192
FXUS65 KBOU 201122
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
522 AM MDT Fri Mar 20 2026

.KEY MESSAGES...

- All time March record high temperatures will almost certainly be
  broken through Saturday. Heat peaks on Saturday with all time
  March records being broken by several degrees!

- Prolonged elevated to critical fire weather conditions due to
  record heat and extremely low humidity levels. Saturday is still
  shaping up to be the most widespread critical day as winds
  increase.

- Brief drop to near normal temperatures Sunday.

- Return of unseasonable warmth, potential record heat (>70%
  chance), and more fire weather concerns again by Tuesday and
  Wednesday.

&&

.DISCUSSION /Through Thursday/...
Issued at 1118 PM MDT Thu Mar 19 2026

Record-breaking heat wave and elevated-to-critical fire weather
conditions continue to be the main headline for the next couple of
days, as the historically strong upper level ridge dominates our
weather pattern. A little overview of what happened today (Thursday):

DIA broke the daily and monthly high temperature record today, with
a recorded max temperature of 85 dg F (Previous daily record was
81 dg set in 1907 and previous monthly record was 84 dg set in
1971). How did this happen? With this strong upper level ridge,
warm and very dry air has continuously been advected into the
region, with 700-mb temperatures reaching up to +12 dg C. In
addition, we had mostly sunny skies, with only a few high cirrus
clouds throughout the day. ACARS soundings showed very steep lapse
rates, almost dry adiabatic up to 500-mb for the second day in a
row. Even with relatively light winds aloft, continuous sunshine
and compressional heating from light downsloping winds allowed
temperatures to skyrocket...higher than what guidance had been
showing (Forecasted high was 83 dg F).

With Friday looking to be very similar as Thursday, and knowing that
the past two days have been warmer than model guidance has
indicated, will be raising temperatures accordingly tomorrow.
Speaking of Friday, it is the Spring Equinox. However it feels more
like summer than it does spring. Forecasted high for DIA is now
85 dg F, which is actually the normal high temperature for June
19! Other than this heat, elevated-to-critical fire weather
conditions are expected, particularly for the northern plains near
the Cheyenne Ridge (see Fire Weather Discussion below).

Our heat-wave will peak on Saturday as model guidance has continued
to show 700-mb temperatures around +15 C, with some hi-res models
now indicating +16 C. This would roughly translate to surface
temperatures around 88/89 dg F. However, flat upper level ridging is
expected on Saturday due to a passing shortwave north of Colorado.
This will result in gusty downslope winds across the plains. With
guidance continuously being on the cooler end of reality, and
expected compressional heating, it is very possible that we could
have temperatures reach 90 F for DIA. This is further supported by
numerous Canadian and ECMWF ensemble solutions showing max
temperature of 90 dg F (GEFS/AIGEFS continues to be on the cooler
end of guidance). If this happens, it will be the first 90 dg day
recorded in the month of March for DIA. The only caveat that
would keep us from reaching the forecasted high temperatures would
be incoming high cloud cover from the associated shortwave.
Relative humidity cross-sections do indicate mid/high-level
moisture by late afternoon/early evening.

Here is the updated max temperature forecasts:

Current records and forecast DAILY high temperatures for Denver
(DIA):

Friday, March 20:   80 (1907) / Forecast High: 85
Saturday, March 21: 78 (1995) / Forecast High: 90

Previous MONTHLY record temperatures for March and max forecasts
through Saturday:

Denver:   83 (1971) / Forecast Max 90
Fort Collins: 81 (2012) / Forecast Max 90
Boulder:   83 (1910) / Forecast Max 89
Greeley:      85 (2010) / Forecast Max 92
Fort Morgan:  85 (2010) / Forecast Max 92
Julesburg:   88 (1967) / Forecast Max 93
Estes Park:   70 (1925) / Forecast Max 77
Dillon:   63 (2012) / Forecast Max 72

Past Saturday, guidance is in good agreement of an upper level
shortwave trekking across the northern United States, with an
associated "cool" front sweeping across the forecast area late
Saturday. Temperatures will moderate to the 60s, which will still be
slightly above normal. As mentioned above, mid-level moisture will
be advected into the region, leading to scattered showers mainly for
the mountains. Any precipitation that does fall will be very light,
as the 90th percentile of QPF for ensemble members still indicate
less than 0.15" for the mountains, and less than 0.10" for the
plains. However, despite the lack of appreciable precipitation,
Sunday will see a brief reprieve of elevated/critical fire weather
conditions.

Warm and dry weather returns on Monday and through the middle of the
week, as the upper level ridge begins to restrengthen over the
southwestern United States. Record-breaking temperatures are
possible once again by Tuesday/Wednesday. Moderate-to-strong
westerly flow is possible, which would mean another round of
widespread critical fire weather conditions.

&&

.AVIATION /12Z TAFS through 12Z Saturday/...
Issued at 520 AM MDT Fri Mar 20 2026

VFR conditions will prevail for all terminals through the TAF
period. S/SW drainage flow is largely holding on this morning
across the metro, but with some variable directions mixing in at
times. At KBJC, WNW winds 10-15 kts will persist for 1-2 more
hours before weakening. Light and VRB winds are expected roughly
through ~20Z, before winds favor a transition to NE flow for mid
to late afternoon. Daytime speeds are expected to remain below 10
kts. Expect a clockwise rotation in winds into the evening as
drainage flow returns. Overnight drainage of 09-13 kts anticipated
for KDEN/KAPA.

&&

.FIRE WEATHER...
Issued at 1118 PM MDT Thu Mar 19 2026

Elevated fire weather conditions are expected across the forecast
area on Friday with the continued warm and dry conditions.
However, winds will be the limiting factor for any critical fire
weather conditions, as west/northwest wind gusts should generally
remain under 25 mph. The only exception would be the northern
plains near the Cheyenne Ridge where gusts up to 30 mph are
expected to occur in the afternoon.

Saturday remains to be the highest concern for widespread critical
fire weather conditions, as that will be warmest and driest day.
Minimum relative humidity values likely will be between 4-7%
across the plains, 7-10% along the foothills and mountain valleys,
and less than 15% across the mountains. Widespread breezy winds up
to 40 mph are expected through the afternoon hours, with strongest
winds confined to the foothills and mountains. A Fire Weather
Watch remains in effect for Saturday.

There will be a brief reprieve of fire danger on Sunday, as a cold
front will bring in a slightly cooler air mass and moisture.
However, that will be short-lived as warm and dry conditions will
return with the upper level ridge rebuilding. Elevated to critical
fire weather conditions are possible Tuesday and peaking
Wednesday as winds strengthen.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Saturday morning through Saturday
evening for COZ211-213>216-238>245-248>251.

Red Flag Warning from 11 AM this morning to 7 PM MDT this
evening for COZ238-242.

&&

$$

DISCUSSION...MAI
AVIATION...BRQ
FIRE WEATHER...MAI

NWS BOU Office Area Forecast Discussion