St. George, Utah 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

108
FXUS65 KSLC 050941
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
341 AM MDT Thu Jun 5 2025

.SYNOPSIS...Unsettled pattern characterized by anomalous moisture
across the southern half of Utah persists through Friday,
bringing threat of localized flash flooding. Drier and warmer
conditions return for the weekend on into early next week.

&&

Key Points:

-Anomalous moisture will aid in the development of scattered
 showers and thunderstorms through the day Thursday, primarily
 across the southern half of Utah, with activity capable of
 frequent lightning and periods of heavy rain. This will bring an
 isolated flash flood threat, especially to rain sensitive areas.

-Moisture will gradually start to decrease Friday, but isolated
 to scattered showers and thunderstorms will once again develop
 across the southern half to two thirds of Utah during the day.
 Localized flash flooding will once again be possible with any
 stronger cell drifting over a more rain sensitive area.

-Drier conditions return for the weekend on into early next week,
 along with the return of anomalous heat. Forecast highs Sunday on
 into early next week include 90s for most of the Wasatch Front
 and western Utah valley locations, and upper 90s to low 100s for
 lower Washington County, lower elevations of Zion NP, and Glen
 Canyon NRA.

.SHORT TERM (Through 12Z/6AM Saturday)...Persistent lingering
moisture, very modest instability, and subtle shortwave impulse
embedded within the broader flow is helping to maintain showers
and a few isolated thunderstorms across southern Utah this
morning. Given the meager instability (mesoanalysis analyzed
~100-250 J/kg), activity has struggled to maintain much
organization, tending to be more pulsey in nature. Still, glancing
at what sensors have found themselves beneath the activity,
seeing some indication of brief periods of rain rates in the
0.5-1.0" an hour rate, so still will need to keep an eye on the
flood threat for rain sensitive areas like Zion NP. Outside of
some increasing clouds, not much of note going on at areas further
north in the forecast area.

Moving into the day Thursday, largely anticipate a forecast
evolution that looks pretty similar to that of Wednesday`s.
Biggest difference appears to be that anomalous moisture will push
a bit further north into central Utah, allowing activity to cover
a broader area. Otherwise, diurnal destabilization with SBCAPE
rising to around 250-750 J/kg will allow scattered convection to
begin developing late morning to early afternoon, with continued
development onward into the evening hours. Like Wednesday,
frequent lightning and periods of heavy rainfall will be the
biggest threat with this activity, and any more organized cell
that drifts over a rain sensitive area in particular (slot canyon,
typically dry wash, burn scar, slickrock area) will pose a threat
of localized flash flooding. Frequent lightning will also be
possible in stronger cells given the destabilization. Those
planning outdoor recreation should keep an eye on the weather
accordingly. While a little activity may linger into the overnight
hours once again, CAM guidance appears much less bullish on this
potential in comparison to what is ongoing this morning.

Axis of anomalous moisture lingers for one final day Friday,
though the overall available moisture will be on the decrease.
With continued weak shortwave impulses sliding through in the flow
overhead, this moisture along with diurnal heating will yield yet
another day of widely scattered convective development late
morning onward through the day. Coverage will once again favor
central and southern Utah. While moisture will be decreasing,
forecast amounts are sufficient that a strong enough cell drifting
over the wrong rain sensitive spot will pose a localized flash
flooding threat. Maintained "Possible" ratings in the local Flash
Flood Potential product accordingly, and those planning outdoor
recreation should once again check the forecast and remain weather
aware.

.LONG TERM (After 12Z/6AM Saturday)...Relatively quiet weather is in
store for the long-term period, with high pressure expected to
build heading into the weekend. Taking a look at the upper-level
pattern, Utah will be situated in overall northwesterly flow
downstream of a ridge just off of the west coast. This pattern is
likely to persist through the weekend, as the ridge is located
atop a closed low, indicative of a weak Rex block. Given mid-level
height rises, expect a warming and drying trend through the
weekend, with high temperatures approaching the low-90s along the
Wasatch Front and around 100F in St. George. Be sure to stay
hydrated if working or recreating outdoors this weekend! It`s also
worth mentioning there is a low (10%) chance of showers
developing across higher terrain both Saturday and Sunday
afternoons, though they should remain isolated at best.

The weak omega block will start to break down early next week as
a stronger Pacific system nudges both features eastward. As the
aforementioned closed low moves inland and towards Utah, it will
weaken, yet also bring increased moisture to the area by mid-week,
primarily across northern Utah. There is still some question as
to how much moisture will increase, but ensemble guidance suggests
moisture returning to somewhere between the 50th and 90th
percentiles. Additionally, despite broad upper-level diffluence,
mid- level heights are still modeled to be above-normal,
potentially limiting any rainfall/flash flooding potential.
Despite these uncertainties, we can expect a return to slightly
more active weather next week.

&&

.AVIATION...KSLC...Light, southeasterly winds will continue through
the morning, becoming light and variable at times. Northwesterly
winds will return around 18-19z, with VFR conditions prevailing.

.REST OF UTAH AND SOUTHWEST WYOMING...Scattered showers and isolated
thunderstorms are ongoing across southwestern Utah early this
morning, bringing a slight chance for thunder to mainly KCDC and
KSGU through roughly 12z or so. More showers and thunderstorms
will develop as early as 18z across southern/central Utah (with
KPVU, KHCR, and KEVW being on the northern periphery). However,
this timing is lower confidence given lingering mid-level cloud
cover this morning which may delay convective initiation.
Intermittent showers and thunderstorms will likely be the story
through the rest of the afternoon, with intensity decreasing after
01-02z. Developing storms will be capable of producing gusty and
erratic outflow winds to 25-35kts.

&&

.FIRE WEATHER...An area of anomalously high moisture will remain atop
much of central and southern Utah through Friday. Lingering
showers and thunderstorms from the overnight hours are expected to
shift out or otherwise decrease in coverage, and in turn daytime
heating will aid in the redevelopment of scattered showers and
thunderstorms across most of central and southern Utah late
morning into the afternoon Thursday. Like on Wednesday, this
activity will have threat of frequent lightning and periods of
heavy rainfall. Coverage of precipitation will once again decrease
through the overnight hours. Friday will see a similar evolution
through the day with isolated to scattered showers and
thunderstorms developing late morning into the afternoon, with
activity most favored over central to southern Utah. That said,
overall moisture will begin to decrease slightly, so anticipate a
bit lower coverage overall. From the weekend on into early next
week, drier conditions are generally favored along with
temperatures increasing back to above seasonal normal.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...None.
WY...None.
&&

$$

SHORT TERM...Warthen
LONG TERM...Cunningham
AVIATION...Cunningham
FIRE WEATHER...Warthen

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