000 AXPZ20 KNHC 201556 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1541 UTC Tue Mar 20 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 1500 UTC. ...SPECIAL FEATURES... Gale Warning: A weakening cold front from 30N129W to 20N140W is preceded by strong southerly flow N of 26N and just E of the front, with seas to 12 ft. A deepening surface low pres system NW of the area near 31N140W will drop SE through this afternoon behind the cold front, dragging a second cold front into the discussion area. Gale force winds on the SE side of this low over the NW corner of the discussion waters have commenced as the pressure gradient is tightening in the southern semicircle of the low. Associated seas are building up to 15 to 17 ft. The low is forecast to then lift N-NE of the area later today, allowing for winds to diminish to 20-30 kt, then becoming 20 kt or less by early Wed. Large NW swell will propagate southeastward through Sat. Please refer to the Pacific high seas forecast for more details on this upcoming event under AWIPS/WMO headers MIAHSFEP2/FZPN03. Gulf of Tehuantepec Gale Warning: Strong to near-gale north flow will surge into the gulf early Wed morning, then increase to minimal gale force Wed night. Gale conditions are then expected to continue through Fri morning, with seas building to a maximum of around 12 ft. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 10N84W to 03N100W. The ITCZ axis continues from 03N100W to 06N120W to 06N130W to 06N140W. Scattered moderate and isolated strong convection is within 150 nm SE of the trough between 85W and 88W, from the equator to 02N between 90W and 93W, within 75 nm NE of the trough and ITCZ between 107W and 109W, from 05N to 08N between 116W and 127W, and also from 05N to 10N W of 129W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see see Special Features Section above for details on gale force winds expected to affect the Gulf of Tehuantepec area. Weak high pressure W of the northern Baja Peninsula extends a ridge axis S to near 18N. The ridge will shift southeast through today and tonight, supporting fresh to locally strong northerly winds on Jalisco, Mexico offshore waters between 105W and 107W. Gentle to moderate northerly winds in the Baja offshore waters will become light to gentle by tonight as the ridge weakens. Gulf of California: Fresh to locally strong northwest flow is forecast across the southern half of the gulf waters through this evening accompanied by 5-6 ft seas. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Fresh to strong northeast winds will develop downstream of the Gulf of Papagayo tonight, with seas building to 7 ft. Stronger winds are expected Wed night through Sat night with seas building to 11 ft. Fresh to strong northerly winds are also expected downstream of the Gulf of Panama Wed night through Sat night. Light to gentle offshore flow will prevail elsewhere. REMAINDER OF THE AREA... Please see see Special Features Section above for details on gale force winds expected to affect the NW portion of the area. A progressive pattern will continue to impact the the northwest portion of the area well into the weekend. A deep layer low pres system located NW of the area is preceded by deep mid to upper level moisture. Clouds and precipitation associated the the low pres system will advance eastward towards southern California and the northern and central Baja California through Wed. $$ Lewitsky