000 AXPZ20 KNHC 070954 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Tue Jan 7 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: A tight pressure gradient has developed between high pressure over the NE Gulf of Mexico, which extends a ridge SW toward eastern Mexico, and low pressure and associated troughing across central Mexico. This combined with nocturnal drainage flow has supported the development of gale force northerly winds in the Gulf of Tehuantepec early this morning. Winds are forecast to further increase to strong gale, just shy of minimal storm force, by later today and tonight, as new high pressure builds down from across Texas southward toward the region, further tightening the pressure gradient. Seas will quickly build to around 23 ft by late tonight into early Wed. Gale force winds will then persists into early Thu before diminishing. There is a potential of another round of gale force gap winds by Sat night. Gulf of Papagayo Gale Warning: High pressure will build toward northern Central America through the day, increasing the pressure gradient over Nicaragua and Costa Rica. This will cause gale force NE to E winds to develop in the Gulf of Papagayo late tonight through Wed afternoon. Seas of 12 to 13 ft can be expected during this period. Winds and seas will only subside slightly, with strong winds prevailing through the weekend. 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 on both Gale Warnings. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A trough axis extends from 1011 mb low pressure over northern Colombia near 09N74W to low pressure near the W coast of Colombia near 04N78W to 03N82W to 05N100W. The ITCZ then continues from 05N100W to 07N110W, then resumes from 08N114W to 07N120W to 07N137W. Scattered moderate and isolated strong convection is noted within 09N115W to 07N106W to 04N109W to 08N117W to 09N115W to 09N115W. Scattered moderate convection is noted from 08N to 10N between 88W and 90W, and also from 05N to 09N between 123W and 137W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See the Special Features section for more details about the Gale Warning for the Gulf of Tehuantepec. Gulf of California: The pressure gradient between high pressure over the SW U.S. and low pressure trough over NW Mexico is tight, leading to strong NW winds in the Gulf of California. These winds will continue through early afternoon before diminishing. Associated seas of up to 8 feet will subside later today. After winds and seas subside later today, the next hazardous marine weather is not expected until at Fri and Fri night, when more fresh to strong NW to N winds are likely to develop into the upcoming weekend, particularly in the central and southern Gulf. NW swell offshore of Baja California Norte is decaying this morning, however, new NW to N swell will arrive Wed afternoon bringing similar seas to the area until early Fri. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... See the Special Features section for more details about the Gale Warning for the Gulf of Papagayo. Large NW swell generated by gales in the Gulf of Tehuantepec will impact waters off Guatemala beginning during the upcoming night through Thu. Seas will build to between 8-14 ft during this time period. Gulf of Panama: Pulses of fresh northerly winds are expected to dominate the Gulf of Panama and waters N of 05N through the remainder of the week. Elsewhere, gentle to moderate S to SW flow will continue over the offshore waters of and S of Costa Rica through the week and into the upcoming weekend. REMAINDER OF THE AREA... High pressure of 1034 mb is centered just N of the area near 34N135W with ridging extending SE toward 13N123W. A surface trough is embedded in the ITCZ, extending from 14N136W to 05N139W. A tight pressure gradient exists between these two features, leading to fresh to strong trade winds over the W central waters. Seas are also up to 8-11 ft in this area. This trough is forecast to push W of 140W through the middle of the week, however, another trough will move in from the E along the ITCZ. Tradewinds are forecast to strengthen and expand by the end of the week into the upcoming weekend, and with an increasing fetch resultant seas will build to up to 11-13 ft. Meanwhile, northerly swell to the N of 25N and E of 125W is leading to seas of up to 10-11 ft. These seas will decay through the day today. New swell will arrive in the same area Wed afternoon and continue through Fri, likely bringing 8-10 ft seas to the region. $$ Lewitsky