000 AXPZ20 KNHC 282150 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Sun Jan 28 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 2045 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Storm Warning: A cold front across the Gulf of Mexico this afternoon will sweep SE across the entire Gulf basin through Mon. Strong high pressure building in the wake of the front increased northerly winds to minimal gale force across Tehuantepec this morning, and these winds continue this afternoon. Winds will increase to strong gales tonight, then 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 03.5N77W TO 07N87W. The ITCZ continues from 06.5N90W to 05N106W TO 07.5N130W to beyond 09N140W. Scattered moderate to strong convection is noted within 90 nm S and 120 nm N of the ITCZ between 100W and 121W, and between 128W and 134W. ...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 N through central portions of the Gulf of California this afternoon. These fresh to strong winds will prevail through Mon morning, with the potential for small areas of winds 25-30 kt, mainly N of 29N, this evening through tonight. Peak seas have built to 9 ft today. NW swell will continue subside over the waters off the coast of Baja California Norte, where seas remain 5 to 8 ft this afternoon. Seas west of the Baja Peninsula will subside below 8 ft this evening through tonight. Seas are then expected to remain at or below 6 ft through Wed 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. Wind gusts to gale force will be possible Mon night through Tue morning across Papagayo as strong high pressure builds S into the NW Caribbean. Elsewhere N of 09N, gentle to moderate offshore flow will prevail through Mon then strengthen Mon night 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 1029 mb is centered north of the area near 38N126W, and extends a broad ridge southward across the discussion area. 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 21N W of 132W, and from 08N to 16N between 123W and 132W, where seas are 9 to 14 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 this afternoon 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 gradually 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. $$ Stripling