Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
344 PM EDT Sat Apr 29 2023

Valid 00Z Sun Apr 30 2023 - 00Z Tue May 02 2023

...Heavy rainfall and severe thunderstorms possible across the East Coast
through Sunday...

...Locally significant and long-duration snowfall event forecast across
the U.P. of Michigan and northern Wisconsin through early next week...

...Below average temperatures to enter the West Coast and much of the
Great Lakes, Ohio Valley, and Northeast; while much warmer temperatures
spread throughout the Intermountain West, northern Rockies, and northern
High Plains...

A wet, cool, and stormy weather pattern is set to impact much of the
Eastern U.S. through at least the beginning of next week, with the main
impacts being associated with an ongoing and rapidly developing storm
system swinging up the East Coast this weekend. A deep upper-level low
currently centered above the Upper Midwest combined with a strengthening
surface low pressure system near the central Gulf Coast are the main
pieces forecast to interact and lead to severe thunderstorm and heavy
rainfall chances through Sunday. Widespread shower and thunderstorm
activity across the Southeast through tonight could produce locally heavy
rain and severe thunderstorms, particularly across Florida and southern
Georgia. Large hail, damaging wind gusts, and a few tornadoes are
possible. As the low pressure system tracks into the Carolinas on Sunday
and strengthens, shower and thunderstorms should spread north into much of
the Mid-Atlantic. The greatest severe weather threat is expected across
eastern North Carolina and southeast Virginia on Sunday, as well as across
southern Florida along an attached cold front. Additionally, heavy rain
may lead to scattered flash flooding into the northern Mid-Atlantic and
Northeast through Sunday night. Two areas have been highlighted as having
the highest chances for flooding concerns and fall with a Slight Risk
(level 2/4) of Excessive Rainfall. The first area of concern includes much
of central Pennsylvania and the southern tier of New York, with the second
area across New Hampshire and southern Maine. The latest forecast for this
region calls for widespread 2 to 3 inches of rain, with locally higher
amounts possible.

On the cold side of this system throughout the Upper Great Lakes and Upper
Midwest, winter weather will continue into the start of May. Very strong
and cold northerly winds on the west side of a deep, mostly stationary
surface low over the Great Lakes will combine with subfreezing air aloft
to produce potentially heavy snowfall downwind of Lake Superior across the
western U.P. of Michigan and northern Wisconsin through early next week.
The long duration snowfall event could yield up to 2 feet of snow by
Tuesday.

Elsewhere, a system approaching the West Coast on Sunday will usher in
much cooler weather to the immediate West Coast before below average
temperatures spread into much of California by the beginning of the week.
Scattered showers, thunderstorms, and high elevation snow are also
possible into the West and northern/central Rockies on Monday and Tuesday.
Meanwhile, well above average and potentially record-breaking warmth will
shift into the northern Great Basin and northern Rockies. Lower elevations
could see high temperatures into the mid-80s, while low 100s spread into
the Desert Southwest. Continued river flooding due to snowmelt is expected
to continue across much of the mountainous western United States. For the
Eastern U.S., unsettled weather will lead to widespread below average
temperatures, with the core of the chilly conditions situated over the
Great Lakes, Northeast, and Ohio Valley. Highs in this region through
Tuesday will struggle to reach above the 40s and 50s.


Snell


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