Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
401 PM EDT Wed Apr 27 2022

Valid 00Z Thu Apr 28 2022 - 00Z Sat Apr 30 2022

...Coastal storm to produce rain and elevation snow across northern New
England through the end of the week...

...Isolated chances for severe thunderstorms and flash flooding over the
next few days throughout the southern/central Plains and Mid-Mississippi
Valley, with critical fire weather expected across the southern High
Plains and southern Rockies through Friday...

...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...

A strengthening area of low pressure over the Gulf of Maine continues to
strengthen, and is forecast to pivot near the Bay of Fundy tonight. As it
does so, rain and higher elevation snow within a developing commahead
region will expand over much of northern New England. Northern Maine in
particular is expected to see the most impacts associated with snowfall,
as accumulations add up to around 4 to 8 inches with locally higher
amounts in the highest elevations, leading to minor potential winter storm
impacts (level 2/5) per the WPC WSSI.  This coastal storm will be slow to
exit as the associated upper-trough closes off and gets stuck beneath a
blocking high near Greenland. Accordingly, breezy northwesterly winds and
snow showers will linger through at least late Friday over northern New
England. The chilly northwesterly flow will also aid in much of the
Northeast and Mid-Atlantic experiencing below average temperatures over
the next several days. In fact, below average temperatures will continue
to stretch into the Midwest and northern Plains thanks to a strong high
pressure system building southward from Ontario. Widespread highs will
reach into the 40s and 50s, with lows dipping into the 20s and 30s.
Sensitive vegetation throughout the Midwest, Ohio Valley, and Mid-Atlantic
will endure frost/freeze chances until late this week, where a swath of
Freeze Warnings are in effect through Thursday and Friday.

Meanwhile, a stationary boundary extending from the Mid-Mississippi Valley
into the central Plains, a forming dryline over the southern High Plains,
and embedded shortwaves within an upper-level ridge will support chances
for isolated severe thunderstorms and instances of flash flooding across
the central U.S. through Thursday. The Storm Prediction Center has issued
a Slight Risk (level 2/5) of severe thunderstorms for today over portions
of the southern Plains, where a few storms could produce damaging wind
gusts and large hail. The marginal severe storm threat shifts slightly
east into the central and southern Plains on Thursday for more damaging
wind gusts and hail. Isolated instances of flash flooding are also
possible on Thursday from the central Plains into the middle Mississippi
Valley as showers and storms form and backbuild along the aforementioned
stationary front. West of the dryline, critical fire weather is forecast
from the southern Rockies to the southern High Plains through the end of
the week. Low relative humidity and gusty winds could create an
environment conducive for rapid wildfire spread, which has also prompted
Red Flag Warnings and Fire Weather Watches to be issued for parts of
Arizona, New Mexico, southwest Colorado, and West Texas.

The next large-scale weather-maker to impact the Nation will begin to take
shape late Thursday as a potent and negatively tilted upper-level trough
enters the Intermountain West. In tandem, an area of low pressure is
forecast to develop over the central High Plains and aid in producing a
widespread area of precipitation extending across the northern Plains and
northern Rockies on Friday. Heavy snow is possible across the higher
terrain of northwest Wyoming and western/central Montana, where snowfall
accumulations up to a foot are possible for locations above 5000 feet and
could impact travel overnight when snowfall is most likely to stick to
road surfaces. The latest WPC WSSI highlights Moderate (level 3/5) winter
storm impacts possible within these higher terrain areas, particularly in
Montana. A round of Winter Storm Watches was hoisted this morning in the
northern Rockies through Friday evening. Additionally, periods of heavy
rain are expected over the northern Plains on Friday. Rainfall totals over
2 inches atop sensitive soils may lead to increasing chances for flash
flooding from south-central North Dakota to central South Dakota, where a
Slight Risk (level 2/4) of excessive rainfall has been issued. Showers and
thunderstorms will also extend into the central/southern Plains and
Mid-Mississippi Valley by Friday afternoon ahead of a sharp dryline, where
all modes of severe weather are possible. SPC has issued an Enhanced Risk
(level 3/5) of severe weather from far southeast Nebraska to eastern
Kansas, with a larger Slight Risk (level 2/5) extending from Nebraska to
the Red River. 

Asherman/Snell

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