926
FXUS65 KSLC 062011
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
211 PM MDT Thu Jun 6 2024

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

&&

.SHORT TERM (Through 12Z Saturday)...
Dangerous heat continues across southern Utah today through
Saturday, with the two hottest days being today and Friday. An
amplified ridge remains in place across the southwest today,
before retreating slightly eastward Friday and starting to
diminish in amplitude by Saturday. This will bring the hottest
temperatures across the eastern half of the state today, shifting
to the eastern half of the state seeing their hottest day on
Friday. High temperatures at St George, Zion, and Glen Canyon NRA
/ Lake Powell will peak in the 104-108 range, with overnight lows
in the mid 70s limiting overnight cooling. Also temperatures this
hot are more similar to conditions in mid July than early June,
thus the early season nature of the heat means folks are not quite
acclimated to these temperatures yet. Excessive Heat Warnings
continue through Saturday for the aforementioned hottest
locations, with Heat Advisories highlighting adjacent areas across
southern Utah where hot daytime temperatures drive more of the
Heat Risk threat, but overnight lows will allow for better
recovery.

The other main hazard to watch for on Friday is increasingly
becoming the potential for scattered showers and thunderstorms
across northern and central Utah capable of producing strong to
isolated severe wind gusts exceeding 58 mph. As the ridge starts
to break down on Friday heights drop across northern Utah
partially in response to a northern stream wave moving through
Montana, but also another weak shortwave moving out of Nevada and
across northern Utah by late Friday afternoon and evening. As this
happens, mid-level moisture and lapse rates with increased speed
shear spread across northern Utah over a very dry subcloud layer
and inverted-v profile. This setup is prime to produce strong
outflow winds from scattered, loosely organized thunderstorm
clusters. HREF probabilities of exceeding 50 mph are highest
across west-central Utah including Juab, and Millard counties at
around 60%, and similar near Wendover and along the I-80 corridor
through the Salt Flats. In addition another area of higher
probabilities extends across eastern Utah including the Uinta
Basin, and Castle Country, at around 40%. Along the Wasatch Front,
there is certainly potential for strong winds to move in by
Friday evening, however confidence in this low at this time
(around 10%) and will depend on whether storms can grow upscale
enough to sustain into the early evening hours into the Wasatch
Front.

.LONG TERM (After 12Z Saturday), Issued 351 AM MDT...
A mostly dry and hot pattern will continue through the long term
period. However, the ridge that is responsible for the heat will
flatten again on Saturday, thanks to a shortwave moving across
northern Utah, allowing temperatures to cool a couple of degrees.
Temperatures will still remain ~10 degrees above normal across
most of the region. This shortwave won`t have much synoptic
support, and environmental shear/instability/moisture will be
lacking. So if any storms are able to form they will likely be
confined to the terrain of the central and northern mountains with
a focus over the Uintas.

Similar surface conditions are expected on Sunday, but flow aloft
will transition to a southwesterly component ahead of a trough
moving onshore. This will help to advect more mid and upper level
moisture into the Great Basin with increasing cloud cover. Given
better shear/instability/moisture on Sunday expect a slightly higher
chance of afternoon convection, particularly over the terrain.
Soundings are highlighting inverted V profiles, indicating drier
conditions near the surface. Given greater winds aloft, the
potential for momentum transfer to the surface will be elevated with
any storms that do form, resulting in gusty and erratic winds.

This trough will pass by to the east on Monday with temperatures
cooling a few degrees on Monday and Tuesday with mostly dry
conditions prevailing as a low amplitude ridge stays positioned
across the Rockies. Guidance is in good agreement that by the end of
next week a cutoff low off the southern California coast will begin
to meander inland. This will prevent the ridge from amplifying,
although temperatures will remain above normal, and provide more
precipitation chances.

&&

.AVIATION...KSLC...Wind direction becomes less certain this evening,
with models split on potential for outflow from convection moving
from NV into ID. If outflow forms, most likely window of arrival at
KSLC is ~02-06Z, and would result in a brief period of gusty NW
winds, with NW winds then likely lingering into the night. Better
consensus on light S flow redeveloping by ~10Z, shifting back NW
late morning to early afternoon Friday. Isolated to scattered high
based convection Friday afternoon/evening will once again bring a
threat of gusty erratic outflow winds to the terminal.

.REST OF UTAH AND SOUTHWEST WYOMING...Through Thursday evening,
isolated to scattered convection moving generally from NV into ID
will have some potential to push gusty outflow winds to northern
terminals. Winds likely would carry a bit more variability
thereafter into the night. Winds trend more diurnally normal Friday
morning into the day, but isolated to scattered high based
convection will once again carry a threat of gusty and erratic
outflow winds in addition to lightning. That said, given high based
nature, largely anticipate cloud cover to remain VFR.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Heat Advisory until midnight MDT Friday night 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

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