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FXUS01 KWBC 201955

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
354 PM EDT Tue Mar 20 2018

Valid 00Z Wed Mar 21 2018 - 00Z Fri Mar 23 2018

...Snow expected from the Ohio Valley into Appalachians and the
Mid-Atlantic northward into New England...

...Severe thunderstorms expected parts of the Southeast and

...Heavy rain with the potential of flash flooding for

Another coastal low/nor`easter is underway as the surface low
located in the Carolinas will move into the Atlantic by tonight.
Meanwhile, a swath of precipitation will move across the Ohio
Valley into the Appalachians, Mid-Atlantic, and Northeast. For
today, the rain/snow line will stretch from New Jersey southward
into the Washington DC metro area through southern Virginia.
North of that line, areas will experience mostly snow especially
throughout the Ohio Valley and central Appalachians.  Along the
rain/snow line, mixed precipitation in the form of rain, sleet,
and snow will occur.  Across the Carolinas and southern Virginia,
rain and thunderstorms will be possible. As the low moves along
the coast tonight, the rain/snow line will shift to the east--with
snow spreading across most of the Mid-Atlantic and coastal areas
of the Northeast and New England.  Snow will continue across these
regions through Wednesday as the low tracks northward along the
East Coast; however, parts of coastal New England can expect
precipitation to change over to rain by Wednesday afternoon.  On
Thursday, most of the precipitation will be in the form of snow in
the New England region as the low treks northward towards the
Canadian maritimes.  Snow may linger by Thursday evening in the
interior of New England but the significant snowfall will come to
an end at that point.  For more information on snowfall for this
event, please see WPC`s winter weather products.

Meanwhile, as the strong cold front from the coastal low pushes
south and east across coastal Georgia/South Carolina and
northern/central Florida, thunderstorms will continue to fire
along the boundary.  These storms have already produced severe
weather and are expected to continue to do so through this
evening. Consequently, SPC has issued an enhanced risk of severe
thunderstorms from coastal South Carolina through central Florida
through this evening.  The front will move into southern Florida
by tonight--with thunderstorms following, albeit not expected to
be severe.

As the East Coast experiences the fourth nor`easter in 3 weeks,
the West Coast will also have a very active period of weather
throughout the short term period.  An impressive axis of moisture
will set up along the central/southern California coast--bringing
a long duration flooding event to the state. Heavy rainfall has
already begun and will continue through Thursday along the
southern California coast.  Burn scars from previous fires will
give way to flash flooding across southern California--in addition
to mudslides and debris flows.  Because of this, a high risk of
excessive rainfall is in effect for Wednesday. A moderate risk
will also be in effect for Thursday as additional heavy rainfall
is expected. Heavy snow is also expected for the Sierra Nevada
mountain range through Thursday night--with snowfall accumulations
2 to 4 feet expected and localized amounts up to 5 feet! Winter
storm warnings are in effect for these areas of the mountain


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