000 AXPZ20 KNHC 192113 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Wed Jul 19 2017 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 1800 UTC surface analysis and satellite imagery through 2115 UTC. ...SPECIAL FEATURES... Hurricane Fernanda is centered near 17.7N 136.3W at 19/2100 UTC moving WNW at 7 kt. Estimated minimum central pressure is 985 mb. Maximum sustained winds are 70 kt with gusts to 85 kt. Scattered moderate to strong convection is within 75 nm SE and 150 nm SW semicircles of the center. Fernanda will continue to weaken and should become a tropical storm tonight, then weaken further as it moves west of 140W by late Thu night. Large swell will continue to expand and spread out ahead of Fernanda to the NW and W during the next few days. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP1/WTPZ21 for more details. Tropical Storm Greg is centered near 14.3N 112.7 at 19/2100 UTC or about 540 nm SSW of the southern tip of the Baja California peninsula, moving W at 9 kt. Estimated minimum central pressure remains 1005 mb. Maximum sustained winds are 40 kt with gusts to 50 kt. Scattered moderate to strong convection is within 150 to 210 nm of the center of the storm. Some intensification is anticipated over the next couple days with Greg approaching near hurricane strength Fri and Sat, before gradual weakening late in the weekend. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP2/WTPZ22 for more details. Tropical Depression Eight-E is centered near 14.1N 121.7W at 19/2100 UTC, or about 850 nm SW of the southern tip of Baja California, moving WSW at 5 kt. Estimated minimum central pressure is 1009 mb. Maximum sustained winds are now 25 kt with gusts to 35 kt. Scattered moderate isolated strong convection is within 60 nm of the center mainly over the SW semicircle due to the presence of persistent northerly shear. This shear will keep T.D. Eight-E a weak system through the next few days with dissipation likely by Sun. The depression will move slowly west or west-southwest tonight, and likely interact with Tropical Storm Greg as it dissipates. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP3/WTPZ23 for more details. ...TROPICAL WAVES... A tropical wave extending from 06N to 16N along 98W is moving west at 10 to 15 kt. This wave is enhancing the convection associated with the monsoon trough from 09N to 15N between 95W and 101W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 08N78W to 10N85W to 09N92W to 13N108W, then resumes west of Hurricane Fernanda from 12N133W to 09N140W. Except as noted above, Scattered moderate isolated strong within 150 NM of line from 06N80W to 10N97W, from 06N to 15N between 100W and 109W, within 120 NM of 11N115W and 10N123W and within 45-60 NM of line from 06N129W to 10N137W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the special features for information on Tropical Storm Greg southwest of Manzanillo, Mexico. Recent 1636 and 1730 UTC ASCAT passes indicated only light to locally moderate winds were observed over the Revillagigedo Islands in the wake of the passage of T.S. Greg. These winds will remain light. A surface trough from the coast of southern California southward to off the coast of the Baja California peninsula near 26N122W will continue to block the advance of the subtropical ridge into the region and maintain generally gentle to moderate winds off the Baja California peninsula through Thursday. Seas will remain 5 to 7 ft in a mix of long period north and southwesterly swell. Gentle southerly flow will persist in the Gulf of California, except for moderate southerly flow over the northern Gulf. Light to gentle variable winds will prevail across the Gulf of Tehuantepec through today, then fresh northerly gap winds will once again pulse to around 20 kt at night. Winds may increase to fresh to strong by the end of the week into the weekend. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... In the Gulf of Papagayo, moderate to fresh offshore winds will pulse to fresh each night with nocturnal drainage through the week, occasionally building max seas to 8 ft in a mix of east swell and longer period southwest swell. Gentle to moderate southerly winds are expected south of the monsoon trough axis. Long period cross-equatorial southerly swell and 6-7 ft seas will continue to propagate into the waters reaching the coast of Central America through the day. Another pulse of large southerly swell will move into the region today and raise seas to 6-8 ft through Thu. REMAINDER OF THE AREA... Please see the special features section for information on Hurricane Fernanda and Tropical Depression Eight-E. Weak ridging is producing moderate to fresh north to northeast winds north of 25N. The ridge will build modestly eastward through mid-week, tightening the gradient north of Fernanda as it moves west of 135W tonight, and produce fresh northeast winds across much of the area north of 25N, helping build seas to 8-10 ft in mixed northerly and southerly swell. $$ Cobb