Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
300 PM EST Thu Feb 23 2023

Valid 00Z Fri Feb 24 2023 - 00Z Sun Feb 26 2023

...Snow and ice to gradually taper down over the Northeast on Friday...

...An unusually cold and slow-moving winter storm to bring very heavy
snowfall and strong winds to California and adjacent areas of the West
through Friday and into the start of the weekend...

...Heavy rainfall and flooding will be possible for parts of southern
California...

...Record-breaking warmth over the East to come to an end, but
temperatures to remain above normal this weekend...

The prolonged winter storm that yielded significant impacts from the West
through the Midwest and into the Great Lakes region with heavy snow,
strong winds and ice over the last few days is gradually winding down.
However, the tail end of this storm will be crossing the Northeast
overnight bringing with it one more round of snow and some freezing rain.
As much as 4 to 8 inches of additional snow is expected across especially
northern New England going through Friday evening before the system
finally begins to exit offshore. Gusty winds may create areas of blowing
and drifting snow. In the wake of this winter storm frigid temperatures
currently over the upper Midwest will move east across the Great Lakes and
into the Northeast by the start of the weekend. The cold temperatures will
not be quite as extreme as they have been in recent days, but expect
temperatures to drop well below normal, with overnight lows locally
dropping below zero. Milder air should begin to arrive by later in the
weekend with temperatures eventually warming to near or above normal.

Meanwhile, very active winter weather will continue across areas of the
West through the end of the week and the start of the weekend as a very
cold and slow-moving storm system drops south down along the West Coast
and gradually pivots into the Southwest this weekend. For tonight and
Friday, California in particular will be the dominant focus for the
greatest winter storm impacts. Multiple rounds of heavy snowfall coupled
with strong winds will lead to blizzard conditions over some of the higher
terrain and mountain passes, including the central and southern Sierra
Nevada, and the high terrain of Transverse Range in southern California.
This may lead to downed trees and power lines which will contribute to
power outage concerns. This storm system will be unusually cold, and snow
levels will be very low. In fact, areas very close to the Pacific Coast
and also into the interior valleys that are not accustomed to seeing snow,
may see some accumulating snowfall. Snowfall should accumulate to as much
as 3 to 5 feet for the Sierra Nevada, with locally heavier totals for the
highest peaks. Lesser amounts of 1 to 2 feet are forecast elsewhere across
portions of the Great Basin and into the Four Corners region as the storm
begins to pivot into the Southwest by this weekend.

While heavy snow and strong winds will tend to dominate the headlines for
this winter storm, one other major concern will be the threat of heavy
rainfall and flooding for some of the immediate coastal ranges of southern
California below the snow level. Several inches of rain are expected
locally, and this will drive locally significant runoff concerns. In fact,
the Weather Prediction Center has depicted a Moderate Risk of excessive
rainfall for portions of the Transverse Range.

Elsewhere, the record-warm temperatures seen across much of the East will
be tempered by the passage of a cold front this evening through Friday,
but many areas of the Mid-South, Southeast, and Gulf Coast will continue
to see above normal temperatures heading through the weekend.

Orrison

Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php