Flood in Utah, May 11, 2023

Area Forecast Discussion
National Weather Service Salt Lake City UT
417 AM MDT Thu May 11 2023

.SYNOPSIS...An unsettled spring pattern will continue through much
of the forecast period, with a warming trend expected this weekend
into next week.

&&

.SHORT TERM (THROUGH 12Z SUNDAY)...High pressure is building into
the Great Basin this morning while an upper low continues to exit
east of the Four Corners. A slightly drier and more stable airmass
has spread into Utah, with Mostly clear skies in place this morning.
Not expecting much in the way of convection today, although isolated
showers may develop over/near the western Uinta Mountains this
afternoon. Afternoon max temperatures will remain near
climatological normals.

A weak disturbance riding over the ridge will drop into Utah
tomorrow. This will do little other than maintain seasonal
temperatures over the area. A bit more notable will be the shortwave
trough over southern Saskatchewan that gets pulled westward tomorrow
around the low which by then will be making its way across the
central/northern Great Plains. This disturbance will quickly pinch
off into a closed low by Saturday afternoon, then retrograde
westward across northern Utah and Idaho creating a rex block in
combination with high pressure over southwest Canada.

Moisture will increase from the east and south, with showers and
thunderstorms increasing first across northeast Utah and southwest
Wyoming late tomorrow afternoon, then gradually becoming more
widespread over the area on Saturday. In addition, a period of
easterly winds will develop over the area. Because the low
retrogrades, H7 cross-barrier flow is not expected to remain in
place for long; rather, it is forecast to become southeasterly after
06z Sunday. In addition, H7 cold advection is fairly weak. However,
an easterly surface pressure gradient is forecast across northeast
Utah and southwest Wyoming Saturday afternoon through Saturday
night. With the lack of support from aloft, expect mainly enhanced
localized canyon winds which should come in below advisory criteria.
NBM probabilities of wind gusts greater than 34kts remain under 50%
across the Wasatch Front and Cache Valley, although it is noted that
hi-res models are yet to be incorporated since the period in
question is beyond the range of most of these models.

.LONG TERM (After 12Z/6AM Sunday)...Come Mothers Day, an area of low
pressure is forecast to track northwest and away from Utah while
high pressure builds over the region. High pressure will be in
control of the weather pattern through the next week. A daily threat
for afternoon showers and thunderstorms are forecast, but these are
expected be over the terrain and diurnally driven. There is no one
day with a better chance for thunderstorms over another next week
and no one area with a substantially better chance over another. The
key here is you have outdoor plans in our higher elevations, be
prepared for a thunderstorm in the afternoon.

Temperatures are creeping on the up and up ever so steadily next
week. We're talking in the 20% to 50% likelihood range for 90
degrees along the Wasatch Front, West Desert and Utah County areas
toward the end of the week. With above normal temperatures predicted
in the 8-14 day outlook we'll go ahead and say...and with that a
more summertime pattern begins.

&&

.FIRE WEATHER...A drier and more stable airmass will be over the
area today. A weak disturbance will bring a few showers and
thunderstorms to northeast Utah tomorrow while the rest of the area
remains dry. Moisture will increase into the area over the weekend
as a low pressure system tracks northwestward through Idaho and
northern Utah, with the moisture then remaining in place through at
least the first half of next week as high pressure builds over Utah.
Expect increased coverage of showers and thunderstorms during this
time while temperatures trend warmer.

&&

.AVIATION...KSLC...Southeast winds are forecast through 15z this
morning when winds are forecast to shift out of the northwest. A
slight increase in northwest winds are forecast mid-day. Look for
winds to shift back out of the southeast at 03z. VFR conditions are
expected with either high based clouds or periods of SKC skies.

.REST OF UTAH AND SOUTHWEST WYOMING...Light winds are generally
expected today across UT and SW WY. Breezy conditions are forecast
at BCE beginning mid-morning and likely to persist throughout the
day. VFR conditions are forecast.

&&

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

WY...None.
&&

Cheng/NDeSmet

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