High Wind in Utah, May 8, 2022

Area Forecast Discussion
National Weather Service Salt Lake City UT
434 AM MDT Sun May 8 2022

.SYNOPSIS...Warm, dry, and windy conditions will continue across
southern Utah today, while a strong cold front crosses the north
late this afternoon and this evening. A cooler and more stable
airmass will follow for Monday, before southerly flow follows for
Tuesday into Wednesday.

&&

.SHORT TERM (Through 12Z Wednesday)...A longwave trough remains in
place across much of the western CONUS early this morning, with
the next shortwave trough currently making landfall along the
Oregon/northern California coast. Meanwhile, a surface front
extends from east central Utah back into southwest Utah/southern
Nevada, and will mix/retreat northward into central Utah today in
advance of the approaching wave. South of this boundary the
combination of strong flow aloft (50-60 kts at 700mb this
afternoon) and pressure falls along the boundary will result in
very windy conditions across southern Utah. Have expanded the
going Wind Advisory to include much of southwest Utah as well as
the central valleys south of I-70. Will need to monitor trends as
a few sites may approach high wind criteria.

The approaching shortwave trough will lift across northern Utah
tonight through early Monday morning. Strong dynamic forcing
this evening will result in a window for widespread precipitation
across the area, with precipitation gradually eroding from south
to north overnight through early Monday morning. Much colder air
will lower snow levels to near 6 kft this evening, then
potentially to the valley floors where precipitation lingers
overnight, primarily north of I-80. Any valley accumulation will
remain confined to grassy/elevated surfaces, while a few inches of
accumulation is expected across the higher terrain.

This much colder airmass will keep temperatures confined to the
upper 40s and low 50s across most northern valleys, a good 15
degrees below climo. A hard freeze looks likely late Monday
night/early Tuesday morning across the Cache Valley, and perhaps
far northern portions of the I-15 corridor from Brigham City to
the Idaho border. Some uncertainty remains regarding cloud cover,
thus have held off on any headlines at this point.

As this wave lifts away from the area Monday, the next shortwave
will dig along the California coast Monday into Tuesday. As the
upper flow backs in response to this digging upstream trough,
gusty southwest winds will persist Monday across the far south,
then overspread much of southern and central Utah Tuesday. With
this backing flow temperatures will recover back into the 60s
across most northern and western valleys Tuesday afternoon.

.LONG TERM (After 12Z Wednesday)...The longwave trough that will
result in windy conditions several days during the week is expected
to reach its southernmost extent Wednesday. There is good agreement
on that with ensemble guidance. Once it reaches southern California,
it will lift northeastward, with the low expected to swing through
Utah. Weather conditions will stay similar from Tuesday to
Wednesday, with continued windy conditions throughout southern Utah.
Temperatures are expected to reach near average throughout southwest
Wyoming and Utah with gusty southwest warm air advection.

There is really good agreement that the trough will lift across Utah
Thursday. As it does, it will be in a weakening phase. This will
result in a much lighter winds compared to prior in the week. It
will also increase precipitation chances, mainly in southwest
Wyoming and northern Utah. Totals are not expected to be much, with
most guidance around 0.05-0.15" for valleys and slightly higher in
the mountains. Temperatures will be a few degrees cooler than
Wednesday with the cold core moving through. Snow levels will
decrease to around 6000 ft. Light snow accumulation is expected
in the northern mountains.

Ensemble guidance has trended northward with a shortwave Friday.
Prior runs had it grazing southwest Wyoming and northern Utah, but
close enough for some moisture. More recent guidance suggests that
misses the region further north. Including all GEFS, EPS, and CMCE
ensemble members, 75% suggest that. The other 25% have a more
amplified trough that would be cooler and bring better precipitation
chances. Temperatures will likely warm to near average, with warmer
than average conditions in southern Utah where the grazing trough
will stay far to the north and ridging will be building. A ridge is
expected to be in place Saturday into next week for much of the west
with warming temperatures.

&&

.AVIATION...KSLC...Northwest winds are expected much of the day.
Winds will increase during the afternoon, with gusts reaching over
20 knots. Ceilings will be lowering ahead of a storm that will bring
light rain showers into the evening. Gusty, erratic outflow winds
are expected from nearby showers from around 21-00Z. As conditions
become less dry and more precipitation builds in, lower ceilings and
better chances for light rain are expected. VFR conditions will
prevail, with the best chance for MVFR ceilings from 01-06Z. Showers
will diminish by sunrise Monday.

.REST OF UTAH AND SOUTHWEST WYOMING...Winds will be gusty throughout
the region during the afternoon. The strongest speeds will be in
southern Utah, with gusts reaching around 40 knots. Scattered
showers will build into southwest Wyoming and northern Utah during
the afternoon. These will result in gusty, erratic outflow winds
near any showers from around 21-00Z. Better chances for light rain
and MVFR ceilings are expected from 00-06Z. Light snow is expected
at KEVW. That could result in IFR conditions during the evening.

&&

.FIRE WEATHER...Strong southwest winds will continue across
southern Utah today into this evening, with gusts in excess of 45
mph can be expected. The airmass across southern Utah will remain
very dry, with RH values again falling into the 10 to 15 percent
range this afternoon.

Meanwhile, a strong cold front will cross northern Utah late this
afternoon and evening, bringing much cooler temperatures along
with valley rain and mountain snow showers. Isolated afternoon and
evening thunderstorms can also be expected across the north. As
much colder air filters into the area, snow levels may fall to the
valley floors across northern Utah late tonight into Monday
morning.

Gusty southwest and low relatively humidity will persist across
southern Utah Monday, while a cool and stable airmass settles
across the north. By Tuesday southerly winds will increase across
the state, and continue into the day Wednesday, ahead of an
approaching low pressure system. This low will cross the area
Wednesday night into Thursday bringing one last chance for
precipitation before a drier and warmer pattern develops heading
into next weekend.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Wind Advisory from 11 AM this morning to 9 PM MDT this evening
     for UTZ119-121>124-126>131.

WY...None.
&&

Seaman/Wilson

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