Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 AM EDT Wed Oct 25 2023

Valid 12Z Wed Oct 25 2023 - 12Z Fri Oct 27 2023

..Significant early season winter storm brings heavy snowfall to portions
of the Northwest, Northern Rockies, and Northern Plains...

...Widespread heavy rainfall with scattered to widespread instances of
flash flooding possible in the Southern Plains Wednesday...

...Much above average temperatures for eastern and central portions of the
country while temperatures turn frigid in the Northern Rockies and
Plains...

A significant early season winter storm has begun across portions of the
Northwest and Northern Rockies and will spread into the Northern Plains
Wednesday. An energetic, deep upper-low dropping southward across the
region will bring multiple waves of heavy snow not only to the mountains
but also to the lower elevations and Plains as heights fall and colder air
flows southward behind a cold front. Storm total snowfall of 6-12",
locally higher, is expected for eastern Montana and western North Dakota.
Totals of 1-2 feet will be possible in the higher terrain of the Cascades
and Northern Rockies. Some snow is expected to mix in with rain for the
interior Northwest and northern Great Basin, but accumulations here should
be limited. A few inches of accumulating snow are also expected further
eastward into eastern North Dakota and northwestern Minnesota, lingering
into Friday just beyond the current forecast period. Heavy snow rates of
1"/hr in some of the snow bands and snow-covered, icy roads will make
travel difficult.

To the east, showers and thunderstorms will continue within a broad warm
sector from the Plains into the Midwest, with two locally enhanced areas
of heavy rainfall expected. Upper-level energy that has been slowly
progressing through northern Mexico will finally begin to eject
northeastward over the Southern Plains on Wednesday, helping to enhance
lift and lead to widespread thunderstorm development/coverage. Anomalously
moist air well established across the region will help storms produce very
heavy downpours, with mean southwesterly flow and continual storm
development leading to repeated rounds of rain, raising the potential for
totals of several inches. A Moderate Risk of Excessive Rainfall (level
3/4) has been introduced from the Texas Big Bend region northeastward
through North Texas into south-central Oklahoma as this threat for very
heavy rainfall, overlapping regions that have already seen rainfall over
the past couple of days, may lead to scattered to widespread instances of
flash flooding. Further to the northeast, a second local maxima of heavy
rainfall continues for portions of the Upper Mississippi Valley/Great
Lakes where moist southerly flow meets a quasi-stationary frontal boundary
draped across the region. Energetic upper flow parallel to the boundary
will help to produce repeated rounds of heavy rainfall. A Marginal Risk of
Excessive Rainfall (level 1/4) is in place for Wednesday in the Upper
Mississippi Valley, with a Slight Risk (level 2/4) on Thursday extending
into the Upper Great Lakes where this rainfall will overlap wetter
antecedent conditions.

In addition to the heavy snow, a winter blast will follow the cold front
pushing southward across the Northern Rockies and Plains, with these
frigid temperatures expanding southeastward through the end of the week.
Highs on Wednesday will be in the 20s for most of Montana, with some
morning lows Thursday dropping into the single digits. Highs will fall
into the 20s and 30s for portions of Wyoming and the western
Dakotas/Nebraska by Thursday. Blustery winds may lead to some subzero wind
chills. Highs will also be below average across the Northwest but no where
near as frigid, with 40s and low 50s forecast. These cooler temperatures
will also expand southward following the cold front into northern
California and the Great Basin by Thursday. The Southwest will remain near
average, with highs in the 70s and 80s. In contrast, temperatures will be
running much above average the next couple of days for most of the central
and eastern U.S. ahead of the cold front as an upper-level ridge builds to
the east. Forecast highs will generally range from the 60s to low 70s for
the Great Lakes and Interior Northeast; the 70s from the Central Plains
eastward through the Middle Mississippi Valley, Ohio Valley, and into the
Northeast; and the 80s for the Southern Plains and Southeast. 

Putnam


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