000 AXPZ20 KNHC 030947 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Mon Dec 03 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 0945 UTC. ...SPECIAL FEATURE... Gulf of Tehuantepec Gale Warning: Strong post-frontal high pressure across the Gulf of Mexico will surge into the Gulf of Tehuantepec in the form of strong northerly winds on Tue morning, increase to near gale force early Tue afternoon, reach minimal gale force late Tue afternoon, with the gale conditions then persisting through late Wed night. The southern extent of strong winds will reach as far S as 12N98W, with maximum seas of 13 ft forecast downstream near 14.5N on Wed night. Winds will diminish to 20 kt or less late Fri night. .INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends W off the Caribbean coast of Colombia at 10N76W to the Pacific coast of Costa Rica, then continues W- NW to 12N97W, then turns SW TO 08N114W where scatterometer winds indicate a transition to an ITCZ which continues W-NW to beyond 08N140W. Scattered moderate isolated strong convection is observed within 30 nm either side of a line from 05N78W to 05N83W to 08N89W,from 06N to 12N between 92W and 106W, and within 150 nm either side of a line from 08N124W to 08N138W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of Tehuatepec...See special features paragraph above. Gulf of California: Gentle to moderate northerly winds are expected across the entire gulf waters this morning, with a fresh NW breeze developing across the central gulf waters this afternoon and continuing through Tue morning. Winds will then gradually diminish to a light and variable breeze throughout by Wed morning. Fresh to locally strong southerly flow forecast N of 29.5N on Wed afternoon, ahead of a pre-frontal trough that will pass through the northern gulf waters on Wed night and Thu, followed by the associated cold front on Fri, with fresh northerly flow forecast briefly behind both the trough and the front. Elsewhere: Moderate northerly flow, and 4 to 7 ft seas, expected W of 110W today while gentle northerly flow, and 3 to 5 ft seas, is forecast E of 110W. Low level winds will gradually clock to the S across the waters W of Baja Norte on Tue night ahead of a cold front arriving at 32N120W late Wed, and reaching the extreme northern Baja Peninsula early Thu, accompanied by long- period NW swell in the form of 7 to 9 ft seas. These seas will propagate S reaching the W shore of the southern Baja Peninsula late Fri, then begin to subside from the N during the upcoming weekend. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Volcanic ash originating from the Fuego Volcano in Guatemala remains well inland at the moment, but is expected to be advected southwesterly later today, and may pass across the Pacific coast near the Guatemala-Mexican border. Gulf of Papagayo...Nocturnal pulses of moderate to locally fresh NE winds are expected through Wed. A strong gap event is forecast on Wed night through Fri night, with seas building to 8 ft downstream near 10.5N87.5W. Elsewhere: The monsoon trough will meander between 08N and 10N this week with light to gentle variable flow, and 3 to 5 ft seas, forecast N of the monsoon trough, and moderate southwesterly monsoonal flow, and 4 to 6 ft seas, forecast S of the monsoon trough. REMAINDER OF THE AREA... A surface high analyzed near 29N126W will shift SE reaching near 22N120W during mid week. This will allow a cold front currently over the far NW waters to continue E reaching a position from 32N127W to 23N137W early Tue while preceded by strong SW flow to the N of 29N within 150 nm E of the front. Fresh to strong westerly winds, and large 8 to 16 ft seas, are forecast tonight W of the front in long-period NW swell. The weakening front will reach from 32N125W to 22N135W on and Tue and from the northern Baja Peninsula to 20N127W early Thu, accompanied by only a moderate SW-W-NW wind shift. The associated leading edge of 8 ft or greater seas will reach from 32N120W to 10N140W early Thu, and from the southern tip of the Baja Peninsula to the equator at 130W on Fri night. $$ Nelson