FOUS11 KWBC 090846
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
446 AM EDT Sun Mar 9 2025

Valid 12Z Sun Mar 09 2025 - 12Z Wed Mar 12 2025


...Upstate New York and Northern New England...
Day 1...

A clipper currently crossing into Ontario will track across
northern New England late tonight. Some Great Lake moisture will be
present in the otherwise continental airmass. Upslope flow onto the
Adirondacks and northern Greens/Whites will lead to snow tonight
with potential for 0.5"/hr snow rates per the 00Z HREF. Given a
weaker clipper will cross this morning, snow from both has Day 1
PWPF for >6" of 30-70% in the highest terrain.


...Washington State to Northwest Montana...
Day 1...

Northern stream shortwave trough crosses WA this evening and
northern MT late tonight. The transitive nature of the trough
combined with modest available moisture will limit total
precipitation, but heavy snow accumulations are still likely above
4000-5000 ft. Day 1 WPC snow probabilities are above 70% for 6+
inches in the higher northern WA Cascades, generally above pass
level, and 30-60% in the higher ridges around Glacier NP. Precip
from this trough quickly cuts off Monday morning across the
Northwest.


...Northwest and California...
Day 3...

A much stronger trough amplifies as it digs off the West Coast
Tuesday night. Enhanced moisture and height falls from the
approaching trough allow moderate precip to cross the PacNW coast
Tuesday night. Snow levels at onset will be near 3500ft in WA,
4500ft in OR, and 5000ft in CA, dropping thereafter through
Wednesday ahead of the trough axis. Particularly heavy snow is
expected in California in noted by Key Messages found on the wpc
website. Further information can also be found in the medium range
discussion (PMDEPD) and from local WFO products.

The probability of significant icing is less than 10 percent.

Jackson

$$
--- SBBSecho 3.20-Linux
 * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)