000 AXPZ20 KNHC 131601 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Sat Jan 13 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 1200 UTC surface analysis and satellite imagery through 1545 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Storm Warning: Strong gale force northerly winds will increase to minimal 35 to 50 kt storm force this evening, with seas building to a maximum of 25 ft downstream of the gulf waters near 14N95.5W overnight. Storm conditions should end around sunrise on Sun, but strong gale conditions will persist through the middle of the week, perhaps ending around sunset on Thu, with winds forecast at 20 kt or less on Fri afternoon. The resultant plume of NE swells, in the form of 8 to 11 ft seas, will propagate outward crossing the equator near 97W, and as far W as 10N125W by late Mon. Gulf of Papagayo Gale Warning: Strong NE winds currently observed across the Gulf of Papagayo will spread WSW to near 06N94W on Sun while increasing to 25 to 30 kt near gale force conditions,but surrounded by a larger area of frequent gusts to gale force. Will forecast a narrow swath of minimal gale force winds from 11N86.5W TO 10N87W late Sun night, but even if the sustained winds remain near 30 kt, expect frequent gusts of 40 to 45 kt. Seas are expected to build to 11 ft downstream of the region on Sun and continue through Mon. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends WSW from the Pacific coast of Colombia at 08N78W TO 06N94W where scatterometer winds indicate a transition to an ITCZ, which continues W through an embedded 1011 mb surface low at 08N111W to 08N131W to beyond 08N140W. Scattered moderate isolated strong convection is observed within 120 nm either side of lines from 07N77W to 04N81W to 05N89W, and from 07N105W to 09N115W. Similar convection is observed within 60 nm either side of a line from 09N126W to 09N138W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See special feature section for information about a storm warning in the Gulf of Tehuantepec. A gentle variable breeze is forecast around a weak N to S orientated trough developing along 114W, with the possibility of weak surface low forming briefly. The trough will shift W reaching along 119W on Sun, then move back E again on Sun night into Mon while gradually losing identity along 115W as as ridge axis builds E into the area from near 23N117W to 16N105W on Mon night. Seas will subside to 4 to 7 ft overnight and continue through midday Sun. 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, with guidance suggesting 20 to 23 second long-period NW swell. Gulf of California: Fresh to locally strong NW winds, and 3 to 5 ft seas are currently observed across the far northern gulf waters. These winds should diminish by late this evening. Moderate NW breezes will continue elsewhere through late Tue before diminishing to a light NW breeze. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... See special feature section for information about a gale warning in the Gulf of Papagayo. Gulf of Fonseca: Strong N to NE winds will develop across the Pacific waters to the N of 11N and E of 92W, including the Gulf of Fonseca, beginning this evening, and continue through Sun morning. The resultant area of 7 to 11 ft NE swell from these gap winds, and the Gulf of Papagayo event further to the S, will merge on Sun with N swell propagating S from the Gulf of Tehuantepec, with 7 to 11 ft seas across the offshore waters from 04N to 14N W of 87W. These seas will continue through Tue before subsiding from the E. Elsewhere, light to moderate SW winds will persist S of Costa Rica and Panama through Sat with seas generally between 3 and 5 ft. Fresh N winds are forecast across the Gulf of Panama beginning this evening, continuing through sunrise on Mon. REMAINDER OF THE AREA... Strong to near gale force southerly winds are observed across the waters from 29N to 32W W of 138W all ahead of a cold front that will reach 32N140W overnight. Although the front will nearly stall from near 32N125W to 27N140W on Tue, large 12 to 22 ft seas primarily due to long period 17 to 22 second NW swell, will propagate SE across the discussion area on Tue and Wed. A secondary cold front will reach 32N140W on Sun night driving seas back up to 20 ft along 32N. $$ Nelson