[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 241707
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
107 PM EDT Tue Oct 24 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 1200 UTC surface analysis and satellite imagery through
1700 UTC.

...SPECIAL FEATURES...

A cold front crosses the Gulf waters from 27N82W SW to 24N85W to
20N92W to SE Mexico near 18N94W. Near gale NW to N winds are
occurring in the vicinity of Veracruz Mexico or S of 21N W of 95W.
Winds in this area are expected increase to minimal gale force
this afternoon as reinforcing cold air pushes southward behind the
cold front from Texas through the SW Gulf waters. As the high
pressure builds southward over NE Mexico and South Texas it will
begin to weaken and reduce the pressure gradient over the southern
Gulf. This will allow gale force winds to decrease to strong by
Wed evening. Winds in this area will decrease further to light on
Thu. Please see the latest NWS High Seas Forecast under AWIPS/WMO
headers MIAHSFAT2/FZNT02 KNHC for more details.

...TROPICAL WAVES...

A tropical wave just to the E of the Lesser Antilles has an axis
extending from 16N59W to 07N60W, moving W around 10 kt. A strong
mid to upper-level trough extending SSW from 30N61W to just east
of puerto Rico near 18N65W to the coast of Venezuela near 10N63W
is interacting with the tropical wave. The trough is subjecting
the wave to strong vertical wind shear, but upper-level divergence
on the east side of the trough is triggering scattered moderate
and isolated strong convection mainly to the east of the tropical
wave axis from 07N to 19N between 50W and 62W. The wave is
expected to continue weakening as it moves slowly west through the
high shear environment.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from Guinea Bissau on the African
coast near 12N15W to 10N20W. The Intertropical Convergence Zone
axis continues from 10N20W to 06N30W to 05N43W to 09N58W. Aside
from the convection associated with the tropical wave, scattered
moderate and isolated strong convection is present within 180 nm
either side of a line from 05N23W to 09N50W.

...DISCUSSION...

GULF OF MEXICO...

A deep mid to upper-level trough progressing eastward through the
Mississippi Valley continues to support a cold front extending SW
from just south of Tampa Florida near 27N82W to 24N85W to SE
Mexico near 18N94W. Upper-level convergence over the Gulf is
limiting deep convection to the moist air along and to the east of
the front over the SE Bay of Campeche. Cloudiness and isolated
showers are found along and up to 60 nm NW of the cold front.
Otherwise, a surface ridge building over the NW Gulf in the wake
of the front is supporting near gale force winds over the SW Gulf.
See the Special Features section for more details. A secondary
reinforcing cold front is frontalizing over the NW Gulf. The added
shot of cold air will increase the northerly winds across much of
the basin tonight and Wednesday. Strong high pressure in wake of
the front will build SE over Texas and the NW on Thursday, then
slide eastward to northern Florida by Fri morning.

CARIBBEAN SEA...

An upper level anticyclonic circulation is centered over the NW
Caribbean near the Gulf of Honduras. This high continues to
provide upper-level divergence which supports scattered showers
and isolated tstms over the NW Caribbean. The sustained convection
has induced surface troughing from the Gulf of Honduras to
western Cuba. Otherwise, a weakening tropical wave is expected to
push slowly eastward from the Lesser Antilles into the eastern
Caribbean and produce showers and thunderstorms. A cold front
currently bisecting the the Gulf of Mexico will across the Yucatan
channel into the NW Caribbean Wed morning, then stall south of
Cuba on Thu. Fresh to strong N winds will channel between the
front and the Yucatan Wed night and Thu morning before the front
weakens.

...HISPANIOLA...

Very dry convergent N flow aloft to the west of an upper-level
trough will support fair weather across the island through Wed
night as moderate to fresh trades prevail.

ATLANTIC OCEAN...

Scattered showers and tstms are occurring over the far NW
forecast waters, or NW of a line from 32N74W to 26N80W. The front
will move SE across the Bahamas to near the Turks and Caicos
islands by Fri morning as it weakens and stalls. Farther east, an
upper- level trough has induced a surface trough extending from
26N58W to 21N63W. Scattered showers and isolated tstms associated
with the trough are occurring from 22N to 28N between 51W and 61W.
This area of convection lies to the SW of a frontal boundary
extending WSW from 32N34W to 27N46W to 28N53W. This boundary has
no significant convection associated with it. Otherwise, broad
surface ridging anchored by 1030 mb high pressure centered over
the NW Atlc near 39N59W dominates the remainder of the basin.

For additional information please visit
http://www.hurricanes.gov/marine

$$
McElroy
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