Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 AM EDT Fri May 02 2025
Valid 12Z Fri May 02 2025 - 12Z Sun May 04 2025
...Upper-level omega block to form across the CONUS, leading to
periods of unsettled weather and large temperatures contrasts
heading into the weekend...
...Heavy rain, flooding, and severe weather threats to stretch
from the Southern Plains northeast into the Ohio Valley Friday...
The mid- to upper level flow pattern will become increasingly
amplified over the next few days with an omega block forming from
California, eastward into the Ohio Valley. This pattern will bring
periods of unsettled weather first to portions of the eastern and
southern U.S., and eventually to the western U.S. heading into the
weekend. Southerly flow supporting a moist airmass along a cold
front stretching from the Lower Great Lakes southwestward through
the Ohio Valley, Middle/Lower Mississippi Valley, and southern
Plains will help to focus the first area of showers and
thunderstorms. The boundary is forecast to slow through Friday and
become quasi-stationary in some areas, bringing repeated rounds of
storms as storms will have a tendency to move generally parallel
to the boundary. The plentiful moisture will lead to locally heavy
downpours, and there is a Slight Risk of Excessive Rainfall (level
2/4) across portions of the Lower Mississippi Valley/Mid-South,
ArkLaTex, and southern Plains where scattered instances of flash
flooding will be possible. In addition, increasing upper-level
winds as an upper-level trough drops southward over the very
moist, buoyant airmass will lead to some more intense clusters of
thunderstorms. The Storm Prediction Center has outlined an
Enhanced Risk of severe weather (level 3/5) stretching from the
Ohio Valley southwestward through the Tennessee Valley, the Lower
Mississippi Valley, and into portions of Texas for the threat of
damaging winds, large hail (especially in Texas), and perhaps a
tornado or two. The front will make some progress south and
eastward into Saturday, bringing shower and thunderstorm chances
to the Northeast, Mid-Atlantic, Appalachians, and Southeast.
Moderate to locally heavy rainfall is expected with some
additional isolated instances of flash flooding possible.
To the West, some scattered showers and thunderstorms will be
possible along a lingering frontal boundary through the Four
Corners region Saturday before a second upper-level trough
solidifying the omega block drops southward from the northeastern
Pacific and over the West Coast by late Friday/early Saturday.
Precipitation chances will first pick up over the Pacific
Northwest Friday evening before spreading into the Great Basin and
northern Rockies Saturday. Some snow will be possible for some of
the higher mountain peaks, particularly in the Sierra Nevada.
The increasingly amplified pattern stretching west to east across
the CONUS will bring large temperatures contrasts heading into the
weekend. Forecast highs from the Ohio/Tennessee Valleys east to
the East Coast will remain above average Friday, with the greatest
anomalies focused across portions of the Mid-Atlantic. Forecast
highs generally range in the 70s across the Northeast and Ohio
Valley with 80s for the Mid-Atlantic and the Tennessee
Valley/broader Southeast. The cold front will bring cooler
temperatures to the Ohio Valley and much of the Southeast Saturday
as highs fall into the 60s and 70s. Highs along the immediate East
Coast will remain well above average and into the 70s north with
80s further south. Portions of the Great Lakes/Midwest and much of
the Plains will be well below average the next couple of days
under the eastern trough, with highs generally in the 50s and 60s
for the Great Lakes/Midwest and 60s and 70s for the
central/southern Plains outside of southern Texas. Much of the
West will be well above average Friday, especially across the
northern Great Basin/Rockies, as highs rise into the 70s and 80s
for most locations. The well above average temperatures will shift
eastward on Saturday as the second upper-level trough drops
southward along the West Coast. Highs across the northern Plains,
northern/central Rockies, and eastern portions of the Great Basin
will remain and rise into the 70s and 80s. Much cooler
temperatures will come to the West Coast under the influence of
the trough with highs dropping into the 50s and 60s.
Putnam
Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php