771 
FXUS65 KSLC 031902
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
102 PM MDT Thu Sep 3 2026

.KEY MESSAGES, Issued 1001 PM MDT Wed Sep 2 2026...


- Gusty southwest winds are expected each afternoon and evening
  across Utah and southwest Wyoming through the end of the work
  week. With minimum relative humidities approaching critical
  values in pockets of western Utah, this will result in some
  locally critical fire weather conditions. 

- An influx of tropical moisture over the holiday weekend will
  increase the risk of flash flooding into early next week,
  particularly on Sunday across central and southern Utah.

&&

.DISCUSSION, Issued 1001 PM MDT Wed Sep 2 2026...
Utah and southwest Wyoming remain sandwiched in
between an upper low off the Pacific Northwest coast and a broad
ridge over the central United States. This has resulted in a
persistent breezy southwesterly flow that is advecting drier air
into the area. Thursday is anticipated to be the driest day for
the region, with minimum relative humidity values approaching
critically low values for portions of western Utah, the northwest
desert in particular. This will likely result in some locally
critical fire weather conditions during the afternoon, but given
the improvement in fuels from recent rains, the fire danger is not
as high as it could be. The airmass over the area will stay just a
bit on the cool side, with maxes running near to up to 5F below
seasonal normals through the end of the work week.

As we enter the holiday weekend, all eyes will turn to the eastern
Pacific where Hurricane Marie is currently tracking westward away
from Mexico. Guidance continues to indicate that the southerly
flow will tap into deep tropical moisture from the system,
bringing that moisture up through Utah and southwest Wyoming by
Sunday. This influx of moisture will bring the return of fairly
widespread coverage of showers and thunderstorms, with any storms
that develop capable of producing heavy rain that could lead to
flash flooding. 

There remains lower confidence than usual in the timing of the 
arrival of this moisture and its trajectory, as this is dependent 
on the precise track of Marie, something that global models can 
struggle with, and also the trough currently over the Pacific
Northwest. The prevailing thought is that the system will spin
just off the coast through the first part of the weekend before
eventually grazing northern Utah early next week. Its passage is
expected to give a more westerly component to the flow, cutting
off the tropical moisture and bringing drier air back in. However,
there remains disagreement as to when it will graze the area, and
how far south the system will actually get. Hopefully details will
become a bit clearer over the next few days. 






&&

.AVIATION, Issued 1109 AM MDT Thu Sep 3 2026...
 

KSLC...Surface winds are expected to ramp up over the next 1-2hrs 
with enhanced southerlies persisting into tomorrow at the KSLC 
terminal. Gusts out of the south up to 30kts are possible this 
afternoon, though higher probabilities exist tomorrow of reaching 
30kts. Sustained winds out of the south are expected to range from 
15-20kts. Otherwise, VFR conditions are expected to persist through 
the TAF period. 

REST OF UTAH AND SOUTHWEST WYOMING...Enhanced south/southwesterly 
winds are forecast to develop across all TAF sites through the 
period. KLGU and our southern UT sites will see the highest wind 
gusts from this, potentially in excess of 30kts in the afternoon 
hours. Due to the strength of this system, winds will remain 
south/southwesterly through the duration of the TAF period. However, 
VFR conditions will persist otherwise across all terminals. 

&&

.FIRE WEATHER...Gusty southwest winds have developed again this
afternoon and are expected to remain especially elevated into 
Friday with widespread gusts 30-45 mph each afternoon. Portions 
of western Utah will see relative humidity values below 15 
percent through this evening; when coupled with strong winds
already in place, areas of critical fire weather conditions are 
expected to develop across this area. Despite critical fire 
weather conditions being realized today, improvements in fuel 
moisture across the region keeps the risk moderated. While winds 
remain gusty across the area on Friday, relative humidity is 
expected to increase above critical levels across most of the 
region with improving overnight recoveries.

Despite increasing moisture through Saturday, a lack of outside
forcing will keep chances for showers and thunderstorms low
through this period. A more significant moisture surge with a
concurrent passage of a strong upper-level wave is expected on
Sunday, resulting in the development of widespread showers and
thunderstorms across a majority of the state. Conditions will be
favorable across central and southern Utah especially for heavy
rain and flash flooding, with a threat for severe wind and heavy
rain across northern Utah. Otherwise, storms are expected to taper
off through early Monday, with drier conditions developing through
mid-week as high pressure redevelops over the region.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...None.
WY...Red Flag Warning until 9 PM MDT this evening for WYZ277.

&&

$$

PUBLIC...Traphagan
AVIATION...Worster
FIRE WEATHER...Whitlam

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