259
FXUS65 KSLC 192149
AFDSLC
Area Forecast Discussion
National Weather Service Salt Lake City UT
349 PM MDT Thu Jun 19 2025
.SYNOPSIS...After record heat, a dry cold frontal passage will bring
a marked cooldown through the weekend. Before this occurs though,
combination of hot, dry and breezy conditions will promote
heightened fire danger with areas of critical fire weather
conditions.
&&
.SHORT TERM (Through 12Z/6AM Saturday)...Mid level water vapor loop
shows a robust ridge extending from Mexico up through the Four
Corners region, and a broad trough across much of the PacNW.
Anomalous H7 temperatures associated with the ridge in turn is
driving record heat across much of the forecast region, with KSLC
achieving the 100F mark for the first time of 2025. Elsewhere
across most lower elevation Utah valleys, widespread 90s to low
100s readings are being observed. Given this warmth, a Heat
Advisory remains in effect for much of northwest Utah including
the Wasatch Front urban corridor. Those recreating or spending
time outdoors are urged to stay well hydrated, take frequent
breaks, wear light colored and lightweight clothing, and have a
means to cool down when needed.
Strong subsidence with the ridge is also precluding precipitation
and further promoting very dry conditions. Daytime relative
humidity values are very low, and given strong southwesterly flow
with the area remaining between the trough and ridge, breezy
conditions are being observed across much of Utah, a combination
leading to heightened fire danger. As such, Red Flag Warnings
remain in effect to highlight these critical fire weather
conditions.
On Friday the base of the trough will start to shift a bit
further southward and inland into the PacNW. This will help to
flatten the strong ridge, resulting in afternoon highs falling
several degrees in comparison to that of Thursday`s high marks.
The gradient ahead of an associated dry cold frontal boundary will
strengthen if anything though, and thus expect another round of
similarly strong to slightly stronger southwesterly wind gusts. As
a result, another day with widespread critical fire weather
conditions is expected.
Overnight into early Saturday the dry cold frontal boundary will
advance from northwest to southeast into Utah and southwest
Wyoming. While precipitation with the front is not anticipated,
winds will quickly shift more north to northwesterly. Temperatures
in turn fall swiftly, with low marks Saturday morning at areas
behind the front back near to even maybe a bit below
climatological normal.
.LONG TERM (After 12Z/6AM Saturday), Issued 413 AM MDT...
A dramatic pattern shift is on course for later this weekend into
next week. A trough moving into the PNW will bring a dry cold
front through the region that will drop temperatures 20-30 degrees
below where they will be Thursday and Friday.
The cooler airmass will slowly ooze into northern Utah during the
day on Saturday before gradually moving into central and southern
Utah by Sunday. A tightening pressure gradient associated with
this trough will enhance southwesterly winds ahead of the trough.
Winds across central and southern Utah will likely peak on
Saturday afternoon with gusts approaching 50 mph. This will also
pair with RH in the low teens to single digits. Behind the front
across northern Utah, temperatures will be running ~5-10 degrees
below normal for this time of year. Overnight lows on Saturday
night will be quite chilly for this time of year with 40s across
most valleys of central and northern Utah. Some high elevations of
northern Utah, including the Wasatch Back, Bear River Valley, and
SW Wyoming have ~50% chance of freezing temperatures.
Throughout the day on Sunday winds will turn northerly and weaken
from northwest to southeast behind the front with RH improving.
Mean troughing will stay in place across the Intermountain West
through the remainder of the week. Even though conditions will
stay mostly dry, winds will likely remain relatively light at the
surface given the weak flow aloft. Temperatures aloft gradually
warm throughout the week which will help to rebound surface
temperatures back to near normal by the middle to the end of next
week.
&&
.AVIATION...KSLC...Gusty south to southwest winds are expected to
remain in place through the remainder of the afternoon and
evening hours. Wind gusts should subside early in the morning
(10-12Z), however, there is about a 20% chance that gusts are
maintained through the overnight. By 15-16Z, gusty south winds are
expected to resume once again. Clear skies persist through the
period.
.REST OF UTAH AND SOUTHWEST WYOMING...Gusty south to southwest winds
will be maintained across Utah and southwest Wyoming through the
remainder of the afternoon and early evening hours, with peak
gusts around 20-30kts. Gusty winds are expected to subside through
the overnight, however, areas immediately downwind of terrain
features may continue to see gusty winds through the night. Gusty
winds resume by mid-morning tomorrow, with speeds increasing to
25-35kts.
&&
.FIRE WEATHER...Persistent hot, dry, and gusty southwesterly flow
will persist across much of Utah through the next 48 hours as a
trough and its parent dry cold front pushes into Utah. In addition
to dry and gusty afternoon conditions, overnight humidity
recoveries are expected to be poor (10-20 percent) across much of
Utah with the exception of far northern Utah where recoveries will
range from 30 to 40 percent. Widespread wind gusts of 25 to 35
mph are expected to subside after sundown, however, ridgetops and
areas immediately downstream of mountainous terrain may continue
to see gusty winds through the overnight hours. Strong southwest
winds become more widespread through the day on Friday, with
speeds bumping up into the 30 to 40 mph range alongside minimum RH
between 5 to 10 percent for a majority of valley areas (10-15%
for highest terrain in northern UT). During the overnight hours
into Saturday, the dry cold front is expected to push into
northern UT and bring some relief to this area.
By Saturday afternoon, the strongest winds during this fire
weather pattern are expected to surface from southwest Iron County
northeastward into the western Uinta Basin. Afternoon wind gusts
through this region could be particularly problematic for any
ongoing, or new, fires as peak wind gusts may reach as high as 50
mph. While the cold front will have progressed into northern Utah,
decreasing the overall fire weather threat, areas to the south of
the boundary will maintain very dry and very windy conditions.
Utah fire zone 478 will drop from the Red Flag Warning by Saturday
but the remainder of the warnings will remain in place through
Saturday evening.
The cold front progresses through the remainder of the area by
late Sunday, bringing cooler temperatures and decreased winds.
That said, areas that remain south and east of the boundary may
continue to see isolated fire weather conditions. Dry conditions
remain in place and no precipitation is expected with this frontal
boundary. Warming temperatures are expected to spread over Utah
once again as we head through the remainder of next week.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Red Flag Warning until 10 PM MDT Friday for UTZ478.
Heat Advisory until 11 PM MDT this evening for UTZ101>106.
Red Flag Warning until 10 PM MDT Saturday for UTZ482>484-489-
492>498.
WY...None.
&&
$$
SHORT TERM...Warthen
LONG TERM...Mahan
AVIATION...Webber
FIRE WEATHER...Webber
For more information from NOAA`s National Weather Service visit...
http://weather.gov/saltlakecity
