Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
359 AM EDT Sat Oct 21 2023

Valid 12Z Sat Oct 21 2023 - 12Z Mon Oct 23 2023

...Showers and storms expected from the Great Lakes into the Northeast
Saturday, with some locally heavy rainfall possible in New England...

...Much above average temperatures continue this weekend for portions of
the central and western U.S...

...Increasing precipitation chances from the Pacific Northwest to the
Northern Rockies Sunday...

Showers and thunderstorms will continue from the Great Lakes to the
Northeast Saturday under the influence of an upper-level trough and
associated low pressure/frontal system at the surface. The low is expected
to rapidly deepen as it tracks along the coast of New England through the
day, helping to enhance moist onshore flow and increase the chance for
some locally heavier rainfall. A Marginal Risk of Excessive Rainfall
(level 1/4) remains in place for much of New England for an isolated risk
of flash flooding. Meanwhile, broad northwesterly flow over the Great
Lakes will also lead to some lighter showers in favorable lake-effect
regions. The rain chances should diminish from west to east overnight
Saturday into the day Sunday as the system moves northeast into Canada,
lingering longest for New England. Conditions will be a bit cool for the
region following a cold front passage, with highs in the 40s and 50s from
the Great Lakes into the Upper Ohio Valley and Interior Northeast and 60s
closer to the coast.

Highs will be running above average by as much as 20 degrees this weekend
for a large portion of the central and western U.S. as an upper-level
ridge remains in place. Forecast highs Saturday are in the 60s and 70s for
the interior Pacific Northwest, the Great Basin, Rockies, and Northern and
Central Plains. It will feel more like Summer further south, with highs in
the 80s and 90s for the Lower Mississippi Valley and Southern Plains with
some low 100s in the Desert Southwest. Some record-tying/breaking highs
are possible. Temperatures will generally drop a few degrees Sunday as the
ridge weakens a bit, but still remain well above average. Highs will be
closer to average for the Southeast and Florida with 70s and some low 80s
expected.

An upper-level trough will approach the West Coast by Sunday morning,
helping to advance a stalled frontal boundary southeastward, bringing
increasing precipitation chances and cooler temperatures from northern
California and the Pacific Northwest into the northern Great Basin and
Rockies. Higher mountain elevations may start to see snow mix in by early
Monday morning. After the noted much above average temperatures Saturday,
highs will drop into the 60s for most locations, with even some upper 50s
possible for northern California.

Putnam


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