000 AXPZ20 KNHC 060246 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Thu Dec 06 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 0300 UTC. ...SPECIAL FEATURE... Gulf of Tehuantepec Gale Warning: Northerly gales will continue in the Gulf of Tehuantepec until early Thu and slowly diminish to fresh conditions by Fri afternoon. NE wind waves are peaking around 13 ft downstream near 14.5N95.5W before winds and seas gradually begin to diminish to below gale force by around sunrise Thu morning. The next Tehuantepecer will begin Sun morning and quickly reach strong gale by Sun night. Peak seas may approach 20 ft. Gales should continue through at least Mon night. .INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 07N78W along the Panama-Columbia border westward to 09N108W, where it breaks for a surface trough along 112W. The monsoon trough then resumes at 10N117W and extends to 10N131W. the ITCZ begins at that point and extends westward to 10N140W. Scattered moderate convection is observed within 120 nm south of the monsoon trough between 85W and 95W. Scattered moderate convection exists within 120 nm of the monsoon trough between 120W and 127W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of Tehuantepec...See special features paragraph above. Gulf of California: The northern Gulf of California may briefly experience a NW strong breeze tonight in association with a pre- frontal trough. After the front reaches the northern Gulf of California Thu night, NW winds should remain at fresh breeze or weaker conditions. Isolated thunderstorms will move NE across the Baja waters and into NW Mexico well ahead of the front Thu through Fri. Elsewhere: winds should generally be gentle to fresh breeze through Mon night. Long-period NW swell of 6-8 ft will reach the zones west of Baja California Fri and spread southeastward while gradually diminishing. The next significant NW swell event may arrive late Mon. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... A thin plume of volcanic ash originating from the Fuego volcano in interior Guatemala is observed on satellite imagery spreading southwest across the Pacific coast of Guatemala between 90.5W and 92W, but is not likely to be reaching the surface. Gulf of Papagayo...Nocturnal pulses of fresh to strong NE winds are expected across and downstream of the Gulf of Papagayo through Fri night, diminishing on Sat and Sun, and likely occurring again on Mon night. Peak seas should be up to 8 ft Thu, but dropping below 8 ft by Fri through Sun. Elsewhere: The monsoon trough will meander between 08N and 10N over the next two days with gentle to fresh E winds forecast N of the monsoon trough, and gentle to moderate SW monsoonal flow forecast S of the monsoon trough. By Sat, the monsoon trough structure W of 90W should be replaced by an ITCZ structure of converging easterly tradewinds. REMAINDER OF THE AREA... A 1008 mb surface low near 33N 120W supporting the cold front approaching Baja California will be absorbed by a stronger low to its west. The merged low will shift SE into the area to near the California-Baja California border Thu evening, and then move E along 32N passing E of 115W on Fri night while weakening. This will drag the aforementioned cold front eastward across the subtropical waters. While the cold front will have winds generally fresh breeze or weaker, large 8 to 12 ft seas, in long- period NW swell, is forecast to propagate E across the area, with the leading edge of 8 ft or greater seas reaching from 32N120W to 10N140W on Thu, and from the southern tip of the Baja Peninsula to the equator at 135W on Fri night. A new cold front will reach 32N140W on Sat evening accompanied by a fresh wind shift and large post-frontal NW swell, which may reach 15 ft by Sun. $$ Landsea