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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 230225
TWDEP Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2342 UTC Thu Jun 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 0000 UTC surface analysis and satellite imagery through
0215 UTC.

…INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH… The monsoon trough axis extends from 11N86W to a 1007 mb low
pressure near 12N95W to 10N105W to 11N116W to 10N121W. The ITCZ axis continues from 10N121W to 07N130W to beyond 06N140W. Scattered
moderate convection is from 08N to 10N between 91W and 94W…and
from 07N to 10N between 110W and 120W. A cluster of moderate to strong convection is noted across the Isthmus of Tehuantepec and parts of the Gulf of Tehuantepec. A diffluent pattern aloft is helping to induce this convective activity.



A surface trough is west of Baja California and extends from
27N119W to 21N121W. This trough is a reflection of an upper-level
low located near 25N121W, and it is also breaking up the usual subtropical ridge in the area, maintaining a fairly light pressure gradient and subsequent wind pattern. Ship observations and scatterometer data confirm the presence of light to gentle winds near the trough. A recent altimeter pass indicated long period northwest swell, with wave height of 8 to 9 ft reaching the western waters of forecast zones PMZ011 and PMZ013. Seas are forecast to subside below 8 ft by early Friday. The trough will dissipate through late Friday, allowing the ridge to build eastward. This will support moderate to occasionally fresh northwest winds along the coast of Baja California through Sunday
with building seas of 5 to 7 ft seas. Looking ahead, the pattern
will repeat again as another weak trough develops off the Baja coast allowing winds to diminish slightly early next week.

The most recent scatterometer pass indicates gentle to moderate southerly flow across the southern Gulf of California, and moderate to fresh winds across the central part of the Gulf. Moderate to fresh southerly winds are also expected over the northern Gulf tonight. On Friday, winds will be mainly light and variable across much of the Gulf of California. Farther south, a broad area of low pressure of 1007 mb is located
near 12N95W. This low is producing disorganized showers and thunderstorms. Environmental conditions appear conducive for some
development of this system by early next week while it moves slowly west-northwestward parallel to the coast of Mexico. So
far, fresh to strong winds are expected across the Gulf of Tehuantepec in association with this system Sunday night through Tuesday, with seas building to 8 ft by late Saturday.

OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR… Gentle to moderate southwest to west winds are expected across most of the forecast area during the forecast period, with the exception of mainly south winds between Ecuador and the Galapagos
Islands, as the pressure gradient remains weak. Additional pulses
of long period SW swell will continue to impact the forecast waters, but seas will remain below 7-8 ft. Seas will continue to
subside to 4-5 ft during the upcoming weekend.


A ridge dominates most of the waters north of the convergence zone and west of 125W. Scatterometer data indicate moderate to
locally fresh N to NE winds in association with this ridge. Northerly swell will continue to propagate across the waters
N of 20N, building seas up to 11-12 ft N of 28N through Friday, as fresh swell moves in around a low pressure system forecsat to
move from east to west just N of the area. Seas will gradually subside from east to west through the upcoming weekend as the low