[Tropical] Tropical Weather Discussion

Tue Nov 3 17:56:36 CST 2020

AXNT20 KNHC 032356
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Tue Nov 3 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
2330 UTC.

...SPECIAL FEATURES...

The eye of Major Hurricane Eta is moving ashore near 13.8N 83.5W
at 2100 UTC, or about 15 nm SSW of Puerto Cabezas, Nicaragua,
moving W at 4 kt. Estimated minimum central pressure is 940 mb.
Maximum sustained wind speed is 120 kt with gusts to 145 kt.
Numerous strong convection is within 75 nm of the center,
including over northeastern Nicaragua. Scattered moderate to
strong convection is elsewhere within 480 nm of the center in the
NE quad, 180 nm SE quad, 150 nm SW quad and 270 nm NW quad,
including portions of Nicaragua and Honduras, as well as portions
of Jamaica, the Cayman Islands, western Haiti, and eastern Cuba.
Eta will move farther inland over northern Nicaragua through Wed
morning, and then move across the central portions of Honduras Thu
morning. Weakening will begin after Eta moves completely inland
late this afternoon and evening and Eta is expected to weaken to
a tropical storm by early Wednesday, and become a tropical
depression Wednesday night. Catastrophic wind damage is expected
where Eta's eyewall moves onshore during the next several hours.

Through Sunday morning, extremely heavy rainfall from Eta will
lead to catastrophic, life-threatening flash flooding and river
flooding, along with landslides in areas of higher terrain across
much of Nicaragua and Honduras, Costa Rica, western Panama,
eastern Guatemala and Belize. Flash flooding and river flooding
are possible across Jamaica, southeast Mexico, El Salvador,
southern Haiti, and the Cayman Islands. In addition, an extremely
dangerous storm surge will raise water levels by as much as 14
to 21 feet above normal tide levels along the coast of Nicaragua
during the next several hours, near and to the north of where the
center is making landfall. For more information on the heavy
rainfall associated with Eta and other hazards, please refer to
the NHC Public Advisory at www.hurricanes.gov for more details.
Please refer to the High Seas Forecast at
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for details on the
marine hazards associated with Eta.

Caribbean Gale Warning: Strong high pressure over the northern
Gulf of Mexico is combining with lower pressure over the
western Caribbean associated with Hurricane Eta and is leading
to near gale force winds over the northwestern Caribbean Sea.
The gradient will tighten just enough to allow for these winds
to reach gale force on Wed over the Gulf of Honduras. The
gradient will slacken just enough by late Wed allowing for these
winds to diminish to strong speeds. Seas will be at maximum value
of 12 ft at that time.

...TROPICAL WAVES...

A tropical wave axis is along 35W from 01N-15N, moving W at 10
kt. This wave is located to the southeast of a rather potent
upper-level trough. This pattern is favorable for the enhancement
of convection near the wave. Satellite imagery shows a large area
of numerous moderate and isolated strong convection from 05N-11N
between 26W-34W. Isolated moderate convection is elsewhere from
04N-13N between 27W-40W.

A tropical wave axis is along 52W from 01N-12N, moving W at 10
kt. Isolated showers are near the wave axis.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends off the west coast of Africa near
12N16W to 10N18W. The ITCZ is from 10N18W to 06N32W, then
continues west of a tropical wave from 06N34W to 04N46W. Aside
from convection related to the tropical wave along 35W, isolated
moderate convection is within 60 nm south and 300 nm north of the
ITCZ between 40W-46W.

GULF OF MEXICO...

A surface ridge extends from a 1028 mb high pressure over Alabama
and Georgia southwest across SE Texas and then southward to
southern Mexico. Meanwhile, Hurricane Eta is moving onshore just
to the south of Puerto Cabezas, Nicaragua. The pressure gradient
between the hurricane and the high pressure is currently causing
near gale force NE winds across the southeast Gulf of Mexico. This
includes the Florida Straits and the Yucatan Channel, where a
morning ASCAT pass suggested that NE winds were in the 28 to 33
kt range. Winds are only moderate over the northwest Gulf of
Mexico. Strong N winds are in the Bay of Campeche south of 20N.
Little to no significant precipitation is noted, although
scattered stratus clouds are seen in the southern half of the
Gulf.

Fresh to near gale force NE winds will continue over the SE Gulf
and the Bay of Campeche, with near gale force NE winds over the
Straits of Florida. Winds will remain moderate to fresh over the
NE Gulf waters by the end of the week and into the weekend.

CARIBBEAN SEA...

Please see the Special Features section above for details on
Hurricane Eta and for details on upcoming gale force winds
over the Gulf of Honduras.

Convection in the western Caribbean west of 73W is due to
Hurricane Eta and its interaction with an old lingering frontal
zone. Bands and clusters of scattered moderate to strong
convection are seen over the west and central Caribbean from just
NE of Hurricane Eta, near 15N82W, extending northeastward to the
Windward Passage. The morning ASCAT pass showed moderate to fresh
trades across the eastern and central Caribbean, east of 75W.
Near gales extend northwestward from Eta's tropical storm force
wind field, all the way through the Yucatan Channel into the SE
Gulf. The entire area north of 18N and west of 80W is experiencing
NE winds of 25 to 33 kt.

Hurricane Eta is forecast to weaken to a remnant low over
Honduras Thu morning. Eta could potentially regenerate into a
tropical cyclone over the northwest Caribbean this weekend.
Scattered to  numerous showers and tstorms will continue to
cover most of the western and central Caribbean through the
end of the week. Strong to near gale force northeast winds
will remain over the NE Caribbean through early Thu. These
winds are forecast to be gale force in the Gulf of Honduras
on Wed. See the Special Features section above for more
information on this Gale Warning.

ATLANTIC OCEAN...

A cold front extends from near 32N52W to 26N65W through the
central Bahamas near 24N75W, then becoming a stationary front
continues to central Cuba near 22.5N80W. Near gale force winds are
north of the front west of 74W, and extend from the Florida
Straits through the central and northwest Bahamas to near 25N74W.
Fresh to strong winds are elsewhere behind the front, except for
moderate anticyclonic winds seen north of 29N and west of 70W.
Scattered to numerous showers and tstorms are noted along and well
southeast and south of the front, stretching almost to Puerto
Rico and the north coast of Hispaniola, from 20N-26N between 65W-
78W. East of 65W, scattered moderate showers are noted along and
within 150 nm ahead of the front. This activity is being enhanced
by a broad upper-level trough over the NW Atlantic to the north of
the area, and an upper-level dynamics tied to a jet stream branch
that rounds the base of the trough. Strong upper-level west winds
are being produced by this jet stream branch.

Farther east, a potent upper-level trough stretches across the
central Atlantic, generally from 15N-30N between 35W-50W. This
upper trough is enhancing scattered convection aloft that extends
N from the tropical wave along 35W to 30N, between 28W-35W.

For the forecast west of 65W, the cold front through the central
Bahamas will stall tonight before gradually dissipating through
Wed night. Strong to near gale force northeast to east winds
behind the front will continue through Thu night over the Bahamas
region and Florida Straits, then become mainly fresh east winds
Fri before increasing again to fresh to strong speeds Sat and Sat
night. Rough seas will continue over the majority of the area
through Thu, then begin to slowly subside through late Fri. Seas
should build again over the waters north and northeast of the
Bahamas Sat and Sat night.

$$
Stripling
This weather bulletin was brought to you by:
www.nashvilleweather.net