796
FXUS65 KSLC 071957
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
157 PM MDT Fri Jun 7 2024

.SYNOPSIS...An early season heat wave will impact the area through
the end of the week, with record-challenging temperatures
anticipated into Friday, especially for southern Utah. As the
ridge flattens through the weekend, the warming trend will curb
and some moisture will move into the area, increasing the threat
of convection, particularly today. The threat of showers and
thunderstorms will continue into early next week.

&&

.SHORT TERM (Through 12Z Saturday)...
The main focus in the short term forecast is the increasing
thunderstorm potential this afternoon into this evening,
particularly the increasing threat of strong to severe wind gusts.
A shortwave trough moving through north-central Nevada late this
afternoon will continue to progress eastward into northern Utah
this evening, and will be the focus for organizing convective
development out of Nevada eastward across northern and central
Utah through this evening. The trough is ushering in lowering
heights aloft, increasing low to mid level lapse rates and mid-
level moisture, as well as increasing uni-directional speed shear
across northern Utah. The convective mode will be slow upscale
growth of terrain forced thunderstorms over Nevada, and are
expected to increase into at least loosely organized multicell
clusters. If enough cold pool / shear balance can be established
with upscale growth, the higher end scenario is a more organized
convective line moving into the Wasatch front this evening, which
would support a bit more widespread strong to severe wind gusts.
The most likely timing remains now through 5pm across the West
Desert, and 5 to 8pm along the Wasatch Front, and 8 to 11pm into
Uinta County Wyoming and the Uinta Basin. In addition, there is a
lower threat for some isolated severe wind gusts across the Swell,
Castle Country, and into the Uinta basin earlier this afternoon,
now through 5pm with an area of showers / thunderstorms moving
through.

Otherwise, heat remains the threat across far southern Utah today
into Saturday where Excessive Heat Warnings and Heat Advisories
remain in effect. The excessive heat will start to diminish on
Saturday, giving way to slightly cooler temperatures later in the
weekend into early next week.

On Saturday, we will be located behind the shortwave trough that
moves through later this evening and overnight. This will largely
diminish the shower and thunderstorm chances on Saturday as we
become more subsident. However, there is still a low chance of
isolated to widely scattered showers and thunderstorms developing
over the higher terrain, and possibly into the West Desert out of
Nevada again later in the day.


.LONG TERM (After 12Z Sunday), Issued 354 AM MDT...
A shortwave will graze northern Utah on Sunday. This will help to
initiate afternoon convection, particularly across northern
Utah/SW Wyoming and the terrain of central and northern Utah. SPC
has a marginal risk for severe thunderstorms for northern Utah and
southwest Wyoming from Salt Lake City northward. Steep lapse
rates along with modest CAPE/Shear profiles will be conducive for
afternoon storms to contain gusty winds that could meet severe
criteria. Soundings depict a dry surface layer up to ~10,000 feet
so any storms that do develop will be high based and capable of
producing microbursts. In addition to the risk for strong to
severe storms, temperatures will be 10-15 degrees above normal,
although slightly cooler across far southern Utah compared to
where they have been (~100F).

By Monday, cooler and drier air starts to move in behind the exiting
shortwave. However, highs will still be ~5 degrees above normal.
Afternoon convection will remain possible across the far eastern
portion of the CWA given the shortwave will be slow to exit to our
east. Temperatures will start to warm again throughout the week as
high pressure settles back into the area. Expect temperatures once
again 10-15 degrees above normal by midweek.

Towards the end of the week a cutoff low off the coast of southern
California will shift east towards the desert southwest. As it does
so, southwesterly flow will begin to increase with increasing winds
near the surface. Isolated precipitation chances will increase as
this low gets closer to southern Utah by Friday.

&&

.AVIATION...KSLC...Start of TAF period active as passing shortwave
will result in high based convection Fri evening. Lightning and
gusty outflow winds will be primary threat with any convection near
terminal. VFR conds largely prevail, though brief dips possible as
if/when strongest convection passes overhead. Additionally, low
confidence, but cannot entirely rule out some brief VIS reductions
from blowing dust if initial strong outflow is on the dry side.
Following passing of convection, winds may become more variable for
a time, but should eventually settle back S and remain as such
through Sat morning. Winds then switch back to NW by early Sat
afternoon. While coverage and overall threat appears lower, some
isolated high based convection once again appears possible across N
UT Sat afternoon/evening.

.REST OF UTAH AND SOUTHWEST WYOMING...TAF period initially active as
passing shortwave triggers scattered high based convection,
primarily at/around northern terminals. This convection will carry
primary threats of gusty outflow winds and lightning. Being high
based, VFR conds likely prevail aside from brief dips when strongest
convection moves overhead. Winds likely see period of variability
following passage of convection, with some terminals then settling
back to a more diurnally normal direction. Moving into Saturday,
things look to follow a more diurnally normal trend. Into Saturday
afternoon and evening, once again will have some threat of isolated
high based convection and associated wind gust threat.

&&

.FIRE WEATHER...
For this afternoon, two main areas for thunderstorms to watch,
one being across the Swell, Castle County and into Uinta Basin
early this afternoon. These storms will have the greatest
potential for dry lightning due to a very dry sub-cloud layer.
Meanwhile the second area will be storms moving out of Nevada
midday, into the West Desert by mid-afternoon, and eventually into
the Wasatch Front this evening. A Marginal Risk of severe winds
(level 1 of 5), is in place today, meaning a few isolated to
widely scattered wind gusts to around 60 mph are possible.
Otherwise, all storms will be capable of strong, gusty and erratic
outflow winds and microbursts. Otherwise, excessive heat and very
dry conditions continues today across southern Utah.

Isolated to widely scattered showers and thunderstorms will
continue into the weekend, although likely with less coverage and
intensity than Friday. The very hot conditions over southern Utah
will diminish gradually over the weekend and into early next week,
but still remain more climatologically hot and still very dry with
RH values into the low teens to upper single digits across far
southern Utah. The heat will start to build again by mid to late,
especially across southern and central Utah.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Heat Advisory until midnight MDT tonight for UTZ121-122-128>130.

     Excessive Heat Warning until midnight MDT Saturday night for
     UTZ123-124-131.

WY...None.
&&

$$

SHORT TERM...Church
LONG TERM...Mahan
AVIATION...Warthen
FIRE WEATHER...Church

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