000 AXPZ20 KNHC 092125 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SAT AUG 09 2008 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 2100 UTC. ...SPECIAL FEATURE... HURRICANE HERNAN IS CENTERED NEAR 15.7N 123.3W AT 2100 UTC MOVING W-NW AT 8 KT. MAXIMUM SUSTAINED WINDS ARE 105 KT WITH GUSTS TO 130 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 956 MB. HERNAN HAS INTENSIFIED SIGNIFICANTLY IN THE LAST 24 HOURS AND HAS A WELL DEFINED 20 NM DIAMETER EYE WITH NUMEROUS STRONG CONVECTION NOTED WITHIN 60 NM OF CENTER. SCATTERED MODERATE TO STRONG CONVECTION IS NOTED ELSEWHERE WITHIN 80 NM NW SEMICIRCLE AND WITHIN 180 NM OVER THE SE SEMICIRCLE. HERNAN IS FORECAST TO REMAIN A MAJOR HURRICANE THROUGH THE NEXT 24 HOURS BEFORE ENCOUNTERING SLIGHTLY COOLER SEA SURFACE TEMPERATURES THEN IN 48 HOURS COOLER SEA WATER TEMPERATURES CAUSING IT TO UNDERGO WEAKENING AFTER 48 HOURS. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADER MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. ...TROPICAL LOWS... .LOW PRES IS ANALYZED NEAR 11N96W 1008 MB. CONVECTION HAS DECREASED OVERALL DURING THE LAST SIX HOURS AND SOME NEWLY FORMED CONVECTION HAS FORMED WELL TO THE NORTHEAST OF THE CENTER AND THIS INDICATES THAT CONVECTION IS NOT WELL ORGANIZED. THE LOW IS FORECAST TO POSSIBLY BECOME A TROPICAL CYCLONE IN THE NEXT 24 TO 48 HOURS AS IT MOVES WEST ABOUT 10 KNOTS. SCATTERED MODERATE TO STRONG CONVECTION IS NOTED WITHIN AN AREA FROM 100 TO 240 NM FROM THE CENTER IN THE NORTHEAST SEMICIRCLE. THE TROPICAL WAVE THAT HAS BEEN ANALYZED EAST OF THE LOW IS NOW DETERMINED TO BE ASSOCIATED WITH THE LOW AND IS ANALYZED FROM 18N95W THROUGH THE LOW TO 05N95W. BOTH THE LOW AND THE WAVE ARE MOVING WEST ABOUT 10 KNOTS. ...TROPICAL WAVES... THE TROPICAL WAVE 12 HOURS PREVIOUSLY ALONG 84W HAS BEEN ADJUSTED AS NOTED ABOVE. A TROPICAL WAVE IS ALONG 108W/109W FROM 05N TO 16N MOVING W AT ABOUT 12 KT THE PAST 24 HOURS. A SURFACE LOW IS ANALYZED ALONG THE WAVE AT AXIS AT 13N ESTIMATED AT 1009 MB. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION IS CURRENTLY OBSERVED WITHIN 75 NM OF THE POINT 14N107.5W. THE CONVECTION IS WEAKLY ORGANIZED BY THE CYCLONIC CIRCULATION. THE SYSTEM IS EXPECTED TO CONTINUE TO MOVE WEST AND NOT TO DEVELOP. ...ITCZ... INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE FROM 06N77W TO 05N90W TO 11N105W TO 15N120W TO 10N130W TO 12N140W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 90 NM OF 06.5N81W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 75 NM OF 12.5N92.5W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION IS WITHIN 60 NM OF 14.5N107.5W AND 15N115W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION IS WITHIN 90 NM OF 13N137W. ...DISCUSSION... A LONGWAVE DEEP LAYER TROUGH LIES OVER THE NE PACIFIC ALONG A LINE FROM NEAR 35N120W TO 20N140W. A REINFORCING SECONDARY TROUGH HAS STRENGTHENED THE NORTHERN PART OF THE TROUGH NORTH OF 27N. AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER NORTHERN TEXAS NEAR 33N101W. SOUTHERLY FLOW BETWEEN THE TROUGH AXIS AND THE ANTICYCLONE DOMINATES THE MIDDLE AND UPPER FLOW NORTH OF 17N WEST OF A LINE FROM NEAR 32N113W TO 18N121W TO 15N140W. THIS AREA IS DRY AND CLOUD FREE IN THE MIDDLE AND UPPER LEVELS. IN THE LOWER LAYERS OVERCAST STRATOCUMULUS IS NOTED NORTH OF 24N BEGINNING ABOUT 200 NM WEST OF THE COAST OF BAJA CALIFORNIA OUT TO NEAR 130W WHERE THE CLOUDS BECOME BROKEN TO OVERCAST WEST OF 130W AND SOUTH OF 25N. MOST MOISTURE ASSOCIATED WITH HERNAN CONVECTION IS NOT BEING ADVECTED NORTHWARD BUT IS REMAINING SOUTH OF 17N AND SOME IS BEING ADVECTED SOUTH OF THE ITCZ. NORTH OF THE ITCZ EAST OF ABOUT 115W THE ATMOSPHERE IS MOIST IN THE MIDDLE AND UPPER LEVELS WITH AREAS OF MULTI LEVEL CLOUDINESS AND EMBEDDED AREAS OF CONVECTION. WEAKENING COLD FRONT IS THROUGH 32N130W TO 27.5N140W HAS BECOME DIFFUSE. A WEAK RIDGE IS NORTHWEST OF HERNAN. ELSEWHERE EXCEPT FOR THE LOWS MENTIONED ABOVE A BROAD TROUGH IS ANALYZED. $$ LL