000 AXPZ20 KNHC 121545 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC MON JAN 12 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 GALE WARNING...THE MINIMAL GALE FORCE CONDITIONS WILL CEASE AGAIN THIS AFTERNOON THEN BEGIN AGAIN LATE TONIGHT AND THEN CONTINUE THROUGH SUNRISE TOMORROW. THE MINIMAL GALE PULSES WILL BEGIN AGAIN TUE NIGHT AND THEN CONTINUE THROUGH WED MORNING. A REINFORCING SURGE LATE THU WILL RESULT IN 30-40 KT CONDITIONS THU EVENING AND FRI THEN DIMINISHING TO 30 TO 35 KT CONDITIONS ON FRI EVENING AND FRI NIGHT. GUIDANCE INDICATES WINDS BELOW GALE ON SAT MORNING. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS NW FROM THE PACIFIC COAST OF COLOMBIA AT 06N77W AND ALONG THE PACIFIC COAST OF PANAMA TO 09N86W...THEN TURNS SW TO 07N91W WHERE SCATTEROMETER WINDS INDICATE A TRANSITION TO AN ITCZ WHICH CONTINUES SW TO 06N96W...THEN TURNS W-NW TO BEYOND 08N140W. SCATTERED MODERATE CONVECTION IS OBSERVED WITHIN 60 NM EITHER SIDE OF A LINE FROM 06N77W TO 03N82W...AND ALONG THE ITCZ WITHIN 75 NM EITHER SIDE OF A LINE FROM 04.5N100W TO 08N117W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED FROM 05-17N BETWEEN 117-132W. ...DISCUSSION... AN UPPER ANTICYCLONE IS OVER THE DEEP TROPICS AT 10N106W WITH A SHORTWAVE RIDGE EXTENDING NW TO A SHARP CREST AT 32N134W. UPPER DIFFLUENCE UNDER THE WESTERN PORTION OF THE RIDGE IS ENHANCING CONVECTION ALONG THE ITCZ AS PREVIOUSLY DESCRIBED WITH THE DENSE DEBRIS MOISTURE COVERING THE DISCUSSION AREA BETWEEN 110-131W. TO THE W OF THE SHORTWAVE RIDGE IS AN UPPER CYCLONE CENTERED NEAR 35N136W WITH A NARROW UPPER TROUGH EXTENDING S ALONG 30N139W TO 20N139W TO A BASE AT 08N133W WITH UPPER DIFFLUENCE DIRECTLY E OF THE TROUGH AXIS ENHANCING CONVECTION. AN ASSOCIATED LOW LEVEL TROUGH EXTENDS FROM 09N138W TO 19N137W. TO THE E OF THE UPPER SHORTWAVE RIDGE IS A BROAD UPPER SHORTWAVE TROUGH WITH MEAN AXIS FROM OVER LOUISIANA AT 31N92W TO ACROSS THE GULF OF TEHUANTEPEC TO BASE OVER THE TROPICAL PACIFIC NEAR 09N99W. THE TROUGH IS ACCOMPANIED BY DRY UPPER AIR SUPPRESSING CONVECTION...EXCEPT THE FOR A NARROW BAND ALONG THE ITCZ AS PREVIOUSLY DESCRIBED. A LOW LEVEL RIDGE EXTENDS FROM 32N129W TO 15N100W. EASTERLY TRADES ARE ENHANCED TO 20-25 KT ACROSS THE TROPICS WITHIN 120 NM EITHER SIDE OF LINE FROM 19N135W TO 13N130W TO 11.5N121W WITH 8- 11 FT SEAS. THE TRADES ARE MOSTLY IN THE 15-20 KT RANGE ELSEWHERE BETWEEN THE RIDGE AND THE ITCZ WITH 7-10 FT SEAS PRIMARILY DUE TO MIXING NE WIND WAVE...LONG PERIOD CROSS EQUATORIAL SE SWELL AND LONG PERIOD NW SWELL. BROAD LOW LEVEL TROUGHING IS EXPECTED TO CONTINUE S OF THE RIDGE BETWEEN 115- 135W THROUGHOUT THE WEEK WITH THE GRADIENT SUPPORTING A SMALL AREA OF 20-25 KT WINDS AND SEAS OF 8-12 FT NEAR THE TROUGH AXIS THAT WILL SHIFT NE WITH TIME. A WEAK COLD FRONT IS EXPECTED TO MOVE INTO NW WATERS ON TUE NIGHT AND STALL FROM 32N133W TO 25N136W ON WED NIGHT. EXPECTING SOUTHERLY 15-20 KT FLOW AHEAD OF THE FRONT...BUT ONLY 10-15 KT NORTHERLY FLOW BEHIND THE FRONT WITH NW SWELL BUILDING SEAS 8-12 FT IN THE FAR NW WATERS BRIEFLY ON WED. GULF OF PAPAGAYO...TRADE WINDS IN THE SW CARIBBEAN CONTINUE TO FUNNEL WSW ACROSS AND DOWNSTREAM OF THE GULF OF PAPAGAYO TO NEAR 09N91W. THESE WINDS ARE EXPECTED TO REACH 25 KT DURING THE MAXIMUM NOCTURNAL DRAINAGE...WITH THESE PULSES OCCURRING EACH NIGHT THROUGH SAT NIGHT. $$ NELSON