Area Forecast Discussion
Issued by NWS Salt Lake City, UT
FXUS65 KSLC 251115
Area Forecast Discussion
National Weather Service Salt Lake City UT
515 AM MDT WED MAY 25 2016
.SYNOPSIS...The elongated upper level trough over the Great Basin
will shift slowly across the state through Thursday. Unsettled
conditions associated with this trough will persist through the end
of the week.
.SHORT TERM (Through 18z Saturday)...The large-scale pattern this
morning consists of a longwave trough with its mean axis extending
from the northern Rockies to the southern/central California coast.
Embedded in this trough are several features. The first is the
closed low that is still lingering over southern Saskatchewan, with
a vort max rotating around it into western Oregon and southeast
Idaho. Next is another closed low over the southern California
coast, while weak ripples remain in the southwesterly flow across
A few weak showers have lingered through the night across portions
of northern Utah and southwest Wyoming. These should expand in areal
coverage across northern and portions of central Utah and increase
in intensity with daytime heating today and will be aided in
development by the aforementioned vort max rotating into southern
Idaho. Meanwhile, the closed low over the SoCal coast will make its
way inland this afternoon and track across northern Arizona this
evening through early tomorrow morning. This low is expected to draw
a bit of moisture into southern Utah which could result in a few
showers over the mountains and higher valleys of southern Utah
developing by late afternoon. Gusty microburst winds are possible
with showers today, but especially across southern Utah where the
boundary layer is drier.
In conjunction with the progression of the aforementioned low, the
mean trough axis will shift east of Utah tomorrow. A somewhat moist
unstable northwest flow will then exist across Utah behind a
weak boundary, with scattered showers expected for much of the area.
A weak shortwave ridge is expected to develop into the area tomorrow
night into Friday morning while the next storm system strengthens
over the PacNW states. The northwesterly flow will continue during
this time and start to spread a drier airmass into the area.
However, this next storm system will amplify and graze northern Utah
late Friday into Saturday so a few showers will continue to linger.
.LONG TERM (After 18Z Saturday)...The bulk of the upper level trough
will remain north of the forecast area Saturday afternoon, but low
level moisture and cold advection should help increase shower and
thunderstorm activity, primarily across the northern 2/3 of the CWA.
Somewhat increased convection will likely continue into Sunday and
Monday as well, with weak forcing coming from both fringes of the
northern trough, as well as a secondary wave meandering across the
Desert Southwest. Have made relatively few forecast changes through
this time, though have increased temperatures a bit, as the northern
branch cold front isn`t quite as strong as previously indicated.
For those looking for warmer and drier weather, it currently looks
like you will get your wish starting Tuesday, and continuing through
much of the work week! Models are in good agreement about building a
ridge over the Great Basin starting Tuesday, with a significantly
warmer and drier airmass over Utah. Have indicated this warmer and
drier weather in the initial day 7 forecast for Wednesday, with
multiple days likely on tap of 80s along the Wasatch Front and 90s
.AVIATION...Scattered showers and thunderstorms will form across
northern Utah again today, and once again winds at the SLC terminal
could become erratic due to these showers. Showers aside, winds are
expected to switch to the northwest around 19Z-21Z.
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