000 AXPZ20 KNHC 080354 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Sun Mar 08 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 0000 UTC surface analysis and satellite imagery through 0345 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: Strong gale force winds continue across the Gulf of Tehuantepec this afternoon as high pressure over eastern Mexico maintains a tight pressure gradient across the Isthmus of Tehuantepec. Significant wave heights have lowered slightly since this morning to around 17 ft. The 12 ft or greater wave heights have propagated to the south and southwest of the Gulf region primarily due to a northeast swell to as far as 09N-10N based on altimeter data from today. The gale force winds will continue through Mon morning, then briefly diminish before pulsing to gale force late Mon night and again on Tue night as well. Please read the latest High Seas Forecast issued by the National Hurricane Center under AWIPS/WMO headers FZPN03 KNHC/HSFEP2 or at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for further details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 05N83W to 03N90W to 04N102W, where latest scatterometer data indicates the ITCZ begins and continues to 06N113W to 08N125W and to beyond the area at 08N140W. A second ITCZ is analyzed from 04S86W to 03S90W to 02S109W. Scattered moderate convection is noted within 120 nm north of the first ITCZ between 125W and 129W, and within 60 nm south of the first ITCZ between 87W and 91W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section above for details on a gale warning in the Tehuantepec region. Weak high pressure of 1019 mb is centered offshore of Baja California near 26N121W this evening. Moderate to locally fresh southerly winds are occurring over the northern Gulf of California. Elsewhere outside of the Tehuantepec region, light to moderate winds remain over the offshore waters under a weak pressure pattern. Strong southwest gap winds will develop over the northern Gulf of California tonight ahead of an approaching cold front that will weaken and dissipate Sun. A large extra-tropical low pressure system and attendant occluded cold and warm fronts is presently located well to the northwest of the discussion area. This system will track southeastward reaching near 31N130W on Mon at which time it will track in a more eastward motion pushing the frontal system toward the Baja offshore waters. Fresh to strong SE to S winds will develop offshore of Baja California Norte ahead of the cold front, which will likely cross the region through mid-week while weakening. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: A north to south tight pressure gradient across Central America and the northwest Caribbean is producing strong northeast winds across the Papagayo region this afternoon. These winds will continue across this region through the middle of next week, with winds pulsing to near gale force each night. Wave heights will peak to around 11 ft downstream of the Gulf each morning for the next several days. Gulf of Panama: High pressure north of the area will maintain fresh to strong north to northeast winds over and downstream of the Gulf of Panama for the next several days. Wave heights with these winds are expected to reach to about 9 or 10 ft well downstream of the Gulf. Elsewhere, large northwest swell associated with the ongoing Gulf of Tehuantepec gap wind event is producing 10-16 ft seas offshore of Guatemala, with seas greater than 8 ft encompassing the waters off El Salvador in mixed NW and E swell. Seas well offshore will remain greater than 8 ft for the next several days in combined Tehuantepec and Papagayo swell, along with long period southerly swell that will reach the waters by Mon. REMAINDER OF THE AREA... Weak high pressure is present over the area north of 19N, except in the far western part of the area where stronger high pressure centered well northwest of the region protrudes east- southeastward over that area. A modest pressure gradient is supporting moderate northeast to east trades north of the ITCZ, except for fresh winds noted west of 130W associated with a weak surface trough. Farther west, a cold front extends into the northern waters from 30N122W to weak low pressure of 1015 mb near 27N126W. A cold front extends from the low to near 24N134W. Afternoon scatterometer data showed fresh to locally strong northerly winds behind the front, with 8-10 ft seas in northerly swell. This front will weaken overnight tonight and dissipate by early Sun evening as it slowly advances eastward. Mixed swell from the Tehuantepec and Papagayo gap wind events is propagating well downstream of the source regions, with seas 8 ft or greater roughly north of 05N between 90W and 105W. By Sun, 8 ft or greater seas will encompass the waters south of 12N between 90W and 110W as gap wind swell mixes with long period southerly swell propagating across the southern waters. A strong cold front will move across the northwest part of the area n Sun and Sun night in associated with low pressure that will move to near 31N133W by Mon morning. Strong to near gale force winds behind the front will build seas to 12-20 ft north of 24N and west of 130W on Mon. The low pressure is expected to track eastward through early next week and pull the cold front across the waters roughly north of 20N. Large long-period northwest swell associated with this system will propagate southward through the middle of next week. $$ Aguirre