Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
228 PM EST Sun Nov 05 2023

Valid 00Z Mon Nov 06 2023 - 00Z Thu Nov 09 2023

...Northwest, California through the Northern Rockies...
Days 1-2...
Unsettled weather will continue to spread from west to east as
another upper level shortwave and its associated frontal band move
slowly across the region tonight and Monday.  While moisture-rich,
southwesterly flow is forecast to fuel widespread precipitation,
including areas of heavy rain along and west of the Cascades, high
snow levels are expected to limit any winter weather impacts for
most areas through late tomorrow.  However, an inch or two of snow
cannot be ruled out at many of the Cascade, Sierra, and northern
Rocky passes.

Winter weather impacts are forecast to become more widespread
Monday night into Tuesday as energy behind the leading wave, helps
to carve out a deeper trough and lower snow levels across the
region.  WPC probabilities indicate a moderate (40 percent or
greater) to high (70 percent or greater) chance for accumulations
of 2 inches or more for most of the Cascade, Sierra, and northern
Rocky passes, with a moderate chance of 4 inches for some,
especially the Cascade and Sierra passes.

Snow will diminish was west to east Tuesday night into Wednesday
as the upper trough moves progressively east and is replaced by
shortwave ridge that will center along the coast late Wednesday.

Northern Plains and Upper Midwest...
Days 1 and 3...
Warm advection precipitation will spread out ahead of the leading
wave as it moves east of the northern Rockies.  Thermal profiles
suggest mixed precipitation for portions of North Dakota on
Tuesday and then for parts of northern Minnesota, northern
Wisconsin, and the U.P. of Michigan on Wednesday.  While
widespread snow or ice accumulations are not expected, light icing
is possible, with WPC probabilities indicating at least a slight
(10 percent or greater) chance for amounts of 0.01 inch or more.

Pereira