Area Forecast Discussion
Issued by NWS Salt Lake City, UT
FXUS65 KSLC 220424
Area Forecast Discussion
National Weather Service Salt Lake City UT
1024 PM MDT SUN AUG 21 2016
.SYNOPSIS...Moisture will spread northward across much of forecast
area tonight and Monday, then remain in place on Tuesday.
Meanwhile, an upper level disturbance will drift slowly across
the region. Drier air will spread over Utah on Wednesday.
.DISCUSSION...Moisture returned northward across the southern
third of Utah today providing the fuel for scattered afternoon
thunderstorms along the terrain. These have since congealed and
propagated southwest through Washington county and into southern
NV/northwest AZ. Meanwhile an elongated upper trough extends
across the desert southwest, with an upper low along the leading
edge of this trough over central AZ. As this low ejects northeast
overnight...the trailing trough axis will lift northward into
southern UT, allowing moisture across AZ to spread northward as
well. This increase in moisture will bring better areal coverage
of showers and thunderstorms across central and southern Utah
Monday afternoon. Very weak flow aloft will support slow cell
movement and potential for locally heavy rainfall assuming
sufficient instability develops to support deep convection.
Convection will likely evolve into several outflow dominant
clusters across southern UT by Monday evening. Along the northern
periphery of this moisture plume convection will tend to be more
high based and dry, although it seems much if not all of the
Wasatch Front will remain on the very northern fringe of any
convective threat. Showers and thunderstorms will likely linger
into Tuesday as what`s left of the mid level trough lifts through
Updated earlier to adjust cloud cover/POPs across southern Utah
for the remainder of the evening/overnight hours, otherwise going
forecast looks in good shape.
.AVIATION...VFR conditions with south winds expected at KSLC
through the overnight hours.
.FIRE WEATHER...Upper level ridge over the Great Basin will shift
east into the central plains as an upper level trough moves through
the Northern Intermountain region early this week. Deep moisture
has expanded north into the southern third of Utah, and will
spread north through much of the state on Monday and expect
scattered storms across central and southern Utah and in the
Uintas, with isolated storms in the northwest portions of the
state. A few storms in the northwest may produce dry lightning on
Monday afternoon and evening, although coverage is not expected to
be significant. Storms across southern Utah will have the
potential to produce locally heavy rainfall on both Monday and
Tuesday. A drying trend then spreads across the state on
Otherwise, expect better RH recover tonight and minimum relative
humidity values will be up quite a bit tomorrow across southern Utah
with plenty of cloud cover and increased thunderstorm coverage.
Relative humidity values will dip quite a bit during the middle of
the week as drier air spreads back into the region.
WY...Red Flag Warning in effect from noon to 9 PM MDT Monday
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