Tropical Weather Discussion
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AXNT20 KNHC 142339

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
739 PM EDT Mon Aug 14 2017

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1800 UTC surface analysis and satellite imagery through
2315 UTC.


Tropical Storm Gert is centered near 30.6N 72.3W at 14/2100 UTC
or about 400 nm WSW of Bermuda moving N at 7 kt. Estimated minimum
central pressure is 992 mb. Maximum sustained wind speed is 60 kt
with gusts to 75 kt. Scattered to numerous moderate convection is
from 26N-32N between 70W-74W. See latest NHC forecast/advisory
under AWIPS/WMO headers MIATCMAT3/WTNT23 KNHC for more details.


A tropical wave extends from 22N25W to 13N27W moving W at 10-15
kt. The wave coincides with 700 mb troughing between 21W-29W and a
maximum in 850 mb relative vorticity at the southern extent of
the wave near 13N27W. The wave is expected to inject energy into
a 1011 mb low embedded within the monsoon trough near 13N35W by
Tuesday. Environmental conditions are expected to become more
conducive for development of this low later in the week with a
medium chance for tropical cyclone formation within 5 days. Widely
scattered moderate convection is from 11N-15N between 26-33W.

A tropical wave extends from 23N43W to 09N47W moving W at 20 kt.
This wave is evident in low to mid-level satellite cloud wind
vectors and coincides with 700 mb troughing between 40W-50W.
Scattered showers are within 90 nm of the wave axis.

A tropical wave extends from 21N62W to 09N65W moving W at 15-20
kt. This wave shows good moisture over the northern portion of the
wave, N of 14N, as noted on SSMI TPW imagery. The wave also
coincides with 700 mb troughing. Scattered showers are over the
Leeward Islands from 13N-20N between 60W-64W.


The monsoon trough extends from the coast of W Africa near 16N17W
to 13N30W to 09N50W. The Intertropical Convergence Zone axis
extends from 09N50W to the coast of South America near 08N60W.
Aside from the convection associated with the tropical waves,
scattered moderate convection is along the coast of W Africa from
07N-13N between 10W-18W.



Weak surface ridging is over the Gulf of Mexico producing 5-15 kt
southerly flow. Winds are strongest along the Texas coast, and
weakest along the Florida SW coast. Scattered moderate convection
is inland from Louisiana to NE Florida. Similar convection is over
east-central Florida, W Cuba, and the Yucatan Peninsula. In the
upper levels, a large upper level low is centered over the N
Yucatan near 21N88W. Strong subsidence is over most of the Gulf,
in contrast to the land areas with airmass thunderstorms. Expect
the ridge to remain in place across the Gulf waters the next
several days. In addition...a thermal trough will develop each
evening across the Yucatan Peninsula. The trough will shift
westward into the SW Gulf waters during the overnight hours and
dissipate across this area each morning. Locally higher winds can
be expected west of the trough axis.


A tropical wave is moving through the eastern Caribbean. Please
see above. The tropical wave will continue to propagate westward
and will be over Puerto Rico tonight. Scattered moderate
convection is over most of Cuba, and NW Haiti. Further S, the
eastern extent of the E Pacific monsoon trough is producing
scattered moderate convection over, S Nicaragua, Costa Rica, and
Panama. 10-25 kt tradewinds are W of the tropical wave with
strongest winds along the coast of N Colombia, and weakest winds
along the S coast of Cuba. The pressure gradient is forecast to
tighten early this week as the Atlantic ridge builds westward in
the wake of T.S. Gert. Expect building seas to 8-10 ft with the
strongest winds across the south-central Caribbean through


Expect daytime heating, local sea breezes, and mountain upslope
lifting to produce scattered showers and tstms during the
afternoon and evening hours across the island the next couple of


Outside the influence of Tropical Storm Gert and the tropical
waves moving across the tropical Atlc waters, the forecast area
is under the influence of the 1026 mb subtropical high near
35N46W. This high pressure area is beginning to build westward
into the SW North Atlc waters along 24N in the wake of Gert as the
system moves northward.

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