000 AXPZ20 KNHC 180338 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0315 UTC. ...SPECIAL FEATURES... HURRICANE HECTOR IS CENTERED NEAR 15.0N 122.1W OR 975 MILES SOUTHWEST OF THE SOUTHERN TIP OF BAJA CALIFORNIA AT 18/0300 UTC MOVING WNW OR 285 DEG AT 11 KT. MAXIMUM SUSTAINED WIND SPEED IS 90 KT WITH GUSTS TO 110 KT. THE OVERALL STRUCTURE OF THE CYCLONE CONTINUES TO LOOK QUITE IMPRESSIVE ON SATELLITE IMAGERY THIS EVENING. IT HAS A VERY WELL DEFINED-BANDING FEATURES AND PRESENTLY THE EYE FEATURE EARLIER PARTIALLY OBSCURED HAS REAPPEARED WITH 15 NM IN DIAMETER WIDTH. GOOD OUTFLOW PATTERN IS STILL PRESENT OVER THE CYCLONE. CONVECTION IS OBSERVED IN SPIRAL BANDS WITH SCATTERED STRONG INTENSITY WITHIN 75 NM W QUADRANT AND 45 NM N AND S QUADRANTS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ELSEWHERE WITHIN 180 NM SE SEMICIRCLE. A TRAILING SPIRAL BAND CONSISTS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION WITHIN 30 NM EITHER SIDE OF A LINE FROM 11N124.5W TO 12.5N122W. HECTOR IS FORECAST TO STRENGTHEN SLIGHTLY WITHIN THE NEXT 24 HOURS THEN BEGIN TO WEAKEN OVER OVER COOLER WATERS THEREAFTER WHILE AT THE SAME TIME UNDERGOING VERTICAL SHEAR. FOR MORE DETAILS SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... SOUTHERN PORTION OF A TROPICAL WAVE IS OVER THE EASTERN PORTION OF THE AREA ALONG 83W N OF 4N TO ACROSS CENTRAL COSTA RICA AND PANAMA...AND CONTINUES NORTHWARD INTO THE WESTERN CARIBBEAN SEA. THIS WAVE IS MOVING W ABOUT 10-15 KT. STRONG CONVECTION IN CLUSTERS ARE ARE WITHIN 30 NM OFF THE SOUTHERN COAST OF COSTA RICA AND NORTHERN COAST OF PANAMA. WEAKENING ISOLATED MODERATE CONVECTION IS TIED TO THE ITCZ AS DESCRIBED BELOW. TROPICAL WAVE ALONG 111W FROM 4N-16N IS MOVING W 15 KT. THIS WAVE IS SLIGHTLY MORE DEFINED THAN THE WAVE TO THE E. LOW CLOUDS ARE CONVERGING INTO THE WAVE IN THE VICINITY OF THE ITCZ...HOWEVER NO CYCLONIC DEVELOPMENT IS BEING OBSERVED. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM WEST OF THE WAVE FROM 7N-13N. TROPICAL WAVE JUST W OF AREA ALONG 141W FROM 4N-19N IS MOVING W 15-20 KT. THIS WAVE IS BEING DRAWN INTO A BROAD AREA OF CYCLONIC TURNING W OF THE AREA. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 30 NM OF LINE 13N136.5W 113N139W. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 9N85W 9N100W 9N110W 13N120W 12N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60-90 NM OF THE AXIS BETWEEN 90W-100W. SCATTERED MODERATE CONVECTION IS WITHIN 180 NM S OF THE AXIS BETWEEN 129W-132W. ISOLATED MODERATE CONVECTION IS WITHIN 180 NM S OF THE AXIS BETWEEN 82W-84W. ...DISCUSSION... MID/UPPER LEVEL RIDGE EXTENDS SW FROM NRN MEXICO TO ROUGHLY 19N115W. A BROAD MID/UPPER TROUGH DIGGING SEWD IS N OF 23N W OF 120.5W. THE TROUGH IS FORECAST TO LIFT NE THROUGH THE NEXT 3-4 DAYS WITH HURRICANE HECTOR TRACKING NW TO THE W OF THE RIDGE AND TOWARDS THE TROUGH. LARGE MID/UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 18N137W WITH RIDGE E TO 125W. THE RIDGE WILL REMAIN NEARLY STATIONARY THROUGH AT LEAST SAT THEN SHIFT SOME WWD. MID LEVEL EASTERLIES LIE S OF 20N WITH HECTOR EMBEDDED IN THEM. MODERATE SUBSIDENCE AND DRY STABLE UPPER LEVEL AIR COVERS THE AREA N OF 13N W OF 125W AND ALSO NW OF A LINE FROM 17N125W TO NORTHERN BAJA CALIFORNIA. AMPLE MOSTLY UPPER LEVEL MOISTURE IS BEING ADVECTED WESTWARD SE OF THIS LINE WITH OUTFLOW FROM HECTOR BEING PART OF THE MOISTURE. A WEAK ANTICYCLONE IS CENTERED OVER GUATEMALA WITH A RIDGE EXTENDING WESTWARD TO NEAR 100W. AN UPPER LEVEL MEAN RIDGE AXIS RUNS NW TO SE FROM SE MEXICO TO NICARAGUA. ANTICYCLONIC AROUND THIS RIDGE CONTINUES TO SPREAD DEBRIS MID-HIGH LEVEL MOISTURE NORTHWARD TOWARDS SE MEXICO. S OF THE RIDGE...STRONG MID/UPPER LEVEL EASTERLIES PREVAIL ALSO SPREADING DEBRIS MID-HIGH LEVEL MOISTURE WESTWARD FROM S AMERICA TO NEAR 110W. AT THE SURFACE...RIDGE EXETNDS FROM 32N132W THROUGH 27N122W TO 25N115W. HIGH PRESSURE GENERALLY COVERS THE AREA N OF 22N. PRESSURE GRADIENT DUE TO THE RIDGE IS PRODUCING NE TRADES OF 20 KT FROM 12N-23N W OF 128W. WINDS ALONG THE BAJA COAST CONTINUE TO BE MOSTLY LIGHT UNDER A WEAK PRESSURE GRADIENT...HOWEVER MODEL GUIDANCE OF BOUNDARY LAYER WINDS INDICATES THAT THE GRADIENT MAY INCREASE JUST ENOUGH TO ALLOW FOR NW WINDS OF 20 KT TO SLIDE DOWN ALONG THE BAJA CALIFORNIA COAST AND OUT TO WITHIN 60 NM OF THE COAST IN IN 48 HOURS. $$ AGUIRRE