Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
326 PM EST Fri Dec 06 2013
Valid 00Z Sat Dec 07 2013 - 00Z Mon Dec 09 2013
...A band of snow/sleet/freezing rain is expected from parts of the Lower
Mississippi Valley to the Northeast...
...Temperatures will be 10 to 30 degrees below average from the Plains to
parts of the Mississippi Valley...
...Rare snow for coastal Pacific Northwest...
A strong cold front extending from the Mid Atlantic coast to the Central
Gulf Coast will slowly push southeastward over the next two days before
returning as a warm front at the end of the period. A strong surface
temperature gradient, as much as 40 degrees, is accompanied by a strong
upper level jet streak north and west of the front. Strong vertical
velocities in vicinity of the jet are responsible for the moderate to
heavy precipitation falling behind the front. A band of heavy snowfall
will set up across portions of the Mid Mississippi Valley and Ohio Valley
this afternoon with up to 10 inches of snow possible. A shallow layer of
cold air in place across the Tennessee and Ohio Valleys is being overrun
by milder air aloft leading to a prolonged period of freezing rain in the
region. Precipitation should end as light snow as colder air filters in
aloft. The precipitation shield is expected to consolidate along the cold
side of the boundary as the upper-level jet max races off to the northeast
By tomorrow morning, strong westerly flow over the Great Lakes will lead
to the formation of snow bands downwind. The cold front in the east will
push slowly southward before settling along the southeast coast late
tomorrow. Rain showers will remain focus in vicinity of the front through
the day. The front will begin returning as a warm front by Sunday morning
with warm advection precipitation breaking out from the Tennessee Valley
to the Southern Mid Atlantic. With cold air damming setting up in lee of
the Appalachians, precipitation will begin as a wintry mix or snow across
portions of central and southern Virgina and the higher terrain of the
In the west, a surface low pushing southward along the west coast will
bring a reinforcing shot of cold air to the Pacific Northwest and later
into southern California. Accompanied with the front will be a round of
snow from southern Washington southward to Central California tonight. By
tomorrow morning, snowfall is expected to overspread much of the
Intermountain West with upslope flow locally enhancing snowfall totals.
This surface low will eventually push out into the southern Plains toward
the end of the period.
In wake of the cold front pushing through the east, very cold temperatures
are taking hold of much of the Nation. Temperatures will be 10 to 30
degrees below normal from the West Coast to the Mid Mississippi Valley.
Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php