866
FXUS65 KBOU 130558
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1158 PM MDT Sun Apr 12 2026

.KEY MESSAGES...

- Critical fire weather conditions expected again on Monday over
  the southern portions of the forecast area and the plains near
  the Wyoming border.

- The next system will bring cooler temperatures and a decent
  chance of precipitation to the forecast area Tuesday into early
  Wednesday.

- Another storm system is possible for the forecast area Thursday
  night into Saturday.

&&

.DISCUSSION /Through Sunday/...
Issued at 1157 PM MDT Sun Apr 12 2026

Satellite pictures are showing mainly upper level cloudiness
moving northeastward across Colorado in southwesterly flow aloft.
Fairly weak low level drainage winds were in place across the most
of CWA late this evening. High temperatures reached the mid 70s
to lower 80s across the plains Sunday afternoon, with current
readings in the upper 40s and 50s.

Models continue to show increasing southwesterly flow aloft for the
CWA overnight through Tuesday with jet level speeds getting into the
85 to 110 knot range Monday afternoon through early Tuesday
afternoon. Speeds decrease later Tuesday afternoon as an upper
trough pushes eastward across the forecast area through mid
morning Wednesday. There is fairly strong upward synoptic scale
energy with the trough on the QG Omega fields late Monday night
through Tuesday morning. Thickness grids now show the main cold
front to move across the CWA Tuesday afternoon and evening. On
Wednesday, there is weak upper ridging over the CWA, then it`s
back to southwesterly flow aloft on Thursday ahead of the next
system on Friday. There isn`t much in the way of synoptic scale
energy both Wednesday and Thursday.

There is some mid and upper level moisture around on Monday, then
deeper moisture associated with the trough is expected to get
into the western half of the CWA later Monday night into Tuesday
morning. The better moisture finally gets into the eastern half of
the forecast area later Tuesday afternoon and evening. Moisture
lingers over the mountains into Wednesday morning. Will leave the
high pops in the mountains (70-90%s) Tuesday and Tuesday evening.
As it still looks pretty warm Tuesday, the freezing level remains
fairly high and alpine snowfall amounts and impacts do not look
significant enough for highlights at this time. Neighboring office
concur. Over the plains will go with 30-70% pops Tuesday
afternoon and night. Of note, it still looks like much of the
forecast area will see measurable precipitation Tuesday into
Wednesday, albeit not significant amounts. Moisture is pretty lean
the rest of Wednesday into Thursday morning, then some upper
level moisture pushes in Thursday afternoon.

For temperatures, highs will continue to be above seasonal normals
on Monday with low to mid 70s for the plains. Tuesday`s highs now
look to be in the upper 50s to upper 60s, with mid 60s to lower 70s
Wednesday. and back into the 70s on Thursday.

For the later days, Friday through Monday, models are still showing
a substantial upper level trough to move across Colorado Friday into
Saturday.  There is still a cold front with upslope flow over the
plains as well as measurable precipitation on the QPF fields.
However, it does not look as strong as it did on yesterday`s models
at this current time.  As there are still many model runs to come
between now and Friday, it will continue bear watching.  Upper
ridging moves in late Saturday continuing through Sunday night
with southwesterly flow aloft by Monday. The airmass looks pretty
dry Saturday through Monday. Temperatures should be below seasonal
normals Friday and Saturday, then warm up Sunday and Monday.

&&

.AVIATION /06Z TAFS through 06Z Tuesday/...
Issued at 1157 PM MDT Sun Apr 12 2026

VFR conditions will persist with only SCT-BKN mid and high clouds
above 11,000 ft MSL for the Denver area TAF sites. The main
challenge will once again surround winds.

We`re finally seeing a return of light S-SW winds which should
hold through about 15Z, with a slight westerly bend 14Z-17Z. Then,
just like yesterday, we`ll be battling the difference between
mixing of stronger westerlies aloft and the corresponding channels
of weak/reverse shear easterlies. We think KAPA will once again
have the best odds of becoming gusty from the WSW to ~25kts by
15Z-17Z and holding through most of the day. Meanwhile, KDEN and
KBJC may once again be the exact opposite with a light E-N flow as
a shear zone develops over southern Denver metro. This time,
short range models are hinting stronger at that shear zone
compared to yesterday, so confidence is a bit higher that we
develop an E-N component (60-70% chance) at KDEN 19Z-24Z versus
WSW (30-40% chance). Therefore, we`ll adjust the TAFs accordingly
for the most likely scenario. KBJC is even more evenly matched
probability between the two, so we`ll opt for a prevailing E wind
but TEMPO W gusting to ~25kts 20Z-24Z.

After 00Z, we would have more confidence of the N-NE wind
developing as a surface low pressure system redevelops in east
central Colorado, but even if those don`t develop winds should
generally be light and VRB through much of Monday night.

&&

.FIRE WEATHER...
Issued at 1157 PM MDT Sun Apr 12 2026

We went with another Red Flag Warning on Monday afternoon for all the
southern CWA border zones and for the north central border plains
Zones along the Cheyenne Ridge. Fire weather conditions will be
critical with humidity levels ranging from 9-16% by afternoon
along with winds gusting up to 30 mph. Fuels remain extremely dry
in these areas.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 11 AM to 8 PM MDT Monday for COZ214-216-
238-241-242-246-247.

&&

$$

DISCUSSION...66
AVIATION...RPK
FIRE WEATHER...66

NWS BOU Office Area Forecast Discussion