Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 PM EDT Mon Oct 23 2023

Valid 00Z Tue Oct 24 2023 - 00Z Thu Oct 26 2023

...A significant early season winter storm will bring heavy snowfall later
Tuesday through Wednesday across portions of the Northwest, Northern
Rockies, and Northern Plains...

...Heavy rainfall and some areas of flash flooding will be possible across
portions of the Southern Plains through Wednesday...

...Much colder than normal temperatures will arrive by midweek across the
Northwest U.S. as much warmer than normal temperatures begin to overspread
much of the South and the Eastern U.S...

A considerably more active weather pattern will be ensuing across the
western half of the country this week as a series of storm systems
advancing through the Western U.S. gradually push east out across the
Plains and the toward the Midwest. In fact, multiple areas of low pressure
will eject across areas of the Pacific Northwest and through the
Intermountain West on Tuesday which will combine with the southward
advance of a much colder polar airmass dropping down from western Canada
to drive a significant early season winter storm.

Heavy snowfall will begin by later Tuesday across the higher terrain from
the Cascades east into the northern Rockies, and the moisture and energy
associated with the ejecting waves of low pressure will allow heavy
snowfall to then overspread portions of the northern High Plains and as
far east as central and western North Dakota by later on Wednesday.
Snowfall totals of as much as 12 to 18 inches are expected across areas of
Montana, with some of the higher elevations of the northern Rockies
expecting to see totals in excess of 2 feet. In addition to the snow, the
southward advance of polar air across the Northwest U.S. will bring
locally strong, gusty winds and temperatures considerably below normal.
This will be the coldest air of the season so far for these areas as some
locations over Montana see temperatures drop down into the single digits
and teens.

A strong front will gradually become draped from the central Plains
northeast through the Upper Midwest and the Great Lakes region which will
separate the aforementioned cold air with what will be a considerably
warmer and more moist airmass pooling over the South, and eventually large
area of the Eastern U.S. Out ahead of the front, the remnant energy and
moisture associated with former tropical cyclone Norma will be ejecting
east across Mexico and well northeast out across the southern Plains going
through Tuesday and Wednesday, with some of this also advancing into the
Upper Midwest.

This will drive a heavy rainfall threat for especially areas of Texas and
Oklahoma where locally a few inches of rain can be expected. Some areas of
flash flooding will be possible, and the Weather Prediction Center has
highlighted a Slight Risk of excessive rainfall for these areas through
Wednesday as a combination of Norma's remnants and the advance of multiple
fronts across the Plains work in tandem to drive multiple rounds of heavy
rainfall. Some of this heavy rainfall will gradually get into the Upper
Midwest as well as waves of low pressure lift northeast across the region.

The warm-sector airmass across much of the South and gradually areas of
the Eastern U.S. will be characterized by much above normal temperatures
with locations likely seeing near record-high temperatures. Many areas
should see temperatures rise into the 70s and 80s, with some areas of the
Rio Grande Valley seeing high temperatures pushing into the 90s by the
middle of the week.

Orrison

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