000 AXPZ20 KNHC 170016 RRA TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0016 UTC Tue Nov 17 2020 Updated Offshore Waters Within 250 nm of Central America, Colombia, and Within 750 nm of Ecuador 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 0000 UTC. ...SPECIAL FEATURES... Low pressure of 1009 mb is centered near 14N109W. This low is part of a broad area of low pressure that is located several hundred miles southwest of the coast of southern Mexico. Latest satellite imagery shows scattered moderate to isolated strong convection within 240 nm of the low in the SW quadrant and within 180 nm of the low in the NW quadrant. Scattered moderate convection is within 180 nm of the low in the SE quadrant. Overall, this convection has continued to become better organized since yesterday. Although atmospheric conditions are forecast to be only marginally conducive, some additional development is possible, and the system could become a short-lived tropical depression within the next couple of days. The low is forecast to move west-northwestward or northwestward away from the coast of Mexico. Conditions are then expected to become unfavorable for further development around mid-week. The low pressure has a medium chance of becoming a tropical cyclone during the next 48 hours. Please refer to the latest NHC Tropical Weather Outlook at www.hurricanes.gov for more details. Gale Warning: A tight pressure gradient resulting from strong high pressure that is surging southward along the eastern slopes of the Sierra Madre Oriental mountains of Mexico and over the western Gulf of Mexico is ushering strong northerly gale force winds through the Chivela Pass and out into the Tehuantepec region. This event will be a long-lived one as these gale force winds are forecast to reach near storm force late Tue night into early Wed and again Wed night into early Thu as the pressure gradient tightens across the area tightens further between major Hurricane Iota approaching the northeastern coast of Nicaragua and the aforementioned strong high pressure. Wave heights are forecast to build to the range of 13-19 ft by early Wed. Wave heights downstream of the Gulf of Tehuantepec are forecast to build to very large values of 20-22 ft ft by late Wed night, with the leading edge of 8 ft or greater wave heights is expected to reach near 04N100W on Thu and to near 03N106W on Fri. Please read the latest NWS High Seas Forecast issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from northern Costa Rica to the coast at 10N86W and continues northwestward to 13N100W and to low pressure near 14N109W 1009 mb, then southwestward to 11N114W to low pressure near 11N119W 1012 mb to low pressure near 09N126W and to 09N135W, where overnight scatterometer data indicated the ITCZ begins and continues to beyond the area at 10N140W. Scattered moderate convection is within 150 nm south of the trough between 83W-88W, within 60 nm NE quadrant of the low pressure near 11N119W and within 60 nm of the trough between 129W-135W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A Gale Warning remains in effect for the Gulf of Tehuantepec. Please, see the Special Features section above for details. A ridge extends across the offshore forecast waters west of Baja California producing mainly gentle to moderate winds. Wave heights are in the 5-7 ft range south of Punta Eugenia, and 7-9 ft north of Punta Eugenia due to long-period northwest swell. The swell will slowly decay through Wed allowing for wave heights north of Punta Eugenia to lower to 5-7 ft. The latest Ascat pass shows moderate to fresh northwest winds across the northern and central Gulf of California, except for lighter wind speeds in the light to gentle range over the southern part of the Gulf. The moderate to fresh northwest winds over the northern part of the Gulf of California will continue through early Tue morning, then become light and variable winds through the end of the week as high pressure west of Baja California weakens and while the dissipating cold front moves across the northeast part of the area. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR...Updated Enhanced southwesterly flow of moderate to fresh speeds is occurring south of the monsoon trough portion offshore Panama along with wave heights of 6-7 ft. This enhanced flow has arisen primarily from the broad cyclonic circulation around major Hurricane Iota over the western Caribbean Sea and that is presently approaching the northeastern of Nicaragua. Elsewhere, moderate to fresh southwest winds are present south of the monsoon trough east of 100W, with mainly gentle W-NW winds north of the monsoon trough. Seas are in the 5-7 ft range. Seas generated in the Tehuantepec region will propagate across the offshore waters of Guatemala and El Salvador beginning this afternoon and continue through Tue, then expand east- southeastward through the offshore waters of Nicaragua through late Wed. Moisture, in the form of scattered showers and isolated thunderstorms, from the remnants of Hurricane Iota that is presently approaching northeastern Nicaragua, may move offshore Central America and out into the offshore waters late Tue night through Thu. REMAINDER OF THE AREA... See the Special Features section above for the details on a broad low pressure that is located several hundred miles southwest of the southern coast of Mexico. A rather weak ridge dominates the waters north of 16N and west of 110W. Gentle to moderate trades are along the southern periphery of the ridge W of 120W as noted in the latest Ascat pass. Seas are in the 6-7 ft range within this. The latest ASCAT pass suggested that weak low pressure of 1012 mb is near 11N119W and also near 09N126W. Scattered moderate convection is within 60 nm in the NE quadrant of the low near 11N119W. Isolated weak showers and thunderstorms are within 60 nm in the SW and NW quadrants of this same low and within 120 nm in the NE and E quadrants of the low pressure near 09N126W. High pressure to the north of these lows will weaken through Tue as a cold front just northwest of the area moves into the northwest part of the area. The front will reach a position from near 32N131W to 27N135W and to 26N140W early Tue, then begin to dissipate from near 32N125W to 26N132W, and continue to dissipate as a stationary front from there to near 23N140W. Fresh to strong winds are expected on either side of the front over the northwest through this is afternoon and evening. Large northwest swell, producing wave heights in the range of 8-12 ft, will follow in behind the front. $$ Aguirre