476
FXUS65 KSLC 172200
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
400 PM MDT Tue Jun 17 2025

.SYNOPSIS...Utah and southwest Wyoming will see continued dry
conditions over the next several days, with temperatures becoming
very hot by the end of the work week. Breezy conditions will also
increase fire danger for the end of the week. A trough will bring
cooler temperatures for early next week.

&&

.SHORT TERM (Through 12Z/6AM Thursday)...Breezy northerly winds
across Utah and southwest Wyoming have materialized in the post-
frontal environment today alongside generally cooler temperatures.
Though we`ve seen some cooling, temperatures remain above average
across Utah and southwest Wyoming but less so across the northern
area. Elevated fire weather conditions remain in place through
the daylight hours as these breezy winds combine with very dry
afternoon conditions.

An upstream ridge, which has begun building into the area this
afternoon, will continue to intensify over the eastern Great Basin
Basin through the next 24 hours. As such, we`ll see temperatures
begin to increase once again starting tomorrow. Across much of
Utah and southwest Wyoming, temperatures are expected to increase
by another 3-6 degrees, placing the Wasatch Front back into the
low 90s and lower Washington County back into the mid-100s. Dry
afternoon humidity is expected to remain in place, however, with
the axis of the aforementioned ridge anticipated to crest overhead
Wednesday afternoon, winds will be generally light and terrain
driven... reducing the overall risk of fire weather concerns.
That said, the next several days past Wednesday will feature a
return to enhanced fire weather and heat concerns.


.LONG TERM (After 12Z/6AM Thursday), Issued 301 AM MDT...
Record-breaking temperatures,
enhanced southwest winds, and very low relative humidity will be the
main story through Thursday. This will be as a ridge to the
southeast strengthens, while a longwave trough approaches British
Columbia. This will result in enhanced southwest flow for much of
the west, including southwest Wyoming and Utah. Gusts much of the
afternoon will range from roughly 20-40 mph, strongest in western
and southern Utah. Minimum relative humidity values will lower into
the single digits and teens, resulting in high fire danger. The set
up will not only be windy and dry, but also warm. At KSLC, the
forecast high of 102F would set a new record for the day. High
temperatures for much of southwest Wyoming and Utah are similar to
KSLC, either near, at, or exceed the daily record. The warmest
conditions locally will be in far southern Utah, with Lake Powell
around 105F and lower Washington County around 110F.

The main difference for Friday with that the trough will approach
the PacNW. That will push the ridge a bit further to the east. Gusts
will be similar to Thursday for many locations, with the biggest
increase throughout southwest Wyoming and northern Utah. There will
be minimal change in relative humidity and slightly cooler
temperatures, with continued high fire danger.

The trough will track into the western U.S. Saturday. Ensembles are
in good agreement on that, but timing uncertainty makes Saturday`s
forecast lower confidence. There is high confidence that dry
conditions will continue. The lower confidence part is that if the
front tracks through early in the day, winds would transition to
northwest and be lighter. That would mitigate fire danger despite
very low relative humidity and dry conditions continuing. The most
likely scenario is that the boundary will push into northern Utah at
some point during the day, with locations south of the boundary by
the afternoon with more gusty southwest winds.

The front will have tracked into southern Utah by early Sunday.
Although dry, it will bring rather strong cold air advection.
Temperatures will lower roughly 25F off the warmest day of the week
Thursday. Valley highs will generally be in the 70s.

The trough will lift northward Monday, but several shortwaves behind
it will likely keep southwest flow in place. Although southwest
winds are not forecast to be as strong as the initial trough, single
digit to teens minimum relative humidity will continue the fire
danger.

&&

.AVIATION...KSLC...Breezy northwesterly winds will prevail at the
terminal through roughly 01z, with the diurnal switch to southeast
delayed a bit to 04-05z. Skies remain mostly clear save for some
passing high cumulus till early evening. Lighter winds are expected
tomorrow as the ridge moves overhead, with northerlies likely
arriving a bit earlier than usual.

.REST OF UTAH AND SOUTHWEST WYOMING...Northwesterly flow continues
across the region for all but SGU, with gusts diminishing after 00z.
Skies remain mostly clear across the entire airspace, save for some
passing high cumulus into early evening. Lighter winds are expected
tomorrow as the ridge moves overhead for all but EVW, where typical
gusty westerlies are likely for the afternoon period.

&&

.FIRE WEATHER...Stiff northerly winds in the post-frontal environment
will continue to bring elevated fire weather conditions across
much of Utah through the remainder of Tuesday. Winds are expected
to subside through the overnight hours with improving humidity
recoveries, mainly across the northern half of Utah. For the
southern half of Utah, improvement to humidity recoveries are
still expected, but poor recoveries are still anticipated (15-25
percent). Wednesday will continue to feature very dry afternoon
humidity alongside warming temperatures, however, winds will be
largely terrain driven which will bring lower concerns of critical
fire weather conditions.

By Thursday, an offshore trough will dip farther south and bring
an increase in dry southwesterly flow across the majority of Utah.
Some of the hottest temperatures of the week are also expected by
Thursday, pairing with the already extremely dry afternoon
conditions. There is generally high confidence that winds will
gust in excess of 30 mph across much of Utah by the afternoon
hours. Strong and dry southwesterly flow is expected to remain in
place across Utah from Thursday through at least Saturday,
bringing widespread critical fire weather conditions. As such, a
Red Flag Warning has been issued for numerous fire weather zones
across Utah. A cold front is anticipated to push into the region
by late Saturday/ early Sunday, decreasing the overall threat of
critical fire weather conditions across the northern area.
Depending on the overall speed of this cold front and how far it
progresses into Utah, critical fire weather conditions may persist
across far southern and eastern Utah through Sunday (this is a
generally low confidence forecast).

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Red Flag Warning from noon Thursday to 10 PM MDT Friday for
     UTZ478.

     Red Flag Warning from noon Thursday to 10 PM MDT Saturday for
     UTZ482>484-489-492>498.

WY...None.
&&

$$

SHORT TERM...Webber
LONG TERM...Wilson
AVIATION...Verzella
FIRE WEATHER...Webber

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http://weather.gov/saltlakecity