Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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FXUS65 KSLC 221542

Area Forecast Discussion
National Weather Service Salt Lake City UT
942 AM MDT Mon Jul 22 2019

.SYNOPSIS...A broad area of high pressure aloft will remain
centered near the four corners region through late in the week.
Monsoonal moisture will spread north across the region beginning
Tuesday, resulting in an increase of mainly afternoon and evening
thunderstorm activity through late in the week.


.DISCUSSION...Morning water vapor and H5 analysis depict an
amplified ridge across the intermountain region, with center of
circulation currently oriented over the 4-corners region. A deep
pool of sub-trop moisture remains in place over northern
Mexico/southern Arizona, with trends slowly advecting north up the
lower Colorado valley. This trend will continue moving forward
with the deep moisture continuing a northward push along the
western periphery of the high into extreme southern/western Utah
and Nevada Tuesday, prior to encompassing the majority of the
area Wednesday on.

In the near term sensible weather will remain hot and dry, with
maxes pushing into the triple digits along the Wasatch front during
peak heating today through Tuesday, while elsewhere temps will be
running some 4-7 degrees above climo. A heat advisory remains in
place for the Wasatch Front/northwest Deserts, as poor overnight
recovery will exacerbate conditions for the heat sensitive groups.

Primary forecast problem this shift will be to delve more into the
the expected moisture push moving forward. No updates made or
planned this update.

.PREVIOUS DISCUSSION...By Wednesday/Thursday PWAT values of 1.00"
or more will cover much of the forecast area outside of the
Utah/Idaho border region. The now well primed air mass should
support terrain-based convection, with the potential for locally
heavy rain. Dynamic forcing would greatly enhance precip, though
with the still broad upper ridge in place centered on the four
corners region any vorticity lobes rotating around the perimeter
of the high will likely track through Nevada. Extreme southwest
and northwest Utah may see enhanced dynamic support from these
features, though the best chance would come at the end of the week
as the upper ridge begins to weaken over the region


.AVIATION...Southeast winds at the SLC terminal are
expected to become northwest between 19-20Z today. VFR conditions
will prevail through the period.


.FIRE WEATHER...The ridge of high pressure has set up over the
Four Corners region which will tap deep moisture over old Mexico
and bring it northward reaching Utah by Tuesday. Initially these
storms are expected to be dry producing strong gusty winds but by
Tuesday night moisture will increase and most storms will be
producing rain. The moisture influx producing wetting rains in
most cases will continue Wednesday through Thursday across
southern and central Utah with the northern tier most likely
remaining dry. However, a disturbance at mid levels moving around
the high is expected to move into northern Utah by Friday morning
which will give northern Utah the best chance for rain. A short
wave moving across the Northern Rockies will squash the high and
bring a drier west to Northwest flow across the region by Saturday
and Sunday, although lingering thunderstorms are possible over the
mountains and eastern zones.


UT...Heat Advisory until midnight MDT Tuesday night for UTZ002>005.




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