000 AXPZ20 KNHC 182205 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2145 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH EXTENDS FROM 05N77W TO 06N91W WHERE LOW LEVEL WINDS SUGGEST THE ITCZ AXIS BEGINS AND CONTINUES TO 08N107W TO 08N123W TO 07N140W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM S OF THE ITCZ AXIS BETWEEN 112W-114W AND WITHIN 30 NM OF 09N120W. ...DISCUSSION... WATER VAPOR IMAGERY SHOWS AN UPPER LOW NEAR 30N129W WITH A SHARP TROUGH FROM THE LOW SE TO 25N124W TO NEAR 21N117W TO 178N108W. THE LOW AND TROUGH ARE LIFTING NORTHEASTWARD. MID/UPPER LEVEL RIDGING IS NOTED TO THE E OF THE LOW AND TROUGH STRETCHING INTO THE AREA FROM 32N119W SEWD TO OVER NW AND CENTRAL MEXICO. BROKEN TO SCATTERED MID AND HIGH CLOUDS E OF THE TROUGH ARE STREAMING NNE TO ACROSS NRN AND CENTRAL MEXICO...AND FURTHER NE TO SW U.S. AND FAR WRN TEXAS REGION. UPPER LEVEL RIDGING EXTENDS ROUGHLY ALONG 133W N OF 21N. A LONGWAVE TROUGH IS PRESENT W OF THE AREA NEAR 149W WITH A SERIES OF SHORTWAVE TROUGHS ROTATING EWD THROUGH IT. AN ASSOCIATED COLD FRONT IS W OF THE AREA ALONG 150W N OF ABOUT 25.5N. AHEAD OF IT...A STATIONARY FRONT EXTENDS FROM 32N143W TO 20N145W. SCATTERED SHOWERS AND TSTMS ARE SEEN ALONG AND WITHIN 180 NM E OF THIS FRONT...AND ARE ADVANCING EWD WITH TIME. BROAD MID/UPPER LEVEL HIGH PRES IS S OF 10N W OF 95W. A ZONE OF DIFFLUENCE ALOFT BETWEEN THE NE PERIPHERY OF THE HIGH PRES AND TROUGH ALONG 25N124W 21N117W TO 17N108W IS AIDING A AREA OF MOISTURE IN THE FORM OF BROKEN MULTILAYERED CLOUDS WITH SCATTERED SHOWERS AND TSTMS FROM 13N TO 18N BETWEEN 101W AND 110W. THE LEFT ENTRANCE REGION OF JET STREAM BRANCH BETWEEN THE TROUGH AND THE HIGH PRES S OF 10N IS ACTIVATING SCATTERED SHOWERS AND A FEW TSTMS N OF THE ITCZ AXIS FROM 10N TO 14N BETWEEN 110W AND 120W. ELSEWHERE AT THE SURFACE...A VERY TIGHT PRES GRADIENT ACROSS CENTRAL AND SRN MEXICO INCLUDING THE ISTHMUS OF TEHUANTEPEC CONTINUES TO BRING QUITE AN IMPRESSIVE SWATH OF STORM FORCE WIND THROUGH THE CHIVELA PASS AND THROUGH THE GULF OF TEHUANTEPEC AS WAS EVIDENT FROM SCATTEROMETER DATA FROM LAST NIGHT...AND EARLY THIS MORNING. SHIP WITH CALL SIGN "3FCB8" SAILING TO THE SE OVER THE SE PORTION OF THE GULF OF TEHUANTEPEC HAS BEEN REPORTING NLY WINDS TO VERY NEAR 50 KT DURING THE COURSE OF THE DAY. MODEL GUIDANCE FROM 30 METER GFS AND NAM GUIDANCE INDICATES THAT THE STORM FORCE CURRENTLY BEING EXPERIENCED THROUGH THE GULF AS WELL AS DOWNSTREAM FROM THE GULF WILL SLOWLY DECREASE TO GALE FORCE TONIGHT INTO EARLY SAT MORNING...AND CONTINUE THROUGH SUN MORNING FOLLOWED BY VERY STRONG TO NEAR-GALE CONDITIONS THROUGH TUE WITH PEAK WINDS REACHING MINIMAL GALE AROUND SUNRISE DUE TO 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 HAVE STRONG PERSISTENT NE WINDS 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 THROUGH SAT NIGHT EXTENDING ROUGHLY FROM 05N TO 14N BETWEEN 92W AND 113W. N TO NE WINDS OF 20-25 KT SURGING THROUGH THE GULF OF PANAMA ARE EXPECTED TO CONTINUE WITH LITTLE CHANGE INTO EARLY NEXT WEEK. THE WAVEWATCH III MODEL GUIDANCE CONTINUES TO EXHIBIT 27 SEC LONG PERIOD NW SWELLS INVADING THE NW PORTION OF THE AREA EARLY ON SAT MORNING. THESE SWELLS ARE PROJECTED TO SPREAD SE ACROSS THE WRN SECTION THROUGH TUE WITH LITTLE CHANGE IN WAVE PERIOD ALONG LEADING EDGE OF THE SWELL. COASTAL AREAS IN MEXICO...THE BAJA PENINSULA IN PARTICULAR...WITH NW EXPOSURE CAN EXPECT HAZARDOUS SURF FROM UNUSUALLY LARGE WAVE HEIGHTS AND BEACH EROSION DURING THIS LONG PERIOD SWELL EVENT. GFS AND ECMWF MODELS SHOW AN AREA OF LOW PRES DEVELOPING WELL N OF THE AREA SAT MORNING. THE LOW PRES IS FORECAST TO MOVE SE TO AROUND 17N142W BY TUE MORNING AS A MODERATELY INTENSE LOW. ASSOCIATED STATIONARY FRONT OR FRONTAL TROUGH ENTERING BASIN SUN WITH STRONG TO NEAR GALE FORCE SE WINDS WELL AHEAD OF BOUNDARY AND SIMILAR W TO SW WINDS W OF FRONT. THESE CONDITIONS HAVE BEEN INCORPORATED INTO THE LATEST ISSUANCE OF THE HIGH SEAS FORECAST (HSFEP2). $$ AGUIRRE