000 AXPZ20 KNHC 121617 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Mon Feb 12 2018 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 1200 UTC surface analysis and satellite imagery through 1445 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: A cold front continues to move across the western Gulf of Mexico north of the area this morning while a high pressure ridge is pushing southward across Mexico and the adjacent waters, to the east of the Sierra Madre Oriental range. Fresh northerly winds have begun to blow across the Gulf of Tehuantepec in the past few hours and will increase to strong by late morning, then will rapidly increase to minimal gale force this afternoon. Gale force northerly winds will then persist, with the strongest winds to 40 kt expected at night starting Tue night. The gale force winds will likely finally diminish early Thu. Please refer to the East Pacific High Seas Forecast under AWIPS/WMO headers HSFEP2/FZPN03 KNHC for more details on this gale warning. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 08N72.5W TO 05N78W TO 04.5N97W. The ITCZ continues from 04.5N97W to 08.5N123W to beyond 08.5N140W. Scattered moderate convection is noted within 60 nm S and 270 nm N of the ITCZ to the W of 128W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section above for more details on a developing gale warning in the Gulf of Tehuantepec. Broad low pressure prevails across southern California and SW U.S. this morning with a cold front extending SW from near San Diego to 30N126W. This pattern is producing mainly light to moderate W to NW winds across the Baja offshore waters, which should generally continue through the week. Seas are building to 4-7 ft in NW swell offshore of Baja California Norte which will continue through mid week. An inverted trough may lift northward across the offshore waters of Baja California by mid week with weak low pressure possibly developing along it. For the Gulf of California, a nearly stationary trough extends from SW Arizona to Baja California Norte. Fresh to strong southwest winds are developing within about 60 nm southeast of the trough in the northern Gulf of California. These winds will persist today, and diminish early Tue. The pressure gradient will tighten across the region by the end of the week, with fresh to strong northerly flow developing in the northern Gulf of California by Thu night, spreading southward across the majority of the Gulf into early next week. Light to moderate N to NE winds prevail across the offshore waters from Cabo San Lucas to the Manzanillo, and are light and variable between Manzanillo and Tehuantepec. Little significant change is expected there for the next few days, except winds may increase to fresh near Cabo Corrientes by the end of the week as the pressure gradient tightens. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... For the Gulf of Papagayo, fresh offshore winds will pulse to fresh to strong each night through the week. The coverage of these winds will expand today through Tue, approaching near gale force by Wed and pulsing to near gale force at night through the end of the week. For the Gulf of Panama, moderate to fresh northerly winds will continue and extend S along the Azuero Peninsula to around 06N today, then will increase to fresh to strong tonight as the local pressure gradient tightens. Fresh to strong winds will then persist through early Fri, even approaching 30 kt near the Azuero Peninsula Wed night. Elsewhere, gentle to moderate offshore flow will prevail N of 09N, and light to gentle S to SW winds will generally prevail S of 09N. REMAINDER OF THE AREA... Deep layered low pressure persisting west of the area near 25N141W continues to support scattered showers from 09N to 13N to the W of 128W. The pressure gradient between the low pressure and strong high pressure well north of the area is maintaining east to southeast moderate to fresh winds across this same area. A surface trough is analyzed from 09N121W to 15N119W. Associated scattered moderate to strong convection is occurring from 10N TO 17N BETWEEN 110W AND 126W, and will generally persist and shift very slowly NE through Wed. Winds near the trough are currently moderate to fresh, however, trades to the west of the trough will increase by the end of the week building fresh seas to around 8 ft as the pressure gradient tightens between building high pressure north of the area, and the troughing. Fresh to strong northerly flow is also noted along the coast of California to southwest of Point Conception. While these winds are not expected to extend south of 30N, associated fresh northerly swell producing seas of 8-10 ft will propagate over the region north of 22N and west of 121W through mid week, eventually mixing with components of the NW swell. $$ Stripling