[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201042
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Mon Sep 20 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 0600 UTC surface analysis and satellite imagery through
1030 UTC.

...SPECIAL FEATURES...

Tropical Storm Peter is centered northeast of the Leeward Islands near
19.1N 59.5W at 20/0900 UTC or 210 nm ENE of the Northern Leeward
Islands moving WNW at 12 kt. Estimated minimum central pressure is
1005 mb. Maximum sustained wind speed is 45 kt with gusts to 55
kt. The center of Peter remains exposed under strong southerly
shear. Numerous moderate to isolated strong convection is
observed within 135 nm to the northeast of the center. Judging
from the estimated wind flow and reports from buoy 41044 north of
the center, seas are likely reaching up to 15 ft, mainly in the
northeast quadrant of the center. Peter is expected to continue
on a WNW track with little change in speed through Tue morning,
then gradually turn toward the NW Tue night. Strong wind shear
should cause Peter to gradually weaken over the next few days.
Peripheral rainbands S of Peter have been producing heavy showers
across the Northern Leeward. Guadeloupe has received 1.79 inches
of rain in the past 24 hours. This trend will continue and spread
to Puerto Rico later today. As a result, the chance for urban and
small stream flooding will greatly increase through Tue. 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 15.9N 32.6W at 20/0900 UTC
or 480 nm W of the Southernmost Cabo Verde Islands moving NW at
13 kt. Estimated minimum central pressure is 1005 mb. Maximum
sustained wind speed is 35 kt with gusts to 45 kt. Seas are
peaking at 8 to 12 ft mainly in the northeast quadrant of the
center. Numerous moderate to scattered strong convection is noted
up to 150 nm from the center. Rose is anticipated to move NW with
little change in speed over the next few days. Slight
strengthening is forecast through tonight before gradual weakening
by Tue. 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 tropical wave is along 20W from 19N southward and moving
W near 15 kt. An area of low pressure is analyzed along with
tropical wave, with and estimate surface pressure of 1009 mb.
Scattered moderate to isolated strong convection is seen from 06N
to 11N between between 21W and 24W.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends across the Senegal coast near 16N16W
to near the Cabo Verde Islands at 14N25W. Another segment of the
monsoon trough reaches from 08N32W to 06N40W, where it transitions
to the ITCZ and continues to 03N50W. No significant convection is
evident along the monsoon trough or ITCZ.

The eastern end of the Pacific monsoon trough extends from near
Cartagena, Colombia to Limon, Costa Rica. No significant
convection is noted along this feature.

...GULF OF MEXICO...

A weak ridge extends from 1015 mb high pressure in the southeast
Gulf near 26N84W westward to the coast of Tamaulipas, south of a
trough extending across the northern Gulf from near Panama City,
Florida to Brownsville, Texas. No significant shower or
thunderstorm activity is evident at this time. Moderate SW winds
are noted across the northwest Gulf, with light to gentle breezes
elsewhere. Slight seas are observed throughout the Gulf.

For the forecast, the weak high pressure will extend across the
eastern and central Gulf of Mexico through Tue. This pattern will
support continued gentle to moderate winds and mostly slight seas
across the Gulf. An early season cold front is expected to enter
the northwest Gulf early Wed and reach from the NE Gulf to
central Bay of Campeche by late Thu, supporting increased winds
and building seas over the northwest and north-central Gulf, late
Wed through Thu. Looking ahead, strong NW to N winds and building
seas are possible off Tampico Thu and Veracruz late Thu into Fri
behind the front.

...CARIBBEAN SEA...

An upper trough north of Puerto Rico is supporting scattered
showers and a few thunderstorms from the northern Leeward Island
to the Virgin Islands. Please read the Special Features section
above for details on Tropical Storm Peter which is forecast to
track well north of these locations.

Elsewhere, divergent flow aloft is supporting a few showers and
thunderstorms from Jamaica, to Grand Cayman, to off the Isle of
Pines. No other significant shower or thunderstorm activity is
noted at this time. Winds are abnormally light across the
Caribbean, with only gentle to moderate winds observed 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 will move to 19.7N 61.4W
this afternoon, 20.4N 63.6W Tue morning, and to 21.4N 65.5W Tue
afternoon. Peter will weaken to a tropical depression as it
continues 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
squalls and thunderstorms to affect the Leeward Islands and
adjacent waters through tonight.

...ATLANTIC OCEAN...

Please read the Special Features section above for details on
Tropical Storm Peter east of the Leeward Islands and Tropical
Storm Rose WSW of the Cabo Verde Islands.

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 1000 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 few showers and thunderstorms are active along a frontal
boundary reaching from 31N58W to 29N70W, where it becomes
stationary and continues to 31N73W. An upper low centered near
23N65W is supporting scattered showers and thunderstorms from 21N
to 26N between 60W and 62W. The Atlantic ridge stretching west-
southwestward from a 1034 mb Azores high to roughly 27N60W
continues to provide light to gentle winds and 3 to 5 ft seas
north of 22N and west of 35W. Outside the influence of Tropical
Storm Peter and Rose, gentle to moderate trades and 5 to 7 ft seas
are noted elsewhere.

For the forecast west of 55W, Tropical Storm Peter will move to
19.7N 61.4W this afternoon, 20.4N 63.6W Tue morning, 21.4N 65.5W
Tue afternoon, and 22.4N 67.2W Wed morning. Peter will weaken to a
tropical depression near 23.2N 68.0W Wed afternoon, then move to
24.2N 68.4W by Thu morning. Peter will change little in intensity
as it moves northward toward Bermuda throughout the rest of the
week. Elsewhere west of 70W, gentle to moderate winds and slight
to moderate seas will persist over open waters through the early
part of the week, with swell to 8 ft associated with the tropical
storm reaching the waters east of 72W by Wed.

$$
Christensen
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