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Eastern North Pacific Tropical Weather Discussion

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.