Area Forecast Discussion
Issued by NWS Salt Lake City, UT
FXUS65 KSLC 221102
Area Forecast Discussion
National Weather Service Salt Lake City UT
502 AM MDT SUN MAY 22 2016
.SYNOPSIS...A broad upper level low pressure system will remain
over the western states through much of the week. This low pressure
will maintain periods of moist unsettled conditions across the
region throughout the week.
SHORT TERM (Through 18z Wednesday)...A storm system remains parked
across the western CONUS this morning. However, the upper low center
has now tracked into southern Alberta, leaving the Great Basin under
a mean longwave trough. An embedded shortwave disturbance currently
near the south end of the Sierra Nevada will rotate into Utah late
this morning into this afternoon. This will enhance low-level
convergence into the existing boundary across west-central through
northeast Utah, which will provide the main focus for showers today.
Otherwise, the airmass will remain on the cool side given H7
temperatures in the -2 to -4C range across northern/western Utah and
0 to +2C across the southeast.
Weak shortwave ridging will develop briefly tonight, which should be
accompanied by a stable enough airmass to keep showers at bay.
However, another shortwave disturbance will quickly arrive over the
West Coast tomorrow while southwesterly flow develops over Utah. A
few showers are expected across mainly northern Utah out of the
lingering moisture and weak ripples embedded in the flow, otherwise
tomorrow will be relatively drier. This shortwave disturbance will
lift across Utah late tomorrow night into Tuesday bringing increased
shower activity once again. Temperatures will trend warmer for
Monday and Tuesday, but still remaining a few degrees below
.LONG TERM (After 18Z Wednesday)...An upper level trough will remain
anchored over the interior west with a series of shortwave
disturbances moving through this trough. The GFS forecast was
preferred over the operational EC run after looking at the 12Z EC
ensemble mean which supported the GFS in keeping the trough axis
farther west over northern California rather than progressing it
into the western Great Basin. Consequently, went with a warmer and
drier forecast from Friday through Sunday. This farther west
position of the trough seems more reasonable due to climatology and
recent tracks of storm systems.
Southerly winds will become breezy Friday, Saturday and Sunday,
especially over western valleys. Temperatures will climb from near
or slightly below normal early in the week to above normal Friday
.AVIATION...A storm system over Nevada this morning will move
NE across the SLC terminal between 15 and 19Z although there is a 30
percent chance that this time reference is 1-2 hrs too early. There
is a 40 percent chance of MVFR conditions between 16 and 19Z. Winds
will shift to west with the passage of this storm system but could
be more erratic than westerly. Clearing will occur this evening.
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