Area Forecast Discussion
Issued by NWS Salt Lake City, UT
FXUS65 KSLC 280951
Area Forecast Discussion
National Weather Service Salt Lake City UT
351 AM MDT THU JUL 28 2016
.SYNOPSIS...High pressure will maintain hot and dry conditions
through much of the remainder of the work week. This high will
move east Friday allowing moisture to slowly increase from the
south through the upcoming weekend.
.SHORT TERM (THROUGH 06Z SUNDAY)...High pressure firmly in place
over the forecast area this morning, resulting in mostly clear and
dry conditions. Another hot day is in store for Utah and southwest
Wyoming with maxes in excess of 10F above seasonal norms for some
locations. It will be hot enough to be hazardous over lower portions
of Utah`s Dixie, including the city of St. George, where an
Excessive Heat Warning is in effect today and tomorrow. Though the
airmass remains dry, it will be warm enough to allow for a few high
based storms to fire off the higher terrain of southern Utah this
afternoon with little rainfall expected.
The ridge is progged to remain in place through tomorrow, keeping
conditions hot and dry. However, the ridge is expected to flatten
some by late Friday as a Pacific Northwest trough moves onshore.
This will allow for a more westerly flow over the area, drawing
moisture into southwest Utah by Friday afternoon, increasing the
chance of afternoon convection. The moisture is expected to continue
to spread northward on Saturday, allowing for an increasing chance
of precip with some cooling of temperatures over southern Utah.
Given the dry airmass over the area, storms will initially produce
little if any rainfall.
.LONG TERM (After 06z Sunday)...With the ridge axis shifting
slightly to the east, midlevel moisture will continue to increase
across the forecast area Saturday night into Sunday and Monday. This
will continue to bring an increasing chance of showers and
thunderstorms to the bulk of the forecast area. However, some of the
storms on Sunday, especially those across northern Utah along the
edge of the moisture plume, may remain high-based and produce strong
gusty outflow winds but little rain. The moisture will remain in
place through Monday, helping temperatures to gradually trend
A shortwave trough crossing the PacNW states and tracking into the
northern Rockies on Tuesday will flatten the ridge and push a weak
cold front into Utah Tuesday night into Wednesday. This will not
only continue to bring slightly cooler temperatures to the area, but
drier air will spread in from the northwest as well. The moisture
and associated showers will become increasingly confined to the
south and east through the midweek period.
.AVIATION...Winds at KSLC will prevail out of the south through
the morning before northwest winds develop around 17-19z. Otherwise,
VFR conditions will prevail through the day under mostly clear skies.
.FIRE WEATHER....High pressure will remain over the desert
southwest, keeping a very warm airmass in place through the end of
the week. Moisture will start to slowly increase across southwest
Utah today which will lead to cumulus buildups or virga and perhaps
very isolated dry thunderstorms across the mountains of southwest
Utah this afternoon. This moisture will continue to gradually
increase and spread northward over the next couple of days. Isolated
thunderstorms can be expected across southwest Utah Friday
afternoon, then isolated to widely scattered thunderstorms will be
possible Saturday through Monday across the majority of the fire
district. Thunderstorms will likely be dry Friday and Saturday and
perhaps even into Sunday as well if the lower levels do not moisten
The airmass will start to dry again from the northwest during the
middle of next week. Thunderstorm activity will become increasingly
confined to the south and east as a result. Otherwise, temperatures
will start trending downward by Sunday and continuing through the
middle of next week.
UT...Excessive Heat Warning from noon today to 9 PM MDT Friday for
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