288
FXUS63 KUNR 150822
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
122 AM MST Fri Nov 15 2024

.KEY MESSAGES...

-Seasonally mild weather will mainly continue through Monday

-System will cross the region this weekend, bringing some chances
 for precip Saturday along with breezy and cooler weather

-Colder most of next week with some chances for rain and snow Tues

&&

.DISCUSSION...(Today Through Thursday)
Issued at 120 AM MST Fri Nov 15 2024

Mild Pac flow will continue through most of the weekend as WSW
flow persists aloft. However, an active jet in the northern Pac
will set the stage for a brief pattern change next week to colder
conds, all ensuing with a digging SW CONUS upper trough and
potential closed upper low. Upper trough will begin to eject out
of the western CONUS, supporting cyclogenesis in lee of the
Rockies. SE winds will increase ahead of this system today with
cooler conds expected per SE upslope flow. This system will cross
the region Sat, supporting chances for rain and snow across the
northwest third Sat. Any snow accums will be light and mainly
confined to NE WY and the northern BH. Portions of the higher
elevations of the BH could see an inch or two of accums if enough
moisture advects into the region with this system given upslope
enhancement. Breezy NW winds can also be expected on the SD plains
Sat, with adv level winds possible in far NW SD. Dry and mild
Sunday and Monday, after which much cooler weather is progged.
Deterministic runs of the GFS/ECMWF/CMC have all settled in line
with their mean ensembles, shifting the track of the upper low and
sfc low well east of the FA next week. This is in response to a
strong northern stream trough which will kick a strong cold front
and the associated baroclinic zone further east. Hence, the
potential for a winter storm next week has significantly been
reduced. Not going to totally rule out the potential for a storm
just yet, esp toward central SD, but the probability for one is
significantly low in the FA. Some light snow will be possible
Tues with the northern stream trough, best chances in the
northern BH. Windy and much cooler weather is then expected for
the middle of the week with signals for a warm up after as a deep
eastern Pac upper trough supports robust downstream ridging over
the Rockies.

&&

.AVIATION...(For the 06Z TAFS Through 06Z Friday Night)
Issued At 856 PM MST Thu Nov 14 2024

VFR conditions will persist through the period. Breezy east to
southeast flow will develop by 18z over much of the region, with
some gusts to around 30 kt.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&

$$

DISCUSSION/KEY MESSAGES...JC
AVIATION...Johnson