000 AXPZ20 KNHC 150942 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Mon Jan 15 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 0600 UTC surface analysis and satellite imagery through 0845 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: Strong gales continue across the Tehuantpec region tonight and extend downwind in a large plume to near 12.5N96W, where seas are as high as 19 ft. Little change is expected overnight before winds begin to slowly diminish and the areal coverage of the strong to gale winds begins to diminish in size through Tue evening. The resultant plume of NE swell will propagate outward crossing the equator between 95W and 110W on Mon afternoon, while reaching far W as 10N120W late Mon. A new cold front will move into the Gulf of Mexico, with the associated high pressure behind it to initiate another round of strong gales across Tehuantepec Tue night through Thu evening or night. Gulf of Papagayo Gale Warning: A band of strong to gale force NE winds extends SW from the Gulf of Papagayo to near 08N88W and is expected to broaden overnight through morning across and downwind of the area. Expect frequent gusts of 35 to 45 kt tonight through Mon morning within this plume of winds. Maximum seas to 11 ft are expected to build tonight through Mon. Wind will diminish to strong, with nocturnal pulses expected to resume each night on Tue night. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends WSW from the Pacific coast of Colombia near 09N75W TO 07N82W TO 05N93W, where overnight scatterometer winds indicated a transition to an ITCZ, which continues W-NW to a 1012 mb surface low at 08.5N121W to beyond 09N140W. Scattered moderate isolated strong convection is observed from 02N to 08N E of 85W to the coast of Colombia. Scattered moderate to strong convection is observed within 120 nm N and 60 nm S of the axis between 87W and 108W, and between 117W and 130W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... W of the Baja California Peninsula: A gentle variable breeze will continue around a weak N to S orientated trough along 119W. The trough will move E on Mon and gradually dissipate as a ridge axis builds E into the area along 22N116W to 15N101W on Mon night. The leading edge of large NW swell will arrive near 30N120W early Mon, with seas of 8 to 13 ft expected W of Baja on Mon night through early Wed in 18 to 22 second long-period NW swell. The large swell will generate very high and powerful surf along the coasts and outer reefs of Baja and mainland Mexico through Wed. Gulf of California: Light to moderate NW flow is forecast across across the entire gulf waters through Thu. See special feature section for information about the gale warning in the Gulf of Tehuantepec. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... See special feature section for information about the gale warning in the Gulf of Papagayo. Gulf of Fonseca: Strong to near gale force winds occurring across the W Caribbean behind a cold front have begun to surge through the mountain gaps of Central America and across the Pacific waters to the N of 08N and E of 92W, including the Gulf of Fonseca. Winds of 20 to 30 kt are expected to extend up to 120 nm downwind of the coasts. The NE swell from these gap winds, and large ENE swells from the Gulf of Papagayo event further to the S, are merging with NW to N swell propagating S from the Gulf of Tehuantepec, setting up a large area of 7 to 12 ft seas across the offshore waters from roughly 04N to 14N W of 87W. These seas will continue through early Tue before subsiding from the E. Fresh to locally strong N winds are forecast across the Gulf of Panama early tonight. Elsewhere, light to moderate SW winds will persist S of Costa Rica and Panama through Sat with seas generally between 3 and 6 ft. REMAINDER OF THE AREA... A cold front stalling from 30N134W TO 26N140W has begun to dissipate overnight. A secondary cold front will move into the far NW part of the area Mon morning and also stall through evening. Large 10 to 20 ft seas, in long period 17 to 22 second NW swell, will propagate SE across the discussion area reaching the Pacific coast of the northern Baja California Peninsula on Mon. Seas will then gradually subside late Tue through Wed night before the next surge of NW swell moves into the NW waters. $$ Stripling