000 AXPZ20 KNHC 141005 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC FRI OCT 14 2011 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0845 UTC. ...SPECIAL FEATURES... AT 14/0900 UTC...TROPICAL STORM IRWIN WAS CENTERED NEAR 18.9N 106.8W AND WAS NEARLY STATIONARY. LITTLE MOTION IS EXPECTED DURING THE NEXT 12 TO 24 HOURS...AND A SLOW SOUTHWARD MOTION SHOULD BEGIN THEREAFTER. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1003 MB. THE MAXIMUM SUSTAINED WIND SPEEDS WERE 40 KT WITH GUSTS TO 50 KT. LITTLE CHANGE IN STRENGTH IS FORECAST DURING THE NEXT 24 HOURS....THE A SLIGHT WEAKENING TREND IS EXPECTED. NUMEROUS STRONG CONVECTION IS WITHIN 60 NM OF THE CENTER. SCATTERED STRONG CONVECTION IS ELSEWHERE WITHIN 120 NM OF THE CENTER IN THE E SEMICIRCLE AND 90 NM IN THE W SEMICIRCLE. PLEASE SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC AND/OR THE PUBLIC ADVISORY UNDER MIATCPEP1/WTPZ31 KNHC FOR MORE DETAILS. ...ITCZ/MONSOON TROUGH... MONSOON TROUGH EXTENDS FROM A 1007 MB LOW OVER NORTHERN GUATEMALA TO 15N100W WHERE IT ENDS. IT THEN RESUMES WELL TO THE SW OF TROPICAL STORM IRWIN FROM 15N122W TO 1012 MB LOW PRES NEAR 10N125W AND TO 08N140W. NUMEROUS STRONG CONVECTION EXISTS FROM 12N TO 15N BETWEEN 89W AND 98W. SOUTH OF THE MONSOON TROUGH...SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 30 NM OF 5N83W TO 5N81W. ...DISCUSSION... A COLD FRONT IS CURRENTLY MOVING INTO THE FAR NW CORNER OF THE AREA. IT WILL REACH A POSITION FROM 30N135W TO 25N140W BY LATE FRI EVENING. NW-N WINDS OF 20 KT AND SEAS BUILDING UP TO 8-10 FT IN A NW SWELL ARE EXPECTED IN THE WAKE OF THE FRONT IN ABOUT 24 HOURS. BY 30 HRS...A RATHER SIGNIFICANT LOW PRES SYSTEM IS EXPECTED TO MOVE TO JUST N OF THE DISCUSSION AREA 31N137W. W-NW WINDS OF 20-30 KT WITH POSSIBLE HIGHER GUSTS ARE EXPECTED TO MATERIALIZE N OF 28N W OF 136W...WITH SEAS 9-15 FT IN NW SWELL. BY LATE SAT NIGHT..THE LOW WILL BE NEAR 31N136W 1005 MB WITH THE W-NW WINDS DIMINISHING SOME TO 20-25 KT N OF 26N W OF THE WEAKENING FRONT FROM 30N132W TO 18N140W...WITH SEAS IN THE RANGE OF 9-15 FT IN NW SWELL. WATER VAPOR IMAGERY SHOWS AN UPPER LOW CENTERED NEAR 21N123W MOVING NWD. THE UPPER LOW IS TRANSPORTING TROPICAL MOISTURE NWD OVER THE AREA TO THE N OF 25N AND BETWEEN 115W-126W AS SEEN ON IR IMAGERY. THIS LOW WILL MOVE TOWARD THE N-NE TODAY BEFORE BEING PICKED UP BY THE DEEP LAYER TROUGH ASSOCIATED WITH THE COLD FRONT IN NW WATERS. A MID TO UPPER LEVEL RIDGE IS BUILDING ACROSS BAJA CALIFORNIA AND SOUTHERN CALIFORNIA. IRWIN WILL MOVE E-SE THEN S AROUND THE SOUTHERN PERIPHERY OF THIS RIDGE. UPPER-LEVEL NLY FLOW DOMINATES THE WATERS E OF 100W. FRESH TO STRONG WINDS ARE FLOWING INTO THE MONSOON TROUGH... WHICH EXTENDS OVER SOUTHERN MEXICO AND CENTRAL AMERICA INTO THE WESTERN CARIBBEAN. WITH THE MONSOON TROUGH EXPECTED TO REMAIN OVER THIS AREA...THESE WINDS WILL CONTINUE THROUGH THE FORECAST PERIOD...WITH SEAS REACHING UP TO 14 FT. FORECAST GUIDANCE SUGGESTS THAT A BROAD AREA OF LOW PRES WILL DEEPEN IN THE VICINITY OF THE YUCATAN PENINSULA OVER THE NEXT FEW DAYS AND FORCE STRONG N FLOW THROUGH THE GULF OF TEHUANTEPEC. WINDS ARE EXPECTED TO REMAIN BELOW GALE FORCE THERE. THE REMAINDER OF THE REGIONAL WATERS ARE DOMINATED BY MERGING NW AND SW SWELL. THIS SWELL WILL SLOWLY DECREASE FROM NW TO SW THROUGH THE NEXT 24 TO 48 HOURS...WHILE ANOTHER SET OF NW SWELLS IS EXPECTED TO ENTER THE AREA WITHIN THE NEXT 12-24 HOURS. $$ AGUIRRE