Area Forecast Discussion
Issued by NWS Salt Lake City, UT
FXUS65 KSLC 111758
Area Forecast Discussion
National Weather Service Salt Lake City UT
1058 AM MST Wed Jan 11 2017
.SYNOPSIS...An upper level weather disturbance will race east
across Utah today. One final disturbance will impact southern
and central Utah Thursday through Friday night. High pressure
aloft will settle into the region this weekend.
.DISCUSSION...The tight near 700mb baroclinic zone that brought
convective precip to northern Utah earlier this morning weakened
as it moved east of the Wasatch range. Trailing this boundary
convective instability has brought a rapid increase in shower
activity across northwest Utah. The deep layer westerly flow
across the north will end up concentrating snow along the Wastach
range this afternoon. Orographic enhancement will occur, with
periods of heavy snow likely, especially across the northern
Weak frontogenesis along the old near 700mb baroclinic zone over
central Utah supported by a shortwave moving east across the
southern Utah should expand convective precip during the
afternoon and early evening hours. This activity should decrease
later in the evening as a shortwave ridge moves into the region
ahead of the upper low moving south along the west coast.
The above mentioned coastal upper low will continue slowly south
along the coast, ending up in northern Baja on Friday. This
feature, though far removed from Utah, could end up producing a
significant precip event for central/southern Utah Thursday
through Friday. The still present near 700mb baroclinic zone will
undergo additional tightening late tonight/Thursday morning.
Shortwaves ejecting out of the coastal upper low supported by a
favorable upper jet nosing into the southern Great Basin could
generate deep lift and substantial amounts of precip near the
baroclinic zone over central Utah.
Still looking at impacts across southern Utah from the upper low
as it settles into northern Baja Friday. The developing
deformation axis across the south late Friday/Friday night will
become the focus for additional precip mainly along and south of
the deformation axis. The deformation will finally sag into the
four corners region Saturday, with high pressure aloft taking over
for the balance of the weekend.
.AVIATION...VFR conditions are expected to hold at the KSLC terminal
for the remainder of the daylight hours, though periodic cigs AOB
6000ft AGL are expected in passing rain/snow showers. Southeast winds
are expected to prevail through 19-20z before trending more
southwesterly for the afternoon hours. Snow showers are expected to
lower cigs/vis to high end IFR or low end MVFR overnight, most
likely in the 02-08 window.
UT...Winter Storm Warning until 10 PM MST this evening for UTZ006>010.
WY...Winter Storm Warning until 10 PM MST this evening for WYZ021.
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