[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 222301
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
701 PM EDT Mon Jun 22 2020

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
2300 UTC.

...SPECIAL FEATURES...

Subtropical Depression Four is centered near 38.2N 65.7W at
22/2100 UTC or 270 nm SE of Nantucket Massachusetts moving ENE
at 8 kt. Estimated minimum central pressure is 1009 mb. Maximum
sustained wind speed is 30 kt with gusts to 40 kt.

Please read the latest NHC Public Advisory at
https://www.nhc.noaa.gov/text/MIATCPAT4.shtml and Forecast/
Advisory at https://www.nhc.noaa.gov/text/MIATCMAT4.shtml for more
details.

...TROPICAL WAVES...

A central Atlantic tropical wave is near 35W south of 18N, moving
W at 15-20 kt. Scattered moderate convection is occurring from
07N to 11N within 120 nm of the wave axis.

An eastern Caribbean tropical wave is near 65W south of 18N, moving
W at 15-20 kt. A stable air mass associated with a significant
Saharan Air Layer outbreak is inhibiting any convection with this
wave.

A western Caribbean tropical wave is near 84W south of 20N,
moving W at 20 kt. Recent satellite imagery indicates that oceanic
convection associated with this wave has diminished.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends off the coast of Guinea-Bissau near
11N16W to 10N25W. The ITCZ extends from 10N25W to 09N34W, then
resumes from 08N36W to the coast of French Guiana near 05N52W.
Scattered moderate convection is noted from 05N to 08N between 14W
and 18W.

GULF OF MEXICO...

A mid to upper-level trough that extends across the mid-Mississippi
Valley into the NW Gulf is supporting numerous moderate and scattered
strong convection over the northern Gulf, generally N of 26N and W
of 84W. Stronger thunderstorms are likely producing gusty winds
and locally rough seas over portions of the northern offshore
waters. Gentle to moderate southerly flow prevails across the Gulf
waters W of 90W this evening, although stronger thunderstorms are
likely producing gusty winds and locally rough seas over portions
of the northern offshore waters. Elsewhere, a weak surface ridge
extends into the eastern Gulf, where winds are light and variable
based on earlier scatterometer passes. Wave heights range from
3-6 ft in the western Gulf to 3 ft or less in the eastern Gulf.

Surface ridging will prevail over the Gulf waters through the
forecast period. Moderate to fresh southerly winds are forecast
over the western Gulf tonight through Thu night as the pressure
gradient tightens between the ridge and lower pressure over
Mexico.

CARIBBEAN SEA...

GOES-16 satellite imagery shows dense Saharan dust covers much of
the Caribbean waters E of 80W this evening. This dry, stable air
mass is inhibiting convection across the region. At the surface,
the pressure gradient associated with strong Bermuda high pressure
is producing moderate to fresh trades across the waters S of 18N,
with strong to near gale-force winds noted in the south-central
Caribbean near the coast of Colombia. Seas in this region peak
around 12-13 ft downstream of the strongest winds, with seas 8 ft
or greater covering much of the waters from 10N to 16N between 73W
and 81W.

Fresh to strong trades over the south-central Caribbean will
expand to the north-central and southwest basin through the middle
of the week as high pressure builds over the western Atlantic.
Winds will pulse to near gale force off the coast of Colombia each
night through Fri night with seas building to 12 ft and higher
during the strongest winds. Fresh to strong winds are expected in
the Gulf of Honduras through Fri night.

ATLANTIC OCEAN...

A surface ridge extends from high pressure centered near 36N51W
across the western Atlantic offshore waters towards the Bahamas
and the east coast of Florida. A weak surface trough is analyzed
from 31N49W to 26N51W to 21N58W, with isolated showers occurring
near the trough axis. Strong high pressure dominates north of the
region, with earlier scatterometer data showing a large area of
fresh to locally strong trades over the waters S of 20N and W of
35W. Combined seas in this region are running 6-9 ft in NE wind
waves and SE swell.

High pressure extends from the central Atlantic to Florida and
will prevail across the offshore waters through the forecast
period. Fresh to occasionally strong easterly winds will pulse
across the waters north of Hispaniola each night through Fri
night.

$$
B Reinhart
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