Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
441 AM EDT Thu Apr 09 2020

Valid 12Z Thu Apr 09 2020 - 12Z Sun Apr 12 2020


...Northeast...
Day 1 (ending 12Z Friday)...
Phasing energy will support a developing upper low over the
Northeast, with a powerful surface cyclone quickly developing and
tracking north along the northern New England coast late Thursday
into Friday.  This system is expected to produce heavy, wet snow
over portions of northern New England.  Heaviest amounts are
expected to center over the mountains of northern New Hampshire
and across central and northern Maine, where WPC PWPF is
indicating that accumulations of 12-inches or more are likely.

...Southern California...
Day 1 (ending 12Z Friday)....
A slow-moving low over Southern California is expected produce
additional heavy snows over the higher elevations of the
Transverse and northern Peninsular ranges, with WPC PWPF
indicating that additional amounts of a 12-inches or more are
likely for portions of the San Bernadino, San Gabriel and northern
San Jacinto mountains.

...Northern Rockies/High Plains...
Days 2 and 3 (ending 12 Sunday)...
A strong cold front associated with a shortwave trough digging
south from western Canada is expected to produce areas of heavy
snow moving south and east along the northern Rockies and adjacent
High Plains Saturday into Sunday.  Areas impacted are expected to
include the western and central Montana ranges, as well as the
Absaroka Range and Bighorn Mountains in Wyoming and the Black
Hills.  WPC PWPF indicates that local amounts of a foot or more
are likely over the two day period.

For Days 1-3, the probability of significant icing (0.25-inch or
greater) is less than 10 percent.

Pereira