Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
301 AM EST Tue Dec 10 2019

Valid 12Z Tue Dec 10 2019 - 12Z Thu Dec 12 2019

...Rain changing over to snow during the early morning on Wednesday a long
the I-95 corridor...

...Heavy lake effect snow along parts of Lake Superior Coastline...

...Wind chill advisory in effect over parts of the Upper Midwest on
Tuesday morning...

Temperatures will be 10 to 20 degrees above average over parts of the East
Coast in contrast, temperatures will be 10 to 25 degrees below average
over parts of the Upper Midwest...

A front extending from the Lower Great Lakes southwestward to the Central
Gulf Coast will move eastward off the East Coast and Gulf Coast by
Wednesday.  The boundary will produce rain from parts of the Northeast
across the Central Appalachians into parts of the Central/Western Gulf
Coast moving off the Northeast Coast by Wednesday evening and the Gulf
Coast by Wednesday afternoon.  The rain will change over to snow over
parts of the Southern Plains and the Lower Mississippi/Southwestern
Ohio/Western Tennessee Valleys by Tuesday morning.  Likewise on the back
edge of the precipitation shield, rain will change over to snow over parts
of the Northern/Central Appalachians into parts of the Lower Mississippi
Valley by Tuesday afternoon.  As the front continues to move eastward,
rain changing to snow will move into the I-95 corridor during the early
morning to late morning on Wednesday producing hazardous traveling
conditions for the morning rush hour.  The rain and snow slowly end over
the Lower Mississippi Valley and Ohio/Tennessee Valleys overnight Tuesday.
 The snow over the Northeast to the Mid-Atlantic will end by Wednesday
evening.  Furthermore, lake effect and lake enhanced snow will develop
over the Upper Great Lakes through Wednesday evening.  

Another front extending from the Middle Mississippi Valley roughly
northwestward to the Northern Rockies will remain quasi-stationary through
Thursday morning.  The boundary will aid in producing scattered snow over
parts of the Northern Rockies/Northern High Plains through Wednesday
morning. 

Meanwhile, upper-level energy will move onshore over the West Coast on
Tuesday evening and moves inland to the Plains by Thursday morning.  The
energy will aid in producing rain over parts of the Pacific
Northwest/Northern California Coast on Tuesday.  As the energy and
associated moisture will move inland producing higher elevation snow over
parts of the Northwest and Northern California overnight Tuesday.   On
Wednesday, snow develops over parts of the Northern Intermountain Region
into the Great Basin.  The snow will become more scattered  

The main feature of interest for the beginning to middle part of the week
will be a strong cold front crossing the eastern U.S. and Gulf Coast
region.  Widespread rain is expected ahead of the front Monday night and
into Tuesday with temperatures briefly above average on Tuesday for the
East Coast.  The front will herald the arrival of an arctic airmass to
much of the Great Lakes region and eventually to the Mid-Atlantic and
Northeast by midweek.  There will likely be enough moisture and upper
level forcing in place behind the front to support a transition to snow
from the central Appalachians to New England before ending on Wednesday. 

The western U.S. initially begins on a tranquil note through most of
Tuesday before a more unsettled weather pattern arrives.  A weakening
front from the eastern Pacific will generally support some light showers
and mountain snow, followed by another round of precipitation by Wednesday
as a stronger storm lurks offshore.  The heaviest precipitation should be
across southern Oregon and northern California.

Elsewhere across the continental U.S., dry conditions can be expected from
the Desert Southwest to the Upper Midwest.  It will continue to be
bitterly cold from eastern Montana to northern Michigan with widespread
subzero lows and single digit highs.

Ziegenfelder


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