000 AXPZ20 KNHC 182120 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC FRI AUG 18 2006 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 2100 UTC. ...SPECIAL FEATURES... HURRICANE HECTOR IS AT 16.7N 126.9W AT 18/2100 UTC MOVING WNW OR 290 DEG AT 12 KT. MAXIMUM SUSTAINED WIND SPEED IS 85 KT WITH GUSTS TO 105 KT. HURRICANE FORCE WINDS EXTEND 30 NM AND T.S. FORCE WINDS WITHIN 125 NM OF THE CENTER. SEAS 12 FT OR GREATER WITHIN 200 NM EXCEPT 225 NM NW QUADRANT. AFTER BEING RAGGED THIS MORNING WITH AN OPEN EYEWALL APPEARANCE ON SATELLITE...HECTOR HAS BECOME BETTER ORGANIZED THIS AFTERNOON WITH AN EYE APPARENT ON BOTH VIS AND IR SATELLITE IMAGERY. THE MOST IMPRESSIVE CONVECTION IS IN THE NW QUADRANT. NUMEROUS MODERATE TO STRONG CONVECTION EXTENDS 120 NM FROM THE CENTER. HOWEVER THIS IMPROVEMENT IN STRUCTURE IS LIKELY TO BE SHORT LIVED AS STEADY WEAKENING IS FORECAST DUE TO HECTOR MOVING OVER PROGRESSIVELY COOLER WATERS AND INTO A MORE DRY STABLE AIR MASS WITH AN INCREASE IN SHEAR. FOR MORE DETAILS SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... SRN PORTION OF TROPICAL WAVE IS OVER THE ERN E PAC ALONG 88W N OF 4N ACROSS CENTRAL AMERICA...AND THE YUCATAN PENINSULA. THIS WAVE IS MOVING W 15 KT OVER THE PAST 24 HOURS. NO ORGANIZATION NOTED NEAR THE ANALYZED WAVE AXIS. HOWEVER A LOW-MID LEVEL SWIRL HAS DEVELOPED 250 NM W OF THE AXIS. UPPER LEVEL WINDS APPEAR FAVORABLE FOR DEVELOPMENT OVER THE NEXT FEW DAYS. TROPICAL WAVE ALONG 115W FROM 5N-13N MOVING W 15 KT. THIS WAVE HAS BECOME SLIGHTLY BETTER DEFINED WITH BROAD LOW-MID LEVEL CYCLONIC TURNING OBSERVED IN THE AREA. HOWEVER MODERATE N-NE SHEAR IS PREVENTING THIS WAVE FROM ORGANIZING SHEARING ALL THE ASSOCIATED CONVECTION TO THE SE OF THE BROAD TURNING FROM 4N-9N BETWEEN 109W-112W. ...ITCZ... ITCZ AXIS ALONG 9N78W 9N114W 13N122W 10N140W. BESIDES FOR THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...ISOLATED MODERATE IS WITHIN 240 NM EITHER SIDE OF THE AXIS E OF 89W. SCATTERED MODERATE FROM 11N-14N BETWEEN 98W-102W. SCATTERED MODERATE WITHIN 120 NM EITHER SIDE OF THE AXIS W OF 134W. ...DISCUSSION... STRONG MID-UPPER LEVEL RIDGE EXTENDS FROM NRN MEXICO SW TO AN ANTICYCLONE NEAR 18N120W. THIS FLOW IS INTERRUPTED BY A WEAKNESS FROM A MID-UPPER TROUGH BETWEEN 120W-128W. THIS WEAKNESS IS WHAT IS STEERING HECTOR N OVER COOL WATERS AND INTO A DRY ENVIRONMENT. FARTHER WEST...A BROAD UPPER LEVEL HIGH IS CENTERED NEAR 19N139W. DRY STABLE AIR AND FAIR WEATHER COVERS THE MAJORITY OF THE AREA NW OF A LINE ALONG 13N140W 15N130W 21N126W 28N115W. WIDESPREAD MOISTURE LIES TO THE SE OF THIS LINE BUT BESIDES FOR HECTOR...THE TROPICAL WAVES AND THE ITCZ...VERY LITTLE OF IT IS DEEP IN NATURE AT THE SURFACE...TYPICAL PACIFIC RIDGE STRETCHES ACROSS THE AREA ALONG 32N130W 25N115W 18N107W. HECTOR IS PUSHING AGAINST THE RIDGE...TIGHTENING THE PRES GRAD...ENHANCING NE TRADES BETWEEN 12N AND 27N W OF 132W WITH WINDS 20 KT AND SEAS 8 FT. CROSS EQUATORIAL WINDS ARE 15 TO 20 KT WITH S SWELLS PRODUCING 8 FT SEAS S OF 6N BETWEEN 90W-115W. WINDS ALONG THE BAJA COAST ARE NW 10 TO 15 KT BASED UPON SHIPS AND QUIKSCAT DATA. GAP WINDS AROUND CENTRAL AMERICA ARE MOSTLY LIGHT ALSO. A PATCH OF CONVECTION HAS MOVED OFF THE COAST OF SRN MEXICO EARLIER TODAY E OF 105W FROM 18N-20N BUT MUCH OF THIS HAS BEEN FALLING APART OVER THE PAST FEW HOURS. GFS MODEL SHOWS LITTLE CHANGE IN THE OVERALL PATTERN OVER THE NEXT 24 HOURS BESIDES FOR HECTOR MOVING WNW-NW. HOWEVER...IT IS DEVELOPING AN AREA OF LOW PRES ON SUN. THIS DEVELOPMENT APPEARS TO BE FROM THE TROPICAL WAVE THAT IS CURRENTLY IN THE VICINITY OF 90W. $$ CANGIALOSI