[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 310603
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
205 AM EDT Fri Jul 31 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 0000 UTC surface analysis and satellite imagery through
0530 UTC.

...SPECIAL FEATURES...

ISAIAS has become a hurricane. The center of Hurricane ISAIAS,
at 31/0600 UTC, is near 20.6N 72.7W. This position also is about
39 nm/70 km to the SE of Great Inagua Island in the Bahamas.
ISAIAS is moving NW, or 305 degrees, 16 knots. The estimated
minimum central pressure is 992 mb. The maximum sustained wind
speeds are 70 knots with gusts to 85 knots. Precipitation:
scattered to numerous strong is from 100 nm to 250 nm of the
center in the SE semicircle, in much of the Dominican Republic
and its coastal waters to the NE of the Hispaniola; similar
precipitation also is between the northern coast of Haiti and
the SE Bahamas near 22N between 71W and 74W. A squall line is
racing toward the WNW about 30 knots, near 24N76W in the
Bahamas. This is the leading edge of the tropical storm-force
winds that are around the periphery of ISAIAS. The center of
ISAIAS will move near or on top of the Southeastern Bahamas
overnight. ISAIAS is forecast to be near the Central Bahamas on
Friday night, and move near or on top of the Northwestern
Bahamas, and near South Florida on Saturday. Little change in
strength is forecast during the next 48 hours. Hurricane-force
winds extend outward up to 26 nm/45 km from the center, and
tropical storm-force winds extend outward up to 210 nm/390 km
from the center.

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

An Atlantic Ocean tropical wave is along 20W/22W, from 21N
southward, moving westward 10 knots. A 1009 mb low pressure
center is along the tropical wave, near 13.5N. Precipitation:
widely scattered moderate to isolated strong is within 540 nm of
the center in the SW quadrant. The low pressure center has a
small window of opportunity in order to become a tropical
depression through Friday, while it moves northward 10 mph,
before the environmental conditions become less conducive for
development. The chance of formation into a tropical cyclone,
during the next 48 hours, is medium.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 42W/43W, from 22N
southward, moving W 20 knots.
Precipitation: any nearby precipitation is in the monsoon trough.

A Caribbean Sea tropical wave is along 85W/86W, from 20N
southward, moving W 20 knots. The wave is passing through parts
of Honduras, Nicaragua, and the westernmost sections of Costa
Rica. Precipitation: isolated moderate to locally strong is
within 60 nm of the coast of Honduras, along the tropical wave.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal sections of
Senegal near 16N17W, to 14N20W to 13N30W, 10N40W, and 08N50W.
Precipitation: widely scattered moderate to isolated strong is
within 360 nm to south of the monsoon trough between 30W and
51W. Isolated moderate is elsewhere from 20N southward from 60W
eastward, including within 430 nm to the west of the 42W/43W
tropical wave from 09N to 17N.

GULF OF MEXICO...

Upper level cyclonic wind flow covers the SW corner of the Gulf
of Mexico, associated with an upper level inverted trough.
Precipitation: scattered moderate to strong in a few clusters,
is from 21N southward between the western sections of the
Yucatan Peninsula and the coast of Mexico that is along 97W/98W.

A surface ridge passes through central Florida, to a 1018 mb
high pressure center that is near 27N88W, to the coast of Mexico
along 25N. Broad surface anticyclonic wind flow spans the entire
area.

Tropical Storm Isaias is centered near 20.5N 71.9W 999 mb at 11
PM EDT moving NW at 16 kt. Maximum sustained winds 50 kt gusts
60 kt. Weak high pressure in the NE Gulf of Mexico will drift
westward during the weekend. Isaias is forecast to move NW to
the Central Bahamas on Friday evening and night,
and then veer more NNW toward the NW Bahamas, and near SE
Florida on Saturday. Isaias is expected to move N, then NE,
across the W Atlantic Ocean, and remain to the east of the Gulf
of Mexico through the weekend.

CARIBBEAN SEA...

A Caribbean Sea tropical wave is along 85W/86W, from 20N
southward, moving W 20 knots. The wave is passing through parts
of Honduras, Nicaragua, and the westernmost sections of Costa
Rica. Precipitation: isolated moderate to locally strong is
within 60 nm of the coast of Honduras, along the tropical wave.

The monsoon trough is along 08N/10N, from Colombia along 74W
westward, to the coastal waters of Central America from
Nicaragua southward. Precipitation: isolated moderate is from
13N southward from 75W westward, in the SW corner of the
Caribbean Sea.

Tropical Storm Isaias near 20.5N 71.9W 999 mb at 0300 UTC moving
NW at 16 kt. Maximum sustained winds 50 kt gusts 60 kt. Isaias
will continue NW and reach the central Bahamas near
23.5N 76.1W Fri evening; then continue NNW through the NW
Bahamas and near SE Florida and reach hurricane strength near
26.7N 79.0W on Sat evening, before moving N and away from the
region through Monday. Tropical storm conditions and large seas
will prevail tonight in the Windward Passage. Fresh to strong
wind flow will persist to the south of Hispaniola into Friday.

ATLANTIC OCEAN...

A surface ridge extends from a 1022 mb high pressure center that
is near 32N58W, toward central Florida.

Broken to overcast multilayered clouds and other precipitation
covers the Atlantic Ocean from 20N to 28N between 63W and 80W,
away from Hurricane ISAIAS.

Tropical Storm Isaias near 20.5N 71.9W 999 mb at 0300 UTC moving
NW at 16 kt. Maximum sustained winds 50 kt gusts 60 kt. Isaias
will continue NW and reach the central Bahamas near 23.5N 76.1W
Fri evening;  then continue NNW through the NW Bahamas and near
SE Florida and reach hurricane strength near 26.7N 79.0W Sat
evening; then turn more N and reach 30.0N 79.5W Sun evening,
before exiting to the NNE Mon and Tue. Very large seas in SE
swell are expected in a large section of the SW North Atlantic
Ocean, to the west of 70W, and through the Bahamas waters from
tonight through Friday, as the center of Isaias moves across the
SE Bahamas late tonight.

$$
mt
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