[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 202313
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Tue Sep 21 2021

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 31N. 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...

Tropical Storm Peter is centered near 20.0N 61.8W at 20/2100 UTC
or 130 nm NE of the northern Leeward Islands moving WNW at 12
kt. Estimated minimum central pressure is 1007 mb. Maximum
sustained wind speed is 45 kt with gusts to 55 kt. On the
forecast track, the center of Peter will pass north of the
northern Leeward Islands and Puerto Rico through Tuesday.
Rainfall around the southern periphery of Tropical Storm Peter
could produce rainfall totals of 1 to 3 inches, with locally
higher amounts possible across portions of the Northern Leeward
Islands, including the Virgin Islands, as well as Puerto Rico and
the northern portions of Hispaniola through Tuesday. This
rainfall may lead to areas of urban and small stream flooding.
Swells generated by Peter are expected to affect the northern
Leeward Islands early this week, and then reach the Bahamas by
midweek. These swells could cause life-threatening surf and rip
current conditions. Please read the latest NHC Public Advisory at
https://www.nhc.noaa.gov/text/MIATCPAT1.shtml and Forecast
Advisory at https://www.nhc.noaa.gov/text/MIATCMAT1.shtml for
more details. Marine interests in the area can read the latest
NHC Offshore Waters Forecasts at
https://www.nhc.noaa.gov/marine/offshores.php

Tropical Storm Rose is centered near 18.4N 34.4W at 20/2100 UTC
or 610 nm WNW of the Southernmost Cabo Verde Islands moving NW
at 14 kt. Estimated minimum central pressure is 1007 mb. Maximum
sustained wind speed is 35 kt with gusts to 45 kt. Rose is
moving toward the northwest, and this general motion with a
decrease in forward speed is expected during the next couple of
days. Rose will likely turn north-northwestward on Thursday. No
significant change in strength is anticipated today, with
weakening likely beginning on Tuesday and continuing through
midweek. Please read the latest NHC Public Advisory at
https://www.nhc.noaa.gov/text/MIATCPAT2.shtml and Forecast
Advisory at https://www.nhc.noaa.gov/text/MIATCMAT2.shtml for
more details. For sea conditions near this system, please read
the Meteo-France High Seas Forecast at
http://weather.gmdss.org/II.html

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 22W/23W, from 19N
southward, moving westward 10 to 15 knots. A 1009 mb low pressure
center is along the wave axis near 09.2N 22.8W or about several
hundred miles south of the Cabo Verde Islands. Showers and
thunderstorms associated with this system are still showing some
signs of organization, although there does not appear to be a
surface circulation at this time. Upper-level winds, however, are
expected to become conducive for further development by midweek,
and a tropical depression is likely to form by Thursday or
Friday while the system moves westward at 10 to 15 kt across the
eastern and central tropical Atlantic Ocean. The latest Tropical
Weather Outlook states that this system has a low change of
tropical cyclone formation through 48 hours, and a high chance
through 5 days. Please, refer to the latest Tropical Weather
Outlook, at www.hurricanes.gov for more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic ocean through the coast
of Guinea near 10N14W, then continues westward to the above
mentioned 1009 mb low pressure center located near 09.2N 22.8W
to 07N37W. The ITCZ extends from 07N37W to 08N42W to the coastal
plains of Suriname. No significant convection is evident along
the monsoon trough or ITCZ.

GULF OF MEXICO...

A weak ridge dominates the Gulf waters producing gentle to moderate
winds and mostly slight seas across the region. Scattered showers
with embedded thunderstorms are noted over the NE Gulf and the
State of Florida. A diffluent pattern aloft supports this convective
activity.

For the forecast, weak high pressure will extend across the eastern
and central Gulf of Mexico through Tue. This pattern will continue
to support gentle to moderate winds and mostly slight seas across
the Gulf waters. An early season cold front is expected to enter
the NW Gulf early Wed and reach from the NE Gulf to central Bay
of Campeche by late Thu before stalling. Fresh to locally strong
northerly winds and building seas are expected in the wake of the
front.

CARIBBEAN SEA...

Please read the Special Features section above for details on
Tropical Storm Peter which is forecast to track well north of
the NE Caribbean.

An upper-level trough that crosses the Windward passage and Jamaica
is helping to induce scattered showers and thunderstorms over
Hispaniola and Puerto Rico. On the W side of this trough, strong
N-NE winds support scattered showers and thunderstorms over most
of Cuba, including the Isle of Youth. Convection has also flared-
up over most of Central America due to a diffluent pattern aloft
and the E extent of the eastern Pacific monsoon trough. Gentle
to moderate trades are seen across most of the basin, with 2 to
4 ft seas, except for light breezes and 1 to 3 ft seas over the
northwest Caribbean.

For the forecast, Tropical Storm Peter is forecast to move northward
toward Bermuda through the rest of the week. As this occurs, trade
winds over the south-central Caribbean will diminish through Thu night.
Look for associated showers and thunderstorms to affect the NE Caribbean
and adjacent waters through Tue morning.

ATLANTIC OCEAN...

Please read the Special Features section above for details on
Tropical Storm Peter located NE of the northern Leeward Islands
and Tropical Storm Rose situated WNW of the southernmost Cabo
Verde Islands. In addition, refer to the Tropical Wave section
for details on a low pressure system, with potential of tropical
cyclone formation along a tropical wave located near 22W/23W.

The Cumbre Vieja volcano on the island of La Palma in the Canary
Islands has been erupting since 19/1410 UTC. The ash plume is
expected to remain below 8,000 ft in the vicinity of the volcano
while drifting SE, causing a reduction in visibility. Marine and
aviation interests should monitor this on-going situation by
reading Volcanic Ash Advisory issued by Meteo-France at
http://vaac.meteo.fr/volcanoes/la-palma/

A cold front enters the forecast area near 31N55W then continues WSW
to near 28N70W where it becomes stationary to the coast of the State
of Georgia. A concentrated area of showers and thunderstorms is
observed along the frontal boundary between 65W-70W. An upper
level low centered near 24N64W is supporting scattered showers
and thunderstorms just N of Hispaniola. A ridge dominates the
Atlantic waters E of 40W, including the Azores, Madeiras and
Canary Islands. The pressure gradient between this ridge and
T.S. Rose is producing a belt of moderate to fresh NE-E winds
roughly from 19N-28N E of 35N. Seas are in the 5-7 ft range
within this area of winds.

For the forecast west of 65W, the frontal boundary will remain
across the waters N of 27N through Tue while gradually weaken.
Strong high pressure in the wake of the front is forecast to
bring moderate to fresh NE-E winds across the forecast region N
of 27N W of 65W. Seas of 8 ft generated by Peter will reach 65W
by tonight, and approach the Turks and Caicos Island late on Tue
or Tue evening.

$$
GR
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