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Prognostic Meteorological Discussion
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FXUS01 KWBC 271933
PMDSPD

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
332 PM EDT Tue Oct 27 2020

Valid 00Z Wed Oct 28 2020 - 00Z Fri Oct 30 2020

...Snow continues across the southern Rockies to the southern High
Plains while significant icing occurs from northern Texas to
central and western Oklahoma...

...Hurricane Zeta is forecast to bring gusty winds and the threat
of flash flooding from the central Gulf Coast north into the Ohio
Valley and Mid-Atlantic through Thursday...

...Critical fire risks and high wind threat in California into the
Desert Southwest today should lessen by Wednesday...

A rather volatile weather pattern is in store from the southern
Rockies to the Deep South and Mid-Atlantic states during the next
couple of days as a major winter storm interacts with Hurricane
Zeta--the 28th tropical cyclone in this extremely active hurricane
season-- which is forecast to make landfall on the central Gulf
Coast late on Wednesday. The energetic cold upper low that is
responsible for the recent widespread snowfall down the Rockies
will deliver more snow from the southern Rockies into the High
Plains through Wednesday. An additional 3 to 6 inches of snow can
be expected over the southern High Plains, including Northwest New
Mexico to the Texas Panhandle, with lesser amounts in the southern
Rockies. Meanwhile, as the low lifts milder air northward from the
western Gulf of Mexico, a swath of freezing rain and mixed
precipitation is forecast to continue into early Wednesday morning
from northern Texas to western/central Oklahoma. Significant icing
has already accumulated in portions of Texas and Oklahoma,
widespread total ice accretion of one-quarter to one-half inch is
likely to cause numerous travel delays, downed tree limbs, and
power outages. Some locations could see as much as an inch of
total ice accretion. Lighter yet still hazardous ice accumulations
are expected for west-central Texas and southern Kansas. By
Wednesday morning, the once frigid air-mass will moderate as
warmer southerly flow should lead to a changeover from ice to rain
throughout much of the central and southern Plains, but some
lingering snow and ice are possible in eastern New Mexico,
southeast Colorado, and both the Texas and Oklahoma panhandles.

The cold upper low will also play a large role in steering
Hurricane Zeta northward across the Gulf of Mexico toward the
central Gulf Coast. The eastern Louisiana coast appears to be the
most likely location where Zeta will make landfall late on
Wednesday. Rain and thunderstorms will expand in coverage across
the interior Deep South tonight near a stalled frontal boundary.
Winds and rain will steadily increase near the Louisiana coast on
Wednesday, with hurricane conditions expected to arrive later in
the afternoon into early evening on Wednesday. Residents within
Zeta`s projected forecast track need to continue monitoring Zeta`s
progress, begin making preparations, and follow the advice of
local officials. Farther inland, a couple inches of heavy rain
with locally higher amounts is forecast to expand eastward from
the central Plains through the Mid-Mississippi and Tennessee
Valleys for the next couple of days. This may lead to isolated
instances of flash flooding. Meanwhile, 2 to 4 inches of rain with
isolated amounts of 6 inches, along with potentially damaging wind
gusts can be expected near the track of Zeta from eastern
Louisiana to Alabama through Thursday morning. As Zeta pushes
northeast along the eastern Appalachians on Thursday, even though
it is expected to weaken to a tropical depression, heavy rain and
gusty winds are still possible from western North Carolina to the
Mid-Atlantic coast.

Farther west, damaging Santa Ana winds across parts of California
should slowly subside this evening as the pressure gradient
weakens. However, critical fire weather remains in place along the
higher elevations of southern California, the Sacramento Valley,
and the lower Colorado River Valley today before lessening further
on Wednesday.

Snell/Kong


Graphics available at
www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php
$$
National Weather Service Regional Headquarters
