000 AXPZ20 KNHC 010813 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 813 UTC Sun Mar 1 2020 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: High pressure centered over the northern Gulf of Mexico is supporting a tight pressure gradient across the Isthmus of Tehuantepec. This has been supporting northerly gales into the Gulf of Tehuantepec since yesterday. These gales will diminish later this morning as the high pressure north of the area weakens and shifts eastward. Peak seas around 15 ft will gradually subside through tonight. Looking ahead, another gale force gap wind event is possible Thu and Thu night as another strong cold front crosses the Gulf of Mexico. Gulf of Papagayo Gale Warning: A strong pressure gradient across Central America and the western Caribbean will support gale force winds and seas to 14 ft over the Papagayo region and downstream through later this morning, diminishing this afternoon. Expect pulses to near gale force tonight and again Mon night. Pacific High Seas Gale Warning: A broad mid to upper-level trough west of 140W has induced the development of a surface trough between 135W and 140W per earlier scatterometer data. Scattered moderate and isolated strong convection is noted from 08N to 14N W of 135W in association with this feature. The tightening pressure gradient between the trough and very strong high pressure building northwest of the region is supporting increasing winds to marginal gale force, and these winds will continue this morning, then shift west of 140W as the trough axis moves westward. Expect associated seas of 12 to 18 ft within the strongest winds this morning. Please read the latest High Seas Forecast issued by the National Hurricane Center under AWIPS/WMO headers FZPN03/HSFEP2 NHC or at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for further details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The ITCZ extends from 03N92W to 02N120W to 04N135W. Scattered moderate convection is noted within 60 nm north of the ITCZ between 105W and 110W, and near 09N109W. Scattered moderate to isolated strong convection is evident from 09N to 12N between 135W and 138W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section above for more details about a gale warning in the Gulf of Tehuantepec region. Gentle to moderate winds prevail across the Baja California offshore waters between an offshore high pressure ridge and a low pressure trough near the Gulf of California. A mid to upper-level trough is approaching the area from the northwest and will drive a cold front southward into the northern Gulf of California and Baja California Norte today. This front will weaken, but be followed by a second reinforcing front tonight that will cross the Baja California region through early next week. Fresh to strong SW to W gap winds are likely developing over the northern Gulf of California this morning ahead of the first front. These winds will reach near gale force north of 29N by tonight, with seas reaching 8 ft in the far northeast corner of the Gulf of California south of Puerto Penasco. Expect strengthening NW winds and building seas over the Baja offshore waters following the reinforcing front, with seas greater than 8 ft expected across the Baja offshore waters by Tue. Wave heights will peak around 16 to 18 ft near Guadalupe Island late Mon. The associated NW swell will continue propagating southward through Wed while gradually decaying. Showers and a few thunderstorms are possible off Baja California Norte and over the northern Gulf of California late today through early Mon associated with these fronts. Much more tranquil marine conditions are currently forecast for the end of next week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please see the Special Features section above for more details about a gale warning in the Papagayo region. A recent pair of altimeter satellite passes indicated seas of 8 to 10 ft off Guatemala and El Salvador this past evening. These seas were related to mixed swell with major components related to the Tehuantepec and Papagayo gap events. A scatterometer satellite pass from around the same time indicated fresh gap winds through the Gulf of Fonseca as well. Winds and seas will diminish through tonight off Guatemala and El Salvador as the gap winds diminish. Farther south, fresh to strong northerly gap winds continue to pulse through and and downstream of the Gulf of Panama. A recent altimeter satellite pass showed seas almost to 8 ft south of the Azuero Peninsula, just west of the main area of gap winds. This pattern is expected to gradually diminish through early in the week as high pressure well north of the area weakens. REMAINDER OF THE AREA... Please see the Special Features section above for more details about a Pacific high seas gale warning. An upper level cyclone centered just north of the Equator near 02N100W. This is situated above an area of fresh trade wind convergence associated with the gap winds farther east to support a few clusters of showers and thunderstorms within 60 nm north of the ITCZ between 105W and 110W. Another cluster of showers and thunderstorms is centered south of Clipperton Island near 09N109W. Recent altimeter satellite data shows a large area of 8 to 10 ft seas south of 10N and east of 110W, in a mix of easterly swell and longer period SW swell. The trade wind flow and the wave heights will diminish early this week as the gap winds weaken. Farther west, recent scatterometer satellite data shows fresh to strong NE winds across the waters west of 120W north of about 08N. Concurrent altimeter satellite data shows 8 to 12 ft seas, likely in a mix of NE trade wind swell and longer period northerly swell. Higher seas persist in the area of near gale to gale force wind from 08N to 14N west of 135W. This is also in an area of scattered showers and thunderstorms, southeast of the upper trough. A cold front will move into the waters north of 20N through Mon, followed by strengthening NW winds and building seas. A new round of NW swell will move southward across the region through early next week, with seas 12 ft or greater expected N of 25N E of 130W by Mon. Marine conditions will gradually improve Tue through Thu night as residual swell decays over the region and high pressure weakens north of the area, allowing the pressure gradient to relax over the high seas. $$ Christensen