000 AXPZ20 KNHC 152122 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Wed Jan 15 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: A ridge across the eastern slopes of the Sierra Madre Oriental of Mexico continue to drive strong to near gale force northerly gap winds across the Tehuantepec region tonight, and will continue throughout the week and into the upcoming weekend. Strong winds during the day to near 30 kt will pulse to gale force mainly at night. Associated seas will build 11 to 12 ft during the periods of gales. Seas in excess of 8 ft continue to reach several hundred miles downstream, mixing with longer period NW swell. Gulf of Papagayo Gale Warning: A persistent ridge across the Caribbean and Central America is supporting strong to near gale force NE to E winds across and downstream of the Gulf of Papagayo region and extending northward to the waters of NW Nicaragua. Winds to minimal gale force will briefly pulse again tonight into early Thu. This pattern will persist through the remainder of the week and into the upcoming weekend, briefly pulsing to minimal gale force Fri night. Seas will build to 10-11 ft each night during the period of peak winds. Please see 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 these two Gale Warnings. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 1006 mb low pressure over northern Colombia near 09N75W to 03N77W to 05N96W. The ITCZ continues from 05N96W to 07N125W to beyond 07N140W. Scattered moderate convection is noted along the coast of Colombia from 02N to 06N to the E of 80W. Scattered moderate and isolated strong convection is noted from 05N to 08N between 130W and 135W, and also from 06N to 08N between 136W and 139W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see above for more on the latest gale force gap wind event in the Gulf of Tehuantepec. Elsewhere, weak ridging extends from 1023 mb high pressure near 33N126W toward Socorro Island. Various recent scatterometer passes indicated mainly moderate NW winds between the ridge and the coast of Baja California this afternoon. Altimeter satellite passes showed 5 to 7 ft seas off Baja California Sur. Lighter winds and lower seas persist across the Gulf of California. The high pressure W of Baja California will shift S through Fri, ahead of a weakening cold front approaching Guadalupe Island. This move will support fresh to strong winds from Baja California Sur to Clarion Island Thu, diminishing Fri as the high pressure dissipates. Looking ahead, new high pressure W of the region will support strong NW winds across the central Gulf of California late Fri through Sun. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please see above for more on the latest gale force gap wind event in the Gulf of Papagayo. The pressure gradient responsible for the gale force gap wind events in Tehuantepec and Papagayo regions is also supporting fresh to strong northerly winds across the Gulf of Panama. Fresh northerly winds across the Gulf and downstream to near 04N will increase to strong each night through the morning hours this week, with downstream seas building to 6 to near 8 ft each night. REMAINDER OF THE AREA... A surface ridge extends across the waters from 1023 mb located near 33N126W. Latest scatterometer and buoy reports show moderate to fresh trade winds across most of the waters s of 20N to the ITCZ, w of 120W. Concurrent altimeter satellite passes indicate 8 to 11 ft seas in this area, a combination of residual northerly swell and shorter period trade wind swell. Farther east, 8 to 9 ft seas will persist along and n of ITCZ, due in part to shorter period swell originating from strong gap winds originating from the Gulfs of Tehunatepec and Papagayo. High pressure shifting southward to off Baja California Sur Thu will support fresh to strong NE winds reaching up to 720 nm to the SW of the Revillagigedo Islands. New high pressure building off southern California Fri into Sat will allow this area of fresh to strong winds to shift westward, from 12N to 20N to the W of 120W. Combined seas in excess of 8 ft will persist in the trade wind region, including a component of persistent northerly swell. A cold front will drop S in to the area and extend from 30N126W to 28.5N134W to 30N138W by Thu evening, gradually dissipating on Fri. A new set of NW to N swell with seas of 8 to 9 ft will arrive behind this front, spreading mainly eastward through the end of the week before decaying. Looking ahead, a cold front supported by a deep layer trough west of 140W will approach 30N140W by early Sat. Global models are suggesting the developing of surface low pressure along this boundary by late Sat, although there is still some uncertainty regarding the position and intensity. Guidance also suggest fresh to strong winds and building seas between this low and high pressure farther E. $$ Lewitsky