000 AXPZ20 KNHC 101617 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC SAT MAR 10 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1515 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE PRIMARILY ITCZ WITH ASSOCIATED CONVECTION IS JUST S OF THE EQUATOR. AN ITCZ SEGMENT EXTENDS FROM 03N95W TO THE EQUATOR ALONG 108W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 90 NM N OF THE ITCZ SEGMENT. ...DISCUSSION... A LARGE MIDDLE TO UPPER LEVEL CUTOFF LOW WAS OVER THE DESERT SW SECTION OF THE U.S. WITH A TROUGH EXTENDING SW ACROSS CENTRAL BAJA CALIFORNIA TO NEAR 19N120W. WATER VAPOR IMAGERY SHOWED AN EXPANSIVE AREA OF SUBSIDENCE ASSOCIATED WITH SW PORTIONS OF THIS TROUGH PREVAILING OVER THE EASTERN SECTION OF THE AREA...AND MAINTAINING VERY STABLE CONDITIONS...AND ALMOST ENTIRELY CLEAR SKIES N OF 20N E OF 124W. ELSEWHERE...RELATIVELY ZONAL FLOW DOMINATED THE UPPER LEVELS OF THE AREA...WITH A BROAD SHORTWAVE RIDGE W OF 120W...A SECOND SHORTWAVE RIDGE E OF THE TROUGH FROM NEAR 07N100W ACROSS CENTRAL AMERICA AND THE W GULF OF MEXICO... WHILE MIDDLE TO UPPER LEVEL TROUGHING CONTINUED FROM THE WESTERN CARIBBEAN SW INTO THE FAR EPAC E OF 97W...PRODUCING SUBSIDENCE AND STABLE CONDITIONS THERE. ACTIVE AND PERSISTENT DEEP CONVECTION NEAR THE MEANDERING ITCZ WAS PRODUCING DIVERGENT FLOW ALOFT ACROSS EQUATORIAL ZONES BETWEEN 95W AND 130W. A VIGOROUS UPPER LEVEL LOW WELL W OF THE AREA TO THE WNW OF THE HAWAIIAN ISLANDS WAS ACCOMPANIED BY A VERY LARGE SWATH OF DEEP LAYER ATMOSPHERIC MOISTURE TO ITS E AND SE. STRONG UPPER LEVEL SW WINDS WERE ADVECTING THIS MOISTURE NE TO JUST OVER THE FAR WESTERN BOUNDARY OF THE DISCUSSION AREA. THE CUTOFF LOW OVER THE SW U.S. WILL GRADUALLY LIFT NE THROUGH SUN IN RESPONSE TO INTENSIFYING SHORTWAVE ENERGY THAT SWINGS IN FROM NE PACIFIC TO INLAND OF THE PACIFIC NW. THIS WILL ACT CREATE AN EVEN MORE ZONAL FLOW ALOFT WITHIN THE NEXT 48 HRS. A WEAK COLD FRONT THAT MOVED INTO THE FAR NW CORNER OF THE AREA EARLIER WILL NOT ADVANCE EASTWARD MUCH THROUGH SUN AS THE BROAD UPPER TROUGH JUST TO ITS N QUICKLY TRANSLATES EASTWARD AS THE SHORTWAVE TROUGH MOVES THROUGH ITS FAR NORTHERN PERIPHERY. THE FRONT IS FORECAST TO SLOWLY WASH OUT THROUGH SUN AS STRONG HIGH PRES BUILDS EASTWARD ACROSS THE NORTHERN WATERS UNDER THE UPPER LEVEL ZONAL FLOW. THE MAIN ISSUE WITH RESPECT TO MARINE INTERESTS OVER THE THE NW AND N CENTRAL WATERS WILL BE THE ARRIVAL OF LARGE LONG PERIOD NW SWELLS TODAY AND INTO EARLY SUN. THESE SWELLS ARE FORECAST TO PRODUCE SEAS OF 10 TO 12 FT TODAY. ELSEWHERE AT THE SURFACE...A RIDGE EXTENDED THROUGH 31N140W SE ACROSS THE STATIONARY FRONT TO NEAR 15N106W. A TIGHT PRES GRADIENT TO THE S OF THE RIDGE WAS INDUCING NE-E 20-25 KT TRADE WINDS FROM 05N-21N W OF 120W...AND FROM 07N-18N BETWEEN 112W AND 120W...WITH SEAS GENERALLY 9-11 FT. THIS AREA OF TRADES IS FORECAST TO CHANGE LITTLE OVER THE NEXT 24 HRS...THEN DIMINISH BOTH IN AREAL COVERAGE AND IN WIND SPEEDS BY 48 HRS AS THE HIGH WEAKENS IN RESPONSE TO A COLD FRONT THAT SKIRTS THE FAR NORTHERN WATERS AT THAT TIME. GAP WINDS... THE GULF OF TEHUANTEPEC...MINIMAL N-NE GALE FORCE WINDS ARE PRESENTLY SPILLING OUT OF THE GULF OF TEHUANTEPEC AND ARE FORECAST TO ONLY LAST A FEW MORE HOURS AS THE PRES GRADIENT OVER SE MEXICO WEAKENS. THESE WINDS WILL THEN DIMINISH TO 20-25 KT IN 24 HRS...AND TO LESS THAN 20 KT IN 36 HRS. THE GULF OF PAPAGAYO...FRESH TRADES ACROSS THE CARIBBEAN CONTINUE TO FUEL GAP WIND FLOW ACROSS CENTRAL AMERICA THEN THROUGH THE GULF OF PAPAGAYO AND WELL DOWNWIND TO NEAR 93W THIS MORNING. WINDS ARE GENERALLY 20-25 KT WITH SOME ISOLATED AREAS TO 30 KT. THIS LARGE PLUME IS NOW SOME 240 NM...WITH SEAS WITHIN THIS PLUME HAVING BUILT TO 8 TO 9 FT. LITTLE SIGNIFICANT CHANGE IS EXPECTED ACROSS THIS AREA IN THE NEXT 24 HOURS. 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 AND DOWNWIND TOWARDS THE SW DURING THE NEXT 48 HOURS....WHERE SEAS WILL REMAIN IN THE 6 TO 8 FT RANGE. LITTLE CHANGE HERE IS EXPECTED DURING THE NEXT 24 HOURS. $$ STRIPLING