Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 132136
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
336 PM MDT Sun Aug 13 2017

.SYNOPSIS...A drier airmass will start working into the area from
the west today. A cold front will move into northern Utah Monday
then stall across central Utah on Tuesday.

&&

.SHORT TERM (Through 00Z Wednesday)...Somewhat drier air has spread
into the forecast area today and PW imagery shows values lower than
yesterday. However, there was enough residual moisture at low levels
for isolated convection to fire once again across pretty much all
but the far northern CWA. Expect this activity to continue into
early evening then die out.

The drying trend continues across the south and east Mon while the
north remains somewhat moist as a cold front moves into the CWA.
The front is associated with a fairly vigorous upper trof that
will be crossing the nrn Rockies and nrn Great Basin Monday and
Monday night.

This front is forecast to be fairly strong with convection
developing along it Mon aftn lasting thru the night and have
raised pops across the north thru Mon night.

Expect gusty southwest winds to develop ahead of the front on Mon
with equally strong or slightly stronger north winds behind it.

Much cooler air follows the front with H7 temps falling to around
+5C over SLC by 12z Tue. This should translate into highs in the
upper 70s to low 80s Tue along the Wasatch Front.

The front stalls over central UT Tue aftn with some convection
along and south of it while morning convection over the north is
suppressed in the afternoon.

.LONG TERM...(After 00Z Wednesday)...The long term portion of the
forecast will begin in the wake of a fairly impressive wave...at
least for early August. Subsidence in the wake of this wave should
put an early end to any remaining convection Tuesday evening.

Northwesterly flow will remain in place across northern Utah
becoming more westerly by Friday. This will bring a series of weak
waves through the area. Drying in the mid-level should limit
convection through at least Friday to the most prone locations such
as the high Uintas and Boulder Mountain.

A stronger shortwave digging down the California Coast may help to
pull enough mid-level moisture north Saturday and Sunday for more
widespread...but still isolated...convection across the higher
terrain.

Main points: fairly anemic moisture over the long term forecast
period will keep convection restricted to the higher terrain.
Temperatures will continue to average near to a bit above
climatological normals for mid-August.

&&

.AVIATION...VFR conditions will persist through the TAF period at
the SLC terminal. Afternoon convection will keep winds from the
south with a small chance to see a brief northwest wind shift, so
opted to not put it in the TAF at this time. Winds will increase out
of the south after 15z Monday ahead of a cold frontal passage during
the afternoon, bringing gusty northwest winds.

&&

.FIRE WEATHER...Isolated thunderstorms will continue into this
evening across much of the district. A drier southwest flow will
develop tonight into Monday as a cold front approaches from the
northwest. The front will move into far northern Utah Monday morning
then work south into central Utah by Tuesday morning before it
stalls.

Gusty south winds will increase Monday ahead of the front and
drier air will spread into the state with RH falling into the
teens in the southwestern valleys. This will bring critical fire
weather conditions to the southwestern valleys where fuels are
cured. Winds north of the front will also be strong and gusty
Monday afternoon and evening but RH will come up as cooler air
spreads in.

Isolated thunderstorms are possible Monday over the mountains
from central Utah northward as well as along the cold front.
Showers will become more numerous along the front as it crosses
northern Utah Monday night. These will diminish Tuesday as the
front stalls. Cooler temperatures will spread in behind the front
across the north.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Red Flag Warning from noon to 8 PM MDT Monday for UTZ497.

WY...None.
&&

$$

Kruse/Wilensky/Dewey

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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