000 AXPZ20 KNHC 131001 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC TUE MAR 13 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0945 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH IS NOT PRESENT ACROSS E PACIFIC. ITCZ AXIS EXTENDS FROM 03N88W TO S OF THE EQUATOR AT 110W. NO SIGNIFICANT CONVECTION IS NOTED. ...DISCUSSION... A BROAD UPPER LEVEL TROUGH CONTINUES TO DOMINATE THE NE PACIFIC WITH ITS SRN PERIPHERY EXTENDING S INTO N PORTIONS OF THE DISCUSSION AREA. SHORTWAVES CONTINUE TO MOVE THROUGH THE BASE OF THE TROUGH...WITH ONE RECENTLY HAVING EXITED THE AREA TO OVER NW MEXICO AND A MORE ROBUST ONE STRETCHING FROM 32N129W SW TO W OF THE AREA AT 24N140W. A JET STREAM BRANCH ENTERS THE AREA THROUGH 20N140W...AND CONTINUES NEWD TO 23N126W TO 26N120W AND TO ACROSS CENTRAL BAJA CALIFORNIA TO WELL INLAND NRN MEXICO AND THE S CENTRAL U.S. A JET CORE WITH WINDS IN THE RANGE OF 75-90 KT IS OVER THE FAR WRN PART OF THE AREA JUST S OF THIS JET STREAM BRANCH FROM 14N-20N W OF 130W. SATELLITE WATER VAPOR IMAGERY SHOWS BROKEN TO SCATTERED HIGH CLOUDS FROM WELL W OF 140W BEING TRANSPORTED INTO THE DISCUSSION AREA BY JET STREAM WINDS. THESE CLOUDS ARE IDENTIFIED TO BE WITHIN ABOUT 300 NM S OF THE JETSTREAM BRANCH. A VERY LARGE DOME OF UPPER LEVEL RIDGING S OF 07N W OF 100W TO WELL W OF 140W TO ACROSS THE EQUATORIAL CENTRAL PACIFIC IS HELPING TO KEEP A GENERAL ZONAL FLOW ALOFT IN PLACE OVER JUST ABOUT THE ENTIRE AREA S OF THE JET STREAM. OVER THE EXTREME FAR SE PORTION OF THE AREA...A MID/UPPER LEVEL TROUGH EARLIER NEAR 90W HAS SHIFTED EASTWARD TO NOW ALONG 84W AND TO SWD TO BEYOND THE EQUATOR. SATELLITE WATER VAPOR IMAGERY SHOWS ABUNDANT MODERATE SUBSIDENCE THROUGHOUT THIS AREA ALLOWING FOR ONLY VERY LIMITED SHOWER ACTIVITY TO DEVELOP NEAR THE TROUGH. A MORE SUBTLE MID LEVEL IS W OF THIS TROUGH EXTENDING FROM 15N108W TO 07N108W. THE TROUGH ALONG 84W WILL MOVE E OF THE ERN PACIFIC EARLY THIS AFTERNOON...WHILE THE ONE ALONG 108W QUICKLY REACHES TO NEAR 91W TONIGHT AND TO NEAR 89W BY WED NIGHT BEFORE MOVING E OF THE AREA. NOT MUCH IN THE WAY OF MAJOR CONVECTION IS EXPECTED WITH THIS SECOND TROUGH AS IT WORKS THROUGH A VERY STABLE ATMOSPHERE IN PLACE. AT THE SURFACE...A COLD FRONT SUPPORTED BY THE SECOND SHORTWAVE TROUGH MENTIONED ABOVE IS JUST NW OF THE AREA CROSSING 32N140W. THIS FRONT IS FORECAST TO MOVE ACROSS THE FAR NW WATERS LATER THIS MORNING...BUT WEAKEN AS IT REACHES FROM 32N130W TO 25N140W TONIGHT THEN STALL AND CONTINUE TO WEAKEN THROUGH LATE WED AS THE BROAD UPPER TROUGH SHIFTS EASTWARD LEAVING THE SHORTWAVE TROUGH BEHIND IN A SHEARED NE-SW STATE. WINDS ARE EXPECTED TO BE RATHER LIGHT ON EITHER SIDE OF THE FRONT THROUGH WED AS INDICATED BY NWP MODEL GUIDANCE. THE MAIN IMPACT OF THE FRONT THROUGH THE NEXT 48 HRS WILL BE ATTRIBUTED TO PULSES OF LONG PERIOD NW SWELLS BEHIND IT THAT PROPAGATE INTO THE NW WATERS RESULTING IN LARGE COMBINED SEAS THERE. CURRENTLY SEAS IN THE RANGE OF 9-11 FT IN NW