000 AXPZ20 KNHC 122204 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Tue Nov 12 2019 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 2145 UTC. ...SPECIAL FEATURE... Gulf of Tehuantepec Gale Warning: A strong arctic cold front has well southward into Mexico, and as of 18Z it stretches from just south of Veracruz, northwestward from there to inland central Mexico and northwest along the east side of the Sierra Madre Occidental mountains. Very strong high pressure of 1040 mb in the wake of the front is analyzed over northern Mexico near Monterrey. The associated very tight pressure gradient is pressing southward along the eastern slopes of the Sierra Oriental mountains. The resultant strong winds have already begin to funnel through Chivela Pass and out into the Gulf of Tehunatepec leading to gale force north to northeast winds there. Visible satellite imagery shows low-level clouds streamers spreading outward from the far southeastern and westward sections of the Gulf of Tehuantepec, which is indicative of an ongoing wind gap event. The north to northeast winds are expected to peak near 45 kt in the Gulf of Tehuantepec late tonight, with wave heights building to near 20 ft at that time. The very tight pressure gradient will relax on Wed as the area of high pressure shifts eastward, with winds diminishing below gale force late Wed night. Mixed northeast and southwest swell will build wave heights up to 9 ft well downstream from the Gulf of Tehuantepec to within an area from 05N to 10N between 90W and 104W by early Thu. Another gale force gap wind event is possible across the region Fri through Sat night. See the latest High Seas Forecast under AWIPS/WMO headers HSFEP2/FZPN03 KNHC or the website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for further details. ...TROPICAL WAVES... The previous tropical wave near 101W is no longer identifiable. A tropical wave with axis along 125W/126W from 04N to 19N is moving westward at about 10-15 kt. Low pressure of 1010 mb is along the wave near 12N125W. Scattered moderate to isolated strong convection is within 120 nm of the low in the northeast quadrant. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from along the coast of northwest Colombia to across northern Costa Rica and to 09N83W to 08N100W to low pressure of 1010 mb near 11N113W to low pressure of 1010 mb near 12N125W and to 08N135W. Scattered moderate to strong convection is within 120 nm south of trough between 126W and 128W. Scattered moderate to isolated strong convection is within 120 nm south of trough between 102W and 106W, also within 60 nm of trough between 91W and 95W, and within 60 nm of trough between 128W and 132W. Scattered moderate convection is seen from 04N to 08N east of 84W to the coast of Colombia, and within 120 nm south of trough between 128W and 130W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A strong Gulf of Tehuantepec gale force gap began a short while ago. Please see the Special Feature section above for more details on the significant event. Elsewhere, a ridge dominates the offshore forecast waters west of Baja California, supporting gentle to moderate northerly winds, and wave heights of 4 to 6 ft. Little change is expected through Thu. Strong high pressure building across north and central Mexico is supporting fresh to locally strong northwest to north winds and wave heights of 7 to 8 ft seas near the entrance of the Gulf of California and farther south between Cabo Corrientes and Los Cabos. Winds and seas are expected to diminish by tonight as the high pressure shifts eastward. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gentle to moderate southwesterly monsoonal flow will continue across the offshore waters of Costa Rica, Panama, Colombia, and Ecuador the next several days. Wave heights will remain in the 4-7 ft range. Large seas generated by a strong gale force gap wind event in the Gulf of Tehuantepec will reach the offshore waters of Guatemala and El Salvador tonight into Wed, with wave heights building to 10 to 14 ft in northerly swell. REMAINDER OF THE AREA... A dissipating cold front extends from near 32N138W to 26N140W. Wave heights of up to 8 ft in northwest are west of the front. Large-long period northwest well associated with an intense low pressure system in central northern Pacific will reach the NW waters on Thu. Wave heights associated with this next event will peak near 13 or 14 ft over the far NW waters by Thu night. A broad area of low pressure has developed several hundred miles south of the southern tip of the Baja California peninsula. Associated showers and thunderstorms are currently disorganized, and are depicted as the scattered moderate to isolated strong intensity from 10N to 14N between 105W and 110W and from 12N to 15N between 110W and 114W. Some gradual development of this disturbance will be possible over the next several days while it moves slowly northward. However, upper-level winds are expected to become unfavorable for any further development of this system by Sunday and Monday. The latest Tropical Weather Outlook gives this system a medium chance of tropical cyclone formation through 5 days. $$ Aguirre