[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 092306
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Sat Jul 10 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
2245 UTC.

...SPECIAL FEATURES...

Post-Tropical Cyclone Elsa is centered near 43.0N 69.5W at
09/2100 UTC or 80 nm ENE of Boston Massachusetts moving NE at 30
kt. Estimated minimum central pressure is 999 mb. Maximum
sustained wind speed is 45 kt with gusts to 55 kt. Scattered to
numerous moderate to strong convection is noted north of 41N and
west of 65W, while a feeding band extends from 29N to 40N
between 67W-77W. Across coastal Maine, 2 to 4 inches of rain
with isolated totals up to 6 inches are possible through this
evening, which could result in considerable flash and urban
flooding. Isolated minor to moderate river flooding is also
expected. On the forecast track, the center of Elsa will continue
to move offshore the northeastern United States coast through
this evening. The system is expected to move over Atlantic Canada
by late tonight and Saturday.

Please read the latest NHC Public Advisory at
https://www.nhc.noaa.gov/text/MIATCPAT5.shtml, Forecast/Advisory
at https://www.nhc.noaa.gov/text/MIATCMAT5.shtml, and the High
Seas Forecast issued by the NWS Ocean Prediction Center at
https://ocean.weather.gov/shtml/NFDHSFAT1.php for more details.
For marine information within 60 nm of the coast, please see
products from your local NWS Weather Forecast Office at
www.weather.gov.

...TROPICAL WAVES...

A tropical wave extends it axis along 30W and south of 10N,
moving west at 10 to 15 kt. Scattered showers are noted from
02N-05N between 25W-31W.

A central Atlantic tropical wave with a large amplitude has its
axis along 47W and south of 24N, moving west at 15 to 20 kt. No
significant convection is noted within this wave at this time.

A low amplitude tropical wave extends its axis along 69W and south
of 12N, moving west at 10 to 15 kt. Scattered moderate convection
is noted along and in the vicinity of the wave affecting
Venezuela and adjacent waters south of 13N.

A tropical wave extends its axis across Nicaragua and the EPAC
along 85W and south of 14N, moving west at 10 to 15 kt.
Scattered moderate to isolated strong convection is noted south
of 13N and west of 80W.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Guinea-Bissau near
11N15W to 08N25W. The ITCZ extends from 06N34W to 05N42W.
Scattered moderate convection is noted south of the monsoon
trough to 07N between the coast of Sierra Leone and 18W.

GULF OF MEXICO...

A surface ridge extends from western Atlantic across central
Florida to the northern Gulf. Recent scatterometer data depicts pass
indicated moderate to fresh SE winds in the Gulf mainly across
the western half of the basin, while gentle to moderate SE winds
prevail elsewhere. Scattered showers and a few thunderstorms are
evident off central Texas coast to off northeast Mexico. Seas
are 5 to 7 ft over the western Gulf, 4 to 6 ft seas in the
southwestern Gulf and 2 to 4 ft over the eastern Gulf.

For the forecast, fresh SE winds will persist over the northwest
Gulf between the high pressure and lower pressure over Texas
through at least late Sat. Similarly, a trough will form off
northwest Yucatan Peninsula, supporting fresh or even strong
winds during overnight hours through late Tue. Meanwhile, gentle
to moderate winds and slight seas will persist over the eastern
Gulf.

CARIBBEAN SEA...

Please refer to the section above for details on the tropical
waves enhancing convection across the basin.

Latest scatterometer data depicts fresh to strong easterly winds
across the majority of the basin, except the northwestern
portion, where gentle to moderate winds prevail. Seas of 13-16 ft
are estimated over the south-central Caribbean mainly south of
12N. Seas of 3 to 5 ft are noted over the northwest Caribbean,
except over the Gulf of Honduras where fresh winds and seas of 4
to 6 ft prevail. Scattered showers and thunderstorms off Panama
and Costa Rica due to trade winds convergence, local drainage
flow and perhaps aided by a tropical wave moving through that
area. No significant shower or thunderstorms activity is noted
elsewhere.

For the forecast, the subtropical ridge north of the area
combined with the Colombian low will enhance strong winds through
the weekend. Strong trades will also prevail in the Gulf of
Honduras into Sat, then pulse nightly into the middle of next
week.

Of note, an atmospheric Kelvin wave along with successive bursts
in the easterly trades will influence the formation of a low along
the monsoon trough over Panama and Costa Rica, resulting in an
enhanced risk of heavy rainfall for these countries and adjacent
Caribbean waters through this weekend.

ATLANTIC OCEAN...

Please refer to the section above for details on the tropical
waves moving across the basin.

A surface ridge extends across the basin, anchored by a 1033 mb
high centered near 36N40W. Recent scatterometer data and buoy
observations depict moderate to fresh E winds across the
tropical Atlantic south of 20N while gentle to moderate winds
prevail elsewhere. Seas range between 3 to 5 ft north of 25N and
5 to 7 ft farther south.

For the forecast, the high pressure will lift north of the area
by early next week. This will support moderate to fresh E winds
south of the ridge axis, with winds pulsing to fresh to strong
along the north coast of Hispaniola mainly during the evenings.

$$
ERA
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