000 AXPZ20 KNHC 162159 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC FRI OCT 16 2009 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2115 UTC. ...SPECIAL FEATURE... HURRICANE RICK WAS CENTERED NEAR 13.0N 100.0W AT 2100 UTC OR ABOUT 270 NM...435 KM S OF ACAPULCO MEXICO MOVING WNW AT 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 981 MB. MAXIMUM SUSTAINED WINDS HAVE INCREASED TO 75 KT WITH GUSTS TO 90 KT. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP5/WTPZ25 KNHC FOR MORE DETAILS. THE OVERALL SYMMETRY OF THE CLOUD PATTERN HAS CONTINUED TO LOOK QUITE IMPRESSIVE THROUGHOUT THE DAY WITH WHAT EARLIER APPEARED TO BE A CDO (CENTRAL DENSE OVERCAST) OVER THE CENTER HAS NOW DEVELOPED INTO A SMALL BUT FAINT EYE AS SEEN IN LATEST VISIBLE SATELLITE IMAGERY LARGE BANDING FEATURES CONTINUE TO BE VERY APPARENT AS OBSERVED IN BOTH VISIBLE AND IR SATELLITE IMAGERY FROM THROUGHOUT THE DAY AND IN THE MOST RECENT IMAGERY. THESE BANDS ARE COMPRISED OF NUMEROUS MODERATE TO STRONG CONVECTION WITHIN 60 NM EITHER SIDE OF 12N101W TO 14N102W TO 15N100W. NUMEROUS STRONG CONVECTION IS WITHIN 90 NM NW AND N OF THE CENTER. SCATTERED STRONG CONVECTION WITHIN 30 NM EITHER SIDE OF THE LINE FROM 10N94W TO 13N97W TO 15N100W MAKE UP THE REMAINDER OF BANDING FEATURE NOTED. WITH REGARDS TO MARINE INTERESTS AWAY FROM THE MAIN AREA OF STRONG WIND AND SEA CONDITIONS WITH RICK...20 TO 33 KT WINDS EXTEND OUTWARD UP TO 300 NM FROM THE CENTER OF RICK... EXCEPT 150 NM IN THE SW QUADRANT. ATMOSPHERIC CONDITIONS APPEAR FAVORABLE FOR RICK TO CONTINUE TO UNDERGO INTENSIFICATION UNDER A LOW SHEAR ENVIRONMENT ALONG WITH VERY CONDUCIVE SEA SURFACE TEMPERATURES THROUGH THE NEXT 48 HOURS AS IT TRACKS WNW. ...TROPICAL WAVE... A TROPICAL WAVE IS ALONG 115W FROM 8N-16N IS MOVING W AT ABOUT 13 KT. SCATTERED MODERATE CONVECTION IS OCCURRING WITHIN 120 NM W OF THE AXIS FROM 12N TO 14N. OTHER CONVECTION IS PRIMARILY TIED IN WITH THE ITCZ AS MENTIONED BELOW. ...ITCZ... THE AXIS OF THE INTERTROPICAL CONVERGENCE ZONE IS CENTERED ALONG 9N78W TO 12N95W TO 9N108W TO 12N119W TO 10N130W TO 11N137W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM EITHER SIDE OF THE AXIS BETWEEN 103W-112W...AND WITHIN 120 NM S OF THE AXIS BETWEEN 113W-117W AND BETWEEN 123W-126W. ...DISCUSSION... W OF 120W... A DEEP LAYER RIDGE WITH A MEAN CENTER NEAR 16N136W DOMINATES THIS PORTION OF THE AREA WITH A SURFACE 1021 MB HIGH NEAR 32N29W. A LARGE DEEP LAYER TROUGH IS JUST NW OF THE AREA MOVING E WITH ITS ASSOCIATED SURFACE COLD FRONT WITHIN ABOUT 60 NM NW OF 30N140W. THE TROUGH