FXUS65 KBOU 230357

Area Forecast Discussion
National Weather Service Denver/Boulder CO
857 PM MST Tue Jan 22 2019

Issued at 854 PM MST Tue Jan 22 2019

Adjusted this evenings minimum temperatures slightly warmer near
the foothills due to downsloping pattern, and slightly cooler out
over Lincoln County due to mostly clear skies expected over the
recent snow and the normal cold spot with light winds.

Also adjusted probability of snow over the mountains up slightly
tomorrow morning and afternoon with higher confidence of seeing
snow, went from likely's to categorical.


.SHORT TERM...(This evening through Wednesday)
Issued at 201 PM MST Tue Jan 22 2019

Storm system exiting the plains this afternoon, with snow
diminishing and winds decreasing by this evening. Will allow the
blizzard warning for zones 41 and 46 to expire at 3 pm MST. There
should be some partial clearing this evening as a short wave
ridge of high pressure moves over the region. A strong
northwesterly flow aloft will remain over the cwa tonight and
Wednesday. The next system will be dropping out of northern
Rockies on Wednesday, as a strong upper level jet moves into
northwest CO by 18z. Increasing clouds from northwest to southeast
on Wednesday. Details in the long term but will issue a Winter
Weather Advisory for the north central mountains starting
Wednesday afternoon. By that time, the leading edge of the left
exit region will be over the mountains with snow increasing in
coverage at that time. Weak to moderate mountain wave development
late tonight into Wednesday morning with westerly winds possible
in and near the foothills and exposed eastern slopes of the Front
Range mountains. Temperatures on Wednesday climb back to near

.LONG TERM...(Wednesday night through Tuesday)
Issued at 201 PM MST Tue Jan 22 2019

An upper level ridge along the west coast and a trough over the
eastern half of North America will result in a northwest flow
aloft over Colorado through this weekend and into next week. A
series of waves embedded in the northwest flow aloft will bring a
chance for mainly mountain snow every other day for the upcoming
week. Temperatures will be near normal to slightly below normal.

The first trough will track across the Four Corners Wednesday
night. Snow is expected to persist through Wednesday night and
into Thursday with this system. Cross sections show a deep layer
of moisture over the mountains with decent lapse rates (6-8 C/km).
This combined with ridge top winds around 30 knots should result
in good orographic driven snowfall across the mountains. Snow
accumulations of 5 to 10 inches are expected with this system for
the mountains. Will issue a Winter Weather Advisory for this. A
cold front combined with lift from the trough and left exit
region of the jet may bring a period of light snow to the Front
Range and near by plains. Snowfall should be light here with up
to inches possible.

After a dry Friday, the next trough looks to track across
Colorado Friday night and early Saturday. This system appears
weak at this time. This should produce a period of light snow in
the mountains. Across the lower elevations, a little light snow
will be possible. This system is expected to be southeast of the
area Saturday afternoon bringing dry conditions back.

Sunday is expected to be mild ahead of the next trough. This
system is expected to move southeast across the Rockies Monday.
This next system looks a little stronger should bring another
round of snow to the mountains and plains Monday.


.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 854 PM MST Tue Jan 22 2019

VFR conditions expected tonight into Wednesday. Light drainage
winds are expected to increase after 09z, becoming northwest
in the late morning to early afternoon, strongest at KBJC with
gusts 25-30 kts after 18z.


Winter Weather Advisory from 11 AM Wednesday to 11 AM MST
Thursday for COZ031-033-034.



Back to Main Forecast Discussion Page