000 AXPZ20 KNHC 040951 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Tue Dec 04 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 around sunrise this morning, quickly increase to near gale force, and reach minimal gale force by early this afternoon, with the gale conditions then persisting through just after sunrise on Thu. The southern extent of strong winds will reach as far S as 12N98W on Wed, with maximum seas of 14 ft forecast downstream near 14.5N on Wed evening. Winds will diminish to 20 kt or less on Fri evening. The next gap event will begin on Sun morning with strong gale conditions developing on Sun night. .INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends W across the Gulf of Panama to the Pacific coast of Costa Rica at 09N83W to 10N86W to 10N100 TO 09N110W where scatterometer winds indicate a transition to an ITCZ which continues W to beyond 09N140W. Scattered moderate isolated strong convection is observed within 30 nm either side of a line from 04N77W to 09N100W to 06N106W and within 150 nm either side of a line from 07N117W to 10N130W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of Tehuantepec...See special features paragraph above. Gulf of California: Fresh northerly winds currently across the entire gulf waters will gradually diminish to a light and variable breeze throughout by late Wed morning. Fresh to locally strong southerly flow is forecast N of 29.5N on Wed evening, 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 early Fri, with fresh northerly flow forecast briefly behind both the trough and the front. Gentle to locally moderate northerly flow expected across the entire gulf waters on Sat. Fresh to locally strong NW flow expected across the southern gulf waters on Sun. Elsewhere: Light to gentle northerly flow, and 4 to 6 ft seas, is expected W of 110W this morning while light to gentle northeast flow, and 3 to 5 ft seas, is expected E of 110W. Low level winds will gradually clock to the S across the waters W of Baja Norte tonight ahead of a cold front arriving at 32N120W on 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 on Sat with seas less than 8 ft by Sun afternoon. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Thin volcanic ash originating from the Fuego Volcano in Guatemala is observed on satellite imagery spreading southwest across the Pacific of Guatemala between 14N and 14.5N, but may not be sinking to near the surface. Gulf of Papagayo...Nocturnal pulses of fresh to locally strong NE winds are expected through Fri night. The resultant NE swell in the form of 6 to 8 ft seas will reach as far W as 10N93W on Thu, and reach near 10N98W on Thu night. 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 currently near 29N121W will shift SE and weaken during the middle of the week. This will allow a cold front currently extending from 32N129W to 21N140W, to continue E reaching a position from 32N122W to 23N133W tonight 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 15 ft seas primarily due to long-period NW swell, is forecast tonight W of the front. The weakening front will reach from the northern Baja Peninsula to 20N130W on Wed night, but only accompanied by only a moderate SW-W-NW wind shift. However 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. Another cold front will reach 32N140W on Sat accompanied by strong winds shift and large post-frontal NW swell. $$ Nelson