Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
300 AM EST Sat Nov 18 2023

Valid 12Z Sat Nov 18 2023 - 12Z Mon Nov 20 2023

...Unsettled weather expands across the western U.S. with strong winds,
high-elevation snows and coastal rains...

...Another system forming over the central High Plains will bring an
expanding area of showers and thunderstorms across the central U.S....

...Great Plains warms up as the West cools down...

More unsettled weather is expected to reach the West Coast through the
next couple of days as a southern stream cyclone merges and phases with a
vigorous northern stream trough.  Northern California is already receiving
frequent rounds of moderate rain ahead of the southern stream cyclone,
with snow beginning to reach into the Sierra Nevada.  By tonight, the
northern stream trough is forecast to merge with the southern stream
cyclone near the West Coast.  This interaction will send an expanding area
of high-elevation snow and valley rain rapidly inland through the
Intermountain West and the Great Basin on Sunday, together with a surge of
cold air with strong winds through much of the western U.S.

Meanwhile, a new low pressure system is forecast to form over the central
High Plains tonight. This system will be energized as the upper trough
moves through western U.S. on Sunday, and then become the main low
pressure system by Monday morning when the upper trough gets ready to exit
the Rockies.  An area of showers and thunderstorms can be expected to
develop over the central Plains on Sunday which will likely expand toward
the north and east quickly Sunday night into Monday morning as the system
further consolidates.

Along the East Coast, a cyclone is forecast to rapidly intensify offshore
and will likely miss New England as it passes east of Maine tonight.  Some
showers are expected to move across the Northeast and down into the
Appalachians today ahead of the front.  Colder air will spread into New
England by tonight, with periods of light snow expected to develop over
the interior sections on Sunday.

Much of the country will be milder than normal before the surge of cold
air behind the upper trough reaches into the western U.S. on Sunday.  The
East will also be very mild before cooler than normal temperatures
overspread the region behind a cold front.  Meanwhile, temperatures climb
over the Great Plains beneath an area of high pressure and out ahead of
the approaching mid to upper-level trough.

Kong


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