000 AXPZ20 KNHC 260302 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC THU AUG 26 2010 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0115 UTC. ...SPECIAL FEATURES... HURRICANE FRANK IS CENTERED NEAR 17.2N 107.5W AT 26/0300 UTC MOVING W-NW OR 285 DEG AT 12 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 984 MB. MAXIMUM SUSTAINED WIND SPEED IS 70 KT WITH GUSTS TO 85 KT. FRANK IS EXPECTED TO TRACK AROUND THE SOUTHERN PERIPHERY OF AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER CENTRAL BAJA CALIFORNIA THE NEXT COUPLE OF DAYS. BY LATE FRIDAY...FRANK IS EXPECTED TO TRACK MORE NORTHWARD DUE TO A MID-LATITUDE UPPER LEVEL TROUGH FORECAST TO BEGIN IMPACTING THE U.S. WEST COAST AND BAJA CALIFORNIA. NUMEROUS MODERATE TO STRONG CONVECTION IS WITHIN 150 NM W AND 90 NM E SEMICIRCLES WHILE SCATTERED MODERATE CONVECTION LIES ELSEWHERE WITHIN 240 NM OF THE SW QUADRANT OF FRANK. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/ WTPZ24 KNHC FOR MORE DETAILS. ...TROPICAL WAVE... A TROPICAL WAVE ALONG 81W N OF 07N IS MOVING W AROUND 15 KT. SCATTERED MODERATE CONVECTION LIES WITHIN 180 NM W OF THE WAVE AXIS AND BETWEEN 75 NM AND 240 NM E OF THE WAVE AXIS N OF 06N INCLUDING OVER PORTIONS OF PANAMA. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED ALONG 07N83W TO 14N107W TO 10N125W TO 11N131W TO 08N140W. SCATTERED MODERATE CONVECTION IS WITHIN 180 NM S OF THE ITCZ AXIS BETWEEN 107W AND 112W AND WITHIN 75 NM N AND 120 NM S OF THE ITCZ AXIS BETWEEN 116W AND 121W. ...DISCUSSION... AN ANTICYCLONIC ALOFT IS CENTERED NEAR 26N112W AND EXTENDS AN UPPER LEVEL RIDGE THROUGH 23N122W TO 21N142W. UPPER LEVEL DIFFLUENCE ASSOCIATED WITH THE ANTICYCLONE IS ENHANCING SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WITHIN 30 NM OF THE COAST OF MAINLAND MEXICO FROM 25N TO 27N AND FROM 21N TO 24N. THIS SOUTHWESTWARD MOVING ANTICYCLONE IS GRADUALLY BUMPING THE WEAK MIDDLE TO UPPER-LEVEL LOW NEAR 30N120W NORTH OF THE DISCUSSION AREA. HURRICANE FRANK IS MOVING AROUND THE SOUTHERN PERIPHERY OF THIS RIDGE AND IS EXPECTED TO CONTINUE TRACKING W-NW THROUGH THE FORECAST PERIOD. SEE THE SPECIAL FEATURES SECTION FOR MORE DETAILS. SATELLITE WATER VAPOR IMAGERY SHOWS MOSTLY MODERATE SUBSIDENCE AND DRY AIR PRESENT OVER A LARGE PORTION OF THE AREA OUTSIDE THE ITCZ REGION N OF 16N W OF 121W. AT THE SURFACE...A RIDGE IMPACTS MUCH OF THE REGION N OF 18N W OF 120W. TO THE S...A PAIR OF 1010 MB WEAK LOWS ARE EMBEDDED WITHIN THE ITCZ. THE FIRST LOW IS CENTERED NEAR 13N116W AND REMAINS NEARLY STATIONARY. SCATTERED MODERATE CONVECTION IS WITHIN 150 NM SW AND 60 NM NE SEMICIRCLES. THIS LOW IS FORECAST TO DISSIPATE OVER THE NEXT 24 HOURS. THE SECOND LOW IS NEAR 11N132W AND IT HAS SCATTERED MODERATE WITHIN 120 NM NE AND 75 NM SW SEMICIRCLES. THIS WESTERN LOW IS FORECAST TO WEAKEN TO A TROUGH AND SLOWLY MOVE W OVER THE NEXT DAY OR TWO. THE 1718 AND 1858 UTC ASCAT PASSES ARE SHOWING ARE BROAD AREA OF 20 KT SOUTHERLY WINDS CURRENTLY FEEDING INTO THESE TWO LOWS. WINDS ARE EXPECTED TO DIMINISH HERE AS THESE LOWS DISSIPATE. FARTHER N...THE PRES GRADIENT IS EXPECTED TO BUILD OVER N CENTRAL WATERS ON FRI BETWEEN THE RIDGE OVER NW WATERS AND DEEPENING LOW PRES IN THE U.S. GREAT BASIN. 20 KT N WINDS AND 8 FT SEAS ARE EXPECTED N OF 27N. ASIDE FROM MARINE CONDITIONS ASSOCIATED WITH HURRICANE FRANK... CROSS EQUATORIAL S AND SW SWELLS WITH PEAK WAVE PERIODS OF 13-15 SECONDS CONTINUE TO BUILD SEAS TO THE 8-11 FT RANGE OVER MUCH OF THE AREA BETWEEN 80W AND A LINE FROM 21N105W TO 10N140W. THIS AREA OF SEAS OVER 8 FT WILL GRADUALLY SHRINK OVER THE NEXT COUPLE OF DAYS AS PERIODS SHORTEN BELOW 13 SECONDS. $$ SCHAUER