000 AXPZ20 KNHC 041518 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1515 UTC Sat Mar 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURES... Strong high pressure northeast of the region will support 30 to 40 kt gap winds over the Gulf of Tehuantepec this morning, and 25 to 35 kt winds this afternoon through tonight. The high will move east cross the east coast of the United States Sunday. This will weaken the pressure gradient across the gap and allow the gap winds over the Gulf of Tehuantepec to decrease below gale force by 1200 UTC Sunday morning. See the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFEP2/FZPN03 KNHC for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The ITCZ extends from 03N99W to 04N120W. The ITCZ then resumes west of a surface trough near 04N122W to 02N136W. Isolated moderate convection is from 02N to 05N between 93W and 106W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Strong high pressure over the northeast Gulf and eastern United States supports gale force gap winds over the Gulf of Tehuantepec. Please see the special features section for more details. High pressure near 31N140W supports gentle to moderate northerly winds offshore Baja California and Mexico waters north of 18N with seas of 4 to 6 ft. An upper trough over northwestern Mexico supports scattered thunderstorms from 21N to 26N, east of 111W, including the southern tip of Baja California. Aside from the Tehuantepec gap winds and large swell from the gap winds between 93W and 99W over the offshore waters, winds south of 18N are gentle to moderate with seas of 5 to 7 ft. On Monday, a cold front is forecast to cross the northeast waters, accompanied by fresh northeast winds and 8 to 9 ft swell offshore Baja California. By Tuesday, strong northwest winds will develop over the Gulf of California, with seas building to 8 ft. Another Tehuantepec wind event is forecast to begin early Thursday as a cold front crosses the Gulf of Mexico. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... High pressure north and east of the region will continue to funnel fresh to strong northeast winds through the Gulf of Papagayo and surrounding waters throughout the forecast period. During the late night and early morning hours, the strongest winds are expected as the regional coverage of strong winds expands to include from 08N to 13N as far west as 93W. Seas will build to 8 to 10 ft within this area as swell propagates westward and merges with large swell propagating from the Gulf of Tehuantepec. Over the Gulf of Panama...north to northeast winds will increase to fresh to strong speeds each night before diminishing during the late afternoon hours through Monday. A period of fresh to strong winds and seas to 8 ft will occur today through Sunday night. Elsewhere...light to gentle breezes and seas of 4 to 6 ft will prevail through early next week. REMAINDER OF THE AREA... High pressure of 1023 MB centered near 31N140W is producing fresh trades from 05N to 18N, east of 123W which is supporting 8 to 10 ft northeasterly swell west of a line from 18N140W to 10N123W to 05N140W. The trades will decrease the next 24 hours as the high continues to weaken, with seas diminishing below 8 ft by Sunday afternoon. A surface trough extends from the ITCZ near 04N120W to 13N115W. Isolated moderate convection is within 90 nm of either side of the trough axis. A cold front will cross the northern waters beginning Sunday night. The leading edge of an 8 to 10 ft batch of northwesterly swell will accompany this cold front. By Tuesday, the 8 to 10 ft swell will cover the waters north of a line from 25N115W to 16N140W. By Wednesday morning the large swell will become confined under an area of fresh trades from about 05N to 25N, west of 118W. $$ LATTO NATIONAL HURRICANE CENTER