AXPZ20 KNHC 230253

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
102 UTC Sun Jul 23 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 0000 UTC surface analysis and satellite imagery through 0230 UTC.


Tropical Storm Greg is centered near 14.9N 126.5W, 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 in the W quadrant of the center. Little change in intensity is forecast through the next 24 hours with slow weakening expected thereafter as Greg tracks over cooler waters and a more stable atmosphere. Greg may weaken to a tropical depression by late Tue. See the latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP2 WTPZ22 for more details.

Newly formed Tropical Storm Hilary is centered near 11.5N 100.2W, or about 385 nm S of Acapulco Mexico, moving WNW at 11 kt. Estimated minimum central pressure is 1005 mb. Maximum sustained winds are 35 kt with gusts to 45 kt. Scattered moderate to strong convection is observed in bands within 120 nm across the N semicircle. Scattered moderate convection was observed elsewhere within 210 nm in the NE and 60 nm in the SW semicircles. Conditions are favorable for significant strengthening during the next 24 to 48 hours, and it is possible Hilary could intensify to a hurricane by late Mon as it continues on a WNW track. See the latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP4 WTPZ24 for more details.

Tropical Depression Ten-E is centered near 14.6N 114.2W, moving W at 6 kt with minimum central pressure of 1006 mb. Maximum sustained winds remain 30 kt with gusts to 40 kt. Scattered strong convection is within 240 nm across the SW semicircle of the low. 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 several lows and tropical cyclones. A segment of monsoon trough is analyzed from 10N85W to 11N97W, and then resumes from 11N129W to 09N135W. The ITCZ extends from 09N135W to 08N140W. Scattered moderate isolated strong convection was noted within 120 nm S of the monsoon trough between 90W and 94W. Scattered moderate convection was from 10N to 13N between 124W and 127W.



Gentle to moderate NW winds off the Baja California peninsula are expected to continue through the weekend, as high pressure of 1028 mb remains centered NW of the area near 34N138W 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.

Moderate E winds are expected across most of the area between Tehuantepec and Acapulco 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 T.D. The forecast track and intensity of T.D. Nine-E is expected to impact the offshore waters within 250 nm of the coast of the Mexican States of Oaxaca and Chiapas tonight through Sun night and the offshore waters of the States of Michoacan, Guerrero Sun through Tue.


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 SW 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 has been absorbed into the larger monsoonal flow to the S of T.S. Greg. 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.