Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
247 PM EST Wed Dec 15 2021

Valid 00Z Thu Dec 16 2021 - 00Z Sat Dec 18 2021

...Extremely powerful storm system to produce a plethora of weather
hazards across the Great Plains and Upper Midwest tonight, including
severe thunderstorms, damaging winds, dangerous fire weather conditions,
and moderate snowfall...

...Heavy snow forecast over the Sierra Nevada through Thursday morning...

...Heavy rain and instances of flash flooding possible throughout parts of
the Southern Plains, Middle/Lower Mississippi and Ohio valleys on Thursday
and Friday...

The major weather story through tonight and into early Thursday morning
will be associated with a strong, potentially record-breaking, low
pressure system racing across the Upper Midwest and eventually reaching
southern Canada on Thursday. This robust storm system will create an
extremely tight pressure gradient just to the south of the center and
along an attached cold front. Thus, dangerously high winds are expected to
impact much of the Central and Northern Plains this evening, as well as
the Midwest and Upper Great Lakes overnight. Widespread wind gusts over 60
mph are forecast and could locally exceed 70 mph. As a result, blowing
dust and power outages will likely be found throughout the region.
Extremely Critical Fire Weather also exists into this evening from the
northern Texas Panhandle to north-central Kansas. The high winds combined
with low relative humidity will create an environment ripe for any
wildfires to spread rapidly and uncontrollably. Farther north, a line of
potentially severe thunderstorms is likely to develop this afternoon and
swing into Iowa and southern Minnesota. These storms will have to the
potential to produce extreme wind gusts as high as 100 mph, as well as a
strong tornado or two. The Storm Prediction Center has issued a Moderate
Risk (level 4/5) of severe weather for this region. Last, but certainly
not least, on the cold side of the system (north and west of the low) snow
is likely to fall across portions of the Dakotas and northern/central
Minnesota tonight. Maximum snowfall amounts may only add up to around 6
inches, but widespread blowing snow may create hazards driving conditions.
By Thursday, light snow is expected to continue across the Upper Midwest
and Upper Great Lakes into the late afternoon as gusty winds slowly
diminish.

Elsewhere, a frontal system sliding down the West Coast will funnel
moisture into the Sierra Nevada and northern California mountains through
Thursday morning. Snowfall totals over 2 feet are possible along the
Sierra Nevada, where Winter Storm Warnings have been issued. Snow showers
will also spread into the Intermountain West and Rockies on Thursday and
produce moderate accumulations throughout the high terrain of Nevada,
Utah, Wyoming, and Idaho. For the Northeast, light snow and freezing rain
is forecast to push through northern New England and Maine tonight before
warmer air arrives on Thursday. Winter Weather Advisories have been issued
across Vermont, northern New Hampshire, and most of Maine to highlight the
potential for a few inches of snow and a glaze of ice.

The next potential weather hazard to monitor towards the end of the week
will likely be located from the Southern Plains to the Ohio Valley, where
a stalled frontal boundary may focus areas of heavy rain and
thunderstorms. Widespread rainfall amounts over one inch, with local
amounts up to 3 inches could occur from eastern Oklahoma to southern
Indiana. This includes much of the region in western Kentucky that is
still cleaning up from the recent tornado outbreak. Isolated instances of
flash flooding are possible, particularly between northern Arkansas and
northern Kentucky. Here, WPC has issued a Sight Risk (level 2/4) of
Excessive Rainfall for Friday. Well above average temperatures are
forecast to engulf much of the eastern and south-central U.S. ahead of the
aforementioned cold front. Widespread highs into the 60s and 70s will
extend over the Southern Plains, Deep South, Tennessee and Ohio valleys,
Southeast, and Mid-Atlantic to end the week. Widespread daily high
temperature records are also in jeopardy and may extend into the Northeast
on Thursday, where parts of Upstate New York and Massachusetts could enjoy
highs into the 60s. Meanwhile, below average temperatures will be confined
to the Intermountain West and Northern Plains. Low temperatures are
expected to dip into the single digits on Thursday and Friday, with
subzero temperatures found across northern Montana and North Dakota.

Snell


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