Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
259 PM EST Thu Feb 17 2022

Valid 00Z Fri Feb 18 2022 - 00Z Sun Feb 20 2022

...Heavy snow and a treacherous icy wintry mix expected from the Great
Lakes to northern New England...

...Severe weather to track through the Mid-South and Tennessee Valley this
evening; flash flooding is possible throughout much of the Ohio Valley and
Interior Northeast...

...An approaching clipper system may produce blizzard conditions on Friday
in parts of the North Central U.S., colder in the Northeast but warming up
in the Great Plains...

A multitude of weather hazards is expected to continue to impact the
Southern Plains through the Northeast as a deepening low-pressure system
and accompanying cold front sweeps across the eastern half of the country
through Friday morning. A large temperature gradient will help fuel the
development and continuation of precipitation along the surface boundary,
with mixed precipitation and snow occurring in the cold sector of the
system, north of the boundary, and the threat of heavy rains and severe
thunderstorms ahead of the advancing cold front.

As the system continues to strengthen, warm, moist air will be advected
from the Gulf of Mexico, allowing for the development of severe
thunderstorms that can produce damaging winds, large hail, and isolated
strong tornadoes. Because of this, the Storm Prediction Center (SPC) has
issued an Enhanced Risk (level 3/5) of severe thunderstorms across the
Tennessee and lower Mississippi Valleys. As the frontal boundary moves
eastward on Thursday so will its threat of severe weather.  While the risk
for severe thunderstorms should wane in the overnight hours, residents
outside of the Enhanced Risk should continue to monitor current conditions
and all products issued by their local forecast office in preparation for
any changes to the going forecast. Further north, the threat for heavy
rain exists for a broad area stretching from the middle Mississippi
Valley, northeastward through the Ohio Valley and interior Northeast,
where the Weather Prediction Center has issued a Slight Risk for Excessive
Rainfall. Portions of Kentucky, Missouri, and Illinois may experience
rainfall rates greater than 1"/hr, with locally higher amounts, due to
convective activity associated with the cold front moving through the
region. While rainfall rates are not forecasted to be as excessive in the
Great Lakes and Interior Northeast, prolonged rainfall in conjunction with
lingering snowpack and frozen grounds may lead to flooding in isolated
areas. As a consequence of this, Flood Watches have been issued for much
of the region through Friday morning. Another potential hazard ahead of
the storm system is the strong southerly winds that will impact much of
the Southeast, Mid-Atlantic, and New England. Winds could gust as high as
55-65 mph in isolated areas through Friday morning, leading to High Wind
Warnings and Wind Advisories being issued for a large portion of the
eastern region.

In the cold sector of this system, the potential for mixed precipitation
and snow exists across a narrow stripe stretching from northern Missouri
eastward through the Mississippi and Ohio Valleys and interior Northeast.
Areas north of the frontal boundary including the south-side of Chicago
and Detroit, where cold, arctic air has filtered in, have the highest
potential for seeing accumulations greater than 4". Isolated areas along
this swath of snow may receive 6-10" where the heaviest bands persist. To
the south of the axis of heaviest accumulations, there is forecasted to be
a region of freezing rain and sleet, where temperature profiles will not
be cold enough to support snow. Due to the broad region expected to be
impacted by wintry precipitation, Winter Storm Warnings and Winter Weather
Advisories have been issued along a nearly 1,500 mile stretch from western
Oklahoma to northern Maine. Residents currently under one of these
products are reminded that traveling during periods of snow, sleet, or
freezing rain is potentially dangerous and to exercise extreme caution if
travel is necessary.

The potent storm system and associated hazards are expected to clear the
eastern region during the early Friday hours, with colder air spilling in
behind it. Farther west, a clipper system entering the Northern Plains
will spread the potential for light snow into parts of North Dakota and
northern Minnesota. While snow fall accumulations are expected to be
light, whipping wind gusts behind the clipper will cause near whiteout
conditions in parts of eastern North Dakota and northwest Minnesota. This
has prompted the issuance of Blizzard Warnings that are in effect through
much of the day on Friday. Snow showers and snow squalls are then expected
to enter the Great Lakes region and parts of the Midwest late Friday and
into Friday night. This clipper system ushers in another shot of below
normal temperatures into the Ohio Valley and the Northeast, but it is a
short lived period of colder conditions as the next surge of springlike
warmth rebounds in the Great Plains Saturday and eventually reaches the
Ohio Valley by Sunday.

Russell

Graphics are available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php