[Tropical] Tropical Cyclone Discussion

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WTNT41 KNHC 160231
TCDAT1

Hurricane Iota Discussion Number  11
NWS National Hurricane Center Miami FL       AL312020
1000 PM EST Sun Nov 15 2020

Iota continues to gain strength. A small eye has occasionally
appeared in satellite images, and the banding features are well
established and fairly symmetric around the center.  The Air Force
Hurricane Hunters investigated Iota earlier this evening, and
they found maximum flight-level winds of 93 kt and maximum SFMR
surface winds of 84 kt around 00Z.  Based on this data and the
continued improvement in organization, the initial intensity is
increased to 90 kt.  The minimum pressure based on dropsonde data
from the aircraft was 961 mb around 00Z, which is a 13 mb drop from
the flight earlier today.  Another Air Force plane is set to be in
the hurricane overnight.

Iota is moving westward at about 9 kt.  A westward to
west-northwestward motion is expected until the cyclone makes
landfall in northeastern Nicaragua Monday night.  After landfall,
the models show a slight bend to the left as the hurricane moves in
the flow on the southeast side of a mid-level ridge centered over
Mexico.  The models are tightly clustered, and the NHC track
forecast is largely an update of the previous one.

The hurricane is in near ideal conditions to continue strengthening
until landfall.  In an environment of warm 29 C waters, very low
wind shear, and a moist air mass all of the normally skillful
models show Iota becoming a dangerous major hurricane before it
strikes the coast. Given the favorable conditions, well-defined
structure of the hurricane, and model guidance there is high
confidence that significant wind, surge, and rainfall impacts will
occur in portions of the hurricane warning area.  After Iota moves
inland, rapid weakening is expected and the hurricane will likely
dissipate over the rugged terrain in Central America in 3 or 4 days.


Key Messages:

1. Iota is expected to continue to rapidly intensify and be an
extremely dangerous category 4 hurricane when it approaches the
coast of Central America on Monday.  Potentially catastrophic
winds and a life-threatening storm surge are expected along portions
of the coast of northeastern Nicaragua and eastern Honduras, where a
hurricane warning is in effect.

2.  Hurricane conditions are expected and storm surge impacts
are possible on Providencia later tonight and Monday.  Tropical
storm conditions are expected and hurricane conditions are possible
on San Andres.

3. Through Friday morning, heavy rainfall from Iota will likely lead
to life-threatening flash flooding and river flooding across
portions of Central America. Flooding and mudslides in Honduras and
Nicaragua could be exacerbated by Hurricane Eta’s recent effects
there, resulting in significant to potentially catastrophic impacts.


FORECAST POSITIONS AND MAX WINDS

INIT  16/0300Z 13.3N  80.2W   90 KT 105 MPH
 12H  16/1200Z 13.5N  81.4W  105 KT 120 MPH
 24H  17/0000Z 13.9N  82.9W  120 KT 140 MPH
 36H  17/1200Z 14.2N  84.3W   75 KT  85 MPH...INLAND
 48H  18/0000Z 14.3N  85.8W   45 KT  50 MPH...INLAND
 60H  18/1200Z 14.1N  87.4W   35 KT  40 MPH...INLAND
 72H  19/0000Z 13.8N  88.8W   25 KT  30 MPH...POST-TROP/INLAND
 96H  20/0000Z...DISSIPATED

$$
Forecaster Cangialosi

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