Scientific Forecaster Discussion
fxus65 kslc 142058
Area forecast discussion
National Weather Service Salt Lake City Utah
258 PM MDT Mon Oct 14 2019
high pressure aloft will dominate through midweek, bringing
slightly above average temperatures to the region. Cooler
temperatures and a more active weather pattern will develop by
late in the week, with much cooler temperatures and even a chance
of snow for northern Utah by Saturday night into Sunday.
Short term (through 00z friday)...
a weak mid-level wave will pass the forecast area to our south
tonight, which will push a weak boundary across the state. While
technically a cold front, the temperature difference will be
minimal behind the front for Tuesday, with some low-lying area
actually seeing warmer temperatures Tuesday from slightly improved
mixing. Otherwise, high pressure aloft will then remain in charge
of the weather across the region through Wednesday. Temperatures
will warm into Wednesday as the mid-level ridge axis moves over
the area, with highs about 5-10 degrees above normal.
By Wednesday night into Thursday cloud cover will thicken ahead
of an approaching trough and cold front, along with increasing
southerly winds. Low temperatures will be much more mild by
Wednesday with the increase southerly flow. This is also a
classic setup for a very mild overnight low at slc, for which we
have gone a few degrees above guidance. Temperatures will remain
warm on Thursday, but will start to cool slightly from Wednesday
as the cold front moves into northern Utah in the afternoon, and
the added cloud cover inhibits diurnal warming. Conditions should
remain dry through the day Thursday.
Long term (after 00z friday)...
the deepening trough feature forecast to slide through the Great
Basin for the coming weekend continues to be advertised well with
much agreement among extended range forecast models, both
deterministic and ensemble members. So, confidence continues with
this feature. Following the surface cold front, unsettled west-
northwest flow will blanket northern and central Utah as the
airmass continues to cool. Temps at 700mb and 500mb continue to
cool and slide through northern Utah Saturday into Sunday. The
best available moisture also begins to pour through Saturday. As
snowlevels drop to near valley floors the question on whether or
not snow will be seen/accumulate on valley floors is still up in
the air (pun intended). Mountains look to see accumulating snow
above 7500 feet through Sunday morning. These specific details are
still coming in line, so with each subsequent model run these
details should come in line better.
VFR conditions will prevail at the slc terminal through the taf
period. Northwest winds in the 4-7 knot range will prevail through
early this evening, before southeasterly winds of 5 knots or less
are expected to resume between 03-04z. Light southeast winds will
prevail through Tuesday morning, and may be a bit more stubborn
than typical in turning to the northwest Tuesday afternoon.
quiet weather conditions prevail through mid week with a dry
airmass and slightly above normal temperatures. A weak boundary
will push across the state tonight, leaving more limited mixing
and light transport winds in its wake for Tuesday, which will
result in poorer clearing indicies. Clearing indicies will rebound
Wednesday and especially Thursday as transport winds and better
mixing result ahead of an approaching cold front. In fact, near-
critical fire weather conditions are possible by Thursday for
portions of southern Utah from dry and windy conditions.
Cooler temperatures will arrive over the weekend, with much below
average temperatures likely by Sunday along with wetting
precipitation and even accumulating snow for northern Utah.
Wyoming...rfw remains in effect until 7pm MDT tonight for wyz277.
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