Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
354 AM EDT Mon Apr 12 2021

Valid 12Z Mon Apr 12 2021 - 12Z Wed Apr 14 2021

...Scattered showers and a few thunderstorms are possible from the Great
Lakes to the Northeast today; accumulating wet snow expected the next
couple of days in the far Northern Plains...

...Mountain snow gradually develops and expands across the northern and
central Rockies; lingering frontal boundary to trigger showers and
thunderstorms in the South Central U.S...

...Favorable conditions for Elevated to Critical fire weather conditions
in the Southwest to continue into the middle of the week...

An upper level blocking jet stream pattern across North America will
result in a low pressure system becoming quasi-stationary over the Upper
Midwest for the next couple of days. The area of low pressure works in
tandem with an upper level low tracking into the northern Mid-Atlantic
today to generate scattered showers and possibly some embedded
thunderstorms from the Great Lakes to the Northeast Coast through Monday
night. Along with unsettled weather, this blocking pattern over Canada
allows for colder than normal conditions to set up shop from the Northwest
into the Nation's Heartland the first half of the week. In fact, enough
sub-freezing air aloft will be available for wet snow to develop near the
Canadian border and over the northern Plains. An extended period of steady
snowfall rates is forecast to result in 6 to 12 inches of snow
accumulations by Wednesday morning for the northern half of North Dakota
into northwestern Minnesota.

Farther west, the blocking pattern will also force a cold upper low to
form and dip across the Pacific Northwest toward the Great Basin for the
next couple of days. This brings colder temperatures together with gradual
development and expansion of mountain snow across the Northwest, the
northern Great Basin, and both the northern and central Rockies. The
coldest temperature departures (15 to 20 degrees below normal) are
forecast to occur in the northern High Plains both Monday and Tuesday. In
contrast, warmer and wetter conditions are anticipated in the South
Central U.S. to kickoff the week. A Slight Risk for severe weather is in
place over central Texas today with a Marginal Risk (for both severe
weather and excessive rainfall) over the Lower Mississippi Valley on
Tuesday.

In the Southwest, low relative humidity levels along with breezy
conditions and dry fuels will support an Elevated Risk for fire weather in
parts of Arizona and New Mexico. There is also an Elevated Risk for fire
weather in central Nebraska today as well. Conditions only grow more
favorable for fire weather as the aforementioned upper trough in the
Northwest deepens, creating a stronger wind field along with persistent
low humidity levels and dry fuels. This has resulted in a Critical Risk
for fire weather in the lower Great Basin on Tuesday. Depending on the
position and intensity of the upper trough, fire weather could remain an
ongoing issue in the Southwest and lower Great Basin into the middle of
the week.

Mullinax

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