[Tropical] Tropical Weather Discussion

Tue Nov 3 12:17:01 CST 2020

AXNT20 KNHC 031816
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 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 1200 UTC surface analysis and satellite imagery through
1750 UTC.

...SPECIAL FEATURES...

Major Hurricane Eta is centered near 13.7N 83.3W at 03/1800 UTC,
or about 15 nm SSE of Puerto Cabezas, Nicaragua moving W at 3
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 Jamaica, the Cayman Islands, Nicaragua and Honduras. The eye
has become less distinct on infrared satellite imagery since
about 0900 UTC this morning and is obscured by clouds. Cloud tops
in the eye wall and core region have also warmed since that time.
On the forecast track, the center of Eta is expected to make
landfall along the coast of Nicaragua within the Hurricane
Warning area today. 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 inland today. Catastrophic wind damage is expected where
Eta's eyewall moves onshore within the next few 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
today, near and to the north of where the center makes 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 34W 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-12N
between 29W-39W. Isolated moderate convection is elsewhere from
04N-13N between 27W-40W.

A tropical wave axis is along 51W 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 06N36W to 03N46W. Aside
from convection related to the tropical wave along 34W, 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 1030 mb high pressure over Alabama
and Mississippi to a 1027 mb high over northeast Mexico near
23N100W. Meanwhile, Hurricane Eta is located near Puerto Cabezas,
Nicaragua. The gradient in 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 recent ASCAT pass suggests that NE
winds are in the 28 to 33 kt range. Winds are only moderate
speeds 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 74.5W is due to
Hurricane Eta and is described above. Another area of scattered
moderate isolated strong convection is seen over the central
Caribbean from 13N-18N between 69W-72W. A stationary front
extends from central Cuba near 22.5N80W to the Isle of Youth.
A dissipating stationary front continues from the Isle of
Youth to 19.5N86.5W. The latest ASCAT pass shows 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 32N58.5W to 24.5N70W to Long
Island, Bahamas near 23N75W. 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, an potent upper-level trough stretches across the
central Atlantic, generally from 15N-30N between 35W-50W. This
upper trough is enhancing scattered moderate convection that
extends N from the tropical wave along 34W to 30N, between
29W-39W.

For the forecast west of 65W, the cold front from 27N65W to 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.

$$

Hagen
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