000 AXPZ20 KNHC 292201 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2145 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Storm Warning: High pressure building in the wake of a cold front in the Gulf of Mexico has tightened the pressure gradient over the area. This has supported northerly winds to gale force across Tehuantepec. Winds will reach storm force this evening through Tue night. 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 early Wed, and fall below gale force early Thu. Please refer to the East Pacific High Seas Forecast under AWIPS/WMO headers HSFEP2/FZPN03 KNHC for more details. Looking ahead, another gale force wind event may commence Fri into Sat. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 08N75W to 06N94W. The ITCZ continues from 06N94W to 05N113W to 07N130W to 10N140W. No significant convection is noted. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of Tehuantepec: Please refer to the special features section above for more on the latest gap wind event. As the winds increase from gale to storm force across Tehuantepec late tonight through Tue, a large and broad wind field will extend well to the SW of the Mexican coastline, to near 09N102W by Tue morning. This will generate a very large area of 10 to 20 plus ft seas in northerly swell across this area. Gulf of California: Winds of 20-25 kt over the far N portion of the Gulf of California will diminish to 20 kt or less this evening. Elsewhere over the open waters, seas 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... Fresh to strong gap winds will increase to near gale force early Tue and early Wed over the Gulf of Papagayo. Elsewhere N of 09N, gentle to moderate offshore flow will strengthen Tue through Wed, approaching fresh to strong offshore of the Gulf of Panama Tue night. Gentle to moderate S to SW winds will prevail S of 09N the next few days. REMAINDER OF THE AREA... High pressure of 1025 mb is centered north of the area near 36N131W. 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 08N to 20N W of 118W, where seas are 9 to 12 ft. The area of high pressure will weaken the next couple of days. This will decrease areal coverage of the fresh to strong trades, with winds diminishing to 20 kt or less by Tue, with seas gradually subsiding to 6-8 ft across the trade wind belt by midweek. Large swell generated from the latest Gulf of Tehuantepec gap wind event will propagate across the waters S of 14N and E of 120W, while gradually subsiding from the middle to the end of the week. $$ Lewitsky