000 AXPZ20 KNHC 120359 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Fri Jan 12 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 0000 UTC surface analysis and satellite imagery through 0245 UTC. ...SPECIAL FEATURE... Gulf of Tehuantepec Gale Warning: Post frontal high pressure across the western Gulf of Mexico will surge across the Gulf of Tehuantpec initially at minimal 30-35 kt gale force just after sunrise on Fri, and quickly increase to 35-45 kt strong gale conditions on Fri afternoon. Seas are forecast to build to a maximum of 20 ft downstream of the gulf waters near 14N95.5W on Fri evening. Strong gales will continue through Sat and then increase to minimal storm force winds Sat night and continue into Sun morning, with seas forecast to build to 24 ft near 13.5N96W by sunrise Sun. This gale event will be long-lived, with winds not forecast to diminish below gale force through at least Thu morning. INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends W from the Pacific coast of Colombia at 06N77.5W TO 07.5N83W TO 06.5N93W, where evening scatterometer winds indicate a transition to an ITCZ, which continues WNW to 06N110W TO 09N140W. Widely scattered moderate isolated strong convection is noted from 05N to 08N between 86W and 94W. Scattered moderate to strong convection is noted from 07N to 10N between 121W and 130W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Moderate northerly winds and 6 to 9 ft seas in long period NW swell are expected across the Pacific waters W of the Baja Peninsula through Fri evening, then winds will diminish to a gentle variable breeze around a weak trough that develop along 115W. The trough will shift slowly W through the upcoming weekend and dissipate along 119W on Mon. Seas will subside to 4 to 7 ft on Sun night, but quickly build back to 8 to 12 ft N of 24N on Mon in very long period NW swell of 18-22 seconds. Gulf of California: Moderate to fresh NW winds through the gulf waters this afternoon have increased to strong through central portions this evening, from 24N to 28.5N, and area expected to increase slightly to 20-30 kt overnight between 24.5N AND 28.5N. Winds are then expected to diminish very slowly through late Fri night. Seas this evening are building 6-8 ft through central portions and will peak at 6-9 ft overnight before subsiding slowly through Sat morning. See special features section for information about a gale warning in the Gulf of Tehuantepec that will likely increase from gale to minimal storm strength Sat night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulfs of Papagayo and Fonseca: Strong NE winds are expected to surge across the Gulf of Papagayo on Sat morning, behind a cold front moving through the Western Caribbean. These strong gap wind conditions will expand N and through the Gulf of Fonseca waters throughout Sat. NE winds will increase to near gale force in and downstream of the Gulf of Papagayo late Sun night and continue through Mon morning. The resultant area of 7 to 11 ft seas will merge with large seas propagating S from the Gulf of Tehuantepec on Sun. Elsewhere, light to moderate SW winds will persist S of Costa Rica and Panama through Sat with generally between 3 and 5 ft. Fresh N winds are forecast across the Gulf of Panama beginning on Sun morning, and continuing through early Mon morning. REMAINDER OF THE AREA... The pressure gradient between high pres centered near 32N132W and lower pressure across the deep tropics is supporting fresh ENE trades from 08N to 21N between 116W and 140W. Large NW swell in the form of 7 to 9 ft seas is currently observed across the Pacific waters N of 10N W of 110W. These seas will slowly subside on Fri and Sat. Strong southerly winds will develop across the waters generally N of 29N W of 138W on Sat, in advance of a strong cold front that will reach 32N140W late Sat night. Although the front will stall from near 32N125W to 27N140W on Tue, associated long period NW swell, at 17 to 22 seconds, will propagate SE across the discussion area on Tue and Wed. $$ Stripling