Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
216 PM EST Mon Jan 18 2021

Valid 00Z Tue Jan 19 2021 - 00Z Thu Jan 21 2021

...Strong, damaging winds and dry weather will foster an increasing fire
weather threat for large portions of California over the next few days...

...Lake effect snow showers and squalls will bring locally heavy
accumulations downwind of the Great Lakes...

...Unsettled weather expected over the Four Corners region with locally
heavy snow expected for the Southern Rockies...

The combination of a developing area of low pressure off the southern
California coast and strengthening high pressure from the Rockies into the
Great Basin will drive increasingly strong and locally damaging winds
across much of California over the next few days. High wind warnings and
advisories are in effect already across much of the state of California,
and portions of the higher terrain including the Sierra-Nevada may see
wind gusts as high as 80 mph. This will likely result in downed trees and
power lines. The strong winds coupled with low relative humidities and the
ongoing drought situation will significantly increase the threat of fires
to large portions of California and especially the southern part of the
state where an enhanced to critical fire threat has been identified by the
Storm Prediction Center. The aforementioned concern for downed power lines
may be a trigger for some of these fires.

Meanwhile, the above mentioned low pressure center offshore of southern
California coast may be able to gradually produce some light to moderate
rain for areas a bit farther down to the south and east including the
deserts of southern California and southern Arizona by the middle of the
week. While the heaviest rainfall is expected to be situated south of the
border across northwest Mexico, any rain will be beneficial across the
Southwest as this entire region remains in a long-term drought.

More significant precipitation totals are expected farther to the east
over the southern Rockies in the wake of a cold front pressing south
across the Intermountain Region and the southern Plains. Heavy snows are
likely across the San Juan mountains of southwest Colorado and also the
Sangre De Cristo range from south-central Colorado down into northern New
Mexico. Going through the middle of the week, some areas are expected to
see as much as 12 to 18 inches of new snowfall. The aforementioned front
crossing the southern Plains will be a focus for some light to moderate
rain farther east across areas of central and eastern Texas and the lower
Mississippi Valley as an axis of showers accompanies the front.

Farther north, cold westerly to northwesterly flow is expected across the
unfrozen Great Lakes over the next few days. This will support heavy lake
effect snow showers and squalls, with a notable focus downwind of Lake
Erie across western New York State, and downwind of Lake Ontario across
northwestern portions of New York State including areas near the Tug Hill
Plateau. Going through the middle of the week, some areas across western
New York are likely to see as much as 1 to 2 feet of new snowfall. Lake
effect snow will also be continuing downwind of Lake Superior and
impacting portions of the Upper Peninsula of Michigan where some
additional totals here of 6 to 12 inches will be possible.

Orrison

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