Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
303 AM EST Thu Nov 11 2021

Valid 12Z Thu Nov 11 2021 - 12Z Sat Nov 13 2021

...There is a Slight Risk of excessive rainfall over parts of the Pacific
Northwest through Friday morning...

...Snow for the Upper Midwest...

...Temperatures will be above average over parts of the
Northeast/Mid-Atlantic...

Moisture will stream into the Pacific Northwest ahead of the next front
that will come onshore by Friday afternoon.  The moisture will produce
rain, heavy at times, over parts of the Northwest from Thursday into
Saturday morning.  Consequently, the WPC has issued a Slight Risk of
excessive rainfall through Friday morning.  The associated heavy rain will
create mainly localized areas of flash flooding, with urban areas, roads,
and small streams the most vulnerable. The excessive rainfall threat
decreases slightly on Friday, as the WPC has a Marginal Risk of excessive
rainfall over parts of the Pacific Northwest and the Northern
Intermountain Region on Friday into Saturday morning.

Meanwhile, a deep low over the Upper Midwest will produce rain and snow
over parts of the Upper Midwest. On Thursday, the snow will march
southward over the Northern Plains, the Upper Mississippi Valley, and
parts of the Middle Mississippi Valley by Friday afternoon. Overnight
Friday, light snow will move into parts of the Ohio Valley and the Great
Lakes, as the snow over the Upper Mississippi Valley tapers off. 

In the meantime, rain will develop along and ahead of the associated front
from the Upper Great Lakes to the Middle Mississippi Valley.  By Friday,
the rain will move eastward into the Great Lakes and Ohio Valley.  In
addition, the temperatures will be above average over parts of the
Northeast/Mid-Atlantic ahead of the front.  Furthermore, as the system
moves eastward, moisture from the Atlantic will stream into parts of the
Northeast on Friday.  The rain, heavy at times, will move into the
Northeast/Mid-Atlantic and the Carolinas.  Hence, the WPC has issued a
Marginal Risk of excessive rainfall over parts of the Northeast on Friday
into Saturday morning.  The associated heavy rain will create localized
areas of flash flooding, affecting areas that experience rapid runoff with
heavy rain. 

Furthermore, on Thursday, showers and thunderstorms will develop over
parts of the Lower Mississippi and Tennessee Valleys into the Western Gulf
Coast. By Thursday evening the showers and thunderstorms move into parts
of the Central Gulf Coast, as rain fills in over the Tennessee valley and
the Southeast. The rain starts to taper off on Friday morning over the
Southeast.

Ziegenfelder


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