National Weather Service Forecast Discussion

000
FXUS65 KBOU 230242
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
742 PM MST Wed Jan 22 2020

.UPDATE...
Issued at 742 PM MST Wed Jan 22 2020

Updated the forecast earlier to increase PoPs and snowfall across
Summit and southern Grand counties. Radar and web cameras showed
an area of snow sliding south across this area. Total snowfall
tonight of 3 inches will be possible in the mountains near I-70.
Most of the snow is expected to fall this evening. Roadways are
cold enough to produce slippery conditions. Elsewhere, it remains
windy over the eastern plains. These winds will slowly decrease
through the night. No other changes are planned to the forecast.

&&

.SHORT TERM...(This evening through Thursday)
Issued at 234 PM MST Wed Jan 22 2020

Water vapor imagery shows a shortwave trough over eastern Wyoming
with a small enhancement of moisture on its southern edge
entering northern Colorado this afternoon. This increased moisture
may allow for better coverage of snow showers through the early
evening in the northern mountains. QG descent moves over northern
Colorado later this evening and overnight on the backside of the
departing shortwave trough. Snow showers over the mountains will
become sporadic so PoPs were lowered through midday tomorrow.
Additional snowfall totals in the mountains will generally be an
inch or two by tomorrow night with somewhat higher amounts across
the Park Range.

Visible satellite and surface observations show a cold front
moving through southeast Wyoming. This front will cool
temperatures tonight to near seasonal normals. Highs tomorrow will
be 5 to 10 degrees below today`s values. Northwest winds will gust
up to 35 mph across the northeast plains during the afternoon. No
precipitation is expected across the plains.

.LONG TERM...(Thursday night through Wednesday)
Issued at 245 PM MST Wed Jan 22 2020

Models have moderately strong northwesterly flow aloft over the
CWA on Thursday night. An upper ridge moves in on Friday into the
early evening hours, followed by a weak and quick moving upper trough
that gets east of Colorado by 18Z Saturday morning. Back to north-
northwesterly flow aloft into Saturday night with another upper
ridge heading this way. The QG Omega fields have downward vertical
motion over the forecast area Thursday night into Friday afternoon.
There is brief shot of weak upward motion progged Friday night, then
downward energy moves back in Saturday and Saturday evening. The low
level wind and pressure fields have pretty weak normal diurnal wind
patterns for the CWA all five periods. There are some north-
northwesterlies progged over the eastern plains Saturday afternoon
and evening. Moisture-wise, cross sections are still showing some
low level moisture in the mountains Thursday night into Friday
morning. The plains are pretty dry. Moisture increases across all
the CWA Friday night with that weak upper trough, but there isn`t
any in the lower levels of the plains. There is some lingering
moisture over all areas Saturday morning, but then it decreases
through Saturday night. Will keep the "chance" of pops going in
the mountains Thursday night, then again Friday night into
Saturday morning. Otherwise it should be dry. For temperatures,
Friday`s highs will be 3-5 C warmer than Thursday. Saturday highs
look to be 1-2 C warmer than Friday`s. For the later days, Sunday
through Wednesday, models have an upper ridge over Colorado on
Sunday. By Monday, an upper trough moves in later in the day and
continues developing somewhat through Tuesday on into Wednesday.
Models show Sunday into Monday pretty dry, then there is an increase
in moisture later on Monday. There is varying amounts of moisture
indicated later Monday through Wednesday, but nothing significant
yet. If model solutions pan out, it should be an unsettle period
with a chance of snow, even over the plains.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 742 PM MST Wed Jan 22 2020

VFR conditions will prevail through Thursday. Biggest forecast
challenge will be wind direction on Thursday. For tonight,
northerly winds will decrease this evening and become light after
midnight across the Denver area. For Thursday, north-northwest
winds are expected for most areas. However, an anticyclone may
form and produce east to southeast winds in the Denver area.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

UPDATE...Meier
SHORT TERM...Danielson
LONG TERM....RJK
AVIATION...Meier

NWS BOU Office Area Forecast Discussion