Scientific Forecaster Discussion
fxus65 kslc 231144
Area forecast discussion
National Weather Service Salt Lake City Utah
444 am MST Thu Feb 23 2017
Synopsis...a cold upper trough over the area today will shift
east on Friday. The next system will cross the area Saturday
afternoon and night, with yet another cold storm on tap for the
first part of next week.
Short term (thru 12z sunday)...a cold upper trof is centered
over nrn Utah early this morning while the associated cold front has
moved off to the east. Snow has ended across most of srn and ern
Utah with instability showers redeveloping over the north.
Expect the snow showers to increase over the north thru at least
midday and continue at times into Fri under the deeply cold and
unstable airmass with the upper trof. Greatest impact for the
northern valleys looks to be this morning as highs today are
forecast to reach the mid 30s and valley roads will tend to run
just wet by midday. The advisory for the Wasatch front and back
ends at noon and altho it is possible that snow could impact
travel again tonight into early Fri, will leave the existing
The instability snow showers will extend swd thru the day into
tonight but do not expect any significant impact from these
outside of the central mtns.
The trof finally shifts east Fri aftn with short wave ridging
bringing an end to any lingering snow showers. The next trof is
forecast to be a positive tilt feature that drops south thru the
wrn states Sat into Sat night and will be over srn Utah by late in
the night. Weak forcing with this trof will result in spotty
mostly light precip with the best chance over the south but the
airmass stays cold enough for it to fall as snow in all areas
outside of the lowest portions of Washington County.
Long term (after 12z sunday)...the trough continues to exit the
area to the southeast on Sunday morning, with the possibility of
some lingering showers, particularly in far southern Utah.
Otherwise, a short-lived break between storms is possible through
the day Sunday.
The next storm system is right on the heels of the last one,
dropping into the Great Basin Sunday night and Monday. There is a
little uncertainty about the timing and structure of this storm,
but in general it looks to have a decent moisture tap, with low
level cold advection west-northwest flow developing by Monday afternoon. Have
generally increased pops Sunday night through Monday night,
especially across the north. With persistent west-northwest flow, northern
mountain snowfall will likely linger through Tuesday as well.
In addition to keeping pops high, have also lowered temperatures a
bit for much of the extended forecast, as 700mb temps generally
stay in the -10c to -16c range late Sunday through late Wednesday.
The coldest day could be Tuesday, with high temperatures currently
forecast to be about 10 degrees below climatological normals for
the last day of February.
Drying and modest warming finally look to be on tap for the end of
next week, as a ridge builds over the West Coast late Wednesday
through Friday. With better than usual agreement for days 7-10, a
quiet beginning to the month of March looks likely.
Aviation...periods of IFR snow will likely continue at the slc
terminal through much of the day. 1-2 inches of snow is expected
through 00z, with accumulations possible on untreated paved surfaces
under the heavier showers, especially before 18z. Winds might be a
bit erratic due to shower activity, but are generally expected to
turn to the west-northwest between 11z and 15z, then increase from
the northwest through the day.
Utah...Winter Weather Advisory until 4 am MST Friday for utz007>010-517.
Winter Weather Advisory until noon MST today for utz001>004-006.
Wyoming...Winter Weather Advisory until noon MST today for wyz021.
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