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Eastern North Pacific Tropical Weather Discussion



000
AXPZ20 KNHC 282144
TWDEP 

Tropical Weather Discussion 
NWS National Hurricane Center Miami FL
2205 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 1800 UTC surface analysis and satellite imagery through
2130 UTC.

...SPECIAL FEATURES... 

Frank has degenerated into a post-tropical cyclone with maximum
sustained winds of 30 knots. The cyclone was center near 24.1N
124.9W, or about 955 miles w of the southern tip of the Baja
California Peninsula, at 2100 UTC Jul 28, moving WNW, or 295
degrees at 06 kt. Frank is expected to and gradually dissipate
over the next 48 hours. This is the last advisory issued on
Frank. Refer to the latest NHC forecast advisory under AWIPS/WMO
headers MIATCMEP2/WTPZ22 KNHC for more details.

A tropical low pressure is analyzed along the monsoon trough at
11N110W, and is estimated at 1009 mb. Scattered moderate
isolated strong convection is observed mainly s of the low, from
08-10N between 107-114W. This low has a medium chance of
developing into a tropical cyclone in the next 48 hours. The low
and associated winds have been included in the latest High Seas
forecasts issued under AWIPS/WMO headers MIAHSFEP2/FZPN03 KNHC.

...TROPICAL WAVES and TROPICAL LOW...

The remnant low of former tropical cyclone Georgette is centered
near 21N134W, and is estimated at 1010 mb. An earlier Rapid SCAT
pass indicated fresh to strong ENE winds within 150 nm N of the
center and suggested the system may be opening up into a trough.
Seas of 7-10 ft were noted in the area of strongest winds. The
low is forecast to weaken to an open trough overnight and extend
from 20N138W to 23N139W by Fri. 

A tropical wave is analyzed from 08N to 16N along 113W/114w, and
has been moving W at about 10 kt. Scattered moderate to strong
convection was noted within 180 nm either side of the wave axis
from 12N to 14.5N.

A second tropical wave analyzed over the w Caribbean from 11-22N
along 82W will move w off the Central American coast tonight, then
slow it's forward speed as it continues w through the Gulf of
Tehuantepec area Fri night into early Sat enhancing the northerly
drainage flow around sunrise Sat. 

..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

A monsoon trough extends WNW from the Pacific coast of Costa
Rica near 09N84W to 08N90W to 12N105W, then through an embedded
1009 mb low pressure near 11N110W, then continues W to 11N120W,
where scatterometer winds indicate a transition to an ITCZ,
which continues SW to through 07N135W to beyond 08N140W.  

Scattered moderate to strong convection was noted within 180 nm
either side of the the monsoon trough between 85W and 95W.
Scattered moderate isolated strong convection was noted within
120 NM S of the axis between 104W and 108W. 

...DISCUSSION...   

N of 15N E of 120W:

A west to east orientated surface ridge is building from 21N120W
to 17N104W. The pressure gradient northeast of the ridge will
support gentle to moderate nw winds across the open Pacific
waters through Fri night, then the gradient will relax some with
light to gentle nw flow expected into early next week. Mostly
expect seas of 4-6 ft.

Considerable convection continues along the Pacific coast of
Mexico and the Gulf of California, roughly within 45 nm either
side of a line from 20.5N105.5W to 29N112.5W. Otherwise...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 to gentle southerly winds across the Gulf
of California waters through Fri. Moderate to fresh southerly
flow, with 3-5 ft seas, is then forecast across the northern
Gulf of California from Fri night to late Sat night.

Fresh northerly flow is expected across the Gulf of Tehuantepec
during the overnight hours through Sat night. Guidance suggests
locally strong n flow on Sun, Mon and Tue nights with seas
building to 8 ft. 

S of 15N E of 120W: 

See section on tropical wave and lows. 

Moderate to locally fresh ne-e winds are expected across, and
just downstream of the Gulf of Papagayo during the overnight
hours through the middle of next week.

Long-period cross-equatorial SW swell, in the form of combined
seas of 6-9 ft, has propagated n to along 10N between 90-115W.
These seas are forecast to subside to less than 8 ft on Sat
night.

W of 120W:

See special features above for information on the remnants of
Georgette and Frank that will gradually dissipate through Fri
night. A tropical low will move w into the area near 11N120W on
Fri night with the possibility of tropical cyclone development.  

$$
Cobb