Area Forecast Discussion
Issued by NWS Salt Lake City, UT
FXUS65 KSLC 250145
Area Forecast Discussion
National Weather Service Salt Lake City UT
745 PM MDT SUN JUL 24 2016
.SYNOPSIS...Strengthening high pressure aloft across the region
will generate very warm and generally dry conditions across most
of Utah throughout the upcoming week. A little moisture will
linger across the far south Monday through Tuesday.
Water vapor loop shows ridging from the southwest CONUS ahead of a
weak trough over the west coast. MDCARS wind observations show a 50-
105kt westerly jet from northern Utah into the lower Great Lakes.
GOES/HRRR/00Z KSLC RAOB indicate the precipitable water value ranges
from 0.15"-0.25" northern mountains to 0.75"-1.00" southern valleys.
RAP 850-700MB thickness/saturated equivalent potential temperature
and streamlines indicate the weak boundary across south central Utah
early this evening will lift north in response to the approaching
weak trough. This will result in isolated to scattered convection
building northeast with time with elevated instability axis
developing northward. Have added PoPs as north as southern Utah
county, Delta and the Uinta Basin overnight to account for this.
NAM shows a 20m increase in 850-700mb thickness at SLC comparing
12z Monday to 12z this morning. Due to the increase in thickness
due to both the expanding warm sector and warmer daytime
temperatures, raised overnight lows to near 70F for SLC.
Another weak short wave passing to our north has kept the airmass
very dry across the northern CWA this aftn while moisture has
lingered over the southern CWA. Convection has formed over the srn
mtns as well as across some of the southern valleys. This should
mostly die off by late eve with the loss of daytime heating.
The moisture is forecast to shift north Mon as a weak trof
deepens along the west coast and the flow backs to swly over our
CWA. This is not expected to be a deep surge altho isolated
pockets of brief heavy rain could develop over the far south. A
weak disturbance lifting out of srn NV ahead of the developing
west coast trof is forecast to keep weak convection active across
western then northern Ut overnight. Don`t expect much if any rain
from this but scattered clouds are possible. This feature however
could give the daytime convection a boost Monday with an earlier
start over the nrn mtns.
The high to our southeast starts to elongate wwd on Tue shutting
off the moisture feed but expect another round of isolated
convection across the south in the moisture that is in place with
a few early aftn cells over the nern mtns.
The northwest stays dry Mon thru Tue with a warming airmass
sending temps to 100 or a little higher along the Wasatch Front.
A strong mid level ridge is forecast to reside across the Great
Basin region at the beginning of the long term period, and remain
the dominant feature through the remainder of the week. As a
result temperatures will remain above normal through this
timeframe with KSLC expected to reach or exceed the 100F mark each
afternoon. Moisture is forecast to gradually seep into the ridge
position as early as Friday allowing for a chance of high based
convection across southern and possibly central Utah. By next
weekend this ridge axis is expected to shift east allowing a south
to southwesterly fetch to potentially draw deeper moisture
northward into the region late next weekend.
.AVIATION...Winds at the SLC terminal are expected to switch to
the southeast between 03-05Z under clear skies.
.FIRE WEATHER...A dry airmass remains in place across the
northern portions of the district while just enough moisture has
spread into the south and east to fuel isolated afternoon
thunderstorms that will persist into this evening. The moisture
creeps north up the east side of the area tonight with a better
chance of thunderstorms over the northeastern mountains on Monday
and Tuesday and a continued chance over the central mountains and
across the south. The northwest will stay hot and dry through
Tuesday. High pressure expands westward on Wednesday spreading the
drier airmass into southern Utah and ending the threat of
thunderstorms. This drier air will remain in place across the
majority of the area Thursday with continued hot temperatures.
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