000 AXPZ20 KNHC 040333 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 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 0000 UTC surface analysis and satellite imagery through 0200 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning...A strong cold front will move through the Gulf of Mexico late tonight through Friday, with high pressure forecast to surge down eastern Mexico in the wake of the front. Winds across the Gulf of Tehuantepec will quickly increase to fresh to strong from the north 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 09.5N74W TO 09N87W TO 09.5N97W TO 07N112W, then transitions to ITCZ, continuing on to 06N124W TO 05N136W. Scattered moderate to strong convection is noted from 04N to 10N between 81W and 95W. Scattered moderate isolated strong convection is noted within 150 nm N and 180 nm S of the trough between 98W and 109W. Scattered moderate isolated strong convection is noted within 180 nm N and 60 nm S of the ITCZ between 112W 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 NWly 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 southwest United States and northwest Mexico by the end of the week, then move across northwest Mexico Friday night through Sunday. Winds will increase slightly across the Pacific waters of Baja California Friday through Saturday night ahead of the front, and become fresh to near gale force in the northern Gulf of California ahead of the front. Behind the front, expect fresh to strong winds 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 north of 22N through early next week. Seas of 2 ft or less currently prevail in the Gulf of California, except 3-5 ft near the entrance, and will build to 5- 8 ft in the northern Gulf this weekend with the increasing winds. 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 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. 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 north of the area near 38N131W extends a ridge southwest to the northeast of the Hawaiian Islands near 25N150W. Another ridge axis extends from near 23N133W east southeastward to near 13N100W. 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 north 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 approach the northwest waters tonight 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 late Thursday afternoon and evening, covering much of the area north of 20N west of 120W Saturday through Sunday. $$ Stripling