Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
247 PM EST Mon Dec 18 2023

Valid 00Z Tue Dec 19 2023 - 00Z Thu Dec 21 2023

...There is a Moderate Risk of excessive rainfall over parts of Northern
New England on through Tuesday morning...

...Lake-effect snow downwind of the Great Lakes and upslope snow over
parts of the Northern/Central Appalachians...

...Rain for most of the West Coast...

The storm system that brought several inches of rain up the Eastern
Seaboard continues to impact the Northeast today with widespread heavy
rain that resulted in river flooding, scattered to widespread areas with
flash flooding with some areas experiencing road washouts. A Moderate Risk
for excessive rainfall is in effect for most of New Hampshire and
central/southern Maine through Tuesday morning. A Slight Risk spans from
eastern New York to eastern Maine while a Marginal encompasses that part
of the region and extends to central New York and most of New Jersey. This
deep storm will continue to produce periods of heavy rain over parts of
New England as it pulls continues to track offshore. Additionally, the
storm will produce showers and thunderstorms over the northern
Mid-Atlantic Coast/southern New England Coast. The threat of heavy rain
ends on Tuesday as the system moves farther into Canada.

In the wake of the deep storm, upper-level energy over the Great
Lakes/Ohio Valley moves eastward to the Northeast Coast by Tuesday
evening. The energy and cold air will aid in creating lake-effect snow
downwind of the Great Lakes and upslope snow over parts of the
Northern/Central Appalachians into Wednesday. Some of the highest
accumulations will focus over parts of the Central Appalachians, southeast
from Lake Michigan in Michigan and Indiana, and along the central and
eastern shore of Lake Erie in Ohio and New York State. The Lake-effect
snow will be much lighter on Tuesday and end over the Upper Great Lakes.

A series of fronts ushering in Pacific moisture will help produce rain
across the Pacific Northwest through the middle of the week. Locally heavy
snow over the highest elevations of the Sierra Nevada Mountains and
lighter snow over the highest elevations of the Cascades and parts of
Idaho and Nevada will be possible. Rain may be moderate to heavy at times
along the coast and points inland. There is a Marginal Risk for excessive
rainfall and isolate areas of flash flooding Tuesday for parts of northern
and central California and for parts of central and southern California on
Wednesday.


Campbell


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