925
FXUS65 KSLC 261002
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
402 AM MDT Wed Jun 26 2024

.SYNOPSIS...Increasing moisture will bring a round of showers and
thunderstorms to much of Utah and southwest Wyoming this afternoon
and evening, with heavy rain and gusty winds the main threats.
Eastern Utah will see additional convective activity on Thursday
with drier air moving into western Utah. Dry and increasingly hot
conditions will develop over the weekend.

&&

.SHORT TERM (Through 12Z/6AM Friday)...High pressure has shifted
east of the area this morning, putting Utah and southwest Wyoming
under a southerly flow aloft. This will allow deeper moisture over
southern Utah to spread northward across the entire CWA. By the
afternoon, anticipating PWs in the 0.8 to 1.0 inch range across
much of the area, and higher over southern Utah. Seeing some
showers and a few thunderstorms persisting overnight over western
Utah due to a weak boundary over west central Utah and some
shortwave energy moving across northwest Utah. This convection is
expected to dissipate by mid-morning, resulting in a lull.
However, will see a good amount of convective development across
much of the area this afternoon owing to the increase in moisture.
Heavy rain will be the greatest threat over southern Utah, and
thus conditions are favorable for flash flooding once again.
However, the presence of shortwave energy ejecting from a Pacific
Northwest trough will put a bit greater instability over northern
Utah. Despite limited shear, storms that develop will be capable
of producing gusty winds and hail.

The previously mentioned Pacific Northwest trough is expected to
graze northern Utah beginning Thursday, shifting the flow aloft to
a west to northwest direction that will bring a gradual drying
trend. Thus, enough moisture and instability will remain around
for another round of afternoon and early evening convection,
though it will be more focused over eastern portions of the
forecast area. Additionally, the trough will bring a cold front
through, bringing maxes back to within 5F of seasonal normals.

.LONG TERM (After 12Z/6AM Friday)...Much drier and cooler air will
move into the region behind a departing trough. This cooler air will
help bring temperatures back closer to normal for Friday. The cooler
air will be fleeting, however, as shortwave ridging builds back in
over the weekend with a return to above normal temperatures (upper
90s for most valleys with mid 100s across southern Utah).

A PNW trough starts to approach by Sunday with southwest flow
increasing. This will result in increasing southerly surface winds
Saturday-Monday with winds particularly strong on Sunday with
widespread gusts 30-40 mph. This will increase the fire weather
risk, but guidance has started to introduce a little more moisture
compared to previous runs, so RH values are now forecast to stay
>10% Sunday afternoon as opposed to single digits that were being
forecast in previous runs.

As the trough approaches on Monday there will be a slight chance
(<20% chance) for some afternoon high based thunderstorms
developing. Anything that is able to develop will be capable of
producing microbursts given the dry sub cloud layer. A frontal
passage associated with the trough will scour out the higher
moisture content as drier and cooler air advect into the region.
This will bring the temperatures down closer to normal for early
next week. Winds aloft will remain elevated as the jet stream stays
positioned across the area with a resultant westerly flow. These
elevated winds will mix down during the afternoon so expect breezy
conditions to continue through most of next week with low relative
humidities that will pose a fire weather risk.

&&

.AVIATION...KSLC...VFR conditions will persist for the KSLC terminal
through the period. Some light showers moving in from the southwest
could bring some mid level clouds and breezy variable winds in the
morning. These will transition to afternoon convection that will
pose a threat for gusty and erratic winds, lightning, and heavy rain.

.REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions will prevail
across the airspace. Light rain showers across western Utah will
gradually transition east and dissipate. A brief lull in activity
will give way to scattered afternoon convection across most of the
region. These storms will pose a risk for gusty outflow winds,
lightning, and heavy rain.

&&

.FIRE WEATHER...Moisture that has been concentrated over southern
Utah will spread northward across the entire state, bringing the
threat of afternoon and evening showers and thunderstorms
areawide. Some storms could be strong with the potential to
produce gusty outflow winds as well as some hail. Locally heavy
rainfall will also be possible with storms, particularly over
southern Utah. A trough moving in from the Pacific Northwest will
bring a drying trend beginning Thursday. However, showers and
thunderstorms will continue to be a threat over eastern Utah. The
drying trend will continue Friday through the weekend, bringing a
threat of critical fire weather conditions due to gusty winds and
low relative humidity to southwest Utah on Friday and across the
entire state by Sunday.

&&

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

$$

SHORT TERM/FIRE WEATHER...Traphagan
LONG TERM/AVIATION...Mahan

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