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Area Forecast Discussion
Issued by NWS Salt Lake City, UT
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FXUS65 KSLC 222145
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
345 PM MDT Mon Apr 22 2024

.SYNOPSIS...Warming trend temperatures associated with high
pressure are expected Tuesday into Wednesday before a cooler and
more stormy pattern develops for the latter part of the week.

&&

.SHORT TERM (Through 12z Wednesday)...Surface obs and MSLP
analysis indicate the remnants of a weak boundary over central
Utah at this time, the driver for slightly cooler temps across the
north today vs. yesterday. Mean ridging encompassing much of the
Great Basin will further build into the region over the next 24-36
hours lifting the aforementioned boundary over the northern third
of the state this evening while providing a subtle W-E zone of
moisture convergence and isolated shallow convection potential.
Buildups tracking in from Nevada more than anything, but a
mountain sprinkle is possible. This zone will remain established
over the north through Tuesday owing to slightly higher probs for
convection, again largely isolated, with little if any rainfall
potential.

With the aforementioned high pressure gradually orienting
overhead, northern areas will once again see an upward tick of
temperatures with only periodic cloud cover associated with
aforementioned convective buildups. Changes to come in the long
term portion of the forecast however...

.LONG TERM (After 12Z Wednesday)...Long term period starts off
with a ridge axis shifting east into the Great Plains, a closed
low approaching the lower California coast, and the local forecast
placed within enhanced southwesterly flow between these two
features. With this, mild H7 temps will promote afternoon high
temperatures around 7 to 15 degrees above climatological normal,
and will see some modestly gusty conditions (gusts generally
~20-30 mph) develop across portions of southern and western Utah.
Widespread precipitation isn`t expected, but combination of a bit
more synoptic support from the aforementioned low, diurnal
heating, and sufficient lingering moisture will likely yield some
isolated to scattered afternoon/evening showers across southwest
Wyoming and northern Utah (generally north of the I-80 corridor).

On Thursday, guidance continues to show decent consensus that the
closed low will lift through the forecast region, opening up as it
begins to interact/phase with the northern stream. With the
exception of portions of far southern Utah, the combination of a bit
more moisture and widespread synoptic forcing will bring about
increasing precipitation chances through the morning, with showers
becoming more widespread through the afternoon. Generally, guidance
continues to favor the northern third of the forecast region in
terms of better QPF amounts Thursday. Additionally, there is some
signal for a bit of destabilization (likely on the order of some
pockets of CAPE up to 200 J/kg or so), so a few thunderstorms will
be a possibility. Given the lower latitude origin of the system, H7
temperatures won`t cool too much, so snow levels largely remain
above 8.5kft to around 9.0kft.

Pattern remains active moving into Friday, as while Thursday`s
trough continues to depart to the northeast, a more potent northern
stream trough begins to dig in from the northwest. Much of the
forecast region will be placed in the divergent exit region of
approaching ~100+ kt upper jet, which in combination with a lower
level cold front gradually working through during the day will yield
widespread precipitation more or less areawide. Still some
uncertainty on how long the initial shortwave lingers, but most
guidance suggests enough trailing energy to keep cooler post frontal
shower activity maintained on into Saturday. Given the colder
origins of this system, will see snow levels fall generally into the
7.5kft to 8.5kft range Friday, and continue down to around 7.0kft to
7.5kft by Saturday. Surface temperatures across the region will also
fall as the colder airmass sinks in, with afternoon highs Friday and
Saturday shifting downward generally to around 5 to 15 degrees below
climatological normal.

Uncertainty remains a bit high Sunday onward into early next week
given differences in how guidance resolves the evolution of the
flow. Individual deterministic guidance depiction ranges from zonal
flow within broad longwave troughing across much of the CONUS to
weak shortwave or weak ridge slipping through. Ensemble members seem
to be similarly weighted with no clear signal really favored. As a
result, kept NBM PoPs which carry isolated to scattered diurnal
activity from central Utah northward Sunday and Monday, and NBM
temps which impart a warming trend as the colder H7 temperatures
exit the region.

&&

.AVIATION...KSLC...VFR conditions will persist across the KSLC
terminal through the period. Conditions will remain dry with a few
mid and high clouds. Winds will likely remain light and out of the
north. There is about a 30% chance they briefly go to a light
southerly flow overnight.

.REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions will persist
for the entire airspace as dry conditions with a some mid to high
clouds continue. Winds will be light and variable across central and
northern Utah with some gusty westerly winds across southern Utah
easing overnight.

&&

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

$$

Merrill/Warthen/Mahan

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