Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 AM EDT Tue Oct 12 2021

Valid 12Z Tue Oct 12 2021 - 12Z Thu Oct 14 2021

...An early-season heavy snow event in the northern/central Rockies will
spread into the northern High Plains tonight and into Wednesday...

...Widespread heavy rains, localized flash flooding and severe weather
across much of the Plains for the next couple of days...

...Big temperature contrast across the country as a battle of the seasons
commences...

An early-season heavy snow event is in progress across the northern and
central Rockies this morning as a large area of low pressure continues to
develop just to the south.  Snow is expanding in coverage across these
areas and is expected to become heavier as the day progresses.  The low
pressure system is forecast to intensify further through tonight as it
tracks northeastward across central High Plains towards the northern
Plains.  The snow is expected to be quite heavy to the west of the storm
track over the northern High Plains tonight.  Winter Storm Watches and
Warnings are currently in effect where snowfall totals of 1 to 2 feet are
possible.  In addition, the heavy snow will be accompanied with very
strong and gusty north to northwesterly winds during the height of the
storm.  This will likely result in blowing and drifting of the snow as the
storm continues to intensify.  By Wednesday, the heavy snow and high
winds will likely spread further north into the western Dakotas and
eastern Montana.  This same system will also support increasing
thunderstorm activity tonight into Wednesday across large portions of the
Plains ahead of a strong cold front pushing eastward across these areas. 
Heavy rains, isolated flash flooding and the risk of severe weather will
accompany these storms, with the greatest risk of severe weather and flash
flooding across portions of the central to southern Plains.

Additional heavy rains and the risk of Flash Flooding will push back into
portions of the southern Plains Wednesday night into Thursday as moisture
associated with currently Hurricane Pamela off the west coast of Mexico is
transported northeastward into the above-mentioned frontal zone which is
forecast to become stationary over the southern Plains at this time. 
While Pamela will likely weaken rapidly when it moves inland into western
Mexico Wednesday, its associated moisture will have a longer-lived impact
as it is transported northeast into the frontal zone across the southern
Plains Wednesday night into Thursday, supporting the heavy rain and flash
flooding potential.

This active pattern, producing weather conditions of both winter and
summer, will also result in large temperature contrast across the nation
over the next few days.  Much below average temperatures are likely from
the northern High Plains, westward through the Rockies and Great Basin,
while much above average temperatures will persist across nearly all of
the central to eastern U.S.

Kong/Oravec


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