Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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FXUS65 KSLC 252150
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
350 PM MDT THU AUG 25 2016

.SYNOPSIS...Moisture over southern Utah will spread northward
through Friday. Drier air will return for the weekend and early next
week.

&&

.SHORT TERM (Through 06Z Sunday)...Initial wave of an approaching
trough is rotating into northern Utah this afternoon. Southerly flow
ahead of this system allowed moisture over southern Utah to spread
northward into central and northeast Utah, where PWs are in the 0.6
to 0.8 inch range. The moisture combined with instability from the
wave has allowed for scattered convection to develop over all but
parts of northern and western Utah, with a few storms producing
heavy rain over southern Utah. The clouds combined with the cooler
airmass behind yesterday`s cold front are keeping maxes a few
degrees below climo across Utah and southwest Wyoming.

The moist airmass will remain in place through tomorrow as the
second part of the trough moves through tomorrow through early
Saturday, and therefore am expected coverage of convection to be
similar to today. By Saturday afternoon, the flow aloft becomes more
west to northwesterly with high pressure moving back in behind the
exiting trough. This will allow the airmass to begin to dry from the
north, though some convection will continue to be possible over
central and southern Utah.

.LONG TERM (After 06Z Sunday)...The drying and warming trend
continues Sunday and Monday, as a high pressure ridge builds over
the Intermountain West. Enough moisture might linger in far
southern Utah to allow for some isolated thunderstorms in the
afternoons off the terrain, but for the most part convective
activity should be greatly reduced across the region through the
beginning of the week.

Southerly winds begin to increase Tuesday, as a Pacific trough
moves into California. Tuesday could be the warmest day of the
week in many locations, particularly because the southerly flow
begins to draw moisture into Utah from the south starting
Wednesday.

While there is some disagreement in the timing/magnitude of this
moisture return, models are in decent agreement about moisture
increasing sometime Wednesday/Thursday. There is still some
uncertainty about whether this will bring showers to the Wasatch
Front, especially since the 12Z ECMWF tries to push drier air into
northwest Utah on Thursday, but at the moment it looks like the
best chance northern Utah has had for a couple weeks. Have
generally increased POPs/sky cover and decreased temperatures for
Wednesday/Thursday, but models will need to lock into this
solution for another couple runs for confidence to truly increase.

&&

.AVIATION...North northwest winds will prevail at the SLC terminal
through about 03-04Z then switch to southeast. VFR conditions will
prevail through the TAF period.

&&

.FIRE WEATHER...Moisture that had been pooled over southern Utah has
spread northward into central and northeastern portions of the
district this afternoon. The moist airmass will remain in place
through Saturday morning, with instability being provided by a storm
system slowly rotating through the district. This will allow for the
continued threat of showers and thunderstorms, primarily during the
afternoon and evening hours over central and southern Utah. High
pressure will build behind the exiting system on Saturday, allowing
for drier air to move back in from the north through early next
week.

&&

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

$$

SHORT TERM/FIRE WEATHER...Traphagan
LONG TERM...Schoening
AVIATION...Struthwolf

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http://weather.gov/saltlakecity

For frequently asked questions about the Area Forecast Discussion
visit...
http://weather.gov/saltlakecity/general/afd_faqs.php



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