH ITS ARRIVAL...WITH SIGNIFICANT WAVE HEIGHTS INCREASING TO 13 FT NW OF THE FRONT. THE FRONT WILL DISSIPATE AS IT MOVES INTO NORTHERN BAJA CALIFORNIA AND NE WATERS BY SAT EVENING...BUT THE PRES GRADIENT IS EXPECTED TO BUILD BETWEEN THE FRONTAL TROUGH AND HIGH PRES FOLLOWING CLOSELY BEHIND IT AS THE NORTHERN STREAM PATTERN BECOMES MORE AMPLIFIED. THIS WILL ALLOW FOR NW TO N WINDS TO INCREASE ABOVE 20 KT OVER NE WATERS OFF THE W COAST OF BAJA CALIFORNIA ON SAT. A BROAD UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED NEAR 09N107W INFLUENCES THE REMAINDER OF THE DISCUSSION AREA. A RIDGE AXIS EXTENDS FROM THE ANTICYCLONE NE INTO THE GULF OF FONSECA WHILE A SECOND RIDGE AXIS EXTENDS SW OF THE ANTICYCLONE TO 07N135W. SCATTERED MODERATE CONVECTION WAS OBSERVED S OF THE ITCZ BETWEEN 109W AND 118W IN THE REGION OF MODERATE UPPER LEVEL DIFFLUENCE ASSOCIATED WITH THE ANTICYCLONE ALOFT. PLEASE SEE THE SECTION ABOVE FOR DETAILS. FARTHER E...SCATTERED MODERATE TO STRONG CONVECTION WAS NEAR THE ITCZ BETWEEN 83W AND 96W. THIS AREA LIES IN A POOL OF 2.25 TO 2.50 INCH PRECIPITABLE WATER VALUES AND UNDER MODERATE UPPER LEVEL DIFFLUENCE. THIS DIFFLUENT REGION ALOFT IS EXPECTED TO SHIFT W FROM 90W TO 100W PRIMARILY S OF 05N OVER THE NEXT FEW DAYS. THEREFORE...LOOK FOR THE STRONGEST CONVECTION TO SHIFT W AS WELL. AT THE SURFACE...1025 MB HIGH PRES LIES OVER NW WATERS NEAR 28N132W WITH A RIDGE AXIS EXTENDING SE TO NEAR 15N105W WHILE LOW PRES AT THE SURFACE ASSOCIATED WITH THE LEADING EDGE OF THE BROAD TROUGH ALOFT OVER NW MEXICO HAS SHIFTED EASTWARD INTO THE WESTERN GULF OF MEXICO WITH 1000 MB LOW PRES ANALYZED NEAR 26N94W. THE PRES GRADIENT ALONG THE MEXICAN PACIFIC COAST NEAR 20N HAS STRENGTHENED BETWEEN THIS LOW PRES TO THE E AND THE RIDGE TO THE W. NW TO N WINDS ARE EXPECTED TO HOVER NEAR 20 KT THERE AND INTO THE SOUTHERN GULF OF CALIFORNIA THROUGH FRI. THERE ARE A FEW OBSERVATIONS TO CONFIRM THESE CONDITIONS WITH SHIP ZCDF4 REPORTED 25 KT WINDS NEAR 17N100W AT 0000 UTC AND SHIP A8EH2 REPORTED 20 KT WINDS NEAR 19N108W AT 1800 UTC. SOUTH OF THE SURFACE RIDGE AXIS LIES A BROAD AREA OF STRONG NE TRADE WINDS. THE 1814 ASCAT PASS SHOWED 20 TO 25 KT WINDS W OF 120W FROM 06N TO 21N. THE HIGH PRES OVER NW WATERS WILL WEAKEN AHEAD OF THE APPROACHING COLD FRONT TONIGHT. THIS WILL SHRINK THE AREA OF STRONG TRADE WINDS WESTWARD A FEW DEGREES FRI WITH LITTLE CHANGE EXPECTED IN THE AREA AND STRENGTH OF THE TRADES SAT. GAP WINDS... THE NEXT TEHUANTEPEC GAP WIND EVENT IS FORECAST TO BEGIN TOMORROW EVENING AS A FAST MOVING COLD FRONT SWINGS THROUGH THE WESTERN GULF OF MEXICO. WINDS OF 20 TO 30 KT ARE EXPECTED SAT. THE EVENT IS EXPECTED TO BE SHORT LIVED...WITH WINDS FORECAST TO DROP BELOW 20 KT OVERNIGHT SAT NIGHT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ SCHAUER