Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
257 AM EST Mon Nov 28 2022

Valid 12Z Mon Nov 28 2022 - 12Z Wed Nov 30 2022

...Heavy snow for parts of the Cascades/Central Rockies and the Upper
Great Lakes on Tuesday...

...Winter Storm Warnings/Winter Weather Advisories for the
Cascades/Northern Intermountain Region and Winter Storm Watch for parts of
the Upper Great Lakes...

...There is a Slight Risk of excessive rainfall and a Moderate Risk of
severe thunderstorms for parts of the Lower Mississippi and Tennessee
Valleys...

Weak onshore flow and upper-level energy will aid in producing coastal
rain and higher-elevation snow over the Pacific Northwest/Northern
California into the Northern Intermountain Region, Northern/Central
Rockies, and Great Basin. The snow has prompted Winter Storm Warnings and
Winter Weather advisories for the Cascades, Northern Intermountain Region,
and Northern/Central Rockies. Overnight Monday, the coastal rain and
higher-elevation snow weaken. However, on Tuesday, a plume of moisture
starts to move into the Northwest. By late Tuesday morning, the snow
levels will lower to near the coast over the Olympic Peninsula, with heavy
snow over the Olympic ranges. The snow will result in reduced visibility
and hazardous driving conditions. 

Meanwhile, on Monday, a front over the Northern Plains moves eastward to
the Upper Great Lakes by Tuesday evening, while a wave of low pressure
over the Central Plains deepens and moves into the Upper Great Lakes by
Wednesday morning. Overnight Monday, snow will develop over parts of the
Northern/Central Plains. On Tuesday, snow will develop over the Middle
Missouri Valley into the Upper Mississippi Valley. Heavy snow will develop
over the parts of the Upper Great Lakes, which has prompted Winter Storm
Watches over the region.

Furthermore, moisture from the Western Gulf of Mexico will stream
northward from the Western Gulf Coast/Lower Mississippi Valley into the
Upper Great Lakes on Tuesday. By Tuesday afternoon, showers and severe
thunderstorms will develop over the Lower Mississippi Valley into the
Western Ohio Valley. Therefore, the SPC has issued a Moderate Risk of
severe thunderstorms over parts of the Lower Mississippi and Tennessee
Valleys from Tuesday into Wednesday morning. The hazards associated with
these thunderstorms are frequent lightning, severe thunderstorm wind
gusts, hail, and a few tornadoes. There is a greater probability of
EF2-EF5 tornadoes and wind gusts of 65 knots or greater over parts of the
region.

Moreover, there will be heavy rain associated with these thunderstorms.
Therefore, the WPC has issued a Slight Risk of excessive rainfall over
parts of the Lower Mississippi and Tennessee Valleys from Tuesday into
Wednesday morning. The associated heavy rain will create mainly localized
areas of flash flooding, with urban areas, roads, and small streams the
most vulnerable.


Ziegenfelder


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