000 AXPZ20 KNHC 130312 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC THU FEB 13 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0030 UTC. ...SPECIAL FEATURES... GULF OF TEHUANTEPEC...A COLD FRONT OVER THE WESTERN GULF OF MEXICO IS USHERING IN HIGH PRES OVER NE MEXICO TO THE EASTERN SLOPES OF THE SIERRA MADRE ORIENTAL MOUNTAINS. THE FRONT HAS MADE ITS WAY THROUGH CHIVELA PASS. THE OSCAT PASS FROM NEAR 1900 UTC SHOWED A STRONG N BREEZE IN THE GULF OF TEHUANTEPEC. WINDS WILL INCREASE TO GALE FORCE BY EARLY THU MORNING. THE GALE WILL BE SHORT LIVED...WITH CONDITIONS EXPECTED TO DIMINISH TO 30 KT BY LATE THU AFTERNOON AS THE COLD FRONT RACES EASTWARD OVER THE GULF OF MEXICO AND THE PRESSURE GRADIENT THROUGH CHIVELA PASS WEAKENS. THE GALE FORCE WINDS ARE EXPECTED TO PEAK AT 35 KT WITH SEAS TO 13 FT THU. N WINDS WILL DIMINISH BELOW A STRONG BREEZE AND SEAS WILL SUBSIDE BELOW 8 FT BY SUNRISE FRI. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS WAS ANALYZED FROM 06N77W TO 09N85W TO 05N95W. THE ITCZ AXIS WAS ANALYZED FROM 05N95W TO 08N120W TO BEYOND 06N140W. SCATTERED MODERATE TO STRONG CONVECTION WAS NOTED S OF THE MONSOON TROUGH FROM 02N TO 07N BETWEEN 81W AND 88W. SCATTERED MODERATE CONVECTION COULD BE FOUND N OF THE ITCZ FROM 08N TO 14N BETWEEN 118W AND 132W. ...DISCUSSION... SOUTHWEST FLOW ON THE S SIDE OF A WEAK UPPER LOW NEAR 16N130W IS TAPPING INTO DEEP LAYERED TROPICAL MOISTURE POOLED ALONG THE ITCZ W OF 120W AS SEEN IN PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE CONVECTION WAS FOUND N OF THE ITCZ FROM 08N TO 14N BETWEEN 118W AND 132W. THIS CONVECTION IS BEING ENHANCED BY UPPER DIFFLUENCE ASSOCIATED WITH THE REAR RIGHT QUADRANT OF THE SOUTHWESTERLY UPPER JET. THE LOW IS FORECAST TO REMAIN QUASI- STATIONARY AS IT OPENS INTO A TROUGH OVER THE NEXT TWO DAYS. THE UPPER JET ON THE LEADING EDGE OF THE TROUGH IS FORECAST TO WEAKEN AS THE NORTHERLY JET W OF THE TROUGH AXIS STRENGTHENS. THIS WILL SHIFT THE BEST CHANCE OF PRECIPITATION WESTWARD ALONG THE ITCZ TO NEAR 130W TOWARD THE MORE DIFFLUENT LEFT FRONT QUADRANT OF THE NORTHERLY JET OVER THE NEXT FEW DAYS. BROAD UPPER DIFFLUENCE IS ALSO ENHANCING THE SCATTERED MODERATE TO STRONG FROM 02N TO 07N BETWEEN 81W AND 88W. DIFFLUENCE HERE IS ATTRIBUTED TO AN UPPER RIDGE AXIS THAT SPANS FROM AN ANTICYCLONE OVER EASTERN COLOMBIA TO THE GALAPAGOS ISLANDS. THE RIDGE AXIS WILL DRIFT NORTHWARD OVER THE NEXT FEW DAYS...WITH A NEW ANTICYCLONE EXPECTED TO DEVELOP ALONG IT N OF THE GALAPAGOS NEAR 04N91W BY FRI. THE EASTERN PORTION OF THE MONSOON TROUGH SHOULD CONTINUE TO BE A FOCUS FOR MODERATE TO HEAVY PRECIPITATION OVER THE NEXT TWO DAYS. THE 1026 MB SUBTROPICAL HIGH NEAR 32N132W EXTENDS A RIDGE AXIS THROUGH THE FORECAST AREA TO NEAR 15N105W. THE ASCAT-A AND ASCAT- B PASSES FROM AROUND 1800 UTC SHOW FRESH TRADE WINDS LIE OVER W WATERS W OF THE RIDGE AXIS. SEAS TO 9 FT PRIMARILY IN NE TRADE WIND SWELL CAN BE FOUND OVER MUCH OF THE AREA FROM 06N TO 22N W OF 129W. THE HIGH IS FORECAST TO WEAKEN AND REMAIN QUASI- STATIONARY AS IT IS ENCROACHED UPON BY A COLD FRONT CURRENTLY FOUND TO ITS NW....FURTHER DIMINISHING THE TRADE WINDS AND SHRINKING THE AREA OF NE SWELL. THIS FRONT EXPECTED TO APPROACH THE FAR NW CORNER OF THE FORECAST AREA BY FRI EVENING. GULF OF PAPAGAYO...THE PRESSURE GRADIENT HAS RELAXED IN ADVANCE OF THE COLD FRONT IN THE GULF OF MEXICO EXPECTED TO BRING GALE FORCE WINDS TO THE GULF OF TEHUANTEPEC. WINDS IN THE GULF OF PAPAGAYO ARE ONLY A MODERATE NE BREEZE AT THE MOMENT BUT ARE EXPECTED TO BRIEFLY BECOME A STRONG BREEZE FRI MORNING AS THE COLD FRONT STRETCHES SOUTHWARD THROUGH CENTRAL AMERICA AND NOCTURNAL DRAINAGE FLOW IS AT ITS PEAK. $$ SCHAUER