High Wind in Utah, March 28, 2022

Area Forecast Discussion...CORRECTED
National Weather Service Salt Lake City UT
433 AM MDT Mon Mar 28 2022

.SYNOPSIS...Unsettled and cooler weather can be expected across
the region through Wednesday. Another weak system will impact the
region Thursday.

&&

.SHORT TERM (Through 12Z Wednesday)...Temperatures across the
northern valleys remain above normal highs for the date as of 4 AM
this morning, with widespread temperatures in the 60s. This will
bring a warm start to the day...and there is some potential highs
will overperform before clouds increase and mid-level cold air
advection begins.

Morning upper air and satellite analysis indicates a ~540dm upper
level low is approaching the California Coast. A 135+kt jet
maxima is rounding the base of this trough with a notable area of
diffluent flow approaching southern Utah this morning.

Ahead of the upper level low, 700mb flow will be at peak
intensity this morning into early this afternoon across western
Utah, when the best chance of strong winds with gusts to 45-50 mph
can be expected. The threat for strong winds will gradually
decrease later in the afternoon into early evening. Current wind
advisories look on track but may run too long into the evening.

As the upper level tracks into southern California and gradually
weakens this afternoon into early this evening, nearly all CAMS
and global model solutions indicate the potential for convection
across the mountains of Utah. While instability isn't notably
high in most cases, preferential jet dynamics should be
sufficient for widespread shower development, with occasional
lightning.

During this portion of the system, snow levels will be quite high,
above 8000-8500 feet into this evening. As the upper level low
continues to fill and crosses southern Nevada tonight into Tuesday
morning, modest mid- level cold air advection should bring 700mb
temperatures down to near -3C across the north and -5C across the
south. This will gradually lower snow levels, though after the
initial well forced precipitation across the northern mountains, a
lull in the precipitation across the north can be expected Tuesday
morning.

Meanwhile, across the south, with the upper level low gradually
filling...the 500mb low looks to redevelop across far northeastern
Arizona Tuesday afternoon into Tuesday evening. Associated with
this will be an area of heavier precipitation crossing southern
Utah from Monday night into Tuesday afternoon/evening.

With the main trough shifting east of the region Tuesday evening,
expect a shift to northwest flow...bringing a period of orographic
enhancement to the Wasatch Mountains and other northwest flow
favoring locations. This period of upslope flow will be associated
with the coldest portion of the system and will add to the snow
totals in these locations.

For now, the western Uinta Mountains look to do well with this
system, particularly during the first portion of the system where
preferential jet dynamics should help to develop period of
moderate to occasionally heavy snow this afternoon into Tuesday
morning. Thus, have issued a winter weather advisory for the
western Uinta Mountains.

As mentioned earlier, a period of moderate to heavy snow is also
expected across the southern mountains, particularly near
Brianhead and potentially near Boulder Mountain. Also issued a
winter weather advisory for these locations.

Other areas to watch for potential winter weather headlines
include the Wasatch Mountains and central Utah mountains though
amounts/impacts look somewhat marginal at this point.

.LONG TERM (After 12Z Wednesday)...A building ridge of high
pressure is forecast across Utah and southwest Wyoming Wednesday.
The wind flow pattern will be out of the northwest most of the
day, allowing for seasonal or even slightly cooler temperatures.
Castle Country may see some downslope winds Wednesday from the
northwest wind direction. Winds at 700 mb are forecast between 30
and 40 kts in this area on current forecast models so we will see
how trends look in the coming days.

It most certainly is a spring time weather pattern looking at the
nature of uncertainty forecast models in the long term period.
Though not particularly significant, models tend to have a tougher
time with weaker systems like the one that is forecast to track
through our area Thursday and Friday. Cluster means paint a
picture of a weak trough with the Canadian model clusters
indicating the weakest trough and the European clusters split on
where to place the trough. That said, this disturbance looks to
progress into Utah from the northwest, providing rain the valleys
and snow showers in the mountains. Some lingering showers over
eastern Utah are possible for Friday. At this juncture we are not
forecasting much in the way of accumulating snow in the mountains.
Temperatures for the last day of March and the first day of April
remain forecast at just slightly cooler than seasonal normals.

The weekend forecast is currently dry under high pressure.
Cluster forecasts do become more divided Sunday into Monday. The
strength of high pressure Sunday is divided to varying degrees
with a potential long wave trough entering the forecast period
early next week, shown in over half the cluster ensembles. That
said, about 20% of the ensembles do not show the trough. The
forecast calls for temperatures to warm through Monday back to
seasonal normals.

&&

.AVIATION...KSLC...Breezy southerly winds are forecast through
much of the day. Wind gusts of 30 to 35 kts are forecast from late
this morning through early this evening. Gusts may occasionally
exceed 40 kts with around a 5% chance that this will occur. CIG
and VIS are expected to remain VFR despite mid-level cloud decks
arriving today. There is about a 20% chance of CIG lowering to
MVFR during the overnight hours. Rain showers are forecast in the
vicinity this afternoon with the best chances to be on station
late this afternoon into this evening.

REST OF UTAH AND SOUTHWEST WYOMING...CIG and VIS are expected to
remain VFR with mid and high based cloud decks. A chance for rain
showers arrives during the afternoon across northern Utah and
southwest Wyoming with the best chances for showers late this
afternoon into this evening. Breezy south to southwest winds are
forecast for much of the day with wind gusts ranging from 25 to 35
kts. Strong south to south-southwest winds are forecast in
southern and western Utah locations through early this evening,
peaking during the afternoon hours. CIG and VIS are expected to
remain VFR with mid and high based cloud decks and the chance for
rain showers arriving during the afternoon in these areas.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Wind Advisory from 10 AM this morning to 8 PM MDT this evening
     for UTZ101-102-115-122.

     Winter Weather Advisory from 6 PM this evening to 6 AM MDT
     Wednesday for UTZ125.

     Winter Weather Advisory from 3 PM this afternoon to 6 AM MDT
     Wednesday for UTZ112.

WY...None.
&&

Kruse/NDeSmet

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