000 AXPZ20 KNHC 112138 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SUN MAR 11 2012 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2130 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH NOT PRESENT ACROSS E PACIFIC. ITCZ AXIS EXTENDS FROM 03N96W TO THE EQUATOR ALONG 108W AND THEN CONTINUES W-SW IN THE SOUTHERN HEMISPHERE. SCATTERED MODERATE CONVECTION NOTED WITHIN 60 NM EITHER SIDE OF AXIS. ...DISCUSSION... A LARGE MIDDLE TO UPPER LEVEL CUT-OFF LOW OVER THE SW U.S. YESTERDAY HAS LIFTED OUT TO THE NE OVER WRN KANSAS THIS EVENING WITH TRAILING MID LEVEL TROUGH EXTENDING SW ACROSS NRN MEXICO AND THE S TIP OF THE BAJA PENINSULA TO NEAR 22N115W. WATER VAPOR IMAGERY SHOWED MODERATE TO STRONG SUBSIDENCE NW OF THE TROUGH AXIS COVERING THE AREA N OF 19N AND SE OF A LINE FROM NORTHERN BAJA CALIFORNIA TO 19N134W. TO THE E OF THIS WAS A SHORTWAVE RIDGE ACROSS CENTRAL AMERICA EXTENDING N-NE INTO THE SE U.S. OTHERWISE...GENERALLY ZONAL FLOW DOMINATED ALL BUT NW PORTIONS OF THE DISCUSSION AREA. A BROAD AND ENERGETIC UPPER TROUGH DOMINATES THE NE PACIFIC N OF 29N WITH SEVERAL SHORTWAVES MOVING THROUGH THE TROUGH. PRESENTLY...A SHORTWAVE MOVING THROUGH THE BASE OF THE TROUGH WAS NEAR THE CENTRAL CALIFORNIA COAST EXTENDING SW TO NEAR 29N140W...WITH MIDDLE TO UPPER LEVEL TROUGH EXTENDING WWD IN A TUTT LIKE FASHION TO BEYOND 20N150W. THIS FEATURE SUPPORTS A WEAKENING COLD FRONTAL BOUNDARY THAT WAS APPROACHING THE FAR NW CORNER OF THE DISCUSSION AREA THIS AFTERNOON. THIS FRONT WILL DRIFT SE AND INTO FAR NW PORTIONS OF THE AREA THIS EVENING AND BECOME NEARLY STATIONARY ON MON BEFORE DISSIPATING TUE. A MORE SIGNIFICANT FRONT IS FORECAST TO MOVE INTO THE NW PORTION OF THE AREA LATE TUE. THE BROAD UPPER TROUGH OVER THE NE PACIFIC IS FORECAST TO SHIFT EASTWARD THROUGH MON AS A MORE PRONOUNCED UPPER TROUGH MOVES INTO THE NW PORTION OF THE DISCUSSION AREA LATE MON INTO TUE. ELSEWHERE AT THE SURFACE...THE EPAC HIGH PRES RIDGE WAS CENTERED ON A 1036 MB HIGH OVER THE NORTH-CENTRAL PACIFIC WELL NW OF THE HAWAIIAN ISLANDS NEAR 36N168W. THE RIDGE BRIDGED ACROSS THE COLD FRONT AND SE TO NEAR 19N107W. THE PRES GRADIENT TO THE S OF THE RIDGE WAS INDUCING NE TRADES OF 20-25 KT GENERALLY N OF 05N TO A LINE FROM 21N140W TO 12N123W WITH SEAS IN THE 8-12 FT RANGE. THIS AREA OF TRADES IS FORECAST TO DIMINISH IN THE SOUTHERN LATITUDES BY THE NEXT 24 HRS...THEN DIMINISH CONSIDERABLY BOTH IN AREAL COVERAGE AND IN WIND SPEEDS BY 48 HRS AS THE RIDGE BREAKS DOWN TO A 1018 TO 1020 MB HIGH CENTER IN THE NE PART OF THE AREA. THIS WILL THEN ALLOW FOR A STRONGER COLD FRONT SUPPORTED BY THE MORE PRONOUNCED TROUGH TO MOVE INTO THE FAR NW WATERS BY TUE PRECEDED BY SW WINDS OF 20 KT. THE MAIN IMPACT OF THESE FRONTS MOVING INTO THE NORTHERN WATERS THROUGH THE NEXT 48 HRS WILL BE THE ASSOCIATED PULSES OF LONG PERIOD NW SWELLS SWEEPING SE ACROSS THE AREA. NWLY SWELL CURRENTLY ACROSS NW PORTIONS OF THE AREA WILL SLOWLY DECAY THROUGH TONIGHT ALLOWING FOR SEAS TO LOWER TO 9 FT FOR THE MOST PART. ANOTHER PULSE OF LONG PERIOD SWELLS WILL ARRIVE WITH THE STRONGER COLD FRONT TUE MORNING AND PRODUCE SEAS OF 9 TO 11 FT N OF 27N AND W OF 125W BY TUE EVENING. GAP WINDS... THE GULF OF TEHUANTEPEC...THE SMALL AND NARROW PLUME OF NORTHERLY WINDS OF AROUND 20 KT CONTINUES THROUGH THE GULF THIS AFTERNOON. SALINA CRUZ JUST W OF THE PLUME HAS REPORTED N WINDS OF 15 KT WITHIN THE PAST HOUR. THESE WINDS ARE EXPECTED TO WEAKEN TO LESS THAN 20 KT LATER THIS EVENING...THEN INCREASE AGAIN TO 20-25 KT EARLY MON THROUGH TUE. THE GULF OF PAPAGAYO...FRESH TRADES ACROSS THE CARIBBEAN CONTINUE TO FUEL GAP WIND FLOW ACROSS CENTRAL AMERICA THEN THROUGH THE GULFS OF PAPAGAYO AND FONSECA AND WELL SW TO NEAR 92W THIS AFTERNOON...WITH DOWNWIND SEAS PRESENTLY AT 8 TO 10 FT. HIGH PRES IS EXPECTED TO BUILD S AND SW ACROSS THE BAHAMAS AND W CARIBBEAN IN THE NEXT 24 HOURS AND WILL REINFORCE THIS FLOW THROUGH THROUGH THE GULF...WITH AREAS TO 30 KT EXPECTED BY MON. THIS AREA OF 20 KT WINDS AND HIGHER IS EXPECTED TO SPREAD WILL DOWNWIND TO 110W BY TUE MORNING DUE TO THE INCREASED PRES GRADIENT ACROSS THE W CARIBBEAN. THE GULF OF PANAMA...TRADES IN THE SOUTHWESTERN CARIBBEAN SEA WILL CONTINUE TO SUPPORT PULSES OF FRESH NORTHERLY FLOW ACROSS THE ISTHMUS OF PANAMA AND ACROSS THE GULF OF PANAMA. SEAS OF 6 TO 8 FT ARE EXPECTED TO CONTINUE S AND SW OF THE GULF. WINDS WILL BEGIN TO DECREASE TO AROUND 20 KT BY 48 HOURS. $$ COBB