Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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400
FXUS65 KSLC 221124
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
424 AM MST Wed Nov 22 2017

.SYNOPSIS...High pressure will continue to strengthen across the
region today, then remain in place through the rest of the week.

&&

.SHORT TERM (Through 00Z Sunday)...An expansive mid level ridge
encompasses much of the Interior West early this morning. Cirrus
which has been spilling overtop of the ridge axis continues to
stream across the forecast area, however with this ridge
amplifying this cirrus has been thinning over the past few hours,
and this trend is expected to continue today. With very warm
temperatures aloft and ample boundary layer mixing, anticipate
temperatures to once again warm 15-20 degrees above climo in most
locations. This will likely result in a few record max temps being
challenged this afternoon. Little change in the overall pattern
is expected for Thanksgiving day with near record temperatures
once again expected.

A progressive shortwave trough is forecast to crest the ridge axis
as it translates through the Pacific Northwest/northern Rockies
Thanksgiving night. This will have little impact on the forecast
area aside from lowering heights and dropping temperatures a
couple of degrees. The ridge is forecast to rebound across the
region Saturday resulting in another dry and very mild day with
max temps again running 15 to 20 degrees above climo at most
locations.

.LONG TERM (After 00Z Sunday)...Global models are in remarkable
agreement during this extended period. The south to north surface
gradient increases through Saturday night which should support a
mild night Saturday night with winds keeping the temps up over the
western valleys. With the 700mb temps at SLC +6 (GFS) and +8 (EC)
Sunday morning we should not have a problem reaching the mid to
upper 60s along the Wasatch Front and the 70s across southern Utah
which will likely cause many Max temp records to fall.

A breezy night Sunday night ahead of the strong cold trough (all
Global Models are similar), should bring another mild night. If the
timing of the cold front is slightly slower timing could allow temps
to reach upper 50s in the northern Utah ahead of the cold front
while a little faster and the temps will remain in the 40s. Looks
like good dynamics with jet support and 700mb baroclinic zone moving
across the CWA Monday. Also the 500mb temps continue to cool through
the afternoon increasing the instability between 700 and 500mb. Snow
levels should crash to the valley floors of northern Utah and west
central valleys by Monday afternoon. Have boosted PoPs for Monday.

Should see some showers linger into the night with the 500mb cold
pool moving overhead. Need to keep an eye on the possibility of lake
enhanced or Lake Effect snow Monday night south and southeast of the
GSL. Also, downslope winds will be quite strong across the central
mountains and into Washington County Monday night.

Colder temps are for Tuesday behind the departing system. Temps
will warm rapidly in the mountains by Wednesday but the valleys
should see inversions to keep temps from moderating too fast under
the building mid week ridge.

&&

.AVIATION...Southeast winds will shift to the northwest at the SLC
terminal between 20 and 22Z this afternoon. VFR conditions will
prevail through the TAF period.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...None.
WY...None.
&&

$$

Seaman/Struthwolf

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