781 axpz20 knhc 260929 twdep Tropical weather discussion NWS TPC/National Hurricane Center Miami FL 1005 UTC Sat Jul 26 2008 Tropical weather discussion for the eastern Pacific Ocean from the Equator to 32n...east of 140w. Based on 0600 UTC surface analysis and satellite imagery through 0915 UTC. ...Special feature... Downgraded Tropical Storm Genevieve centered near 17.1n 119.1w...or about 625 nm...1155 km...west-southwest of Cabo San Lucas Mexico...at 26/0900 UTC moving W at 12 kt. Maximum sustained winds have decreased to 60 kt with gusts to 75 kt. Estimated minimum central pressure is 990 mb. See latest NHC forecast/advisory under AWIPS/WMO headers miatcmep3/wtpz23 knhc for more details. The core convection of Genevieve appears to be weakening and covering a smaller area than six hours ago. Water vapor imagery indicated that Genevieve was embedded within a large area of mid to upper level dry air and is forecast to move over progressively cooler waters. The combination of the two factors should result in a steady weakening of the cyclone. ...Tropical waves... Tropical wave along 93w N of 05n moving W 10-12 kt. An upper level low to the NW of the tropical wave continues to support a region of upper level diffluence in the vicinity of the wave. Despite this upper level support convection is limited along the wave axis itself. ...ITCZ... ITCZ axis is centered along 08n78w to 10n98w to 09n105w to 11n114w to 09n140w. Scattered moderate isolated strong within 120-150 nm S of the axis between 97w and 112w and N of 03n to the coast of Panama and E of 80w. Scattered moderate within 60 nm of the axis W of 133w. ...Discussion... A break in the upper level ridge along 135w is allowing the remnant mid to upper level moisture of Fausto northward toward a mid latitude trough approaching the W coast of the conus. The inverted mid level trough tracking S of Fausto is expected to be left behind and continue W out of the forecast area. Further E... Tropical Storm Genevieve is forecast to take a slightly more N of W track as it encounters the weakness in the ridge to its NW. The ridge over the SW and Southern Plains is also being compromised...in this case by the remnant of Dolly tracking across NW Mexico. Expect the mid level shortwave energy associated with Dolly to shear out to the north today...with the northern energy passing N into the New Mexico while the southern energy tracks W into the Gulf of California. This southern energy...in conjunction with the shortwave energy currently triggering the convection along the W central Mexican coast and a broad area of upper level diffluence will help the cause for convection over the Gulf of California tonight and tomorrow. Meanwhile...an upper level low moving across far southern Mexico should continue wwd into the E Pacific with the aforementioned tropical wave in Tow on its E side. Look for convection to favor the area se of the tropical wave near Costa Rica and Panama for now...in the region of upper level diffluence. Behind the tropical wave. Winds have increased to over 20 kt in the vicinity of the Gulf of papagayo as strong NE to E flow seeps through Central America from the Caribbean behind the tropical wave. $$ Cobb

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