National Weather Service Forecast Discussion

000
FXUS65 KBOU 282347
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
447 PM MST Sat Jan 28 2023

.SHORT TERM...(This evening through Sunday)
Issued at 136 PM MST Sat Jan 28 2023

A moderate to strong zonal flow is will be over northern CO
through this evening, with an area of weak mid/upper level qg ascent
in place as a short wave trough move across WY.  MRMS is showing
some snow banding occurring over the mountains and spreading into
the urban corridor early this afternoon.  A colder airmass has
spread into nearly all of northeast plains and will settle along the
Front Range Foothills and Palmer Divide through Sunday.  The best
chance of snow through this evening will be through this evening as
the Pacific moisture continues to overrun the shallow arctic
airmass. Although the depth of the moisture will be fairly shallow
from the urban corridor eastward, there will be enough moisture
in the mid/upper level coupled with the upper level jet to keep
the banded snowfall in place until 01-02z. Will continue with the
Winter highlights for the mountains through 5 pm this afternoon,
but no plans to extend them at this time. The banded snowfall
could be an issue for skiers making their way back to Denver this
afternoon, so be prepared for possible delays. Later in the
evening, spatial cross-sections show some drying in the mid/upper
levels which could lead to a brief period of light freezing later
this evening. Late tonight into Sunday, light snowfall may linger
primarily along the west facing slopes north of Interstate 70, but
decreasing elsewhere with weakening upper level support. Across
the northeast plains, the low level moisture will deepen slightly,
but it will be cold enough to stay as light snow. South of
Interstate 70 over eastern Elbert and Lincoln counties, there will
be less moisture aloft with no seeders. Best chance of fog will
be down in this area tonight into Sunday morning. On Sunday
another trough drops southward out of the Pacific Northwest.
Generally weak mid/upper level qg ascent with the best moisture
through the afternoon over zone 31. Although the best chance of
accumulating snowfall will be north of I-70, there are no plans
to expand the winter weather highlights into zone 33 at this time.

.LONG TERM...(Sunday night through Saturday)
Issued at 136 PM MST Sat Jan 28 2023

A shortwave trough looks to move over northeastern Colorado
Sunday to Monday night. There is some model variability in timing
and location. The surface low will likely be located over
southeastern Colorado which will bring weak upslope flow to the
area. Along with this trough a cold air mass will be in place and
near record temperatures could be reached early in the week.

Sunday we increased POPs over what NBM had, with weak upslope flow
less than one inch of snow is expected for lower elevations
through Monday. The northern mountains will continue to see
heavier snowfall. Along the I-70 mountain corridor lighter
snowfall amounts are expected. Temperatures will drop off
significantly with highs in the teens and lows into the negative
single digits. Windchill temperatures will be well into the
negative teens.

Monday will remain cold and snow will begin to lessen over the
northern mountains as the trough exits. Light upslope flow will
continue which could give light flurries to the front range and
plains with less than one inch of accumulation. Windchill
temperatures will be much colder Monday morning especially for the
plains with values close the the negative 20 degree mark.

Tuesday the trough will hopefully have passed and winds switch
back to a more westerly flow. Thanks to this downslope flow we
will see some warming across the front range. Temperatures could
climb back into the high 20s to low 30s.

Wednesday through Friday show drying and warming with a small
ridge building Wednesday night through Friday. Another chance at
a shortwave trough comes through Friday evening into Saturday.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 439 PM MST Sat Jan 28 2023

Quite varying conditions within the areal extent across the
terminals. KDEN has dropped to 1/4 mile visibility and don`t see
any reason why that will change much through the night. BJC cigs
also dropping into IFR the past hour while the low stratus is just
flirting with APA. All terminals will be IFR for much of tonight
but not expecting much -sn or freezing drizzle, spotty at best so
won`t mention in TAF`s for now. Slowly lifting ceilings/vsbys
Sunday morning but overall confidence in that is low. Could see
another shot light snow by Sunday evening.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until 5 PM MST this afternoon for COZ031-
033.

Winter Storm Warning from 5 AM Sunday to 5 PM MST Monday for
COZ031.

Winter Weather Advisory until 5 PM MST this afternoon for COZ034.

&&

$$

SHORT TERM...Cooper
LONG TERM...Chavez/Gimmestad
AVIATION...Entrekin

NWS BOU Office Area Forecast Discussion