Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
300 PM EST Mon Dec 17 2018
Valid 00Z Tue Dec 18 2018 - 00Z Thu Dec 20 2018
...Active pattern continues for the West, with rain in lower elevations
and heavy snow in higher elevations...
...Snow for the Interior Northeast through Monday night...
...Rainy for the Southern Plains by Tuesday evening, moving into the Lower
Mississippi Valley and Southeast by Wednesday...
Strong onshore flow will continue bringing moisture to the Pacific
Northwest and the Northern Great Basin through the first half of the
workweek, and a frontal system moving through is expected to enhance
precipitation chances. Along the coast and in lower elevations, the
precipitation will remain rain, and a Marginal Risk of excessive rainfall
is in place now through Wednesday morning, with an embedded Slight Risk in
far southern Oregon and far northern California for Tuesday. In higher
elevations of the Washington Cascades, snowfall will be measured in
multiple feet rather than inches, with colder temperatures and ascending
air over mountains. Through Wednesday, the Northern Rockies could see 12
to 18 inches of snow. Strong winds are also forecast with this event, with
High Wind Warnings and Watches and Wind Advisories in place.
A low pressure system off the New England coast is forecast to keep
tracking northward overnight Monday into the Canadian maritimes. In the
meantime, wraparound snowfall is expected for the Interior Northeast
through Monday night, with 2 to 4 additional inches possible in eastern
An upper-level low is forecast to develop and move through the Four
Corners region on Monday night, tracking eastward into the Plains on
Tuesday. Showers and thunderstorms are expected to form ahead of the
upper-level low by Tuesday evening in the Southern Plains, and will move
into the Lower Mississippi Valley and Southeast on Wednesday. Rainfall is
forecast to be generally under an inch in these areas, with locally higher
amounts above an inch.
Temperature-wise, a cold front moving through will lead to temperatures 5
to 15 degrees below average in the Northeast on Tuesday. Florida could see
slightly below average temperatures as well. The rest of the U.S. will
generally be warmer than normal; the Northern Plains in particular is
expecting high temperatures 15 to 25 degrees above average.
Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php