000 AXPZ20 KNHC 141003 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Mon Aug 14 2023 Tropical Weather Discussion for the eastern Pacific Ocean from 03.4S to 30N, east of 120W including the Gulf of California, and from the Equator to 30N, between 120W and 140W. The following information is based on satellite imagery, weather observations, radar, and meteorological analysis. Based on 0600 UTC surface analysis and satellite imagery through 0930 UTC. ...SPECIAL FEATURES... Major Hurricane Fernanda is centered near 15.6N 117.7W, or 620 nm southwest of the southern tip of Baja California at 14/0900 UTC, moving west at 7 kt. Estimated minimum central pressure has lowered to 959 mb. Maximum sustained wind speed has increased to 110 kt with gusts to 135 kt. Satellite imagery shows a cyclone that is continuing to rapidly intensify. A well-defined eye is visible and is surrounded by thick eyewall. An overnight ASCAT pass depicted winds of 20-33 kt in the periphery of the cyclone. Peak seas have build to around 39 ft. The satellite imagery reveals numerous moderate to strong convection is within 60 nm of the center, except 120 nm in the SW quadrant. Outer rain bands consisting of scattered moderate convection are within 30 nm of a line from 13N119W to 14N116W, and within 30 nm of another line from 15N116W to 17N117W to 16N119W and to 15N118W. Fernanda is forecast on a general west to west-northwest motion, with some increase in forward speed over the next few days. Fernanda is a category 3 hurricane on the Saffir-Simpson Hurricane Wind Scale. Additional intensification is forecast over the next 12 to 18 hours, with Fernanda forecast to become a category 4 hurricane on today. Gradual weakening is expected to begin thereafter. Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website - https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and the latest Fernanda NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Newly upgraded Tropical Storm Greg is centered near 11.3N 139.8W at 14/0900 UTC, moving west at 11 kt. Estimated minimum central pressure is 1005 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Satellite imagery shows scattered moderate to isolated strong convection removed to the west of Greg under vertical easterly shear. This convection is noted from 11N to 12N between just west of 140W to near 142W. An overnight ASCAT-B and C data pass indicated peak winds of minimal tropical storm force north and northwest of the center of Greg. Greg is forecast to continue a westward to west-northwestward motion for the next few days. On this track, Greg will move into the central Pacific basin overnight. Some slight additional strengthening is possible during the next couple of days as it moves farther away from the discussion during the next few days. Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website - https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and the latest Tropical Depression Eight-E NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. A tropical wave along 95W is producing a large area of disorganized showers and thunderstorms over the far eastern portion of the east Pacific. This activity is described as of the numerous to strong type intensity. Latest satellite imagery shows that it covers the area from 10N to 16N between 92W-100W. Environmental conditions appear conducive for development during the next several days, and a tropical depression is expected to form by midweek while the system moves generally west- northwestward, roughly parallel to the coast of southern and southwestern Mexico. This system has a medium chance of becoming a tropical cyclone during the next 48 hours. Please refer to the latest NHC Tropical Weather Outlook at wwww.hurricanes.gov for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from northwest Colombia to 09N79W to 08N92W to 08N101W to 09N110W. The ITCZ extends from 10N119W to 11N135W. Scattered moderate to strong convection is within 120 nm south of trough between 91W-95W. Scattered moderate to isolated strong convection is within 180 nm south of the trough between 104W-108W. Scattered moderate convection is within 180 north of the trough between 101W-106W, and within 60 nm north of the trough between 120W-126W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A surface ridge dominates the offshore forecast waters of Baja California producing gentle to moderate NW to N winds along with seas of 4-6 ft. Inside the Gulf of California, gentle to moderate southeast winds are south of 30N, while moderate S to SW winds prevail across northern part of the Gulf. Seas are generally 1-3 ft over the Gulf, except for slightly higher seas of 3-4 ft near the entrance. Hurricane Fernanda is expected to move generally west-northwestward away from the area. This will allow for moderate S to SE swell to the southwest of Isla Socorro to subside during this morning. For the forecast, moderate to fresh NW winds are expected offshore the coast of Baja California from Punta Eugenia to Cabo San Lazaro mainly at night through the next few days. Fresh north gap winds are forecast to pulse in the Tehuantepec region today, and may increase to fresh to strong speeds beginning on Tue through the end of the forecast period as a tropical depression is expected to form from an area of disorganized showers and thunderstorms over the eastern Pacific associated with a tropical wave. The tropical system is expected to move generally west-northwestward, roughly parallel to the coast of southern and southwestern Mexico though the week. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to fresh easterly winds are in the Gulf of Papagayo region extending westward to near 91W. Light to gentle westerly winds are elsewhere north of 05N, and mainly moderate south to southwest winds between the Equator and 05N. Gentle to moderate southerly winds are over the waters between Ecuador and the Galapagos Islands. Seas are generally 3-5 ft due to a long- period south to southwest swell, except 1-3 ft in the Gulf of Panama, and 3-6 ft offshore Colombia. For the forecast, the moderate to fresh easterly winds in the Gulf of Papagayo region will diminish early Tue. Elsewhere, gentle to moderate winds and moderate seas will continue through the week, except the moderate south to southwest winds over the waters between Ecuador and the Galapagos Islands will increase to fresh speeds starting Thu. Looking ahead, a tropical wave along 95W is producing a large area of disorganized showers and thunderstorms over the far eastern portion of the east Pacific. Environmental conditions appear conducive for development, and a tropical depression is expected to form in the next few days, while the system moves west-northwestward, roughly parallel to the coast of southern and southwestern Mexico. Expect increasing winds, seas, and unsettled weather during this time mainly over the offshore waters from El Salvador north to Guatemala. ...REMAINDER OF THE AREA... Please refer to the section above for details on Hurricane Fernanda and on newly upgraded Tropical Storm Greg located in the extreme western part of the area. Outside of the systems mentioned above, a weak pressure gradient remains west about 110W. A surface ridge remains in control of the weather conditions across the region. Gentle to moderate winds and moderate seas prevail under the influence of the ridge. For the forecast, latest NHC forecast advisory has Hurricane Fernanda continuing to rapidly intensify over the next day or so. It is forecast to become a Category today. It is forecast to reach near 15.9N 118.8W by early this afternoon with a maximum sustained wind speed of 125 kt with gusts to 150 kt, then begin to gradually weaken as it reaches near 16.5N 120.5W by late tonight with a maximum sustained wind speed of 110 kt with gusts to 135 kt, to near 17.0N 122.5 with a maximum sustained wind speed of 100 kt with gusts to 120 kt by early Tue afternoon and to near 17.3N 124.9W by late Tue night with a maximum sustained wind speed of 85 kt with gusts to 105 kt by late Tue night. Fernanda is forecast to weaken to a tropical storm near 17.5N 130.3W by late Wed night and weaken further to a post- tropical remnant low west of the area by late Fri night near 18N.5N 142.7W. $$ Aguirre