NWS Salt Lake City, UT wrote its last area forecast discussion before the first event at May 29, 10:58 AM MST, 1 hour 42 minutes earlier. Its key messages:
Area forecast discussion, May 29, 10:58 AM MST, 1 hour 42 minutes before
Area Forecast Discussion
National Weather Service Salt Lake City UT
1158 AM MDT Fri May 29 2026
.KEY MESSAGES...
- Strong wind gusts will be possible with thunderstorms Friday. A
categorical Marginal Risk (level 1 of 5) of severe weather
across portions of southeast Utah for this severe wind gust
potential.
- Thunderstorms may result in isolated flash flooding Friday if
tracking over rain sensitive basins of southern Utah such as
slot canyons and dry washes.
- Elevated to locally critical fire weather conditions will
develop across portions of the Henry Mountains and San Rafael
Swell Friday afternoon due to gusty winds and low relative
humidity.
- Precipitation and wetting rain becomes more widespread across
northern Utah Friday night into Saturday. Accumulating snowfall
in excess of 4" is expected for the Uintas above around 10000
feet.
&&
.DISCUSSION...The broad low which has remained across the western US
for several days will finally begin more of an eastward
progression through the Great Basin through Friday. Already seeing
moisture associated with this increasing, as evidenced by area
radars picking up on shower activity across southern Utah. With
increased cloud cover and the low helping to shift the ridge,
temperatures are running a bit cooler today and will peak at
levels lower than yesterday's high.
As the core of the low continues to shift east, synoptic forcing
for ascent will increase across the area, initially favoring
southern Utah with coverage later on shifting to areas further
north. In general this moisture is more concentrated around the
mid levels, supporting higher based showers and thunderstorms. As
such, given mean afternoon destabilization on the order of around
100-300 J/kg along with 25-35 kts bulk shear, will see activity
capable of producing gusty and erratic outflow wind gusts. In
general, think most activity will support gusts in the 35-50 mph
range or so. However, it does appear a corridor of enhanced DCAPE
may develop across portions of south central to southeast Utah,
supporting around a 5% chance of severe gusts in excess of 58 mph.
For this area, the SPC has indicated a categorical "Marginal
Risk" of severe weather, risk level 1 of 5. As activity shifts
further north later in the day, waning instability and increasing
saturation should begin to limit the gusty wind threat.
While storms Friday afternoon are expected to be somewhat higher
based in nature, there still will be a nonzero threat of locally
excessive rainfall in any storm that becomes more organized.
Generally, anticipate this to mostly be a threat to more rain
sensitive basins such as slot canyons and dry washes across
southern Utah. As such, opted to add "Possible" to the Flash Flood
Potential Rating for many southern Utah parks and recreation
areas. Those planning recreation in such places will want to keep
an eye on the weather, or consider alternatives on other less rain
sensitive locations.
Late Friday evening on into Saturday the low will start to eject
more northeastward through Utah and into southwest Wyoming and
northwest Colorado. The highest concentration of moisture will
wrap around into the core of the low, which will also have
favorable synoptic forcing even with more limited instability. As
such, should see a more persistent area of showers and stratiform
rain across northern Utah and southwest Wyoming as the low
gradually tracks through. Models continue to support fairly
widespread amounts of around 0.10" to 0.25" for much of the
Wasatch Front, and potential for an area more in the 0.50" to
1.00" range where a deformation axis may set up around the low.
Right now the rough consensus for such a band is around the
Weber/Davis County area, though the exact track of the low will
dictate where it ultimately may set up. Also think there could be
a favorable upslope component with the low shifting east of the
terrain, allowing benches to squeeze out a bit more. The EFI also
highlights the Uintas on through Uinta County, WY with signal for
climatologically anomalous precip, which tracks with the current
forecast low progression. Currently have around 0.50" to 1.00"
water for these areas, but wouldn't be surprised to see some
locally higher amounts.
