AXPZ20 KNHC 252204

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Thu May 25 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 1800 UTC surface analysis and satellite imagery through 2145 UTC.


The Monsoon Trough axis extends from 10N85W to 11N95W to a 1008 mb low near 13N101W to 10N110W to 10N120W to 09N130W. The intertropical convergence zone axis extends from 09N130W to 07N140W. Scattered moderate to strong convection is from 03N to 09N between 79W and 84W. Scattered moderate to isolated strong convection is from 06N to 10N between 88W and 92W, and also within 180 nm south of the axis between 110W and 114W. Scattered moderate convection is within 60 nm south of the axis between 115W and 118W.

In addition, scattered moderate to isolated strong convection is within 120 nm of the center in the southeast quadrant of the low.



A weak high pressure ridge protrudes east-southeastward across these waters from well to the northwest of the area. The associated gradient is supporting generally moderate northwest winds across the Baja California Peninsula waters. Light to gentle northwest to north winds are noted elsewhere over the Mexican offshore waters to Acapulco. Seas are in the 4 to 5 ft range in mixed southwest and northwest swell across these waters, except across the Michoacan through Chiapas offshore waters where winds and seas are higher. This is due to 1008 mb low pressure located near 13N101W. Moderate to fresh south to southwest, with seas in the 8 to 10 ft range are occurring on the southeast side of the low with 4 to 7 ft seas elsewhere across the two offshore zones. The low is forecast to gradually dissipate through the next 18 hours or so, allowing for associated winds and seas to subside. The pressure gradient is\ forecast to tighten slightly to the north of 20N through Friday as the ridge slightly builds into the region, with winds and seas increasing slightly across those areas. Gentle to moderate SE winds occurring elsewhere between Tehuantepec and offshore of Acapulco will gradually weaken and veer southwest to west through Friday.

In the Gulf of California, mainly light to gentle variable winds are expected through the day except in the northern Gulf, with seas of 2 ft or less, except 3 to 5 ft near the entrance to the Gulf. Low pressure just to the north of the area over SW Arizona will linger through the end of the week. A trough extending south to southwest from the low to Baja California Norte will linger as well. Fresh to nearly gale force southwest to west winds have developed to the southeast side of the trough, and will persist through Friday night. The winds are enhanced through the gaps in the higher terrain of Baja. Seas are forecast to build to 6 to 8 ft late tonight to the southeast of the trough.


Gentle southwest to west winds prevail between the Papagayo region and Tehuantepec, with seas of 4 to 6 ft in SW swell. Expect NW to W monsoonal winds to spread across the coastal waters through Friday as a tropical wave moves across the area through Friday. Nocturnal offshore winds will pulse to fresh levels near the Gulf of Papagayo by Saturday night, behind the wave, and again on Sunday night. Moderate SW winds will continue to the S of 09N through Thursday night. A few pulses of SW swell are forecast to propagate across the area through the next several days, occasionally building seas to 7 ft. Otherwise, little change is anticipated through the upcoming weekend and early next week.


A weak ridge extends from 28N140W southeastward through 22N130W to 23N122W. The ridge is slowly shifting southeastward as a weak trough from 30N126W to 25N135W, and a cold front along and to the north of 30N are pushing southward. Moderate northerly winds follow the trough and front in the northern waters, with long period north swell producing seas of 7 to 9 ft across the area from 29N to 32N between 126W and 132W this afternoon into this evening, before subsiding to less than 8 ft Friday evening. Elsewhere N of the deep tropics, the weak ridge will maintain moderate trade winds south of 18N, with seas of 5 to 7 ft expected through Friday. Slightly stronger high pressure to the northwest of the area will build southward by the end of the weekend and into early next week, supporting increasing trades to moderate to fresh levels and resultant seas of 5 to 8 ft across the waters north of the convergence zone.

$$ Aguirre