000 AXPZ20 KNHC 102221 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2020 UTC Sun Dec 10 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 1800 UTC surface analysis and satellite imagery through 2130 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Storm Warning: A very tight pressure gradient across the Isthmus of Tehuantepec remains supported by 1036 mb high pres over N central Mexico will support storm force winds of 40-50 kt across the Gulf of Tehuantepec until early Mon morning, with seas in the 14-22 ft range. A large area of gale force winds of 30-40 kt surrounds the storm force winds within 120 nm either side of a line from 16N95W to 14N96W to 12N98W, with corresponding seas in the 12-19 ft range. Fresh to strong NE-E winds extend downstream from the gulf to near 11N and 102W, where seas run 8 to 11 ft in NE swell. Seas 8 ft or greater are propagating well away from the Gulf to near 105W this evening, and will propagate even farther W to near 110W on Monday. The ongoing storm conditions are forecast to weaken to a strong gale by early this afternoon and continue into early Monday before weakening further to minimal gale force early on Tuesday. These conditions are forecast to continue through Wednesday night of the upcoming week. Gulf of Papagayo Gale Warning: The pressure difference between a very tight packing of isobars pressing southward across the northern portion of Central America from 1036 mb high pres over N central Mexico and broad low pres over the remainder of Central America and the SW Caribbean Sea has induced NE gale force winds of 30-35 kt over the Gulf of Papagayo. N-NE winds of 20-30 kt are elsewhere downstream from the gale force winds over an area from 07N-11N between 85W-88W. The pres gradient will loosen enough to allow for these gale conditions to diminish to strong to near gale force NE winds late Monday night and to strong NE winds Tuesday. Seas of 8-10 ft will propagate to the SW well away from the gale force wind area reaching from 05N-11N between 86W-90W early on Monday, and from 04N-10N between 86W-91W early on Tuesday. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The Monsoon Trough axis extends from western Colombia at 09N74W to 07N80W to 08N86W to 07N96W to 10N115W to 07N127W to 07N136W. The ITCZ continues from 07N136W to beyond 08N140W. Scattered moderate and isolated strong convection is present from 06N to 09N between 77W and 87W...from 08N to 10N between 113W and 118W and from 06N to 09N between 124W and 134W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of Tehuantepec: Please see Special Features section above for details on an ongoing storm event. High pressure over the Great Basin will remain strong enough to maintain fresh to strong northerly winds over the northern Gulf of California this evening before it weakens. N-NE winds funneling through the Baja California peninsula into the Pacific waters have diminished to 15-20 kt. Seas will subside below 8 ft off the coast of Baja California tonight. Elsewhere gentle to moderate winds and 4-6 ft seas will persist through next week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Please, see Special Features section above for details on an ongoing gale event. Strong high pressure ridging southeastward across northern central America is combining with low pressure over the remainder of Central America to generate strong to gale force NE winds through the Gulf of Papagayo and nearby waters. Large NE swell from a Tehuantepec gap wind event will spread across the offshore waters of Guatemala and El Salvador through Mon. Localized gap pulses of strong NE winds are possible off the coast of El Salvador and Guatemala, including Gulf of Fonseca beginning early today. REMAINDER OF THE AREA... A cold front is crossing the NW corner of the area. A tight pressure gradient between the front and high pressure over the northern waters is bringing strong S to SW winds to area N of a line from 32N134W to 29N140W along with seas of 10-14 ft in NW swell. The cold front will reach a position from near 32N136W to 27N140W this evening as winds subside to 20 kt or less. Seas will run 8-15 ft in NW swell N of a line from 32N132W to 24N140W. This front will begin to weaken by early tonight from near 32N136W to 27N140W, with winds on either side of it becoming 15-20 kt. Seas of 11-15 ft in NW swell are expected W of the front while seas of 8-10 ft are expected within 180 nm SE of the front at that time. The front will dissipate by late Monday night, however, long period NW swell will maintain seas of 8-11 ft W of a line from 32N122W to 13N124W to 08N140W. The swell will gradually decay through Wed morning, with seas of 8-10 ft expected W of a line from 20N121W to 00N135W. The pressure difference between a trough near 136W and the high pressure over the northern waters is forecast to result in strong NE-E winds beginning late Monday night from 13N- 18N, and to the W of 129W along with seas of 8-10 ft. This area of strong winds will shift to W of 130W by early on Tuesday, then diminish to 15-20 kt late Tuesday. $$ CAM