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Tropical East Pacific Satellite

NHC Tropical Weather Discussion (East Pacific)

National Hurricane Center – Tropical Weather Discussion (East Pacific)

NHC East Pacific Tropical Weather Discussion

AXPZ20 KNHC 250248
TWDEP Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Mon Sep 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 0000 UTC surface analysis and satellite imagery through 0200 UTC.


Tropical Storm Pilar is centered near near 21.8N 106.3W, or about 15 nm NNE of Las Tres Marias, 1003 MB, at 0300 UTC moving N or 350 DEG at 8 KT. Maximum sustained winds 35 KT gusts 45 KT. Scattered moderate to strong convection is within 120 nm of the coast of Mexico from 21N to 24N. Pilar is expected to slowly track toward the NNW to N through Tuesday night and move along or just offshore of the coastline. Interaction with land will lead to a gradual weakening of Pilar, and is expected to become a tropical depression by Mon evening and then dissipate by Tue evening. Heavy rainfall causing flash floods and mudslides will be possible for Mexican states from Colima, Jalisco and Nayarit, and southern Sinaloa through Monday night. See the latest NHC Forecast/ Advisory under AWIPS/WMO headers MIATCMEP3/WTNT23 KNHC for more details.

..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH… The monsoon trough extends from 09N76W TO 08N80W to low pres near 14N92.5W 1007 MB TO 11N115W to low pres near 13.5N124W TO 11N133W to beyond 11N140W. Scattered moderate to strong convection is N of 06.5N to the coast between 80W and 89W, and from 10N to 15.5N between 91W and 110W, and within 90 nm S of the trough axis between 116W and 136W.


OFFSHORE WATERS WITHIN 250 NM OF MEXICO… A high pressure ridge building SE across the waters north of 25N will aid in freshening NW winds west of Baja California Norte overnight. Elsewhere, expect increasing winds and seas spreading northwestward from near Cabo Corrientes to the southern Gulf of California as Tropical Storm Pilar slowly tracks NNW and weakens during the next few days. Fresh SW to W monsoonal winds well offshore of the Gulf of Tehuantepec will maintain SW wind waves moving into the SE waters with seas 5-7 ft.


An active monsoon trough near the coast of Central America from Guatemala to Panama will remain the focus for active convection in coastal waters the next few days. Expect moderate SW to W winds to prevail south of the trough through Tuesday night. Farther south, gentle to moderate south to southwest winds will persist south of 05N through Tuesday night. Long period southerly
swell will decay and allow seas west of Ecuador and south of the
Equator to subside from around 7 ft to around 6 ft during the next couple of days.


NW swell generated by strong winds north of the area are producing 6 to 7 ft seas N of 24N between 116W and 125W. Seas in the area will continue to subside as the NW swell decay. Fresh to strong winds around low pres embedded in the monsoon trough near 13.5N124W are supporting a surrounding area of 8 to 10 ft seas in mixed swell. The low will shift to the ENE during the next few days. Otherwise, high pres centered well N of the area and low pressure associated with the monsoon trough will maintain moderate to occasionally fresh trade winds W of 120W through tonight. Low pressure passing north of the area will weaken the high, allowing trades to decrease during the second half of the week. $$