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Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 262133
TWDEP 

Tropical Weather Discussion 
NWS National Hurricane Center Miami FL
2205 UTC Thu Jul 21 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 1800 UTC surface analysis and satellite imagery through
2145 UTC.

...SPECIAL FEATURES... 

Hurricane Frank is centered near 21.5N 117.6W, or about 500
miles...800 km WSW of the southern tip of the Baja California
Peninsula, at 2100 UTC, moving slowly WNW, or 285 degrees at 09
kt. The maximum sustained winds have increased to 70 kt with
gusts to 85 kt. The estimated minimum central pressure has
dropped to 986 mb. Currently, scattered moderate isolated strong
convection is observed within 120 nm SE, and within 90 nm over
the NW semicircles of the center. Frank has likely peaked in
strength as a minimal hurricane, and is forecast to begin a
weakening trend within 24 hours. Refer to the latest NHC
forecast advisory under AWIPS/WMO headers MIATCMEP2/WTPZ22 KNHC
for more details.

Tropical Storm Georgette is centered at 18.4N 128.6W at 2100
UTC, and is nearly stationary. Maximum sustained winds are down
to 50 kt with gusts to 60 kt. Estimated minimum central pressure
is up to 996 mb. the low level center is now exposed with deep
convection at a minimum and only flaring up within 60 nm of the
center in a few bursts. Georgette is expected to weaken over
cooler waters and overall unfavorable environment and should
become a remnant low within 48 hours. Refer to the latest NHC
forecast advisory under AWIPS/WMO headers MIATCMEP3/WTPZ23 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 these systems.

...TROPICAL WAVE...

A tropical wave is analyzed N of 09N along 103W, and has been
moving W at about 12 kt. Scattered moderate isolated strong
convection is noted from 10-15N within 180 nm W of the wave
axis. Expect this tropical wave to lose identity over the next
day or so. 

..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

A monsoon trough extends WSW from the pacific coast of Colombia
at 08N78W to 07N83W, then turns nw to 10N88W to 09N95W to
11N109W where scatterometer winds indicate a transition to an
ITCZ. The ITCZ extends SW to 08N130W, then resumes SW of
Georgette at 14N136W to 12N140W. Scattered moderate isolated
strong convection is observed along the pacific coast of
Colombia, Panama and Costa Rica within 30 nm either side of a
line from 03N78W to 07N78W to 07N81W TO 10N86W. Similar
convection is noted within 60 nm either side of a line from
05N88W to 08N94W to 09N106W, within 150 nm either side of a line
from 10N113W to 08N127W, and within 60 nm of 13.5N137W. 

...DISCUSSION...   

N of 15N e of 120W:

Tropical storm force winds associated with tropical cyclone
Frank will move west of 120W on on Wed, and associated seas of 8
ft or greater will shift w of 120W by Wed night. See special
features above additional information on Frank.

A west to east orientated surface ridge will build from 21N120W
to 15N106W in the wake of tropical cyclone 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 Fri. A gentle to moderate southerly
flow is expected to begin on Fri night, and will persist through
Sat across the gulf waters.

Moderate northerly flow expected 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 Sat night into
Sun morning, with seas building to 8 ft.  

S of 15N e of 120W: 

See section on tropical wave. 

Moderate e winds are expected across, and just downstream of the
Gulf of Papagayo during the overnight hours tonight and on Wed
night, then guidance is hinting at fresh easterly drainage flow
on Thu night as a surface low develops near 10N91W. The low
should move westward through the upcoming weekend, with
increasing chance of tropical cyclone formation later in the
week.

Long-period cross-equatorial SW swell, in the formed 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 on
Sat before beginning to subside. Combined seas are forecast to
less than 8 ft on Sun.

W of 120W:

See special features above for information on tropical cyclones
Georgette and Frank that will pass westward through the northern
portion of this discussion area through this upcoming weekend.
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