777
FXUS65 KBOU 192058
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
258 PM MDT Thu Mar 19 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 159 PM MDT Thu Mar 19 2026

A historically strong upper high over the Desert Southwest will
continue to dominate our weather through Saturday. This will result
in an unprecedented heat wave for this early in the season.

Downslope flow, nearly full sunshine, further warm advection, and
a very dry airmass will support a continuation of record warmth
Friday and Saturday. 700 mb temperatures will rise from +11C
today to +12C on Friday, and then an astounding +15C for Saturday.
Light downslope flow also means shallow inversions, and full
sunshine will have no problem heating dry adiabatically far past
700 mb (in fact up close to 600 mb today and Friday, and
potentially all the way up to 500 mb on Saturday). That`s more
like June weather than March, just as the intensity of the upper
level high over the Desert Southwest.

This supports high temperatures soaring above record high
temperatures, and potentially more than 10 degrees above daily
records by Saturday! Even monthly record high temperatures will
get obliterated in this heat wave, with those being broken by 5-7
degrees in many locations. The latest forecast have actually
trended up another degree or so based on the last two days
of observations and expected compressional warming on Saturday as
flow aloft strengthens again. The only thing that could get in the
way would be a little cirrus that arrives in the afternoon, but so
far the majority of that holds off until Saturday evening. With
compressional heating, it is not out of the question that we could
get up to 90F for the official high on Saturday in Denver and 92F
in downtown! Fort Collins official high forecast is already at
90F, and above 90F for many of our plains locations.

Here is the updated max temperature forecasts:

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

Friday, March 20:   80 (1907) / Forecast High: 84
Saturday, March 21: 78 (1995) / Forecast High: 89

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

Denver:   83 (1971) / Forecast Max 89
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 91
Julesburg:   88 (1967) / Forecast Max 92
Estes Park:   70 (1925) / Forecast Max 76
Dillon:   63 (2012) / Forecast Max 72

Beyond the heat, model guidance is still in good agreement of an
upper level shortwave trough racing across the northern United
States over the weekend, with an associated cold front (actually
more like a `cool` front) sweeping across the forecast area
Saturday night. Temperatures will moderate to the 60s for Sunday`s
highs, which will still be slightly above normal. We still can`t
rule out a few showers with some mid level moisture advection, but
they will be scattered and light. Any precipitation will almost
certainly less than a tenth of an inch per various ensemble
output.

Warm and dry weather returns on Monday and through the middle of the
week, as the upper level ridge amplifies again over the Desert
Southwest. This time the ridge seems a little more elongated,
essentially meaning more westerly flow and a deeper concern for
more widespread critical fire weather conditions - likely peaking
toward Wednesday. Temperatures will also be warming, and good
agreement that we`ll be soaring back to record highs by the middle
of the week. If it wasn`t for this heatwave, this next one toward
Wednesday would also be on track to set record monthly high
temperatures.

Some indications in the longer range output for a pattern change
toward the beginning of April....

&&

.AVIATION /18Z TAFS through 18Z Friday/...
Issued at 1157 AM MDT Thu Mar 19 2026

VFR conditions will persist through the TAF period, with mostly
clear skies and only FEW cirrus clouds. Winds are light southerly
and even trying to transition to VRB through 20Z. After that, it`s
a wash (equal chances) at KDEN of whether we stay VRB, go
westerly (due to mixing), or light north/northeast diurnal
upslope. KBJC will have a higher (70% chance) of becoming W-NW
with gusts to 20-25 kts.

For tonight, it looks like a slower transition once again to
normal southwest winds 04Z-06Z. Then, we`ll likely see VRB winds
for a couple hours 17Z-20Z Friday, before a more northerly but
still light diurnal wind develops.

&&

.FIRE WEATHER...
Issued at 159 PM MDT Thu Mar 19 2026

Elevated fire weather conditions can be expected through Friday
due to the extremely low humidity levels (less than 10% across the
plains). Breezy conditions and gusts of 25-30 mph along the
Wyoming border (Cheyenne Ridge area) will support critical
conditions there, so Red Flag Warnings are in effect until 7 pm
today, and then again from 11 am to 7 pm for Friday. Elsewhere
winds will be lighter.

Saturday continues to have the highest concern for widespread
critical fire weather conditions. That will be the hottest and
driest day, and winds will also be increasing during the
afternoon as westerly flow aloft strengthens. Humidity readings
will plunge further to 4-7% across the plains, and just 6-10% in
the foothills, and to near 10% across the high mountain valleys.
Winds are expected to increase with gusts to 25-35 mph, with the
strongest winds across the foothills and high mountain valleys.
We`ve received some fuel status updates from land managers, and we
now appear to be reaching critically dry fuels across most of the
foothills and high mountain valleys. Thus, those locations were
added to the Fire Weather Watch for Saturday. Critical conditions
may last well into the evening given the increase in flow aloft
and very slow humidity recovery expected.

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

&&

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

Red Flag Warning until 7 PM MDT this evening for COZ238-242.

Red Flag Warning from 11 AM to 7 PM MDT Friday for COZ238-242.

&&

$$

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

NWS BOU Office Area Forecast Discussion