NWS National Hurricane Center Miami FL
726 PM EDT Sun Jul 21 2019
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
Caribbean Gale Warning: A tightening pressure gradient will bring
NE to E gale force winds tonight from 22/00Z to 22/12Z near the N
coast of Colombia from 11N-13N between 74W-76W. Seas are expected
to be between 9-14 ft. After 12Z Monday morning, winds will remain
below gale force.
An eastern Atlantic tropical wave is along 30/31W S of 16N, moving
W at 15-20 kt. Scattered showers are from 05N-07N between 25W-31W.
A tropical wave has been added to the analysis along 43W from
06N-21N. This wave is completely embedded within the middle of a
strong outbreak of Saharan dust, and no convection is present.
A central Atlantic tropical wave is along 53/54W S of 18N, moving
W at 10-15 kt. Scattered showers and isolated tstorms are seen
south of 07N between 50W-57W, including over portions of Suriname
and French Guiana.
An eastern Caribbean tropical wave is along 64W south of 19N and
is moving W around 15 kt through the Virgin Islands. Isolated
showers are possible within 180 nm of the wave axis north of 15N.
Scattered tstorms are over eastern Venezuela and near Trinidad.
A western Caribbean tropical wave is along 81W S of 18N, moving W
around 15 kt. No significant convection is noted north of 10N.
However, numerous moderate with embedded isolated strong
convection is over Panama and the East Pacific, with a few of the
storms spilling into the SW corner of the Caribbean south of 10N.
The monsoon trough extends from the coast of Guinea-Bissau near
11N15W to 08N24W to 07N34W. The ITCZ begins near 07N34W to 06N43W
to 07N52W, then continues W of a tropical wave from 09N55W to the
coast of Venezuela near 09N61W. Aside from the convection
mentioned in the Tropical Waves section, scattered showers are
seen within 180 nm S of the ITCZ between 34W-48W.
GULF OF MEXICO...
An upper level trough axis is stretching across the western
Atlantic from 32N78W southwestward to 26N86W to the SW Gulf near
21N97W. An upper-level high is centered over western Kentucky and
southern Illinois. Upper-level divergence of the upper-level
northeasterly flow in between the upper trough and upper high is
being maximized over the northern Gulf of Mexico. The upper-level
divergence is enhancing scattered moderate convection from 25N-29N
between 88W-96W. Scattered moderate convection is also along the
west coast of the Florida Peninsula. Elsewhere north of 24N east
of 97W, scattered showers and isolated tstorms are present. An
area of upper-level diffluence is enhancing scattered moderate
convection over the western Yucatan Peninsula and eastern Bay of
Campeche from 19N-22N between 88W-91W. Isolated showers and
tstorms are also seen over the Yucatan Channel. At the surface,
there is weak ridging and not much of a pressure gradient.
Therefore, winds are gentle across most of the Gulf of Mexico,
except locally stronger near any strong thunderstorms.
A ridge along the northern Gulf of Mexico will retreat E Tuesday
night and allow a cold front to move into the northern Gulf. The
front will then stall and weaken Wed and Thu. Gentle to moderate
winds will continue across most of the basin, except for fresh
winds pulsing to the W of the Yucatan peninsula at night.
Mid to upper level troughing is over the eastern Caribbean east of
about 68W. However, most of the upper level divergence from this
is giving way to convection in the Atlantic. Scattered showers and
tstorms are over Puerto Rico, Hispaniola, Jamaica and portions of
Cuba. Scattered showers and isolated tstorms are over the NW
Caribbean north of 18N west of 81W. Other than the convection
mentioned in the Tropical Waves section, and the convection in the
NW Caribbean, no other significant convection is seen across the
basin. Strong to near gale force trades are seen on Sunday
morning's ASCAT pass from 11N-14N between 73W-77W.
High pressure N of the area will support fresh to strong trade
winds over the central Caribbean Sea through next week. Winds
along the coast of Colombia will reach gale force tonight. See the
Special Features section above for information on the Caribbean
Gale Warning. Fresh easterly winds will pulse over the Gulf of
Honduras tonight and Mon night.
An upper level trough stretches from 32N78W across northern
Florida and into the Gulf of Mexico. Scattered showers and
isolated tstorms are west of 78W from 26N-30N. A surface trough
extends from 27N72W to the SE Bahamas. This trough is producing
scattered showers and isolated tstorms from 21N-27N between 67W-
75W. The trough will move W to reach the waters between the
Bahamas and Florida late Monday. This trough has a low chance of
developing into a tropical cyclone during the next 48 hours, and
it should enhance rainfall over the Bahamas through Monday.
Surface ridging covers the remainder of the subtropical Atlantic
from 20N-30N, east of 66W. The ridge will maintain gentle to
moderate east to southeast winds across the western Atlantic through
Tuesday night. The ridge will start retreating eastward on
Tuesday night, enabling a trough to move over the NW waters from
Florida Wed morning. Fresh to occasionally strong E winds will
pulse N of Hispaniola each night through the middle of next week.
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