000 AXPZ20 KNHC 140943 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Sun Jan 14 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 Storm Warning: A very strong pressure gradient across southern Mexico occurring behind a western Caribbean cold front is producing gale to minimal storm force northerly winds of 35 to 50 kt across Tehuantepec tonight, extending downwind to near 12N97W, with maximum seas of around 22 ft. The storm force winds should end around sunrise this morning, but strong gale conditions of 40 to 45 kt will persist through Tue. Another cold front will move across the Gulf of Mexico during the middle of the upcoming week and act to strengthen winds across Tehuantepec Wed and Thu. Gales may finally end Fri night or Sat morning. The resultant plume of N to NE swells producing a large area of 8 to 11 ft seas, will propagate S and SW, crossing the equator between 93W and 109W on Mon night, while reaching far W as 10N125W by late Mon. Gulf of Papagayo Gale Warning: Strong NE winds currently observed across the Gulf of Papagayo will continue to spread SW and reach as far SW as 07N93W by sunrise Sun, when gale force winds will commence from the gulf to near 09N87.5W and continue until mid afternoon. Winds are then expected to diminish slightly, then will increase to gale force again Sun night through Mon morning. Seas will build to 11 ft during this time, and continue through Mon. Strong high pressure across the U.S. behind the W Caribbean cold front is the force behind these winds, and will begin to weaken Tue and Tue night, with winds and seas subsiding modestly across the Papagayo region. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends WSW from the Pacific coast of Colombia W across Panama to the Pacific coast near 08.5N83W TO 05N92W TO 06N97.5W. Overnight scatterometer winds indicated a transition to ITCZ at 06N97.5W to a 1012 mb surface low near 07N113W to 10N134W to beyond 08N140W. Scattered moderate to strong convection is observed from 01N to 07N E of 82W to the coast, and from 03.5N to 07N between 83W and 91W. Scattered to locally numerous moderate to strong convection is observed within 150 nm N of the axis between 95W and 115W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... W of the Baja California Peninsula: A gentle variable breeze is occurring around a weak N to S orientated trough along about 114W. The trough will shift W reaching along 117W this afternoon, then drift back E again on Sun night into Mon and dissipate. Seas are currently 4 to 7 ft in N to NW swell will little change expected Sun. The leading edge of large and very long period NW swell will arrive near 30N120W early Mon, and build across the Baja offshore waters Mon and Tue. Seas of 8 to 13 ft are expected W of Baja on Mon night through Tue night in 18 to 22 second long-period NW swell. Gulf of California: Moderate to fresh NW winds, and 2 to 5 ft seas are currently observed across the north and central gulf waters. These winds should diminish slight Sun and Sun night. A moderate NW breeze will continue elsewhere through late Tue before diminishing to a light NW breeze. Elsewhere between the mouth and the Gulf of California and Tehuantepec light to gentle winds and moderate seas of 4 to 6 ft in NW swell prevail. Large NW swell will move into the area waters Tue to Wed and generate seas of 6 to 9 ft. See special feature section above for information about the storm warning and gale conditions across the Gulf of Tehuantepec. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... See special feature section above for information about the gale warning for the Gulf of Papagayo. Gulf of Fonseca: Strong N to NE winds behind the W Caribbean cold front have begun to surge across Central America and through the gaps across the Pacific waters to the N of 11N and E of 92W, including the Gulf of Fonseca tonight. The NE swell from these gap winds, and large E swells from the Gulf of Papagayo event further to the S, will merge by Sun afternoon with N swell propagating S from the Gulf of Tehuantepec, resulting in 7 to 11 ft seas across the offshore waters from roughly 04N to 14N W of 87W. These seas will continue through Tue before subsiding from the E. Fresh N winds across the Gulf of Panama will continue through sunrise on Mon. Elsewhere, light to moderate SW winds will persist S of Costa Rica and Panama through Sat with seas generally between 3 and 5 ft. REMAINDER OF THE AREA... A cold front has moved into the far NW corner of the discussion area, passing through 30N138W TO 29N140W. Strong to near gale force southerly winds ahead of the cold front have lifted out to the N of the area, leaving SSW winds near 20 kt just ahead of the front, and W winds 20-25 kt behind the front. Although the front will nearly stall from near 32N125W to 27N140W on Tue, large 10 to 16 ft seas due to long period 18 to 22 second NW swell, will propagate SE across the discussion area Mon through Wed. A secondary cold front will reach 32N140W on Sun night and help to maintain seas 15-18 ft along 32N. $$ Stripling