River Flood Warning 6, NWS Salt Lake City, UT

Area Forecast Discussion
National Weather Service Salt Lake City UT
344 PM MDT Sun Apr 30 2023

.SYNOPSIS...High pressure will bring warming temperatures more
reminiscent of early summer through early in the week. A cooler,
unsettled pattern is expected to develop Thursday and continue
into next weekend.

&&

.SHORT TERM (Through 12Z Tuesday)...An amplified mid level ridge
extends across the Intermountain region this afternoon,
maintaining a very warm air mass across the forecast area.
Temperatures this afternoon have reached the low to mid 80s along
much of the Wasatch Front, and near 90 around the St George area.

This ridge will shift east tonight as an upper trough located just
off shore encroaches on the Pacific Coast. As this transition
begins this evening, pressure falls across NV will induce an
easterly gradient across northern UT, and will allow for locally
gusty winds along the Wasatch Front. Speeds will remain below
advisory thresholds, but could see some locally breezy to windy
conditions near the canyons along the Wasatch Front this evening,
before the gradient relaxes overnight.

As the upper trough impinges on the Pacific Coast Monday,
southerly flow will strengthen across the eastern Great Basin,
resulting in breezy to windy conditions along/west of I-15.
Currently not anticipating winds to reach advisory criteria (70%
confidence), and thus have held off on any headlines. The air mass
remains quite warm with 700mb temps forecast around 10C Monday
afternoon, and thus will see another day of near record temps
across northern Utah where max temps will run 15-20F above climo.
Slightly cooler air aloft will begin to work its way into southern
Utah, however max temps here will still run 10F for so above
climo.

A slight influx of mid level moisture ahead of the upstream trough
along with an increase in synoptic scale lift later in the day
will yield a window for high based convection late
afternoon/evening. This will be most likely across the
northeastern CWA (north of I-80 and east of I-15), but can't be
ruled out across northwest UT, and perhaps spreading into central
UT as well. Strong microburst winds would be possible with any
high based convection which develops.

.LONG TERM (After 12Z/6AM Tuesday)...An area of low pressure will
continue to churn off the west coast with very little movement
forecast through Wednesday. The timing of when this low will push
onshore California has not changed much though perhaps a little
later than the last model runs. What this'll all mean for Utah is a
windy, but dry Tuesday and Wednesday followed by rain with snow
above 8,000 feet Thursday. Modest amounts of instability could allow
for thunderstorm development Thursday afternoon and evening as well.
Winds are expected to be strongest in far southwest Utah Wednesday
with a low level jet of 40 knots across Nevada and through northern
Arizona. An 80+% likelihood for 35 knot gusts or stronger are
forecast from Cedar City to Leeds as a result. Fairly widespread
precipitation is forecast to begin Thursday afternoon across Utah
and southwest Wyoming. Chances for showers will be fairly short-
lived across southern Utah, ending by Friday morning, with continued
chanced for precipitation through Friday in northern Utah.

By the weekend, the general consensus is that the low begins to
track to the north and potentially retrograde northwest of Utah
while losing strength. This transition occurs as yet a deeper low
develops off the west coast. By Monday, Utah's forecast does look to
be influenced by this next incoming but this in-between period is
where the forecast is less certain especially in northern Utah. At
the moment, northern Utah has a 30 to 60 percent chance for rain
showers Saturday and Sunday while southern Utah is dry. &&

.AVIATION...KSLC...The SLC terminal will see VFR conditions through
the evening with mostly clear skies. Northwest winds will prevail
through the remainder of the afternoon, with some light and variable
or southeasterly winds for parts of the terminal through about 22Z
or 23Z with the lake breeze front overhead. There is a 30 percent
chance that the lake breeze front will not fully cross the terminal.
Prevailing southeasterly winds are expected to return between 01Z
and 03Z.

.REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions will continue
across Utah and southwest Wyoming through the overnight hours with
some scattered clouds. Winds will be generally light and terrain
driven, though some periodic southerly wind gusts up to 30 mph will
impact portions of southwest Utah through the early evening.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Flood Watch through Friday morning for UTZ107.

WY...None.
&&

Seaman/NDesmet

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