Tropical Weather Discussion
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000
AXPZ20 KNHC 280235
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Thu Jul 28 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
0245 UTC.

...SPECIAL FEATURES...

Tropical Storm Frank is centered near 23.4N 122.7W, or about 815
miles...1310 km W of the Southern tip of the Baja California
Peninsula, at 0300 UTC Jul 28, moving WNW or 300 degrees at 7
kt. The maximum sustained winds have diminished to 45 kt with
gusts to 55 kt. The estimated minimum central pressure has risen
to 1000 mb. Currently, scattered moderate isolated strong
convection is observed within 90 nm in the west and 60 nm in the
east semicircles of the storm. Frank is expected to weaken to a
remnant low sometime on Thursday. Refer to the latest NHC
forecast advisory under AWIPS/WMO headers MIATCMEP2/WTPZ22 KNHC
for more details.

Also refer to the latest high seas forecast under AWIPS/WMO
headers MIAHSFEP2/FZPN03 KNHC for more details on the wave
forecasts associated with Frank.

...TROPICAL WAVE...TROPICAL LOW...POST-REMNANT LOW GEORGETTE

A tropical wave is analyzed from 10N to 17N along 112, and has
been moving W at about 15 kt. Isolated moderate to strong
convection is noted from 10-17N within 120 nm east of the wave
axis.

Scattered moderate isolated strong convection is observed within
240 nm over the E semicircle, and within 120 nm over the W
semicircles of a 1009 mb low pressure center embedded in the
monsoon trough near 11N109W. This low has a medium chance of
developing into a tropical cyclone within 5 days.

The post-tropical remnant low of Georgette was centered near
21N131W moving WNW at 8 kt. The maximum sustained winds are
estimated to have dropped off to 25 kt, with earlier ASCAT A and
B passes from 1804 and 1858 UTC indicating 20 to 25 knot winds
within 120 nm in the N semicircle of the remnant low. The
remnant low of Georgette is expected to continue to weaken, and
should dissipate within 24 hours.

..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

A monsoon trough extends WNW from the pacific coast of Costa
Rica near 09N84W to 11N95W to a 1009 MB Low Pressure near
10N109W then continues to 10N127W. The axis of the ITCZ is now
west of 140W. Scattered moderate isolated strong convection was
noted within 120 NM of the axis between 118W and 123W.

...DISCUSSION...

N of 15N e of 120W:

Tropical storm force winds and 8 foot seas associated with Frank
have moved west of 120W. See special features above additional
information on Frank.

A west to east orientated surface ridge will build from 21N120W
to 15N106W on Thu in the wake of tropical storm Frank. The weak
gradient northeast of the ridge will support light to gentle nw
winds through the upcoming weekend, with seas of 4-6 ft.

A nnw to sse orientated trough will meander e and w over the
Baja California Peninsula, and the northern Gulf of California
this week, supporting light and variable winds across the Gulf
of California waters through early Fri. A gentle to moderate
southerly flow is expected to begin late Fri, and will persist
through early Sat night across the gulf waters.

Moderate northerly flow is expected across the Gulf of
Tehuantepec late Thu night into the early daylight hours on Fri,
and then again late Fri night into Sat morning with seas
building to about 6 ft. Model guidance is suggesting a slightly
stronger drainage flow on Mon night into Tue morning with fresh
to locally strong n-ne winds, and seas building to 8 ft.

S of 15N e of 120W:

See section on tropical wave and a surface low.

Fresh NE to E winds are expected across, and just downstream of
the Gulf of Papagayo during the overnight hours tonight, then
guidance is hinting at moderate to locally fresh easterly
drainage flow on Thu night as a weak surface low develops near
09N91W. The low should move westward through the upcoming
weekend.

Long-period cross-equatorial SW swell, in the form of combined
seas of 6-8 ft, is forecast to propagate n across the equator
between 100-115W on Thu, and reach along 08N between 90-115W by
late Fri, then begin to subside. Combined seas are forecast to
less than 8 ft on Sat night.

W of 120W:

See section above for information on the remnant low of
Georgette and Tropical Storm Frank that will pass westward
through the northern portion of this discussion area through
Friday. Combined seas of 6-9 ft, primarily due to mixing swell,
are expected to surround the large seas near the cyclone, and
cover the waters elsewhere to the n of 12N through the upcoming
weekend.

$$
Cobb



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