Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
309 AM EST Mon Mar 04 2024

Valid 12Z Mon Mar 04 2024 - 12Z Thu Mar 07 2024

...West Coast & Northern/Central Rockies...
Days 1-3...

Broad troughing over the Northwestern corner of the CONUS will
continue to weaken and lift northward over the next couple of days
as another much weaker Pacific system approaches CA late Wednesday
into Thursday. Upper jet, focused along the OR/CA border into the
central Rockies, will weaken and lift northeastward into Tuesday,
but with a modest influx of moisture into the region. The focus
will be over the OR Cascades into northwestern and far northern CA
eastward to the central ID ranges D1 then shifting eastward from
ID into the western WY ranges from Yellowstone southward D2. Low
snow levels around 1000-2000ft early D1 will continue to rise over
the next two days, leveling off around 2000ft over central OR but
over 4000ft into NorCal. Two day snowfall probabilities for at
least 12 inches of snow are high (>70%) over the Klamath Mountains
and Shasta/Siskiyous into the Oregon Cascades eastward across the
central ID ranges and into western WY, generally above 5000ft to
7000ft from west to east. By D3, coverage of snow will be much
less over the West in general, with lingering light snow over the
same areas into the CO Rockies.


...Northern Plains...
Day 3...

Weak shortwave over southern Canada will move eastward just across
the MT/ND border late Wednesday into early Thursday, with a
surface boundary and forming area of low pressure lifting across
the Red River Valley of the North, spreading light snow across the
region. Models vary quite widely on the amount of QPF (nearly all
snow) -- the GFS/NAM wettest, ECMWF driest, and CMCreg in the
middle. Consensus/bias-corrected blends suggest a more modest
approach which would yield a couple of inches or so of snow,
focused near the ND/MN/Canadian intersection. WPC probabilities
for at least 4 inches of snow are low at this time -- about
10-20%.


Fracasso