433
FXUS65 KSLC 012156
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
356 PM MDT Sat Jun 1 2024

.SYNOPSIS...High-based convection will bring a threat of dry
microbursts to northern Utah this afternoon/evening. An
increasingly hot and dry airmass will build in to southern Utah
this weekend, while temperatures will be moderated to some degree
by a series of weak cold fronts across the north. Strong high
pressure will bring the hottest temperatures of the season to the
Beehive State Wednesday into Thursday.

&&

.SHORT TERM...Starting with the large-scale pattern, a shallow
shortwave trough is currently moving slowly across SE-OR and
southern ID, likely to continue moving eastward while brushing
through northern Utah. In the lower levels, a weak, quasi-
stationary boundary continues to sit zonally-oriented across
northern Utah and southwest Wyoming. Along this boundary, expect
scattered showers and isolated thunderstorms to continue
developing through the afternoon. Currently, radar reveals these
showers over the Uinta Mtns down to the Book Cliffs, as well as
areas near Wendover and even isolated showers starting to push off
the Oquirrh Mtns. The SPC Mesoanalysis suggests 500-1000 J/kg of
CAPE is present across these areas, and combined with 30-40kts of
bulk shear, showers are more likely to persist after they come
off of higher terrain. The main threat with these showers is gusty
and erratic outflow winds from dry microbursts given dry low
levels and steep lapse rates. Hi-res guidance highlights southwest
WY particularly for strong gusts exceeding 50 mph (20% chance).

One detail to note is the presence of strong surface convergence
over the Salt Lake Valley between the lake breeze and
synoptically-driven southerly flow, which may result in
persistent storms developing over the valley this afternoon...and
thus a continued threat of gusty outflow winds and lightning.

Across southern Utah, hot and dry conditions will persist, with
breezy southwesterly winds this afternoon decreasing after sunset.
Temperatures will remain around 5 degrees above normal.

Heading into tomorrow (Sunday), the aforementioned shortwave
trough will push the weak boundary through northern and central UT
as a cold front. Thus, temperatures will cool by a few degrees
across these areas. Additionally, expect drier conditions aside
from a chance for some isolated showers and thunderstorms across
the Uinta Mtns in the afternoon.

.LONG TERM (After 12Z Monday), Issued 407 AM MDT...
A grazing shortwave trough will drag a rather dry cold front into
Utah early next week. Models and ensembles are in good agreement
of a strong ridge building into the western U.S. later in the
week.

Zonal flow throughout southwest Wyoming and Utah will strengthen
Monday as a longwave trough digs into the PacNW. The trough will
track almost directly east, from Washington into Idaho and
Montana. A weak, relatively dry cold front will track into Utah
during the day Monday, bringing isolated to scattered rain showers
to southwest Wyoming and northern Utah. Precipitation totals will
generally be 0.1" or less, with the highest totals in southwest
Wyoming and near the Idaho border. Winds will be enhanced
throughout southwest Wyoming and Utah, strongest for places with
downslope winds from the west, like the Uinta Basin and Castle
Country, where gusts will exceed 30 mph.

Tuesday will be the coolest day of the week, with a dry northwest
flow. Gusty west to northwest winds are likely for southwest
Wyoming and much of Utah, with peak gusts for the same locations
as Monday.

There is strong model agreement on a powerful ridge in the
eastern Pacific tracking inland Tuesday and Wednesday. For
southwest Wyoming and Utah, Thursday and Friday will likely be the
warmest days of the week. Highs and lows will be 10-20F warmer
than normal for those days. High temperatures will get into in the
90s for most valleys, including the urban corridor of northern
Utah, and 100s for lower Washington County. Record high
temperatures are generally 3-5F warmer than forecast high
temperatures each day.

&&

.AVIATION...KSLC...Northwest winds will prevail into this evening.
Gusty and erratic outflow winds are possible (30-50% chance) from
showers and thunderstorms moving near the terminal this evening,
mainly 23Z-02Z. Winds may become light and variable for a period
after any outflow winds overnight, likely trending back to light
south drainage winds through early Sunday morning. Northerly
gradient should then support an earlier shift back to the NW by mid
to late Sunday morning.

.REST OF UTAH AND SOUTHWEST WYOMING...Widely scattered showers and
thunderstorms over northern Utah and southwest Wyoming this
afternoon through early evening will mainly have bases at/above
10kft, and will be capable of gusty and erratic outflow winds.
Across southern Utah, gusty southwest winds will continue this
afternoon before dying down this evening after sunset. Drier
westerly flow will prevail on Sunday.

&&

.FIRE WEATHER...Isolated high-based showers and thunderstorms are
expected across the northern half of Utah this afternoon and
evening. Gusts near these showers are likely to exceed 40 mph,
with the strongest storms producing gusts up to 60 mph. A couple
of weak cold fronts will then impact northern Utah, one early
Sunday and one likely late Monday into Tuesday. Each frontal
passage will increase RH, and the Monday front will bring very
light precipitation (and thus low chances for wetting rains,
especially across extreme northern Utah). For southern Utah,
expect hot, dry, and breezy conditions today, remaining hot and
dry for the near future. By Wednesday, strong high pressure will
build, producing very hot and dry conditions state-wide.

&&

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

$$

Cunningham/Church/Wilson

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