Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
340 PM EDT Sun Oct 22 2023

Valid 00Z Mon Oct 23 2023 - 00Z Wed Oct 25 2023

...Impactful snow to enter parts of the Northwest, Northern Rockies, and
northern High Plains on Tuesday...

...Heavy rain chances and flash flood potential increases across the
southern Plains early this week...

...Freeze Warnings and Frost Advisories issued for parts of the Ohio
Valley and central/southern Appalachians tonight...

A busy weather pattern is set to take shape across much of the central and
northwestern United States to start the workweek, with impactful winter
weather making an appearance. A cold airmass located over western Canada
sinking southward along with a deep upper-level low swinging over western
Washington by Tuesday will allow for heavy snow to develop across the
Cascades and northern Rockies, as well as into much of the northern High
Plains of Montana into midweek. Forecast snowfall amounts will become more
certain over the next 24 hours, but probabilities for at least 8 inches of
snow are high (70-90%) across the Cascades and probabilities for at least
4 inches of snow by Wednesday morning are also high across the
central/western Montana. Be sure to prepare for winter driving conditions
if residing or traveling to this part of the country, especially given
this is likely the one of the first widespread impactful snowstorms of the
season.

Meanwhile, strong southerly flow extending from the southern Plains to the
Great Lakes will include elevated atmospheric moisture content early this
week associated with Tropical Storm Norma currently located over the
southern Gulf of California. Heavy rain potential begins on Monday across
parts of Texas, including the Edwards Plateau and Rolling Plains. A
Marginal Risk (level 1/4) of Excessive Rainfall as been issued for this
region through Monday night. By Tuesday, an approaching upper-level low
over northwest Mexico will allow for a better environment conducive for
numerous showers and thunderstorms across the southern Plains. A few
inches of rain due to repeating storms capable of containing intense
rainfall rates could lead to scattered instances of flash flooding from
southeast Kansas to northwest Texas, where a Slight Risk (level 2/4) of
Excessive Rainfall has been issued for Tuesday. Rain and thunderstorm
chances will also extend northward along a frontal boundary approaching
the Upper Great Lakes/Midwest over the next few days, with isolated flash
flooding and severe storms not out of the question.

Tranquil weather conditions are expected elsewhere across the Nation.
Above average temperatures will be located over the central U.S., with
below average temperatures under high pressure along the East Coast. Early
morning temperatures on Monday could start out near the freezing mark
across the Ohio Valley and central/southern Appalachians. Thus, Freeze
Warnings and Frost Advisories have been issued.

Snell


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