Despite it being the end of May, this storm system does actually
look to have enough cold air with it to result in some high
elevation snow. That said, outside of any rate driven reductions,
snow levels don't look to far much lower than around 9500 feet at
best. Given the signal for higher water amounts across the Uintas,
the higher locations generally above 10000 feet look to actually
see accumulating snowfall. Generally these amounts are in excess
of 4", with potentially up to 10" in the higher reaches, though
mild antecedent conditions and dense nature of the snow will
likely help to limit accumulation to an extent. While no Winter
Weather headlines appear necessitated, those planning recreation
in the high Uintas or travel through open seasonal roads such as
Mirror Lake Highway should be prepared for snow.
Temperatures through the weekend fall to around 5-10 degrees
below seasonal normal as the low moves through. This looks to be
short lived though, as ridging then appears favored to become the
increasingly dominant influence on the forecast area once again.
With that, forecast carries a warming trend through the upcoming
week along with limited precipitation chances.
&&
.AVIATION...KSLC...Challenging surface wind forecast through this
evening. As of late morning, the lake breeze boundary had settled
across the terminal, with north winds on the north half of the
terminal and south winds on the south half. Good model consensus
in WNW winds overspreading the terminal between 19Z-20Z associated
with the lake breeze. Showers with gusty/erratic winds will
impact the terminal between 22Z-02Z, with most likely outcome
indicating peak gusts around 30kts. However, there is a 10% chance
for gusts up to 45kts. Thunder chances are very low, between
10-20%. Gusty and erratic winds continue through 02Z when model
consensus indicates a return to SSE winds. Can't rule out a period
of variable winds, in the presence of precipitation during the
above-mentioend period. Rain develops around 08Z and continues
through around 16Z, with MVFR cigs. Low (10% chance) for IFR CIGs.
Likely development of W-WNW sfc winds just beyond 18Z Sat with
isolated showers/storms through the afternoon.
.REST OF UTAH AND SOUTHWEST WYOMING...Gusty/erratic winds will
impact the region with showers/isolated thunderstorms moving from
south to north, developing over central Utah around 21Z and
quickly moving north across northern Utah/SW Wyoming, exiting to
the north between 02-03Z. Wasatch Front terminals will be impacted
between mainly 22Z-02Z. Most gusts will be in the 25-35kt range,
but can't rule out isolated gusts up to 45kt. Brief reductions in
visibility due to BLDU may accompany some of this activity. Rain
then overspreads northern Utah and SW Wyoming overnight through
Saturday morning with widespread MVFR CIGs, isolated IFR CIGs and
mountain obscuration from central Utah northward. Conditions
gradually improve through the afternoon as steady, widespread rain
transitions to scattered showers/isolated thunderstorms across
northern Utah.
&&
.FIRE WEATHER...Southerly wind gusts Friday around 25-35 mph in
combination with minimum humidity values around 15 percent will
result in elevated to locally critical fire weather conditions
across eastern valleys where fuels are sufficiently dry.
Additionally, an area of low pressure will gradually move in and
lift northeastward through Utah Friday into Saturday. For Friday
this will result in showers and thunderstorms during the afternoon
to early evening, with activity initially favored over southern
Utah, shifting northward late evening into the overnight hours.
This system will provide around a 30-60% chance of wetting rains
for the southern and central mountains, 40-70% chance for northern
mountains, and a greater than 80% chance for the Uintas.
Additionally, temperatures will be cool enough with the system to
bring accumulating snow to the high Uintas, with 4" or greater
expected above 10000 feet, and locally up to 10" possible in the
higher reaches.
Following the low pressure system departing, high pressure is
favored to build back into the region and become the dominant
weather influence. This will start a warming and drying trend from
Sunday onward into the upcoming week. Temperatures will push to
around 5 to 10 degrees above normal, and afternoon humidity values
will largely fall back into the low teens to single digits.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...None.
WY...None.
&&
PUBLIC...Warthen
AVIATION...ADeSmet
FIRE WEATHER...Warthen
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