000 AXPZ20 KNHC 081557 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC FRI MAR 06 2015 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...STRONG GALE CONDITIONS AT SUNRISE THIS MORNING ARE EXPECTED TO DIMINISH TO A MINIMAL GALE THIS AFTERNOON...AND FURTHER DIMINISH TO BELOW GALE FORCE THIS EVENING. MAXIMUM SEAS OF 17 FT NEAR 14N96W AT SUNRISE THIS MORNING SHOULD DIMINISH TO 12 FT OVER THE SOUTHERN WATERS OF THE GULF OF TEHUANTEPEC THIS EVENING. COLD WATER UPWELLING IS OBSERVED ON IR SATELLITE IMAGERY AS FAR S AS 12.8N96W. TONIGHTS NOCTURNAL MAXIMUM DRAINAGE SHOULD INCREASE THE NORTHERLY FLOW TO 30 KT WITH SEAS TO ABOUT 10 FT...THEN CONDITIONS WILL QUICKLY IMPROVE TO 15-20 KT ON MON AFTERNOON. THE NEXT TEHUANTEPEC EVENT IS EXPECTED TO BEGIN WITH 20-25 KT NORTHERLY WINDS DURING THE MAXIMUM DRAINAGE LATE TUE NIGHT...THEN GRADUALLY INCREASE TO A MINIMAL GALE EARLY ON WED NIGHT. LATEST GUIDANCE IS MORE AGGRESSIVE ON THIS NEXT EVENT...AND NOW SUGGESTS THE GALE CONDITIONS WILL PERSIST THROUGH SUNRISE ON FRI. A MINIMAL GALE WARNING IS IN EFFECT ACROSS THE GULF OF PAPAGAYO AND EXTENDING ABOUT 120 NM TO THE SW TILL EARLY THIS AFTERNOON. THE MINIMAL GALE CONDITIONS ARE EXPECTED TO DEVELOP AGAIN DURING MAXIMUM DRAINAGE LATE TONIGHT AND CONTINUE THROUGH SUNRISE ON MON...THEN QUICKLY DIMINISH TO 20 KT OR LESS ON MON EVENING. GUIDANCE HAS BECOME MORE AGGRESSIVE OVER THE PAST 24 HOURS AND NOW SUGGESTS A MAX OF 30 KT...NEAR GALE...WINDS LATE MON NIGHT...WITH ONLY A MINOR 25 KT PULSE ON TUE...WED AND THU NIGHTS. THIS ENHANCED NE 20-30 KT WINDS HAD SPREAD N ALONG THE COAST OF NICARAGUA TO ACROSS THE GULF OF FONSECA LATE LAST NIGHT...BUT ARE NOT EXPECTED TO EXCEED 15-20 KT TONIGHT...AND REACH ONLY 10-15 KT ON MON NIGHT. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A LOW LEVEL TROUGH EXTENDS SW ALONG THE PACIFIC COAST OF COLOMBIA. SCATTEROMETER WINDS INDICATE THAT THE ITCZ FORMS NEAR 02N85W AND EXTENDS W TO 02N100W TO 02N110W TO AN EMBEDDED TROUGH AT 05N123W...THEN THE ITCZ TURNS SW TO 02N135W WHERE IT LOSES IDENTITY. BROKEN TO LOCALLY OVERCAST LOW-MID LEVEL CLOUDS WITH EMBEDDED LIGHT SHOWERS ARE OBSERVED WITHIN 120 NM OF THE ITCZ TO THE W OF 93W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED WITHIN 90 NM OF 04.5N122W...IN ASSOCIATION WITH THE EMBEDDED TROUGH THAT EXTENDS FROM 02N122W TO 07N123W. SCATTEROMETER WINDS...BUOY AND IR IMAGERY INDICATE A VERY WEAK SOUTHERN HEMISPHERE ITCZ FROM 0.5S86.5W TO 03.4S120W TO BEYOND 03S140W. OVERCAST LOW-MID LEVEL CLOUDS WITH EMBEDDED LIGHT SHOWERS ARE OBSERVED WITHIN 120 NM OF THIS SOUTHERN HEMISPHERE ITCZ. ...DISCUSSION... ALOFT...AN UPPER LEVEL ANTICYCLONE IS OBSERVED NEAR 06N131W WITH A SHORT WAVE RIDGE EXTENDING N TO A CREST AT 35N128W. TO THE W OF THIS RIDGE IS A DEEP LAYERED CYCLONE STATIONARY AT 37N151W. A SERIES OF SURFACE COLD FRONTS ARE ROTATING AROUND THE CYCLONE. ONE OF THESE COLD FRONTS WILL PASS E OF 140W ON MON EVENING PRECEDED BY SOUTHERLY 20-25 KT WINDS AND SEAS OF 8-12 FT. THIS WEAK FRONT WILL STALL ALONG 32N126W TO 27N130W ON WED EVENING AND DISSIPATE BY THU. POST-FRONTAL NW SWELLS WILL RESULT IN COMBINED SEAS OF 7-10 FT W OF THE FRONT ON TUE AND WED. TO THE E OF THE UPPER RIDGE IS AN UPPER TROUGH THAT EXTENDS SW FROM WESTERN NEW MEXICO TO A BASE OVER THE SUBTROPICAL PACIFIC AT 22N111W. AN UPPER ANTICYCLONE IS OVER THE DEEP TROPICS NEAR 08N92W. DENSE DEBRIS MOISTURE...ORIGINATING FROM ITCZ CONVECTION OVER THE CENTRAL PACIFIC...IS ADVECTED E ALONG A 600 NM WIDE PLUME INTO THE DISCUSSION ACROSS THE UPPER RIDGE...AND THEN ROTATES SE AND NE THROUGH THE UPPER TROUGH AXIS ACROSS NORTHERN MEXICO...AND THEN FANS OUT ACROSS THE SE CONUS. OTHERWISE...THE UPPER LEVELS APPEAR VERY DRY ACROSS THE TROPICS S OF 16N E OF 113W AND SUPPRESSING CONVECTION ALONG THE ITCZ. A SURFACE RIDGE EXTENDS FROM 32N128W TO 15N101W. THE TRADES SW OF THE RIDGE ARE AT 20-25 KT WITH COMBINED SEAS OF 7-10 FT IN MIXING NE TRADES...ALONG WITH LONG PERIOD S AND NW SWELL. NE SWELL...ORIGINATING FROM A RECENT STORM EVENT IN THE GULF OF TEHUANTEPEC...WILL PROPAGATE WSW INTO THE TROPICAL WATERS TO THE S OF 13N...AND SPREAD W ACROSS THE WATERS BETWEEN 110-120W EARLY THIS WEEK MIXING WITH THE NE TRADE WIND SWELL. THE CROSS EQUATORIAL SOUTHERLY SWELL IS ALSO EXPECTED TO CONTINUE EARLY NEXT WEEK. .GULF PANAMA...A NARROW SWATH OF NORTHERLY 20-25 KT WINDS ARE EXPECTED TO CONTINUE THROUGH TONIGHT BEFORE DIMINISHING TO 15-20 KT ON MON. THE SOUTHERN EXTENT OF STRONG N WINDS SHOULD REACH NEAR 03N82W. $$ NELSON