Red Flag Warning 4, NWS Salt Lake City, UT

758 
WWUS85 KSLC 031958
RFWSLC

URGENT - FIRE WEATHER MESSAGE
National Weather Service Salt Lake City UT
158 PM MDT Thu Jul 3 2025

UTZ497-498-041000-
/O.UPG.KSLC.FW.A.0002.250704T1800Z-250705T0300Z/
/O.EXA.KSLC.FW.W.0004.250704T1800Z-250705T0300Z/
Mojave Desert-Grand Staircase-
158 PM MDT Thu Jul 3 2025

...RED FLAG WARNING IN EFFECT FROM NOON TO 9 PM MDT FRIDAY FOR
WIND AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES 497 AND
498...

The National Weather Service in Salt Lake City has issued a Red
Flag Warning for wind and low relative humidity, which is in
effect from noon to 9 PM MDT Friday. The Fire Weather Watch is no
longer in effect.

* AFFECTED AREA...Fire Weather Zone 497 Mojave Desert and Fire 
  Weather Zone 498 Grand Staircase.

* WINDS...Southwest 15 to 25 mph with gusts 30 to 35 mph.

* RELATIVE HUMIDITY...10 to 15 percent.

* IMPACTS...Critical fire weather conditions are possible. Any 
  new fire starts or existing fires may spread rapidly.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are expected. A combination of strong winds...low relative
humidity...and warm temperatures can contribute to extreme fire
behavior.

&&

$$

UTZ492-495-041000-
/O.CON.KSLC.FW.W.0004.250704T1800Z-250705T0300Z/
Central Utah West Desert-Color Country West Desert-
158 PM MDT Thu Jul 3 2025

...RED FLAG WARNING REMAINS IN EFFECT FROM NOON TO 9 PM MDT
FRIDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES
492 AND 495...

* AFFECTED AREA...Fire Weather Zone 492 Central Utah West Desert 
  and Fire Weather Zone 495 Color Country West Desert.

* WINDS...Southwest 15 to 25 mph with gusts 30 to 35 mph.

* RELATIVE HUMIDITY...As low as 10 percent.

* IMPACTS...Critical fire weather conditions are expected. Any 
  new fire starts or existing fires may spread rapidly.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are expected. A combination of strong winds...low relative
humidity...and warm temperatures can contribute to extreme fire
behavior.

&&

$$

For more information from the National Weather Service visit
http://weather.gov/saltlakecity

804 
WWUS85 KSLC 040743
RFWSLC

URGENT - FIRE WEATHER MESSAGE
National Weather Service Salt Lake City UT
143 AM MDT Fri Jul 4 2025

UTZ492-495-497-498-050000-
/O.CON.KSLC.FW.W.0004.250704T1800Z-250705T0300Z/
Central Utah West Desert-Color Country West Desert-Mojave Desert-
Grand Staircase-
143 AM MDT Fri Jul 4 2025

...RED FLAG WARNING REMAINS IN EFFECT FROM NOON TODAY TO 9 PM MDT
THIS EVENING FOR WIND AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER
ZONES 492, 495, 497, AND 498...

* AFFECTED AREA...Fire Weather Zone 492 Central Utah West 
  Desert, Fire Weather Zone 495 Color Country West Desert, Fire 
  Weather Zone 497 Mojave Desert and Fire Weather Zone 498 Grand 
  Staircase.

* WINDS...Southwest 15 to 25 mph with gusts 30 to 35 mph. Winds
  may remain elevated through around midnight, especially across
  the West Desert.

* RELATIVE HUMIDITY...10 to 15 percent.

* IMPACTS...Critical fire weather conditions are expected. Any 
  new fire starts or existing fires may spread rapidly.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are expected. A combination of strong winds...low relative
humidity...and warm temperatures can contribute to extreme fire
behavior.

&&

$$

For more information from the National Weather Service visit
http://weather.gov/saltlakecity

222 
WWUS85 KSLC 042040
RFWSLC

URGENT - FIRE WEATHER MESSAGE
National Weather Service Salt Lake City UT
240 PM MDT Fri Jul 4 2025

UTZ492-495-497-498-050300-
/O.CON.KSLC.FW.W.0004.000000T0000Z-250705T0300Z/
Central Utah West Desert-Color Country West Desert-Mojave Desert-
Grand Staircase-
240 PM MDT Fri Jul 4 2025

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM MDT THIS EVENING
FOR WIND AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES 492,
495, 497, AND 498...

* AFFECTED AREA...Fire Weather Zone 492 Central Utah West 
  Desert, Fire Weather Zone 495 Color Country West Desert, Fire 
  Weather Zone 497 Mojave Desert and Fire Weather Zone 498 Grand 
  Staircase.

* WINDS...Southwest 15 to 25 mph with gusts 30 to 35 mph. Winds 
  may remain elevated through around midnight, especially across 
  the West Desert.

* RELATIVE HUMIDITY...10 to 15 percent.

* IMPACTS...Critical fire weather conditions are expected. Any 
  new fire starts or existing fires may spread rapidly.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are expected. A combination of strong winds...low relative
humidity...and warm temperatures can contribute to extreme fire
behavior.

