000 AXPZ20 KNHC 290309 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 118 UTC Mon Jan 29 2018 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 0300 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Storm Warning: A cold front across the Gulf of Mexico will sweep SE across the remainder of the Gulf basin through Mon. Strong high pressure building in the wake of the front has tightened the pressure gradient over the area. This has increased northerly winds to minimal gale force across Tehuantepec. Winds will reach storm force Mon evening through Tue. The area of high pressure dominating the Gulf of Mexico will then start to shift eastward, gradually loosening the pressure gradient. Winds will diminish to gale force Wed, and fall below gale force on Thu. Please refer to the East Pacific High Seas Forecast under AWIPS/WMO headers HSFEP2/FZPN03 KNHC for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 07N77W to 06N84W to 06N94W. The ITCZ continues from 06N94W to 07N113W to 07N122W to beyond 10N140W. Scattered moderate isolated strong convection is noted within 90 nm N of the ITCZ between 110W and 117W. Scattered moderate isolated strong convection was noted within 60 nm S of the ITCZ W of 138W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of Tehuantepec: Please refer to the special features section above for more on the upcoming storm force gap wind event. As the winds increase from gale to storm force across Tehuantepec late Mon through Tue, a very large and broad wind field will extend well to the SW of the Mexican coastline, to near 09N101W by Tue morning. This will generate a very large area of 10 to 20 plus ft seas in N to NE swell across this area. Gulf of California: Winds of 20-30 kt prevail over the N and central portions of the Gulf of California. Fresh to strong winds will prevail through Mon morning, with the potential for small areas of winds 25-30 kt, mainly N of 29N, tonight. Seas are peaking at 9 ft. Winds will diminish to 20 kt or less Mon. NW swell will continue subside over the waters off the coast of Baja California Norte, where seas remain 5 to 8 ft this evening. Seas west of the Baja Peninsula will subside below 8 ft tonight, then are expected to remain at or below 6 ft through Fri as a tranquil pattern prevails. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to fresh gap winds will pulse to strong the next several nights over the Gulf of Papagayo. Elsewhere N of 09N, gentle to moderate offshore flow will prevail through Mon then strengthen Tue through Wed. Gentle to moderate S to SW winds will prevail S of 09N the next few days. REMAINDER OF THE AREA... High pressure of 1027 mb is centered north of the area near 37N127W. The pressure gradient between this area of high pressure and lower pressure in the vicinity of the ITCZ is supporting fresh to strong trades from 09N to 18N W of 130W, where seas are 9 to 13 ft. NW swell also continues to propagate across these waters and is mixing with the wind generated NE waves. Seas 8 ft or greater associated with this mixing swell covers much of the forecast waters west of 110W and will continue through Monday afternoon. The area of high pressure will shift further N and away from the area during the next couple of days. This will decrease areal coverage of the fresh to strong trades Mon, with winds diminishing to 20 kt or less by late Mon night, and seas gradually subsiding to 8-10 ft across the trade wind belt. $$ AL