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Eastern North Pacific Tropical Weather Discussion

AXPZ20 KNHC 250244

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0245 UTC Thu Aug 25 2016

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 Depression Thirteen-E has developed and was centered 
near latitude 15.7 North, longitude 110.9 West. The depression is
moving toward the west-northwest or 295 deg at 10 kt. Maximum
sustained winds remain 30 kt with gusts to 40 kt with an
estimated minimum central pressure of 1006 mb. Scattered to
locally numerous moderate to strong convection was noted within
150 nm in the NE and within 120 nm in the SW semicircles. The
tropical depression is forecast to strengthen during the next 48
hours, and is expected to become a tropical storm on Thursday.

A large and complex tropical wave is along about 131W/132w,
moving westward at 15 knots. The associated moisture and
convection spans the area from 09N to 15N between 123W and 131W.
An elongated 1008 mb surface low has not become better defined
this evening and is located near 12N125W. A broad zone of fresh
easterly trade winds prevails north of the low from about 13N to
17N between 118W and 129W, where seas are running 6-8 ft.
Environmental conditions are conducive for a gradual improvement
in organization of this system, and it has a medium chance for
tropical cyclone development within the next 48 hours.




The monsoon trough extends from near 10N85W to 08N95W to 10N102W.
The ITCZ begins near 10N136W and extends through 10N140W. Widely
scattered to scattered moderate to strong convection is occurring
within 120 to 180 nm S of the monsoon trough between 85W and 101W.



A narrow surface ridge extends from the NE Pacific southeastward
through 30N125W to near Las Islas Tres Marias. This ridge will
change little during the upcoming weekend, and combine with the
persistent trough meandering along the Baja California peninsula
and Gulf of California to produce mainly light to moderate 
northerly flow prevailing outside of the Gulf of California.
Expect mainly light to gentle southerly flow In the Gulf of
California, except for occasionally fresh wind flow in the
northern Gulf where the pressure gradient will be slightly

Active convection associated with tropical depression thirteen-E
over extreme western portions of PMZ015 and PMZ023 will move west
of the area overnight. East to northeast winds of 15-20 kt
occurring across the waters this morning will gradually diminish
tonight and become light and variable as a weak ridge builds
across the area behind the exiting depression.

High pressure across the Gulf of Mexico continues to drive
20-25 kt northerly winds across the Gulf of Tehuantepec with seas
6-9 ft. These winds will increase slightly again overnight then
remain at 20-25 kt Thursday, before diminishing to 15-20 kt 
Friday afternoon.


Moderate to locally fresh offshore winds are expected across
most of the area e of 95W and north of the monsoon trough today,
with strongest winds 15-20 kt across the Gulf of Papagayo
region. Winds are expected to become light and variable late
Thursday into Friday, except for 15-20 kt offshore winds across
Papagayo, then become onshore at 10 kt or less over the weekend.


The weak center center of the post-tropical remnant low of Kay
is a 1015 mb low pressure center near 24N124.5W. No deep
convective precipitation is present with the low pressure center.
The remnant low will continue to move west- southwestward, and
gradually dissipate into an open trough early Thursday. A broad
area of 20 kt NE winds with seas 6-8 ft in found within 120 nm
across the NW semicircle of the low.

A broad high pressure ridge dominates the remainder of the area,
extending from a large 1040 mb high near 50N140W. As the low
center along 125W and associated tropical wave move westward
during the next few days, the pressure gradient between the
monsoon trough and the ridge will yield freshening winds across
the trade wind belt, generally south of 21N, from just northeast
of the low center to beyond 140W. Seas of 6-8 ft in this area in
mixed swell will increase slightly to 7-9 ft during this time.
South of the monsoon trough, a large area of fresh southwesterly
monsoonal flow is supporting seas of 8 to 9 ft north of 07N
between 115W and 125W. The strength and areal coverage of these
fresh winds will increase south and southeast of the low as it
shifts westward over the next few days, and act to increase seas
to 6-8 ft in mixed south and southwest swell.