000 AXPZ20 KNHC 180343 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC FRI JAN 18 2013 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 0330 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH EXTENDS FROM 07N78W TO 08N85W TO 07N90W WHERE LOW LEVEL WINDS SUGGEST IT TRANSITIONS TO THE ITCZ TO 06N100W TO 11N122W TO 07N140W. NO SIGNIFICANT CONVECTION IS NOTED. ...DISCUSSION... SATELLITE WATER VAPOR IMAGERY SHOWS A SHARPENING UPPER TROUGH LIFTING NEWD ALONG 32N131W 26N128W 21N121W. HIGHLY AMPLIFIED UPPER RIDGES ARE E AND W OF THE TROUGH WITH THE ONE E OF THE TROUGH ALONG AN AXIS FROM 32N121W TO 28N118W TO 23N112W...AND THE ONE W OF THE TROUGH ALONG 32N137W 25N137W TO 19N137W. A SHARP DEEP LAYER TROUGH IS W OF THE AREA ROUGHLY ALONG 146W...AND IS ADVANCING EWD. OVER THE FAR SRN PORTION OF THE AREA BROAD MID/UPPER RIDGING IS PRESENT S OF 15N W OF ABOUT 100W. MOSTLY BROKEN MID AND UPPER LEVEL CLOUDS ARE BEING CHANNELED ENE AHEAD OF THE TROUGH ALONG 32N131W 26N128W 21N121W TOWARDS BAJA CALIFORNIA AND MOST OF CENTRAL MEXICO. UPPER DIFFLUENT FLOW S OF THE TROUGH IS RESULTING IN AN AREA OF BROKEN LOW AND MID LEVEL CLOUDS WITH EMBEDDED SCATTERED SHOWERS AND ISOLATED TSTMS FROM 10N TO 15N BETWEEN 108W AND 116W. AT THE SURFACE...A 1024 MB HIGH CENTER IS N OF THE AREA AT 36N130W WITH A RIDGE SSE THROUGH 32N132W TO 21N140W. A SURFACE TROUGH RUNS JUST PARALLEL TO THE NRN COAST OF BAJA CALIFORNIA NW AND N ALONG THE COAST OF CALIFORNIA. THE COMBINATION OF THE TROUGH AND VERY STRONG HIGH PRES OVER NRN MEXICO IS BRINGING NW WINDS OF 20-25 KT THROUGH THE GULF OF CALIFORNIA N OF 25N. THESE WINDS ARE FORECAST TO DIMINISH TO 20 KT OR LESS IN JUST A FEW HOURS. BASED ON PREVIOUS SCATTEROMETER PASSES...N TO NE WINDS OF 35-50 KT ARE FUNNELING THROUGH THE GULF OF TEHUANTEPEC. EXPECT THE CULPRIT VERY TIGHT PRES GRADIENT TO PERSIST THROUGH THE NEXT FEW DAYS WHILE IT BEGINS TO GRADUALLY WEAKEN. THIS WILL BRING THESE WINDS UP STORM FORCE ACROSS THE GULF THROUGH FRI MORNING...GALE FORCE WINDS THROUGH SUN MORNING THEN VERY STRONG TO NEAR-GALE CONDITIONS THROUGH TUE WITH PEAK WINDS REACHING MINIMAL GALE AROUND SUNRISE FROM DIURNAL EFFECTS. NO SIGNIFICANT CHANGE IS EXPECTED IN THE SYNOPTIC PATTERN...WITH NORTHERLY WINDS IN THE GULF OF MEXICO AND PERSISTENT STRONG PRES GRADIENT IN CENTRAL AMERICA. THE GULF OF PAPAGAYO WILL ALSO BEGIN TO EXPERIENCE STRONG PERSISTENT NE WINDS FRI THROUGH MON IN THIS SYNOPTIC PATTERN. FRESH TO STRONG E-NE WINDS WILL EXTEND FAR DOWNWIND FROM THE SOURCE REGIONS NEAR TEHUANTEPEC AND GULF OF PAPAGAYO...RESULTING IN VERY LARGE AREA OF ELEVATED SEA HEIGHTS IN NE SWELL THU THROUGH LATE SAT EXTENDING ROUGHLY FROM 05N TO 14N E OF 107W. N TO NE WINDS OF 20-25 KT ARE FORECAST TO SURGE THROUGH THE GULF OF PANAMA BEGINNING FRI EVENING AND CONTINUE INTO EARLY NEXT WEEK. THE WAVEWATCH MODEL GUIDANCE SHOWS 27 SEC LONG PERIOD NW SWELL REACHING NW PORTION EARLY SAT MORNING THEN SPREADING ACROSS WESTERN WATERS THROUGH TUE WITH LITTLE CHANGE IN WAVE PERIOD ALONG LEADING EDGE OF THE SWELL. COASTAL AREAS IN MEXICO WITH NW EXPOSURE CAN EXPECT HAZARDOUS SURF FROM UNUSUALLY LARGE WAVE HEIGHTS AND BEACH EROSION DURING THIS LONG PERIOD SWELL EVENT. AN OCCLUDED FRONTAL SYSTEM WITH LOW PRES CENTERED WELL W OF THE AREA AT 37N150W WILL DRIFT N-NW THROUGH FRI NIGHT AND DRAG A FRONTAL BOUNDARY...CURRENTLY EXTENDING FROM THE LOW TO 30N145W TO 21N150W...SLOWLY NORTHEASTWARD AND APPROACH 140W FRI NIGHT AND SAT. THIS WILL CAUSE SE WINDS TO INCREASE TO 20-25 KT NW OF A LINE FROM 30N135W TO 22N140W AND BUILDING SEA HEIGHTS TO 9-15 FT IN NW SWELL THROUGH THE WEEKEND TO WITHIN AN AREA BOUNDED TO N OF 22N W OF 134W BY SUN. GFS AND ECMWF MODELS SHOW AN AREA OF LOW PRES DEVELOPING NEAR 35N155W EARLY SAT MORNING THEN FORECAST TO MOVE SE TO AROUND 17N142W BY TUE MORNING AS A 1004-1006 MB LOW. WINDS AND SEAS WILL INCREASE W OF 130W SAT THROUGH MON AS THE LOW INTENSIFIES W OF THE DISCUSSION AREA. $$ AGUIRRE