&&

$$

For more information from the National Weather Service visit
http://weather.gov/saltlakecity

241 
WWUS85 KSLC 050255
RFWSLC

URGENT - FIRE WEATHER MESSAGE
National Weather Service Salt Lake City UT
855 PM MDT Fri Jul 4 2025

UTZ492-495-497-498-050400-
/O.EXP.KSLC.FW.W.0004.000000T0000Z-250705T0300Z/
Central Utah West Desert-Color Country West Desert-Mojave Desert-
Grand Staircase-
855 PM MDT Fri Jul 4 2025

...RED FLAG WARNING WILL EXPIRE AT 9 PM MDT THIS EVENING FOR WIND
AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES 492, 495, 497,
AND 498...

Relative humidity has increased above 15 percent and winds
continue to drop off this evening, thus the Red Flag Warning will
be allowed to expire. 

$$

For more information from the National Weather Service visit
http://weather.gov/saltlakecity

Area Forecast Discussion
National Weather Service Salt Lake City UT
434 PM MDT Wed Jul 2 2025

.UPDATE...Aviation section updated to reflect developing outflow
winds in the Salt Lake Valley.

&&

.SYNOPSIS...A monsoon surge will bring the threat of
thunderstorms to much of the region through Thursday. Drier air
will work into the area for Friday and continue into next weekend.

&&

.DISCUSSION...Scattered showers and isolated thunderstorms have
developed across much of Utah and southwest Wyoming this
afternoon, just ahead of a weakening closed low currently crossing
California. Earlier morning cloud cover across southwestern Utah
has limited convection in this area, though with several more
hours of daylight and the current mesoanalysis suggesting around
300-600 J/kg of surface-based CAPE, still expecting more showers
and thunderstorms with gusty outflow winds up to 40-50 mph to
develop. That said, storms over southern NV have not been as
limited, and may produce stronger outflows that move into
southern/western Utah this evening.

Flash flooding will remain a threat heading into the evening hours
as synoptic lift starts to increase ahead of the aforementioned
closed low. Showers will become a bit more stratiform overnight,
but are likely to persist in some fashion, aided by the closed
low weakening into an open wave as it crosses the southern Great
Basin and into our area. Some high-res guidance is more limited in
areal coverage than others, but the flash flood threat should be
less given limited overnight instability.

Behind the trough, drier air will begin to filter into the area
from the southwest. There is still some question with how quickly
this occurs, which might affect thunderstorm coverage, particularly
further southwest. While the flash flood threat will be less
across western Utah, guidance is actually suggestive of a stronger
flash flood threat across eastern Utah, thanks to improved
moisture through the column (better precipitation efficiency)
combined with more shear (more organized, longer-lasting storms).

Dry, southwesterly flow will develop on Friday, resulting in
enhanced fire weather conditions across southern Utah (see Fire
Weather section). Please check with local officials regarding firework/fire
bans and restrictions to reduce the threat of wildfire ignitions
Friday afternoon and evening. While areas Salt Lake City and north
have the highest potential for afternoon showers and thunderstorms,
isolated showers and thunderstorms may extend further south into
central Utah during the afternoon. These storms may also be a bit
more organized thanks to a grazing shortwave trough.

High pressure is expected to develop this weekend and into early
next week, producing hot and dry conditions across the area.

&&

.AVIATION...KSLC...UPDATED...Developing thunderstorms are expected
to impact the terminal around 23z-01z with lightning and outflow
winds of 30-40kts likely. Vicinity showers may keep winds gusty and
erratic before the diurnal southeasterly flow becomes dominant
around 02z, with a 30% chance of being delayed until about 04z due
to persisting weather.

.REST OF UTAH AND SOUTHWEST WYOMING...Increasing monsoonal moisture
across the region has produced widespread thunderstorm coverage this
afternoon. Impacts to flight categories for regional terminals
remain very slight, but can't rule out brief CIG/VIS reductions to
MVFR/IFR conditions through about 03z across southern Utah terminals
where better shear and instability may produce heavier precipitation
cores. Otherwise, storms will be capable of producing gusty and
erratic outflow winds between 30-40 kts if they move into the
vicinity of any regional terminals before sunset.

&&

.FIRE WEATHER...A slow moving low pressure system will shift
eastward across Utah tonight and tomorrow, weakening as it does
so. This will likely result in continued shower activity overnight
tonight across southern and eastern Utah in particular, though
lightning activity will be much more isolated overnight. Drier air
will just begin to filter into the area from the west by Thursday
afternoon, resulting in higher wetting rain chances over eastern
Utah. Overnight RH recoveries will be excellent through at least
Friday morning statewide.

Friday will feature increasing dry, southwesterly flow up to 30-35
mph across southwestern and south-central Utah within an air mass
where RH becomes critical, thus a Fire Weather Watch has been
issued. Additionally, as an upper-level disturbance grazes
northwestern Utah, northern Utah may experience afternoon
thunderstorms and gusty outflow winds, with higher chances further
northwest. High pressure will build into the area for the
weekend.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Fire Weather Watch from Friday afternoon through Friday evening
     for UTZ492-495-497-498.

WY...None.
&&

Cunningham/Verzella

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