SWELL LOCATED N OF 27N W OF 128W WILL EXPAND EASTWARD THROUGH WED NIGHT WITH 12 FT STAYING JUST N OF THE AREA PER CONSENSUS OF WAVEWATCH GUIDANCES. THE 9-11 FT SEAS SLOWLY DECAY TO 8 FT DURING THU. ELSEWHERE AT THE SURFACE...THE EPAC HIGH PRES RIDGE WAS CENTERED ON A 1031 MB HIGH OVER THE NORTH-CENTRAL PACIFIC WELL NW OF THE HAWAIIAN ISLANDS. THE RIDGE EXTENDS THROUGH INTO THE AREA THROUGH 26N140W AND NE TO WEAK 1019 MB AT 28N122W AND SE TO SRN PART OF THE BAJA PENINSULA ALONG 112W. THE PRES GRADIENT TO THE S OF THE RIDGE WAS INDUCING NE TRADES OF 20 KT GENERALLY FROM 04N TO 15N W OF 131W...FROM 06N-10N BETWEEN 90W-106W AND FROM 08N-14N BETWEEN 112W-131W. SEAS WITHIN THESE TRADE AREAS ARE IN THE RANGE OF 8-10 FT....WITH THE HIGHEST SEAS FOUND W OF 131W. THESE AREAS OF TRADES ARE FORECAST TO DIMINISH ACROSS THEIR SRN BOUNDARIES DURING THE NEXT 24-36 HOURS AS THE 1019 MB HIGH CENTER SHIFTS SOME TO THE NE...BUT IT SHOULD STRENGTHEN AGAIN AT OR NEAR 48 HRS TIGHTENING THE PRES GRADIENT TO ITS S. E OF 112W...WINDS ARE DOMINATED BY GAP WIND FLOW SPILLING FROM THE CARIBBEAN ACROSS CENTRAL AMERICA AND THEN DOWNSTREAM ACROSS THE EPAC...WITH LIGHT NE-E WINDS S OF 06N. COMPOSITE TOTAL PRECIPITABLE WATER (TPW) IMAGERY FROM CIMSS SUGGESTS WHAT APPEARS TO BE A LOW LEVEL LOW AMPLITUDE TROUGH MOVING WESTWARD ALONG 116W. SCATTERED TSTM ACTIVITY IS WITHIN 30 NM OF 10N116W. GAP WINDS... THE GULF OF TEHUANTEPEC...AN OSCAT PASS FROM NEAR 0600 UTC THIS MORNING REVEALED N-NE WINDS OF 20-25 KT THROUGH THE GULF WITHIN 30 NM OF A LINE FROM 16N95W TO 14N95W VERY LIKELY DUE TO NOCTURNAL DRAINAGE FLOW. HIGH PRES WILL BEGIN TO BUILD ACROSS THE GULF OF MEXICO AND THE WRN CARIBBEAN DURING THE NEXT FEW DAYS BRINGING AN INCREASE TO THE N-NE WINDS ALONG WITH INCREASING THE LENGTH OF WIND SWATH THROUGH THE GULF. MODEL GUIDANCE HAS BEEN CONSISTENT IN HINTING THAT THESE WINDS MAY BRIEFLY APPROACH 30 KT DURING THE EARLY MORNING HRS THROUGH THU WITH A POSSIBILITY OF THEM PULSING TO GALE FORCE LATE AT NIGHT WED AND THU. THE GULF OF PAPAGAYO...FRESH TRADES ACROSS THE CARIBBEAN CONTINUE TO FUEL GAP NE 20-25 KT WINDS ACROSS CENTRAL AMERICA THEN THROUGH THE GULF OF PAPAGAYO AND JUST DOWNWIND OF THE GULF FONSECA...EXTENDING WELL SW TO NEAR 91W THIS MORNING. SEAS OF 8-10 FT ARE DOWNSTREAM OF THE FLOW WITH THE MAX SEAS NEAR 09N91W. AS STATED ABOVE...HIGH PRES IS EXPECTED TO BUILD S AND SW ACROSS THE GULF OF MEXICO AND WRN CARIBBEAN WITHIN THE NEXT 48 HOURS. THIS WILL ACT TO REINFORCE THIS FLOW THROUGH THROUGH THE GULF WITH WINDS INCREASING TO 30 KT. DOWNSTREAM NE-E 20 KT WINDS ARE FORECAST TO REACH NEAR 115W BY 48 HRS. 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. THE OSCAT PASS FROM NEAR 0600 UTC LAST NIGHT SHOWED N-NE WINDS OF 20 KT N OF 05N BETWEEN 79W-82W TO INCLUDE THE GULF. WINDS MAY PULSATE BRIEFLY TO 25 KT AT NIGHT ON WED AND THU WITH MORE OF NLY COMPONENT. SEAS ARE EXPECTED TO REMAIN AT LESS THAN 8 FT THROUGH THE NEXT 24-48 HRS. $$ AGUIRRE