747
FXUS65 KBOU 131120
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
520 AM MDT Mon Apr 13 2026

.KEY MESSAGES...

- Critical fire weather conditions expected again today 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. A few inches of snow for the higher mountains with
  slick travel possible over the higher passes mainly at night.

- 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 /12Z TAFS through 12Z Tuesday/...
Issued at 520 AM MDT Mon Apr 13 2026

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

We`re starting with light S-SW winds which should hold through
about 14-15Z, with a slight westerly bend through 17Z. Then, just
like yesterday, we`ll be battling the difference between mixing
of stronger westerlies aloft and the corresponding weak/reverse
shear easterlies. We think KAPA will once again have the best odds
of becoming gusty to ~25kts from the WSW by 15Z-17Z and holding
through most of the day, while 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. Short range models are still 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)
versus WSW this afternoon (30-40% chance). Therefore, we`ve
adjusted the TAFs accordingly for the most likely scenario. KBJC
is a more evenly matched probability, 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. Then a more E-SE hybrid flow between gradient
and drainage, or a weak anticyclone overnight. However, it`s a
weak gradient so even if those winds don`t develop they should
generally be light and VRB through much of tonight. Then more
confidence of an E-SE wind developing Tuesday morning.

&&

.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 this morning to 8 PM MDT this
evening for COZ214-216-238-241-242-246-247.

&&

$$

DISCUSSION...66
AVIATION...20
FIRE WEATHER...66

NWS BOU Office Area Forecast Discussion