000 AXPZ20 KNHC 062204 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2027 UTC Sat Jan 6 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 Gale Warning: Strong high pres ridging over the western Gulf of Mexico continues to support gale force N-NE winds over the Gulf of Tehuantepec. Winds will subside below gale force on Sun evening, then fall to moderate speeds by Mon morning as the ridging over the Gulf of Mexico weakens and shifts E. NE swell generated by the persistent strong winds will propagate downstream and maintain seas 8 ft or greater as far SW 10N100W tonight and 09N103W Mon morning. Please refer to the latest high seas forecast issued under AWIPS/WMO headers HSFEP2/FZPN03 for more details. Gale Warning for Northwest Waters: A strong 1011 mb low pressure system is centered near 28.5N130W. A stationary front extends from 30N129W through the low to 21N124W to 16N132W. The surface low is supported by a sharp upper-level trough extending from 32N131W through a low centered near 24N136W to beyond 17N140W. The surface low is expected weaken and dissipate during the next 24 to 36 hours as it drifts N to near 30N, allowing winds and seas near the low to subside. However, the upper-level trough will support development of another surface low by Sunday afternoon near 23N129W, which will generate an area of strong winds SE of the center. The new low will lift north behind the first low, then weaken and dissipate as well by Mon afternoon. This will subside, but will be overtaken by longer period NW swell 8 ft or greater through mid week. Please refer to the latest high seas forecast issued under AWIPS/WMO headers HSFEP2/FZPN03 for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 07N78W to 07N86W to 05N96W. The intertropical convergence zone continues from 05N96W to 06N113W to 10N127W. No significant convection is associated with the trough and ITCZ. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see Special Features section above for more details about the ongoing gale force wind event in the Gulf of Tehuantepec. Looking ahead, another gale force wind event is possible in the Gulf of Tehuantepec early next week as high pressure builds behind the next cold front forecast to move into the Gulf of Mexico. NW swell will propagate into the offshore waters off Baja California Norte Tuesday, with seas building to around 13 ft by Tue night. Elsewhere, relatively tranquil marine conditions are expected during the period. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Winds will pulse to 30 kt in the Gulf of Papagayo tonight, and again Sunday night into early Monday. The Papagayo gap winds will diminish through mid week. Light to gentle NE-E winds will prevail elsewhere to the N of 09N, with gentle to moderate S to SW winds expected S of 09N. REMAINDER OF THE AREA... Please see Special Features section above for details regarding a gale force low center near 130W. A sharp upper-level trough remains quasi-stationary along 135W, Generally supporting patchy rain from 11N to 30N between 122W and 130W. A few thunderstorms are evident from 13N to 15N between 130W and 132W. The subtropical ridge remains fairly week due the presence of the active low pressure areas, keeping trade wind flow and local wind waves relatively modest W of 130W. Long period NW swell 8 ft or greater will propagate across most the area through mid week. $$ CAM