Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
322 PM EST Wed Nov 10 2021

Valid 00Z Thu Nov 11 2021 - 00Z Sat Nov 13 2021

...Persistent heavy rain and higher elevation snow continue with series of
Pacific storms impacting the Northwest...

...Storm system bringing rain, thunderstorms, and a wintry mix to the
eastern half of the country...

A series of Pacific storm systems will impact the Northwest through the
forecast period. An atmospheric river will help encourage waves of high
moisture into the region leading to widespread heavy rain. A Marginal Risk
of Excessive Rainfall remains in place for northwestern Oregon through
Thursday morning with rain rates as high as 0.75 inches possible. A second
surge of moisture will impact the area during the day Thursday with a
Slight Risk of Excessive Rainfall issued for the Cascades of Washington
west to the coast and south into far northwestern Oregon. Rainfall totals
of 2-4 + inches are possible, especially where orographic enhancements
along the mountains will promote heavier rainfall. A Marginal Risk remains
in place for the most of the same areas on Friday as the heavy rain
chances continue, with another 1-2 + inches forecast. In all cases, the
greatest concern for flooding will be along any burn scars. Snow chances
should remain isolated to higher mountain peaks as generally warmer air in
place will keep snow levels high. Some scattered rain and snow showers are
also likely for the Northern and Central Rockies ahead of each system
through the period.

An active weather pattern is currently in place across the central U.S. As
an upper-level trough exists the Rockies and moves over the Plains, a
surface low pressure system over the Central Plains will strengthen and
continue to the northeast through the forecast period, bringing widespread
rain, thunderstorms, and a wintry mix to most of the eastern half of the
country. A cold front will move across the Midwest and Southern Plains
Wednesday evening east to the Great Lakes, Ohio Valley, and Southeast on
Thursday, finally reaching the East Coast on Friday. Widespread rain and
thunderstorms are likely ahead of the cold front. Severe weather is
possible through this evening for portions of northeastern Kansas,
central/eastern Oklahoma, and northern Texas. The Storm Prediction Center
has issued a Slight Risk of severe weather for the threat of large hail,
gusty winds, and an isolated tornado or two. Otherwise, any thunderstorms
are not expected to reach severe levels through the rest of the period. As
colder air is funneled southward on the back side of the system, a wintry
mix of rain and snow will overspread the Northern Plains Thursday and
Upper Midwest Friday. The chance of accumulating snow has been increasing
in more recent model guidance and totals of 2-4 inches, locally higher,
appear possible.

A shortwave rounding the the upper-level trough will help encourage a
second surge of colder, Canadian air southward through the Midwest and
Plains Thursday night into Friday. Many areas across the Northern Plains,
Mid- to Upper Missouri Valley, and Upper Midwest will see highs in the 30s
on Friday, while the Ohio Valley to Central Plains will be in the 40s and
50s. Meanwhile, temperatures will be warm and above normal ahead of the
cold front, with 50s for New England warming into to the low 70s for the
southern Mid-Atlantic, Southeast, and Gulf Coast.

Generally tranquil and dry conditions are expected across the Southwest,
southern Great Basin, and California. Above normal high temperatures are
forecast with 60s for the Great Basin and 70s and 80s for the Southwest
and California. Some highs in the low 90s are possible for desert portions
of the Southwest on Friday.

Putnam


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