000 AXPZ20 KNHC 040935 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 807 UTC Thu May 4 2017 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 0800 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning...A strong cold front will move across the western the Gulf of Mexico Thursday and Thursday night...with high pressure forecast to surge southward along the eastern Mexico coast in the wake of the front. Winds across the Gulf of Tehuantepec will quickly increase to fresh to strong from the N late Thursday night...then reach minimal gale force around sunrise Friday. Gale force winds will then persist until around sunrise Saturday before diminishing to fresh to strong through Saturday evening. Seas will build to 14 ft Friday morning through afternoon then gradually subside to less than 8 ft by Sunday morning. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough axis extends from 08N79W to 08N90W to 10N99W to 05N114W. The ITCZ extends from 05N114W to 05N135W. Scattered moderate convection is from 03N to 09N between 89W and 98W...from 05N to 09N between 103W and 110W...and from 03N to 07N between 124W and 132W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See the special features section for information on the Gulf of Tehuantepec Gale warning. Mainly light to moderate NW winds will prevail across the waters NW of Cabo Corrientes through Friday morning...with light to moderate W to SW winds prevailing E of Cabo Corrientes to Puerto Angel. A cold front will approach the SW United States and NW Mexico by the end of the week...then move across NW Mexico Friday night through Sunday. Winds will increase slightly across the Pacific waters of Baja California Friday through Saturday night ahead of the front then become fresh to near gale force in the northern Gulf of California ahead of the front. Behind the front...fresh to strong winds are forecast offshore of Baja California Norte and in the northern Gulf of California. Combined seas of 5-7 ft currently prevail in the open waters of the Pacific and will build behind the front...reaching 8-12 ft in NW swell N of 22N through early next week. Seas of 2 ft or less currently prevail in the Gulf of California...except for 3-5 ft near the entrance. With the front and anticipated stronger winds across the northern Gulf...seas will build to 5- 8 ft in the northern Gulf this weekend. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light to gentle onshore winds will prevail during the day and gentle to moderate offshore winds during the night through the next several days. Offshore winds in the Gulf of Papagayo will increase to moderate to fresh late Saturday night into early Sunday. Seas will remain mainly ranging from 4-6 ft. Looking ahead...global models continue to indicate the chance of low pressure developing along the east to west trough in the tropical eastern Pacific...between Central America and 95W late in the weekend into early next week. Little movement of this system is suggested initially...which could lead to heavy rain accumulations across portions of the region from Costa Rica northwestward toward southwestern Guatemala. Additionally...the starting date of the eastern North Pacific hurricane season is quickly approaching...and any low pressure system to develop in this area will need to be closely monitored. REMAINDER OF THE AREA... High pressure of 1021 mb centered N of the area near 36N131W combines with a 1018 mb high centered near 22N122W providing overall tranquil weather conditions and mostly light to gentle anticyclonic winds in the vicinity of the high centers. The pressure gradient between this area of high pressure and lower pressure in the vicinity of the ITCZ is supporting gentle to moderate tradewinds with seas in the 5-7 ft range N of the ITCZ. Little change in winds is expected across this tradewind zone through Friday before the pressure gradient tightens modestly through the weekend...leading to a gradual freshening of winds. A cold front approaching the NW waters this morning will freshen winds across this area Thursday night through the upcoming weekend with stronger high pressure building across the area in the wake of the front. The front will also usher in a fresh pulse of northwesterly swell with seas greater than 8 ft moving into the northwest waters Thursday evening into early Friday... covering much of the area north of 20N west of 120W Saturday through Sunday. $$ HUFFMAN