Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
345 AM EDT Thu Apr 28 2022

Valid 12Z Thu Apr 28 2022 - 12Z Sat Apr 30 2022

...Developing storm system over the central U.S. on Friday to generate
areas heavy snow across the northern Rockies, heavy rain over the northern
Plains, and severe thunderstorms in the central/southern Plains...

...Coastal rain and inland snow to continue across parts of Maine through
Friday...

...Critical to extreme fire weather located throughout parts of the
Southwest, southern Rockies, and southern High Plains...

An active weather pattern will begin to take shape later today and extend
into early this weekend as a multifaceted weather system develops over the
central United States. Before this system develops, there is the chance
for isolated instances of flash flooding and severe weather along a
quasi-stationary boundary extending from the middle Mississippi Valley to
the Central Plains. A Marginal Risk (level 1/4) of excessive rainfall is
in effect for today from southeast Nebraska and eastern Kansas into much
of Missouri, where rainfall amounts over an inch could pose isolated flash
flooding concerns. The Storm Prediction Center has issued a Slight Risk
(level 2/5) of severe weather over western Nebraska, and a larger Marginal
Risk (level 1/5) that extends southward and just east of dryline
throughout the central and southern Plains today. By early this evening, a
negatively tilted upper-level trough crossing the Intermountain West will
lead to a developing precipitation shield over the northern Rockies. Heavy
snow is forecast across parts of Montana, Idaho, and northwest Wyoming.
with moderate snowfall accumulations confined to regions above 5000 feet
in elevation. Additionally, a few damaging wind gusts and some hail can't
be ruled out across southeast Idaho, northern Utah, and southwest Wyoming.
A strong low pressure system will begin to develop on Friday over the
central Plains as the aforementioned upper-level trough begins to close
off while continuing to push eastward. This will lead to an expanding
precipitation shield over the northern Plains and Mid-Mississippi Valley.
Widespread rainfall amounts up to, and locally exceeding, 2 inches may
produce scattered areas of flash flooding from south-central North Dakota
to central South Dakota. A Slight Risk (level 2/4) of excessive rainfall
is in effect for this region. Elsewhere, there is higher confidence that
severe thunderstorms capable all hazard types will impact an area
extending from southeast Nebraska to north-central Oklahoma, prompting SPC
to issue an Enhanced Risk (level 3/5) of severe weather. Thunderstorms
forming ahead of a dryline and approaching cold front may contain
tornadoes and produce significant hail. With multiple strong storms, heavy
rainfall rates are also likely and could lead to isolated flash flood
concerns. By Saturday, the maturing low pressure system will continue to
produce locally heavy rain over the northern Plains, with wet snowflakes
mixing into the northern High Plains and Black Hills. Heavy rain and
severe thunderstorms will also remain possible along the advancing cold
front forecast to extend from the Midwest to the Southern Plains.

Elsewhere, a wobbling upper-level low located over the Gulf of Maine will
continue to produce unsettled weather over northern New England over the
next few days. Northern Maine in particular will experience the greatest
impacts, with snowfall accumulations up to 5 inches and gusty winds
possible throughout northern portions of the state. Conditions will
finally begin to improve on Saturday as the system gradually slides
further into the Atlantic. Meanwhile, an attached cold front that has
surged through the western Atlantic and is currently found near central
Florida could lead to scattered thunderstorms capable of producing heavy
rain and urban flash flooding through Friday. A Marginal Risk of excessive
rainfall has been issued along the southeastern Florida Atlantic
coastline. Behind this cold front much of the eastern U.S. will experience
a chilly end of the workweek. In fact, lows into the upper 20s and low 30s
will likely lead to frost/freeze concerns over parts of the Ohio Valley
and Mid-Atlantic through at least Saturday. The combination of dry air and
gusty winds over the Mid-Atlantic will also lead to fire weather concerns.
Fire Weather Watches and Red Flag Warnings have been issued for parts of
eastern Pennsylvania and New Jersey.

Fire weather is also a potential hazard across the Southwest, southern
Rockies, and southern High Plains over the next few days. The combination
of gusty southwesterly winds, low relative humidity, above average
temperatures, and dry terrain will lead to critical to extreme fire
weather conditions today and Friday. More specifically, SPC has issued an
area of extreme fire weather danger over parts of southeast Colorado on
Friday. Any new wildfires could start with ease and new/existing fires may
spread uncontrollably. Red Flag Warnings and Fire Weather Watches are in
effect over southern Nevada, northern Arizona, the entire state of New
Mexico, parts of southern Colorado, West Texas and the Texas Panhandle, as
well as western Oklahoma.

Lastly, a frontal system entering the Pacific Northwest on Friday night
will spread lower elevation/coastal rain and mountain snow into the
region. Precipitation amounts are expected to remain under an inch.

Snell

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