Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
407 AM EDT Mon Oct 25 2021
Valid 12Z Mon Oct 25 2021 - 12Z Wed Oct 27 2021
...There is a Slight Risk of excessive rainfall over the Sierra Nevada
Mountains and coastal New England...
...Heavy snow for the Sierra Nevada Mountains...
...There is an Enhanced Risk of severe thunderstorms over parts of the
Central/Southern Plains on Tuesday; there's a Slight Risk of severe
thunderstorms for much of the Mid-Atlantic today...
Heavy rain and snow are forecast to continue impacting the West coast as a
powerful low pressure system churns its way through the West over the next
day or so. Heavy rain is still likely across lowland parts of the Sierra
Mountains and Pacific Northwest, as this atmospheric river event begins to
wind down. Between 1-3 inches of rainfall is possible over the central
Californian portion of the Sierra, with isolated higher amounts possible
here. A Slight Risk of Flash Flooding is in effect due to elevated terrain
as well as already saturated soils from the recent precipitation. Heavy
snow is also expected over the higher elevations of the central California
Sierra, where between 1-2 feet with isolated higher amounts, are possible
today. Many of the highest Rocky Mountain peaks will pick up several
inches of snow today as the cold front moves through the region. A cool
Pacific air mass will settle over the West over the next couple of days as
high pressure builds across the region.
Meanwhile, rain and scattered thunderstorms are forecast to spread into
the Mid-Atlantic and Northeast out ahead of a low pressure system
currently gliding across the Midwest. A Slight Risk of severe
thunderstorms was issued by the Storm Prediction Center over much of the
Mid-Atlantic and parts of the Ohio Valley for today due to increased
instability across the region. Damaging wind gusts appear to be the main
concern associated with this severe weather threat, but a brief tornado or
two are also possible in eastern Ohio/western West Virginia. Rainfall will
focus the most over southern/coastal New England over the next two days. A
Slight Risk for Excessive Rainfall leading to Flash Flooding is in effect
for this area, particularly on Tuesday when this rain event will have
entered its second day. Rainfall totals are forecast to be between 1-3
inches, with higher amounts possible along coastal Massachusetts.
Temperatures will rise into the 70s and 80s across much of the East Coast
before dropping behind a cold frontal passage on Tuesday.
Temperatures are expected to climb to above average highs today along the
foothills of the Rockies as the deep upper trough associated with the
potent Pacific system pulls warm air as far north as Montana. As the
Pacific system emerges from the Rockies on Tuesday, it will bring with it
an influx of moisture and instability to the Southern/Central Plains. This
will lead to scattered thunderstorms and the threat of severe weather. An
Enhanced Risk of Severe Thunderstorms is in effect for a swath stretching
from northern Texas to southern Kansas where a dry line may setup. An MCS
may develop toward Tuesday evening in this area while this environment may
also be conducive to supercells and large hail greater than 2 inches.
Graphics are available at