Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
241 AM EST Wed Nov 15 2023

Valid 12Z Wed Nov 15 2023 - 12Z Fri Nov 17 2023

...Heavy rainfall and locally significant urban flash flooding will be a
major concern today and tonight for southeast Florida...

...Locally heavy snowfall expected today across portions of the Northern
Rockies...

...Unsettled weather remains in the forecast across much of California...

...Dry and mild conditions will continue across the Intermountain West,
Plains, and Midwest while gradually expanding toward the Mid-Atlantic and
Northeast over the next couple of days...

The biggest story for next couple of days will be the slow-moving storm
system over the Gulf of Mexico which will be gradually moving east while
bringing generally cool temperatures and beneficial rains to
drought-stricken areas of the central and eastern Gulf Coast region along
with parts of the interior of the Southeast. However, as this storm system
approaches the Florida Peninsula later today and through tonight, a
combination of strong energy associated with an upper-level trough and the
pooling of tropical moisture along a quasi-stationary front draped near
far southern Florida, should set the stage for very heavy rainfall
potential. This will especially be the case for the highly urbanized I-95
corridor of southeast Florida from West Palm Beach and Fort Lauderdale
down through Miami and Homestead.

Concentrated areas of slow-moving showers and thunderstorms are expected
over these areas, and this will be influenced also by the gradual
development of a wave of low pressure over the Florida Straits along the
aforementioned front. Extremely heavy rainfall rates are expected which
may approach or exceed 2 to 3 inches per hour. The persistence of these
high rainfall rates today into tonight may produce rainfall totals upwards
of 3 to 6 inches with some isolated max amounts approaching 10 inches by
early Thursday. This will drive a concern for significant urban flash
flooding as a result. The Weather Prediction Center has issued a Moderate
Risk of excessive rainfall to address these concerns. Low pressure just
offshore of the Florida Atlantic coast on Thursday will then begin to lift
northward and may still produce some additional heavy rains along the
immediate east coast of Florida as onshore flow persists, but the heaviest
of the rains should gradually shift offshore which will allow for any
additional flooding concerns to begin to gradually diminish.

Meanwhile, a front currently draped over portions of the northern Great
Basin and adjacent areas of the Northern Rockies coupled with a couple of
weak waves of low pressure and Pacific moisture should bring a threat of
shower activity to these areas including areas of heavy snow over the
Bitterroots today and including Glacier National Park. Snowfall totals by
early Thursday may reach as high as 4 to 8 inches with some spotty amounts
over a foot possible for the highest elevations. High pressure and drier
conditions will arrive on Thursday which will bring the precipitation here
gradually to an end.

Unsettled weather will again be expected to impact California over the
next couple of days as a storm system off the West Coast continues to
meander and moves only very slowly eastward going through the latter part
of the week. Pacific moisture though will be streaming inland and there
will be areas of light to moderate rain, and especially for the coastal
ranges. Some light accumulating snowfall will be possible for the higher
terrain of the Sierra Nevada.

The remainder of the country will continue to be generally dry and very
mild given the lack of any cold air pushing south from Canada.
Temperatures across the Intermountain West, Plains, Midwest, and Ohio
Valley will be as much as 15 to 25 degrees above normal for this time of
the year. This mild air will be reaching the Mid-Atlantic and Northeast by
later in the week.

Orrison


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