Area Forecast Discussion
Issued by NWS Salt Lake City, UT
FXUS65 KSLC 230057
Area Forecast Discussion
National Weather Service Salt Lake City UT
657 PM MDT FRI JUL 22 2016
.SYNOPSIS...An upper-level trough moving east through the northern
Rockies will push a dry cold front through northern Utah tonight.
The southeastern half of the state will see isolated showers or
storms Monday and Tuesday. Building high pressure aloft will lead to
above-normal temperatures next week.
Water vapor loop shows a strong open wave over the northern Idaho
border, with a ridge centered over southern California. MDCARS wind
observations show a 75-110kt southwesterly jet from the Oregon
across the northern Rockies. GOES/HRRR/00Z KSLC RAOB indicate the
precipitable water value ranges from 0.30"-0.60" far northwest Utah
to 1.00"-1.30" eastern valleys.
Update to freshen up the forecast based on latest radar trends and
latest guidance. While the deepest convection is making its way to
the Colorado border, shallower convection continues to developing
ahead of a cool front which is near Delta to Utah Lake. Behind this
boundary was able to remove PoPs further to the north and northwest.
Northern and southwest Utah are clear already so was able to make
the sky forecast more optimistic in these areas. Updated forecast is
also a couple degrees warmer with the overnight lows. Despite the
clearing and drying taking place this evening on the cool side of
the boundary, the effects of a hot summer day will tend to linger
along the urban corridor.
A second update is possible late this evening if there is a
significant change in convective coverage, though any other updates
will likely be minor.
An upper trof is crossing the nrn Rockies this aftn with the
associated dry cold front beginning to enter nwrn Ut. A surface
thermal trof out ahead of the front lays stalled across nwrn UT
and isolated convection has been firing along this feature.
Farther south deep moisture remains in place across the mtns and
ern valleys while the west is starting to dry out. A few of the
cells over the mtns and east has become strong with heavy rain and
The dry cold front should merge with the thermal trof late this
aftn or this eve then heads south with some convection remaining
focused along this boundary through this evening. The drier air
spreading in behind this boundary will end the threat of
convection across the north.
This boundary doesn`t quite sweep the moisture out of the state
but drier westerlies do spread across the south tomorrow as well.
This drying should limit convection to isolated at best over
about the sern 1/2 of the CWA.
A cooler airmass spreads into the north behind the front as well
with 5-10 deg cooling on Sat from today while the south sees
A new weak upper trof along the coast backs the flow to swly again
across the CWA on Sun with a little moisture beginning to spread
back into the south. Don`t expect much difference in convective
coverage Sun however and temps start to warm back up across the
Another extended period of 100+ degree max temps looms for
portions of the Wasatch front beginning on Monday. The good news
is that overnight wind speeds will be lower than during the past
week, which will allow for slightly better overnight cooling and
hopefully avert another streak of record-high min temps.
On Monday, a mid- and upper-level height gradient from west to east
across the southwestern U.S. will induce southerly flow from Arizona
northward into Utah. Modest advection of moisture into the region
will bring PWATs closer to average across the southeastern half of
the CWA. This area can expect increased cloud cover and a chance of
isolated showers or storms through Tuesday, while mostly clear skies
and above-normal temperatures predominate over the north.
An upper-level ridge will build over the Great Basin and
southwestern U.S. through the middle and latter portions of the
week. Subsidence along the northern edge of this feature will
continue to produce a dry airmass with clear skies and above-normal
temperatures through the extended period.
.AVIATION...Northerly winds will persist at the SLC terminal
through the evening hours. Winds may become light and variable
toward sunrise. VFR conditions through the valid TAF period.
.FIRE WEATHER...Showers and thunderstorms that fired over the
mountains and east will dissipate this evening. A dry cold front
crossing northern Utah this evening will spread cooler more stable
air across the north Saturday with some drying expected across the
south as well. It will stay dry Sunday although a little moisture
will start to return north into southern Utah in the afternoon.
Moisture will increase across the south again Monday into Tuesday
while it stays hot and dry across the north.
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