Hail in Utah, May 15, 2016

Area Forecast Discussion
National Weather Service Salt Lake City UT
932 AM MDT SUN MAY 15 2016

.SYNOPSIS...A storm system moving into the area today will last
through early next week. This system will bring a return to cooler
temperatures and showery conditions with a few thunderstorms to
much of Utah and southwest Wyoming.

&&

.DISCUSSION...Morning water vapor and H5 analysis depict an upper
low over the PacNW with center of circulation over NE Oregon.
Downstream of this an ejecting short wave is lifting NE across
northern Utah and and Idaho. This wave is currently driving the
attendant cold front south along the Wasatch Front with current
location over southern Salt Lake County southwest through Dugway.

Two primary areas of precip to note, firstly along and ahead of
the front beneath a zone of weak diffluent flow aloft, and second
oriented along the primary H7 baroclinic zone over northwestern
Utah where CAA is being maximized in an increasingly frontogenic
environment. Though vertical profiles indicate minimal instability
breadth of forcing is aiding to spark isolated thunderstorms in
both areas.

The aforementioned front made a shallow and rapid surge across
the GSL earlier this morning, but advancement has slowed for the
time being as the mid level CAA support needs to once again catch
up to it. As this occurs, anticipate showers/storms to expand in
areal coverage from about Salt Lake south to the I-70 corridor
later this morning into the early afternoon, with this zone
translating largely east from there later today into this evening.
Latest Hi- res guidance including HRRR support this, with areas
upstream of this frontal zone minimally unstable enough to support
more isolated to scattered coverage of convection. Made several
updates through this evening to increase PoPs coincident with this
frontal zone passage, increase cloud cover, and add gusty
northwesterly wind mention in the western valleys for a few hours
coincident and post frontal passage.

Not much else to note in the near term, outside of a continuation
of warm and dry conditions across the southeast today, with breezy
southwesterly winds in the pre-frontal environment.

The upper low will continue to take a southeasterly trajectory
from its current locale, eventually orienting over southern
Idaho/northern Utah overnight tonight through tomorrow. Areas of
focused showers (with convective threat waning after midnight)
look to hold across central/eastern Utah overnight though coverage
should trend more scattered in nature as forcing should largely be
limited to weakly convergent areas and terrain interactions.
Diurnal support tomorrow will aid for increased convective
development areawide beneath the cold core of the system overhead.

&&

.AVIATION...Gusty northwest winds will diminish at the KSLC terminal
by late morning. Periodic showers and isolated thunderstorms are
possible through most of the day, and as such periods of erratic
winds may be possible. VFR conditions should remain with a 10%
chance of a brief drop in CIGS to MVFR in heavier showers. Expect a
late switch to southeast winds this evening.

&&

.SLC Watches/Warnings/Advisories...
UT...None.
WY...None.
&&

Merrill/Dewey

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