Text Products for AFD Issued by SLC

Area Forecast Discussion
Issued by NWS Salt Lake City, UT
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FXUS65 KSLC 200937
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
337 AM MDT Sat Apr 20 2024

.SYNOPSIS...High pressure over the Great Basin will build into
Utah and southwest Wyoming by this evening, bringing dry
conditions and very mild temperatures. A dry cold front on Monday
will curb the warning trend. A more stormy pattern is expected to
return by the middle of next week.

&&

.SHORT TERM (Through 12Z/6AM Monday)...High pressure is making its
way into the Great Basin this morning as a weakening Pacific storm
system makes its way from Arizona into New Mexico. This system,
along with a bit of instability from a stalled front near the
Utah/Idaho border, is resulting in a few very light showers
focused over southern Utah, with little if any precipitation
hitting the ground.

The Great Basin ridge will track east today, moving into Utah by
this evening as the Desert Southwest trough continues east across
New Mexico into Texas as it continues to weaken. Thus, a small
amount of instability will be available, primarily over southern
and eastern portions of the forecast area. As a result, cannot
rule out the possibility of a few showers this afternoon over the
higher terrain. However, the trend by the evening will be toward
stabilization. Temperatures will continue their warming trend,
with maxes running around 5F above climo over northern portions of
the area, and up to 10F above climo over southern Utah.

With high pressure firmly in place on Sunday, will see dry
conditions areawide as warming of the airmass continues. Maxes on
Friday will average 15F above seasonal normals across the entire
forecast area.

.LONG TERM (After 12Z/6AM Monday)...Given depressed heights and
a northwest flow ushering in cooler temperatures aloft, high
temperatures on Monday will be a few degrees cooler than on Sunday,
though dry weather conditions should prevail.

Nearly all ensemble members suggest an amplifying ridge over the
Great Basin on tuesday, with 700MB temperatures rising to 6-10C.
Given readings and a moderate southwest flow promoting mixing, high
temperatures are expected to be 10 to 15 degrees above normal.

The ridge axis will shift eastward on Wednesday as a trough of low
pressure reaches the Pacific Coast.  Differences begin to emerge in
the ensemble solutions, with roughly 70 percent suggesting a deeper
closed low off the California Coast, while 30 percent favor a broad
trough of low pressure along the Pacific Coast.  Either way, another
warm and generally dry day is in store for much of the forecast
area, though a few convective showers will be possible across
northwest Utah.

By Thursday, roughly 70 percent of ensemble members suggest a
broad trough of low pressure over the region as northern and
southern stream energy phases. Given forcing and adequate
moisture, chance pops (30- 50 percent) over valley locations of
northern and central Utah and likely pops (60-70) over mountains
look reasonable. Given modest QPF, high snow levels (above 9K
feet) and low snow ratios, accumulations and impacts look to be
minimal.

Ensembles are in excellent agreement (90 percent of members) with a
deepening trough over the Great Basin on Friday into Friday night.
With cold air advection, snow levels will lower to roughly 7K feet.
Deterministic models are indicating frontogenesis with a potential
for significant precipitation totals during this period.

25th-75th percentile NBM QPF projections are roughly from a trace to
0.5" for valley locations of northern and central Utah and 0.50-
1.00" for the mountains, with lower precipitation totals across
southern Utah.

&&

.AVIATION...KSLC...VFR conditions are expected to prevail through
the TAF period under mid and upper level cloud cover. Winds will
persist out of a northerly direction, reverting back to a southerly
flow around 08Z. Between 03-08Z, there will likely be periods of
light and variable flow of 5kts or less. There is a 30% chance that
winds will revert to southerly before 08Z.

.REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions are expected to
prevail across the forecast area through the TAF period.
Predominantly northerly winds are expected to prevail through the
late evening hours, reverting back to light drainage flows during
the overnight hours. Otherwise, scattered to broken mid and upper
level cloud cover will prevail through the early morning, briefly
clearing, then clouding up again late tomorrow morning.

&&

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

$$

SHORT TERM...Traphagan
LONG TERM/AVIATION...Barjenbruch

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