Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
349 AM EDT Sat Apr 08 2023

Valid 12Z Sat Apr 08 2023 - 12Z Tue Apr 11 2023

...Pacific Northwest...
Days 1-3...

Zonal mid-level flow into the Pacific Northwest today will
gradually back to be more SWly Monday as a sharpening shortwave
dives southward from the Gulf of Alaska. Increasingly confluent
flow within this wind shift will drive an AR into WA state and
British Columbia, with the peak IVT reaching above 5000 kg/m-s by
Sunday. This backing low and mid-level flow will drive pronounced
WAA into the region as the most intense height falls and PVA shift
north of the US/Canada border, pushing snow levels as high as
6000-7000 ft late Sunday, with only modest reduction into Monday
to around 4000-5000 ft. With the most intense precipitation and
lowest snow levels expected to remain across British Columbia,
impactful snow is expected to feature a minimal footprint through
Sunday night, reflected by WPC Day 1.5 probabilities for 6"+ are
above 50% in the higher terrain of the Olympics and WA Cascades
each day.

The next low drops from the Gulf of Alaska is Monday and directs
an atmospheric river through the Pacific Northwest Sunday

 3-day snow totals may exceed 2-3 feet in the highest terrain of
the Olympics and Cascades.



...Upper Midwest...
Day 1...

A frontogenetically forced band of locally moderate snow over
north-central WI will continue moving east this morning, crossing
the northern L.P. of MI by around noon. ion probabilities is
narrow. Snow totals after 12Z in the northern sections of the L.P.
of MI are likely to top an inch at higher than lake level
elevations.


The probability for icing over 0.1" is less than 5% Days 1-3.


Jackson