Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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FXUS65 KSLC 171030
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
430 AM MDT Sat Jun 17 2017

.SYNOPSIS...A dry cold front will continue moving south through
Utah today and tonight. High pressure will strengthen over the
Great Basin Monday and persist through mid week bringing very hot
temperatures.

&&

.SHORT TERM (Through 12Z Monday)...Cold front (at 3am) from about
central Utah Lake west southwestward across Juab County. This
front will continue to make progress all the way to southern Utah
by this afternoon. Although the PWs across NW UT are nearly 1 inch
this morning, the air mass coming in is rather stable behind this
front with the 500mb temps warming this afternoon while the 700mb
temps cool some. Therefore, the threat of showers or
thunderstorms is minimal at best. Have continued a slight chance
over the Uinta Mtns, but confidence is low that even any
convection will develop there.

Winds over the western Uinta Basin will be quite breezy today as
well in downslope areas of Castle Country in the wake of this cold
front. Some down slope winds are expected in Dixie tonight for
some localized breezy conditions.

Despite the cold front reaching southern Utah this afternoon, not
expecting any cooling as the 850 mb temps are actually forecast to
be 1 degree C warmer than yesterday. Nearly similar temperatures are
expected Sunday.

Across the north in the wake of the cold front, temperatures will be
a refreshing 5-10 degrees cooler than yesterday. Temperatures will
only inch up some Sunday.


.LONG TERM (After 12z Monday)...Strong high pressure aloft
centered over AZ at the start of the long term period will
dominate the forecast area through Tue. The very hot airmass under
the high will bring near or above record temps portions of
southern and southeastern UT. The north will warm also with temps
along the Wasatch Front near 100 by Tue.

Isolated convection should begin Mon across the srn mtns becoming
a little more widespread Tue and persisting Wed.

The ridge flattens on Wed as a low amplitude trof moves into the
PacNW and nrn Rockies but cooler air from this wave does not
spread into nrn UT until Wed night and Thu. So the heat will
persist unchanged area wide Wed then the north cools down Thu
while the south remains hot. A cooler airmass stays in place
across the north Fri and the south cools a little as the high
aloft weakens a bit.

Convection is suppressed over the north Thu and Fri as the low
levels cool and the airmass stabilizes but should develop over the
south again both aftns.

Med range models diverge on the evolution of the high after Fri
but it looks like the modest cooling trend will persist. There
are also hints that moisture will increase a little Sat with a
potential increase in the coverage of convection.

&&

.AVIATION...Northerly winds will persist at the KSLC terminal
through the day. Winds could become light and variable at times
between about 12-15z. Any cigs will remain well abv 7000 ft.

&&

.FIRE WEATHER...Cold front (at 3am) from about central Utah
Lake west southwestward across Juab County. This front will
continue to make progress all the way to southern Utah by this
afternoon. Although the PWs across NW UT are nearly 1 inch this
morning, the air mass coming in is rather stable behind this front
with the 500mb temps warming this afternoon while the 700mb temps
cool some. Therefore, the threat of showers or thunderstorms is
minimal at best. Have continued a slight chance over the Uinta
Mtns, but confidence is low that even they will see any
convection.

Winds over the western Uinta Basin will be quite breezy today as
well in downslope areas of Castle Country in the wake of this cold
front. Although the winds are expected to reach RFW criteria, the
min RH is likely to come up short in the upper teens. Some down
slope winds are expected in zone 497 tonight for some localized
breezy conditions.

Despite the cold front reaching southern Utah this afternoon, not
expecting any cooling as the 850 mb temps are actually forecast
to be 1 degree C warmer than yesterday. Temperatures will reach
above 100 degrees with RHs in the single digits from 497 and 498
into 494 through next Thursday.

Across the north in the wake of the cold front, temperatures will
be 5-10 degrees cooler than yesterday and will only inch up some
Sunday. The min RHs will remain in the upper teens and 20s today
and Sunday but then will lower below 15% Monday through Thursday.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Excessive Heat Watch from Monday afternoon through Thursday
     evening for UTZ013-019>021.

WY...None.
&&

$$

SHORT TERM/FIRE WEATHER...Struthwolf
LONG TERM/AVIATION...Wilensky

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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