AXPZ20 KNHC 240922

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Fri Nov 24 2017

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 0900 UTC.


A gale warning remains in effect for Gulf of Tehuantepec. Minimal gale force winds are noted across the Gulf of Tehuantepec and downstream to near 14N96W with seas of 12-13 ft. The most recent scatterometer pass indicated that the fresh to strong N to NE winds extend farther south to near 12N97W. Winds are forecast to diminish below gale force by mid-day today, and to 20 kt or less late Sat morning. The NE swell generated by this gap wind event is mixing with long-period cross equatorial swell, with seas 8 ft or higher well downstream of the Gulf of Tehuantepec along 09N between 94W and 100W. Expect winds of 20 kt or less and seas of less than 8 ft only briefly on Sat afternoon. Strong N winds are forecast to resume again on Sat night, with gale conditions expected by mid-day Sun. Latest guidance is suggesting another 30 to 40 kt gap wind event on Sun night, with seas building to 16 or 17 ft by early Mon morning. Gale conditions will persist on Mon.


The monsoon trough extends from 09N84W to 08N90W to 07N101W. The ITCZ continues from 07N101W to 11N117W to 10N130W to 09N135W to beyond 10N140W. Scattered moderate convection is occurring from 08N to 10N between 130W and 133W.



See Special Features paragraph above for information on the Gulf of Tehuantepec Gale Warning.

A weak ridge dominates the offshore waters of Baja California producing mainly light to gentle winds and seas of 3 to 4 ft. Seas will begin to build this afternoon in NW swell, and peak at 4 to 7 ft at 13 to 15 seconds across the waters W of Baja tonight, then subside some on Sat into Sun. Long-period NW swell in the form of 7 to 9 ft seas will reach 30N120W by early Mon morning, and spread S across the offshore forecast waters W of Baja with 8 to 13 ft seas at 17 to 19 seconds Mon night and Tue. Also on Monday, expect increasing winds of 20-25 kt across the waters N of 26N, including the Sebatian Viscaino Bay as a stronger high pressure builds across the northern forecast waters.

Gulf of California: Recent scatterometer pass indicated gentle to locally moderate winds across the entire Gulf. This flow will continue through tonight. The pressure gradient will relax further, with light and variable winds expected through Mon. Strong to near gale force NW flow is expected to develop across the northern gulf on Mon night, with fresh to strong winds spreading south across the central and southern parts of the gulf through Tue night, with seas building around 8 ft across the long fetch waters.


Fresh to locally strong NE winds are forecast across the Gulf of Papagayo during the overnight and early morning hours with the assistance of the nocturnal drainage flow. Seas will build to around 8 ft downstream of the gulf by early Mon morning. Moderate to locally fresh NE winds are expected across the Gulf of Fonseca on Mon.

Light and variable winds, and 3 to 5 ft seas are expected elsewhere through Sun night to the N of the monsoon trough which has been meandering between 09N and 11N. Moderate southerly winds, and 3 to 6 ft seas, are forecast S of the monsoon trough.


A stationary front is near 30N140W. A broad surface low will develop along the front just W of the area by this evening. The low will move NE of the area tonight with the associated cold front entering the forecast waters. The front is forecast to reach from 30N136W to 22N140W tonight, and extend from 30N129W to 20N139W by Sat night. Fresh to strong southerly winds are expected ahead of the front, but mainly N of 26N. A reinforning or secondary cold front will reach the far NW corner of the area by Sat morning followed by fresh to strong NW winds and seas up to 10 or 11 ft. The fronts are forecast to merge on Sun.

A pair of altimeter passes indicated seas of 10 to 14 ft from 20N to 27N W of 134W while seas of 8 ft or greater in long period NW swell are propagating across the waters NW of a line from 30N123W to 14N140W. This swell event will beging to subside and shrink in area to mainly S of 15N and W of 125W by late Sat. At that time, another swell event will be reaching the NW waters.

$$ GR