Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
344 PM EDT Sat Oct 09 2021

Valid 00Z Sun Oct 10 2021 - 00Z Tue Oct 12 2021

...A pair of storm systems tracking through the Nation's Heartland to
generate severe weather and excessive rainfall from the Southern and
Northern Plains to the Great Lakes...

...September-like heat to continue across much of the eastern half of the
Lower 48; potential for tropical development off the Carolina Coast
tonight and into Sunday...

...Amplifying upper trough to inject some of the coldest air of the season
into the West early next week; heavy mountain snow and much below normal
temperatures likely...

An increasingly amplified weather pattern will cause considerably cooler
temperatures in the West to rub shoulders with a more late summer-like
air-mass in the East, concocting a myriad of hazardous weather conditions
into next week. To start, a storm system in the Northern Plains will be
responsible for producing severe weather from the Dakotas to the northern
Great Lakes this evening. There is also a flash flood threat in parts of
the Dakotas and northwest Minnesota, leading to the issuance of a Slight
Risk for Excessive Rainfall today. A trailing frontal boundary extending
into the southern High Plains and corresponding upper level disturbance
aloft is set to produce spotty showers over parts of the region, as well
as mountain snow in the southern Rockies. By Sunday, this upper level
disturbance will strengthen over New Mexico allowing for a a threat for
severe weather to transpire over the Southern Plains. The Storm Prediction
Center has an Enhanced Risk for severe storms in central Oklahoma and far
northern Texas. The storm system further strengthens and tracks northeast
into the Midwest on Monday, bringing along with it the threat for severe
storms from the mid-Mississippi Valley to the Great Lakes.

The abnormally warm temperatures throughout much of the East, making it
feel as if the calendar is still closer to Labor Day rather than Halloween
for some, is attributed to a strong upper level ridge positioned over
eastern Canada and a bridging of the ridge axis over the South Central
U.S.. High temperatures this afternoon soared into the 90s in the South
Central U.S. with some locations making a run at the century mark. In
addition, Red Flag Warnings were issued across parts of the central to
southern High Plains due to favorable fire weather conditions this
afternoon. Numerous daily record warm minimum temperatures are anticipated
tomorrow in the Midwest but considerably warmer than normal minimum temps
will also be observed along the East Coast. High temps are forecast to
reach the 80s in the lower Great Lakes on Sunday with 80s also on tap
again on Monday in the Great Lakes and parts of the Mid-Atlantic. Much of
the South will not only see highs in the 80s (some 90s mixed in) both
Sunday and Monday, but dew points ranging between 60-70 degrees will make
for slightly higher heat indices. Lastly, eyes are on the Carolina coast
as the National Hurricane Center has designated an area of low pressure
with a 50% chance of development over the next two days. No matter its
classification, expect rainy and gusty conditions along the North Carolina
Outer Banks this evening and into Sunday.

Conversely, a frontal system tracking into the Pacific Northwest this
evening is associated with a deepening upper trough diving south through
British Columbia. This storm's cold front is set to usher in the coldest
air of the season to date in the western third of the country by Monday.
In wake for the cold frontal passage, high winds will ensue from the Great
Valley of California to the Desert Southwest. High Wind Watches have been
issued in advance due to the heightened risk for hazardous wind gusts.
Freeze Watches have also been posted for the western Nevada Basin. As the
front crosses the northern Rockies, plummeting snow levels give way to
periods of snow breaking out Sunday evening. By Monday, as the trough
continues to strengthen, so will the evolving frontal system in the West,
leading to heavy snow for the many mountain ranges in the Intermountain
West. Latest snowfall forecast indicate anywhere from 6 to 12 inches
(locally higher amounts possible) may accumulate in the northern Rockies,
including ranges such as the Absarokas, Teton, Wind River, and Big Horns.
This upper trough becomes quite intense by early Tuesday, setting the
stage for copious amounts of snow in parts of the Rockies and a potential
severe weather outbreak in the southern and central Great Plains.

Mullinax


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