000 AXPZ20 KNHC 280235 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Thu Jul 28 2016 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 0245 UTC. ...SPECIAL FEATURES... Tropical Storm Frank is centered near 23.4N 122.7W, or about 815 miles...1310 km W of the Southern tip of the Baja California Peninsula, at 0300 UTC Jul 28, moving WNW or 300 degrees at 7 kt. The maximum sustained winds have diminished to 45 kt with gusts to 55 kt. The estimated minimum central pressure has risen to 1000 mb. Currently, scattered moderate isolated strong convection is observed within 90 nm in the west and 60 nm in the east semicircles of the storm. Frank is expected to weaken to a remnant low sometime on Thursday. Refer to the latest NHC forecast advisory under AWIPS/WMO headers MIATCMEP2/WTPZ22 KNHC for more details. Also refer to the latest high seas forecast under AWIPS/WMO headers MIAHSFEP2/FZPN03 KNHC for more details on the wave forecasts associated with Frank. ...TROPICAL WAVE...TROPICAL LOW...POST-REMNANT LOW GEORGETTE A tropical wave is analyzed from 10N to 17N along 112, and has been moving W at about 15 kt. Isolated moderate to strong convection is noted from 10-17N within 120 nm east of the wave axis. Scattered moderate isolated strong convection is observed within 240 nm over the E semicircle, and within 120 nm over the W semicircles of a 1009 mb low pressure center embedded in the monsoon trough near 11N109W. This low has a medium chance of developing into a tropical cyclone within 5 days. The post-tropical remnant low of Georgette was centered near 21N131W moving WNW at 8 kt. The maximum sustained winds are estimated to have dropped off to 25 kt, with earlier ASCAT A and B passes from 1804 and 1858 UTC indicating 20 to 25 knot winds within 120 nm in the N semicircle of the remnant low. The remnant low of Georgette is expected to continue to weaken, and should dissipate within 24 hours. ..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A monsoon trough extends WNW from the pacific coast of Costa Rica near 09N84W to 11N95W to a 1009 MB Low Pressure near 10N109W then continues to 10N127W. The axis of the ITCZ is now west of 140W. Scattered moderate isolated strong convection was noted within 120 NM of the axis between 118W and 123W. ...DISCUSSION... N of 15N e of 120W: Tropical storm force winds and 8 foot seas associated with Frank have moved west of 120W. See special features above additional information on Frank. A west to east orientated surface ridge will build from 21N120W to 15N106W on Thu in the wake of tropical storm Frank. The weak gradient northeast of the ridge will support light to gentle nw winds through the upcoming weekend, with seas of 4-6 ft. A nnw to sse orientated trough will meander e and w over the Baja California Peninsula, and the northern Gulf of California this week, supporting light and variable winds across the Gulf of California waters through early Fri. A gentle to moderate southerly flow is expected to begin late Fri, and will persist through early Sat night across the gulf waters. Moderate northerly flow is expected across the Gulf of Tehuantepec late Thu night into the early daylight hours on Fri, and then again late Fri night into Sat morning with seas building to about 6 ft. Model guidance is suggesting a slightly stronger drainage flow on Mon night into Tue morning with fresh to locally strong n-ne winds, and seas building to 8 ft. S of 15N e of 120W: See section on tropical wave and a surface low. Fresh NE to E winds are expected across, and just downstream of the Gulf of Papagayo during the overnight hours tonight, then guidance is hinting at moderate to locally fresh easterly drainage flow on Thu night as a weak surface low develops near 09N91W. The low should move westward through the upcoming weekend. Long-period cross-equatorial SW swell, in the form of combined seas of 6-8 ft, is forecast to propagate n across the equator between 100-115W on Thu, and reach along 08N between 90-115W by late Fri, then begin to subside. Combined seas are forecast to less than 8 ft on Sat night. W of 120W: See section above for information on the remnant low of Georgette and Tropical Storm Frank that will pass westward through the northern portion of this discussion area through Friday. Combined seas of 6-9 ft, primarily due to mixing swell, are expected to surround the large seas near the cyclone, and cover the waters elsewhere to the n of 12N through the upcoming weekend. $$ Cobb