AXPZ20 KNHC 221558

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1605 UTC Sat Jul 22 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 1200 UTC surface analysis and satellite imagery through 1430 UTC.


Tropical Storm Greg is centered near 15.1N 124.2W, moving W at 11 kt. Estimated minimum central pressure is 1001 mb. Maximum sustained winds are 45 kt with gusts to 55 kt. Scattered strong convection is noted within 90 nm NE and 120 nm across the SW semicircles. Greg is forecast to intensify only slightly during the next 36 to 48 hours as it moves westward before reaching cooler waters and a more stable atmosphere by Tuesday . See the latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP2 WTPZ22 for more details.

Tropical Depression Nine-E is centered near 10.0N98.2W, or about 480 nm SSE of Acapulco Mexico near 9.6N 96.6W, moving WNW at 10 kt. Estimated minimum central pressure remains 1006 mb. Maximum sustained winds are 30 kt with gusts to 40 kt. Scattered moderate to strong convection is observed in bands within 360 nm across the NW semicircle. Conditions are favorable for significant strengthening during the next 24 to 48 hours, and it is forecast to become a tropical storm later today, intensifying to a hurricane by early Monday as it continues on a WNW track. See the latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP4 WTPZ24 for more details.

Wind and convection associated with a surface low centered near 14.7N112.8W has gained sufficient organization this morning to be classified as Tropical Depression Ten-E. This system is moving W at 6 kt with minimum central pressure of 1005 mb. Maximum sustained winds are 30 kt with gusts to 40 kt. Scattered strong convection is within 240 nm across the SW quadrant of the low due. This system is forecast to move slowly westward to west- northwestward at 10 kt or less through early next week, and will gradually strengthen. See the latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP5 WTPZ25 for more details.


The monsoon trough is ill-defined in the Eastern Pacific due to the presence of numerous lows and tropical cyclones. A segment of monsoon trough is analyzed from 09N74W to 10N92W, and then resumes from low pres near 11N126.5W to 09N135W. Scattered strong convection is noted from 03N to 08n between 77.5W and 80W, within 75 nm of the Mexican coast between 22N and 24.5N, and within 90 nm either side of low and trough between 126W and 133W.



Gentle to moderate NW winds off the Baja California peninsula are expected to continue through the weekend, as high pressure of 1027 mb remains centered NW of the area near 34N137W and will shift NW. Seas will remain 4 to 7 ft in a mix of long period north and southwesterly swell. Gentle southerly flow will generally prevail in the Gulf of California, except for moderate southerly flow over the northern Gulf.

Fresh to strong northeasterly gap winds across the Gulf of Tehuantepec have begun to diminish this morning as T.D. Nine-E shifts slowly W of the area. Moderate E winds are expected across most of the area between Tehuantepec and Acapulco this afternoon and tonight becoming E to SE through early Mon. Seas of 5-8 ft in mixed N and SW swell this morning will become 5-7 ft in S to SE wind swell being generated by the T.D.


Across the Gulf of Papagayo, moderate to fresh offshore winds will pulse to fresh each night with nocturnal drainage flow through the week, occasionally building max seas to 8 ft in a mix of east swell and longer period southwest swell.

Gentle to moderate southerly winds are expected south of the monsoon trough axis E of 95W. Long period cross-equatorial SWly swell creating 5-7 ft seas will continue to propagate into the waters reaching the coast of Central America through the weekend. Another pulse of large southerly swell will move into the region Mon and Tue.


The remnant low of T.D. 8-E is analyzed near 11N126.5W, with fresh SW monsoonal winds within 180 nm SE of the center. The weak low is expected to dissipate by tonight.

The pressure gradient between high pressure north of the area and an active zone of tropical systems between 10N and 16N will maintain fresh trade winds and 6-7 ft seas north of 20N the next several days. Northerly swell in the form of 7-8 ft seas will propagate S of 32N between 125W and 135W the next two days.

$$ Stripling