Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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860
FXUS65 KSLC 221620
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
920 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.

&&

.DISCUSSION...Mid level ridging continues to dominate the
intermountain region this morning allowing dry conditions and
anomalously warm temps locally. H7 temps continue to warm and will
so for the next 12 hours, with values expected to punch up to +4-5
C across northern Utah, and up to +9 C down towards Utah`s Dixie.
These are some of the warmest H7 temps ever for this time of the
year.

Ample mixing coupled with the aforementioned anomalously warm
airmass will drive temps some 15-20 degrees above normal values
once again today. Expecting near record or record temps for quite
a few areas by this evening as such. Going forecast handles this
well, and outside of minor sky cover tweaks, remains in place.

PREVIOUS DISCUSSION...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...Winds at the SLC terminal are expected to switch to the
northwest around 19-21Z, though periods of light and variable winds
are also possible through much of the day.

&&

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

$$

DISCUSSION/AVIATION...Merrill/Schoening
PREVIOUS DISCUSSION...Seaman/Struthwolf

For more information from NOAA`s National Weather Service visit...
http://weather.gov/saltlakecity

For frequently asked questions about the Area Forecast Discussion
visit...
http://weather.gov/saltlakecity/general/afd_faqs.php



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