IS FORECAST TO BROADEN AND SLOWLY LIFT NE THROUGH THE NEXT 24-48 HOURS AS THE COLD FRONT BECOMES STATIONARY AND WEAKENED ALONG A LINE FROM 30N137W TO 27N140W. SEAS OF 8-10 FT IN NW SWELLS WILL FOLLOW IN THE WAKE OF THE FRONT. THE FRONT WILL DISSIPATE LATE SAT AFTERNOON INTO SAT EVENING AS SEAS SUBSIDE TO LESS THAN 8 FT. TO THE S OF THE RIDGE CENTER...A 1008 MB LOW IS ALONG THE ITCZ NEAR 12N136W. THE PRES GRADIENT BETWEEN THE LOW AND WEAK SURFACE RIDGING TO ITS N IS RESULTING IN WINDS OF 20-25 KT WITHIN 360 NM IN THE N AND NE QUADRANT WITH SEAS IN THE RANGE OF 9-12 FT. THE LOW...MOVING W 10-15 KT...IS FORECAST TO MOVE W OF THE AREA IN 24 HOURS AS THE SURFACE RIDGE ALSO SHIFTS W OVER THE NEXT FEW DAYS. E OF 120W... A MID/UPPER LEVEL TROUGH EXTENDS FROM ALONG THE WRN U.S. SOUTHWARD INTO THE AREA ROUGHLY ALONG 119W. A SMALL UPPER LEVEL CYCLONIC CIRCULATION MOVING W 15 KT IS ON THE TROUGH NEAR 20N. A MID/UPPER LEVEL ANTICYCLONIC CIRCULATION IS OVER WRN MEXICO NEAR 20N101W WITH A RIDGE EXTENDING NW TO WELL N OF THE AREA ACROSS THE WRN U.S. TO THE SW OF THE ANTICYCLONE...THE UPPER FLOW PATTERN BECOMES DIFFLUENT AIDING ITCZ CONVECTION BETWEEN 103W-112W. THE RIDGE IS FORECAST TO WEAKEN DURING THE WEEKEND AS THE AFOREMENTIONED TROUGH PROGRESSES EASTWARD ACROSS THE WESTERN U.S. A DAMPENING INVERTED MID/UPPER LEVEL TROUGH IS W OF THE DIFFLUENT ZONE ALONG 16N112W 10N115W...AND MAY HELPING TO SUPPORT CONVECTION RELATED TO THE TROPICAL WAVE ALONG 115W. TO THE E OF THE AREA OF HIGH PRES MENTIONED ABOVE N-NE WINDS OF 20 KT ARE OCCURRING N OF 24N BETWEEN 119W AND 125W WITH SEAS 9-12 FT IN NW SWELL DUE TO A TIGHT PRES GRADIENT BETWEEN A N TO S TROUGH ACROSS THE GULF OF CALIFORNIA AND THE SURFACE RIDGE. THESE WINDS ARE FORECAST TO MERGE WITH WIND CONDITIONS RELATED TO THE OUTER FRINGES OF 20-33 KT WINDS ASSOCIATED WITH HURRICANE RICK IN 48 HOURS. A DEEP LAYER MID LATITUDE TROUGH IS FORECAST TO AMPLIFY OVER THE GULF OF MEXICO SAT PUSHING A RATHER STRONG AUTUMN COLD FRONT THROUGH THE BAY OF CAMPECHE. STRONG HIGH PRES IN ITS WAKE WILL USHER NORTHERLY WINDS THROUGH THE ISTHMUS OF TEHUANTEPEC BY SAT EVENING...WITH N TO NE WINDS INCREASING TO 20-25 KT...AND TO 25-35 KT BY SAT EVENING AND TO 30-40 KT BY SUN AFTERNOON WITHIN 45 NM EITHER SIDE OF A LINE FROM 16N95W TO 13N97W. SEAS THERE ARE FORECAST TO BUILD INTO THE RANGE OF 10-14 FT BY SUN AFTERNOON. ELSEWHERE WITHIN 90 NM EITHER SIDE OF A LINE FROM 16N95W TO 13N99W N-NE WINDS ARE FORECAST TO INCREASE TO 20-30 KT WITH SEAS BUILDING 8-10 FT BY SUN AFTERNOON PER LATEST MODEL GUIDANCE. $$ AGUIRRE