000 AXPZ20 KNHC 051539 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1458 UTC Sun Jan 5 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Storm Warning: Strong high pressure remains just N of the area across eastern Mexico and the N Gulf of Mexico this morning. The associated pressure gradient has weakened slightly during the past several hours, and the storm force northerly winds funneling across the Gulf of Tehuantepec overnight have diminished to 40-45 kt in the past couple of hours. Associated peak seas are estimated at around 21 ft downstream of the Gulf near 13.5N96W. As this high pressure system continues to shift slowly eastward and weaken, winds across Tehuantepec are forecast to diminish below gale force by midday Monday. Gale force winds are then forecast to return by early Tue, with near storm conditions possible Tue evening, persisting through early Wed morning. A wide swath of 12 ft or greater seas will prevail over the area through Mon. Seas of 8 ft or greater may diminish some Mon night before new fresh swell is generated from the returning gale force winds on Tue. 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... The monsoon trough extends from low pres 1012 mb near 05.5N75.5W to 08.5N90W to 08N96W. The ITCZ continues from 08N96W to 03.5N108W to 06.5N127W to beyond 07N140W. Scattered moderate isolated strong convection is noted from 01.5N to 05.5N between coast of Colombia and 92.5W, and from 07N to 12.5N between 110.5W and 127.5W. Scattered moderate to strong convection is noted from 06N to 10N between 98W and 102W, and from 06N to 08.5N between 133W and 141W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See the Special Features section for more details about the Storm Warning for the Gulf of Tehuantepec. Gulf of California: Moderate to fresh NWly winds will prevail through the remainder of the weekend and then increase to strong by early Mon through Tue morning, as strong high pressure builds across the Great Basin region. Winds will then diminish Tue through Wed as the high pressure shifts E and weakens. Peak seas during the strong winds on Mon and Tue will reach to around 8 ft. Remnant long period NW swell of 6-8 ft is decaying across the offshore waters of Mexico, and sea heights will continue to slowly subside today. New NW swell will arrive offshore of Baja California Norte later today, propagate SE and subside early Tue, with yet another pulse of swell arriving Wed. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Large fresh northerly swell generated by the storm force gap winds in the Gulf of Tehuantepec mentioned above will impact the offshore waters of Guatemala and El Salvador through early Mon. Seas up to 10-15 ft, highest offshore of Guatemala, are forecast this morning and will subside very slowly through Mon. Gulf of Papagayo: Strong NE to E winds will prevail through much of the week, with near gale force winds possible this morning, and again early Wed. Downstream seas are expected to be around 9 ft this morning, and will build to near 10 ft on Wed morning. Gulf of Panama: Pulses of fresh northerly winds are expected to dominate the Gulf and waters N of 05N through 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, while very long period, high energy NW swell currently reaching and producing large and dangerous surf conditions at the coast will gradually diminish later today. REMAINDER OF THE AREA... An old frontal boundary in the far NW to N central waters has recently dissipated. Strong 1038 mb high pressure is just NW of the area near 35N139W with a ridge reaching SE of the high all the way to near Cabo Corrientes. A tight pressure gradient south of the ridge exists, producing fresh to strong tradewinds mainly N of 08N and W of 120W. Recent altimeter data have shown seas of 8-13 ft across this area, with highest seas W of 130W and due south of the high. The high and ridging will weaken through the early part of the week, allowing for trades to diminish which will assist in subsiding seas. That will be short lived as the pressure gradient re-tightens by mid-week as a N to S trough propagates westward in the vicinity of the ITCZ. Developing gale force winds N of the area near Point Conception, California will generate fresh northerly swell which will push S into the area across our waters N of 25N and E of 125W tonight through Mon night, causing seas to reach 12-15 ft. These conditions will improve by late Mon into Tue. $$ Stripling