000 AXPZ20 KNHC 221601 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC FRI APR 22 2016 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 1545 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A TROUGH AXIS EXTENDS FROM THE NEAR THE COAST OF COSTA RICA AT 09N85W AND EXTENDS SW TO 07N90W WHERE LATEST SCATTEROMETER DATA INDICATES IT BECOMES DEFINED AS THE MONSOON TROUGH AXIS TO 06N96W TO 07N102W TO 06N111W...AND THE ITCZ AXIS TO 05N120W TO 07N130W TO 05N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS SEEN WITHIN 180 NM S OF THE TROUGH BETWEEN 84W-90W. SCATTERED MODERATE CONVECTION IS FROM 03N-08N BETWEEN 95W-101W...WITHIN 60 NM N OF THE ITCZ AXIS BETWEEN 125W-128W... AND ALSO WITHIN 60 NM S OF THE TROUGH BETWEEN 84W-85W. ...DISCUSSION... UPPER LEVELS... AN UPPER LOW IS NOTED ON WATER VAPOR IMAGERY NEAR 25N115W MOVING QUICKLY EASTWARD. IT IS EMBEDDED WITHIN AN UPPER TROUGH THAT STRETCHES FROM JUST W OF THE PACIFIC NW REGION OF THE U.S. SE TO NORTHERN BAJA CALIFORNIA...AND SW TO THE UPPER LOW. A TROUGH EXTENDS FROM THE UPPER LOW TO NEAR 16N115W TO NEAR 08N117W. MODERATE TO STRONG SUBSIDENCE WITH ASSOCIATED DRY AND STABLE CONDITIONS ARE NOTED W OF THE UPPER TROUGH AND LOW. A WELL PRONOUNCED JET STREAM BRANCH EXTENDS THROUGH 15N120W...AND NE TO 20N110W AND TO OVER CENTRAL MEXICO. BROAD ANTICYCLONE FLOW IS TO THE SE OF 07N105W. THE MODERATE TO STRONG SW FLOW PATTERN NOTED BETWEEN THESE TWO FEATURES IS TRANSPORTING OVERCAST MID/HIGH CLOUDS EASTWARD ACROSS THE FAR EASTERN PACIFIC FROM 14N-21N AND TO ACROSS CENTRAL MEXICO FROM 19N-24N. DISTURBANCES RIDING NE ALONG THE JET STREAM ARE INTERACTING WITH THE ALREADY VERY MOIST AND UNSTABLE AIR IN PLACE S OF THE JET STREAM LEADING TO SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE WATERS FROM 10N-17N BETWEEN 100W-115W. THE UPPER LOW AND ASSOCIATED TROUGH ARE FORECAST TO SHIFT EASTWARD AND WEAKEN OVER WESTERN MEXICO LATE TONIGHT INTO SAT. AT THE SURFACE... A WEAK RIDGE REMAINS IN PLACE N OF 18N W OF 119W. THE RIDGE WILL CHANGE LITTLE THROUGH TONIGHT. A WEAK COLD FRONT IS NOTED ON FIRST VISIBLE SATELLITE IMAGERY TO BE CROSSING INTO THE NW PART OF THE AREA. LIGHT TO MODERATE NLY WINDS ARE BEHIND THE FRONT...HOWEVER A LARGE NW SWELL TRAIN IS PROPAGATING INTO THE NW PART OF THE AREA. IT BRINGING COMBINED SEAS OF 8-10 FT W OF LINE FROM 32N132W TO 27N140W. THE SWELL IS FORECAST TO GRADUALLY MOVE THROUGH MUCH OF THE NW AND CENTRAL PORTIONS THROUGH SAT. THE LEADING EDGE OF THE SWELL TRAIN IS FORECAST REACH NW OF A LINE FROM BAJA CALIFORNIA NORTE TO 27N140W BY EARLY ON SUN WITH RESULTANT SEAS STILL IN THE RANGE OF 8-10 FT. THE PRES GRADIENT WILL TIGHTEN N OF 29N BETWEEN 116W-117W BY LATE TONIGHT AND INTO EARLY ON SAT AS THE HIGH PRES RIDGING OVER THE FORECAST WATERS COMBINES WITH LOW PRES OVER THE INTER- MOUNTAIN REGION OF THE U.S. THIS WILL LEAD TO STRONG NW-N WINDS ACROSS THE AFOREMENTIONED AREA W OF BAJA CALIFORNIA NORTE. THIS WINDS CHANGE LITTLE ON SAT...THEN EXPAND SOME TO THE W SUN AS THE RIDGING INTENSIFIES. SEAS OF 9-12 FT IN NW SWELL ARE EXPECTED WITHIN THIS AREA OF STRONG NW-N WINDS. A TIGHT PRE GRADIENT BETWEEN THE BRIDGE ACROSS THE AREA...AND LOWER PRES IN THE VICINITY OF THE ITCZ HAS INCREASED THE TRADES TO 15-20 KT N OF THE ITCZ AND W OF 121W. COMBINED SEAS ARE 8-9 FT ACROSS THE TROPICS FROM 07N-12N W OF 134W. THIS AREA WILL BE CONFINED FROM 07N-17NW W OF 121W BY EARLY SAT...AND FROM 06N-16N W OF 123W BY EARLY SUN WITH SEAS OF 8-10 FT IN MIXED NE WIND WAVES AND NW SWELL. GAP WINDS... AFTER BEING QUIET FOR A WHILE...STRONG NORTHERLY DRAINAGE FLOW IS FORECAST BY THE NWP MODEL GUIDANCE ACROSS THE GULF OF TEHUANTEPEC BEGINNING LATE TONIGHT...AND LASTING THROUGH SAT MORNING BEFORE DIMINISHING TO 15-20 KT SAT AFTERNOON...AND BECOMING LIGHT AND VARIABLE MAINLY S-SW WINDS ON SUN. SEAS WITH THE NORTHERLY FLOW ARE EXPECTED TO BUILD TO 8 FT EARLY ON SAT...AND SUBSIDE TO LESS THAN 6 FT LATE SAT. $$ AGUIRRE