AXPZ20 KNHC 281547
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1605 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
Based on 1200 UTC surface analysis and satellite imagery through
Tropical Depression Frank is centered near 23.7N 124.4W, or about
920 miles w of the southern tip of the Baja California
Peninsula, at 1500 UTC Jul 28, moving wnw, or 290 degrees at 07
kt. The maximum sustained winds have diminished to 30 kt with
gusts to 40 kt near the center surrounded by strong winds out to
about 60 nm. The estimated minimum central pressure has risen to
1006 mb. Currently, moderate convection is flaring
intermittently within 150 nm nw of the center. Frank is expected
to weaken to a post-tropical remnant low pres within 24 hours
and gradually dissipate over the next 3 days. 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 these systems.
...TROPICAL WAVE AND TROPICAL LOWS...
The remnant low of former tropical cyclone Georgette is centered
near 21.5N 134W, and is estimated at 1010 mb. Strong ne to e
winds are observed within 150 nm n of the center with seas of 7-
10 ft. The low is forecast to weaken to an open trough from
20N138W to 23N139W early Fri, from 20N139W to 22.5N140W early
Sat, then dissipate just w of 140W late Sat.
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 good chance of developing into
a tropical cyclone in 3 to 5 days.
A tropical wave is analyzed from 08N to 16N along 112W, and has
been moving W at about 10 kt. Scattered moderate isolated strong
convection is noted within 60 nm of 13.5N113.5W.
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 Colombia
at 08N78W to 12N103W, then through an embedded 1009 mb low
pressure at 11N110W, then continues w to 08N129W, then turns sw
to 08N129W where scatterometer winds indicate a transition to an
ITCZ, which continues wsw to beyond 07N140W.
Scattered moderate isolated strong convection is observed along,
and to the s of the monsoon trough, within 150 nm either side of
a line from 08N79W to 08N89W. Similar convection is observed in
clusters within 45 nm of 08.5N94.5W and 09N104W. Isolated
moderate to strong convection is noted in small clusters within
60 nm of 10.5N122W and 12N126W and 08N127W.
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
strong n flow on Sun, Mon and Tue nights with seas building to 8
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
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.