821
FXUS65 KBOU 201156
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
456 AM MST Tue Jan 20 2026

.KEY MESSAGES...

- Elevated to critical fire weather conditions across the far
  northeast plains today, with mild and dry conditions across the
  region.

- Glancing arctic outbreak on Friday, with a slight moderation for
  the weekend. Light snow also possible.

&&

.UPDATE...
Issued at 253 AM MST Tue Jan 20 2026

The Fire Weather Watch for this afternoon has been upgraded to a Red
Flag Warning. The Red Flag Warning will be in effect for Logan,
Sedgwick, and Phillips Counties from noon to 5PM. This event is more
on the marginal side and is not a slam dunk by any means. But RH
values are forecast to drop into the 13% to 20% range with winds
gusting up to 35mph this afternoon, which given how dry the fuels
are, we decided to go with an RFW. Winds this morning and early this
afternoon will be breezy in the Front Range and the Foothills as a
weak mountain wave sets up. Winds were increased for these areas,
with occasional gusts up to 70mph in the mountains, up to 60mph in
the foothills, and up to 45mph pushing into the adjacent plains.
Luckily, these areas saw snow yesterday, which helps to limit the
fire weather concerns. But even with the added moisture, we will be
looking at elevated fire weather conditons this afternoon for the
Foothills due to these strong winds and drying conditions.

&&

.DISCUSSION /Through Monday/...
Issued at 222 PM MST Mon Jan 19 2026

It`s been a quiet and sunny day for most of our CWA following the
overnight snowfall. The exception to that has been across most of
Weld county, which is just finally starting to burn off some
persistent stratus/fog that developed earlier this morning. We
should still see highs reach the 30s across most of the forecast
area this afternoon with little else of note.

Tonight should be relatively quiet as dry northwesterly flow aloft
continues. Ridgetop winds do strengthen a bit overnight and there
will be some gusty winds across most of the Front Range. Can`t
rule out a couple of gusts of 60-70 mph overnight or sometime
Tuesday, but any mountain wave development looks brief/weak.

Tomorrow will be warmer as the cold airmass pushes a little east
of our CWA. With warming mid-level temperatures and a more
pronounced downslope component, temperatures should be quite a bit
warmer than today - closer to 50F across most of the plains. The
warm/dry/breezy conditions will lead to some fire weather
concerns... see the fire weather section below for more details.

A weak cold front is then expected to push into the area late
Tuesday evening or Tuesday night, which should usher in slightly
cooler (near normal) temperatures for Wednesday and Thursday.

A much stronger cold front is forecast to arrive sometime between
Thursday and Friday, with well below normal highs likely behind
it. We`ll likely remain right on the edge of the colder weather as
the deep longwave trough settles over the Upper Great Lakes, but
highs on Friday look like they`ll struggle to reach 25F or so. A
weak shortwave rounding the base of the trough may also bring some
light snow to the area, though QPF forecasts leave a lot to be
desired.

There is more uncertainty as we get into the weekend, as there`s
quite a bit of spread across guidance. As a whole, the GEFS is
predominantly on the warmer side, the GEPS is cooler, and the
ECME has the most intra-ensemble spread. Unsurprisingly the NBM
(and our official grids) were somewhere near the middle of this
range for both Saturday and Sunday.

&&

.AVIATION /12Z TAFS through 12Z Wednesday/...
Issued at 442 AM MST Tue Jan 20 2026

VFR conditions are expected through this TAF package. Winds at
KBJC this morning will be intermittently gusty from the west.
Winds at KDEN and KAPA will generally stay from the SW/SSW early
this morning, before turning W/WNW around 17Z. Winds will increase
from the WNW around 19Z at all TAF sites, with gusts around 25kts
at KBJC and 19kts at KDEN and KAPA. Winds will weaken and turn
more N/NE around 0Z. Winds will veer this evening, turning towards
drainage overnight. There is potential for some wind gusts from
the NE as the cold front pushes through around 0Z. Right now,
confidence is too low to include any mention of gusts this evening
in the TAF, but it`s something we`ll be watching.


&&

.FIRE WEATHER...
Issued at 222 PM MST Mon Jan 19 2026

Elevated to critical fire weather conditions are expected to
develop Tuesday afternoon across the far northeast corner. There
is broad support from model guidance, with the GEFS hot dry windy
index (HDWI) near the 75-90th percentile. However, there is still
a rather large amount of uncertainty regarding how much wind will
be able to mix down during the afternoon... and similarly how low
RH will drop. The HRRR remains on the bullish side for both
factors, with mixed signals across most of the other reliable
short range guidance. Confidence of seeing Red Flag conditions was
just a little more than 50/50... and so we`ve opted for a watch
for Logan/Sedgwick/Phillips counties, northeast of the band of
snow that fell earlier today.

Across the Denver metro and South Park, we`ll certainly see dry
enough conditions yet again Tuesday afternoon. Most of the I-25
corridor saw enough snow to at least briefly limit the overall
fire danger, and winds aren`t quite forecast to reach criteria
there. Most of South Park also has less receptive fuels and so
we`ve held off on a watch for there as well.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from noon today to 5 PM MST this afternoon for
COZ248-250-251.

&&

$$

UPDATE...AP
DISCUSSION...Hiris
AVIATION...AP
FIRE WEATHER...Hiris

NWS BOU Office Area Forecast Discussion