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Eastern North Pacific Tropical Weather Discussion

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


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.