National Weather Service Forecast Discussion

000
FXUS65 KBOU 061119
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
419 AM MST Mon Feb 6 2023

.SHORT TERM...(Today and tonight)
Issued at 419 AM MST Mon Feb 6 2023

Lots going on today, though it may not amount to much beyond wind.
Frontal shower band associated with the main shortwave trough is
moving over our mountains now. Vail Pass looks pretty messy, but
the back edge of the band is about there. So the main period of
snow should be past the I-70 mountain corridor by 6 AM. Some
light snow will continue behind it, but from a pretty shallow
cloud layer. We`ve had a couple little ripples in the winds the
last few hours, but there will be a stronger, better organized
push of WNW winds with what`s left of the shower band (virga or
maybe just the winds) coming across Denver through mid morning.
There could be peak winds in the 30-40 mph range, and maybe even
higher up near the Wyoming border as this little pop of wind goes
by. After that, we should be more northwest and maybe not quite as
strong for a bit.

So that`s the morning. This afternoon into early evening, we`ll
have a batch of convection associated with the cold pool aloft
now over northwest Wyoming sagging across the mountains and
adjacent plains. The laps rates will be decent for several hours,
but there`s not a lot of moisture. The general low level winds
should still be northwesterly, but some anticyclonic turning into
the foothills may help a little with the low level drying,
especially south of Denver. We expect a fair coverage of weak
showers, but very little of this to stick given likely air
temperatures in the mid to upper 30s as it comes through. Better
odds of an inch of snow in the foothills and maybe southern
Douglas county where this will be colder and last a little later
into the evening. There should be pretty good clearing and drying
on the plains later tonight. Some lingering clouds for the
mountains but probably not much snow. Other than temperature
adjustments for the mountains being warmer at the current hour,
not much else needed to be changed for the temperatures.

.LONG TERM...(Tuesday through Sunday)
Issued at 419 AM MST Mon Feb 6 2023

Tuesday...

Weak ridging aloft will result in a period of dry
conditions Tuesday through a decent portion of Wednesday. Highs will
be slightly below normal in the upper 30s/40s in the plains and
urban corridor and 20s/30s for most of the high country.

Wednesday and Thursday...

Wednesday will be a bit warmer with some recovery in
the 700mb temperatures. The next system approaches from the
northwest with flow aloft becoming zonal. QG ascent increases late
afternoon with a sufficient moist layer over the high country
developing. This will get snowfall initiated in the high country
starting the afternoon. Westerly component winds increase a good
amount over the high country and a front drops southeastward from
the high country across the plains Wednesday evening. This will
support gusty NW winds in most areas. Ensembles show a good chance
for gusts 35-45 mph. Some of the high peaks and portions of the
plains (Cheyenne Ridge) may experience locally higher gusts. Snow
continues in the high country overnight. As the front drops south
that evening, the plains may see a chance for a band/organized
area of snow showers to push across with the better chances south
and east of the Denver metro (40-50%). Overall, this isn`t
looking like a favorable event for the plains. The lack of upslope
flow will again result in a layer of dry air to overcome. This is
reflected in the model soundings for DEN as well. There is some
uncertainty in the exact details of the system, but overall this
system is not likely to cause major impacts. The system is quite
progressive with dry, subsident air working in towards the
afternoon Thursday. This will decrease snow across the high
country throughout the day. For the event, accumulations in the
mountains still look to fall in the 3-7" range. Lower confidence
in amounts for the plains due to dry air limiting snow. At most, a
trace to an inch for the urban corridor and plains. Minor impacts
to travel can be anticipated for the high country due to falling
snow, slick roads. With gusty winds continuing through Thursday,
blowing snow may also be a factor in areas receiving fresh
snowfall, mainly the higher elevations. The post-frontal airmass
will be quite a bit cooler keeping highs in the 30s across the
plains.

Friday through the weekend...

Ensemble guidance is in good agreement that an upper level ridge
pushes into the region Friday bringing dry conditions and a slow
warming trend. By Saturday, a good percentage of members show
highs rebounding to above-normal values. An upper level trough
approaches the region Sunday. At this point, model consensus keeps
the system well south of Colorado which includes the better
moisture and synoptic support. Another shot of snowfall for the
mountains is looking more likely this far out. Will have to keep
an eye on it for any tracking changes this week.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 419 AM MST Mon Feb 6 2023

West winds at 15-30 knots will develop over most of the Denver
area by 13z, and then shift to northwest as a cold front passes
between 15z-17z. A period of ceilings in the 060-080 range is
expected between 20z and 04z with isolated snow showers. Winds
will diminish after 00z.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 8 AM MST this morning for COZ031.

&&

$$

SHORT TERM...Gimmestad
LONG TERM...Mensch
AVIATION...Gimmestad

NWS BOU Office Area Forecast Discussion