000 AXPZ20 KNHC 121602 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC WED MAR 12 2014 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. ...SPECIAL FEATURES... GULF OF TEHUANTEPEC GALE WARNING...A COLD FRONT MOVING ACROSS THE NW GULF OF MEXICO THIS MORNING WILL SWEEP SOUTHWARD ACROSS THE WESTERN GULF OF MEXICO THROUGH TONIGHT. THE DENSER AIRMASS BEHIND THE FRONT WILL FUNNEL ACROSS THE ISTHMUS OF TEHUANTEPEC AND INTO THE GULF OF TEHUANTEPEC EARLY THU MORNING. THIS AIRMASS WILL MIX DOWN TO THE SURFACE RESULTING IN NLY WINDS REACHING TO GALE FORCE STRENGTH WITH SEAS BUILDING TO 15 FT BY EARLY THU AFTERNOON. THE WINDS AND SEAS WILL GRADUALLY DIMINISH INTO FRI AS THE HIGH PRES BEHIND THE FRONT SHIFTS EASTWARD ACROSS THE NORTHERN GULF OF MEXICO. A LARGE PLUME OF SHORT PERIOD NE SWELLS RANGING FROM 8 TO 12 FT GENERATED BY THE TEHUANTEPEC EVENT WILL MIX WITH LONGER PERIOD NW SWELL OVER THE WATERS FROM 10N TO 14N BETWEEN 94W AND 105W BY EARLY FRI...HOWEVER THESE SWELLS WILL BE SHORT-LIVED AS WAVEWATCH GUIDANCE DEPICTS THEM TO DECAY TO BELOW 8 FT BY FRI EVENING. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH EXTENDS FROM 10N86W TO 05N98W. THE ITCZ AXIS EXTENDS FROM 05N98W TO 03N106W TO 03N115W TO 03N120W TO 01N130W. NO SIGNIFICANT CONVECTION. ...DISCUSSION... SATELLITE WATER VAPOR IMAGERY SHOWS A NEGATIVELY TILTED UPPER TROUGH THAT EXTENDS FROM NEAR 22N117W SE TO 18N112W WHERE IT BROADENS SSE TO 13N112W TO NEAR 00N105W. DIVERGENCE ALOFT E OF THE TROUGH IS HELPING TO SUSTAIN AN AREA OF WIDELY SCATTERED SHOWERS AND TSTMS FROM 03N TO 10N BETWEEN 103W-111W. MODEL GUIDANCE IS IN AGREEMENT WITH THE WATER VAPOR IMAGERY THAT A SPLIT FLOW PATTERN HAS SET UP ALOFT N OF THE HAWAIIAN ISLANDS...WITH THE SOUTHERN STREAM CARVING AROUND THE BASE OF A SHARP UPPER TROUGH ROUGHLY ALONG 145W EXTENDING S TO NEAR 10N. DIVERGENCE ALOFT E OF THE TROUGH IS RESULTING IN A VERY NOTICEABLE AREA OF OVERCAST MULTILAYERED CLOUDS WITH NUMEROUS SHOWERS AND ISOLATED TSTMS OVER THE FAR WESTERN PORTION OF THE DISCUSSION AREA FROM 09N TO 10N W OF 131W. AN UPPER LEVEL DIFFLUENT FLOW PATTERN TO THE SE OF THE TROUGH IS BRINGING OVERCAST TO BROKEN MOSTLY MID AND HIGH CLOUDS FROM 03N TO 09N W OF 129W. WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE UNDERNEATH THESE CLOUDS. FAST UPPER LEVEL WLY FLOW IS ADVECTING SOME OF THE HIGH CLOUDS EASTWARD TO NEAR 127W WHERE THEY DISSIPATE IN DRY UPPER LEVEL ENVIRONMENT. GLOBAL MODEL GUIDANCE SUGGEST THAT A SMALL UPPER LOW MOVING E NEAR 31N130W WITH A TRAILING TROUGH SW TO NEAR 24N132W WILL QUICKLY SHIFT EASTWARD TO THE FAR NE PORTION OF THE AREA BY THU AFTERNOON WITH THE TRAILING TROUGH COMING INTO PHASE WITH THE AFOREMENTIONED TROUGH CURRENTLY W OF THE DISCUSSION AREA ALONG 145W. AN UPPER LOW IS FORECAST TO DEVELOP ON THE SOUTHERN TAIL END OF THE TROUGH ON FRI NEAR 13N140W. BROAD UPPER ANTICYCLONIC FLOW WILL FOLLOW IN THE WAKE OF THE TROUGH. AT THE SURFACE...A RIDGE PRESENTLY EXTENDING FROM 32N134W SE TO NEAR 19N119W WILL BE REINFORCED BY AN AREA OF STRONGER HIGH PRES THAT BUILDS S AND SW OVER MUCH OF THE FORECAST AREA THU AND FRI. A TIGHTENING PRES GRADIENT BETWEEN THE HIGH AND LOW PRES OVER THE TROPICS WILL BRING AN INCREASE TO NE TRADE WIND FLOW FROM ABOUT 09N TO 20N AND W OF 120W BY FRI WITH SEAS THERE MAXING OUT TO 8 FT. LOW- LEVEL CONVERGENCE EXPECTED WITHIN THIS AREA SHOULD LEAD TO AN INCREASE OF SHOWER/TSTM ACTIVITY S OF 10N TO NEAR AND ALONG THE ITCZ REGION. A NW SWELL TRAIN WITH SEAS TO 9 FT IS CONFINED TO NW OF LINE FROM 30N136W TO 28N140W. THESE SWELLS ARE FORECAST TO REACH NW OF A LINE FROM 30N125W TO 23N140W BY EARLY THU BEFORE DECAYING 6- 7 FT ON FRI. OTHER GAP WINDS... THE TEHUANTEPEC GAP WIND EVENT...THE HIGH PRES THAT WILL BUILD BEHIND THE FRONT CURRENTLY PASSING ACROSS THE WESTERN GULF OF MEXICO WILL INITIATE FRESH TO STRONG GAP WINDS THROUGH THE GULF OF PAPAGAYO THU NIGHT INTO FRI MORNING...WITH ANOTHER PULSE FRI NIGHT INTO SAT MORNING. SIMILARLY...STRONG TRADE WINDS OVER THE SW CARIBBEAN SEA WILL PUSH THROUGH PANAMA FRI INTO SAT. $$ AGUIRRE