510
FXUS65 KBOU 191816 CCA
AFDBOU

Area Forecast Discussion...CORRECTED
National Weather Service Denver/Boulder CO
1216 PM MDT Sun Apr 19 2026

.KEY MESSAGES...

- Dry and unseasonably warm weather continues through Wednesday.
  Highs will be nearly 20 degrees above normal Tuesday and
  Wednesday.

- Critical fire weather conditions likely on Wednesday due to
  increasing winds and very low humidity, with elevated to critical
  conditions lasting into Thursday.

- Pattern change to cooler and unsettled weather Friday through the
  upcoming weekend.

&&

.DISCUSSION /Through Sunday/...
Issued at 1125 AM MDT Sun Apr 19 2026

A strong upper level ridge centered over the Rockies will dominate
our weather through Tuesday. We`ll see continued warm advection, lee
troughing, shallow inversions, and a very dry airmass...all of which
lead to unseasonably warm daytime temperatures. Highs Monday will
be warming another 6-9F from those observed today, and Tuesday
should tack on another 3-4F as 700 mb temperatures warm to +12C.
That puts Tuesday`s high temperatures into the 80s across all of
the plains, with 60s to mid 70s foothills and mountain valleys,
and upper 40s and 50s higher mountains. The slightest advection of
mid level moisture and strong daytime heating may result in a
high based sprinkle in the mountains by late in the day Tuesday
otherwise dry weather will persist.

The main concern for this forecast cycle will be significant fire
weather conditions developing by Wednesday. Southwest flow aloft
will strengthen as the upper level trough along the West Coast
ejects rather quickly E-NE across the Great Basin and Northern
Rockies. Temperatures will be just as warm, if not a little warmer
than Tuesday given strong downslope flow and lack of any cold
advection until late afternoon and evening. Stronger, gusty
southwest winds can be expected with gusts around 35-40 mph over a
good chunk of the forecast area by afternoon, and locally
stronger winds along the Front Range by evening as the upper level
trough axis passes and low level gradients max out. We see some
pretty impressive surface gradients here, topping out between 13
and 17 mb between Denver and Grand Junction, indicative of at
least approaching High Wind criteria. An early look at cross
sections shows 50kt near 700 mb and strong subsidence to aid
momentum transport after the trough passage, so definitely
something to keep an eye on for the next couple days. See more
details with regard to fire weather parameters in the Fire Weather
Section below.

Breezy to windy conditions will likely persist into Thursday with
post trough subsidence and moderate northwest flow aloft.
Temperatures will be cooler with highs most likely settling back
into the mid to upper 60s for the plains.

Looking farther ahead, there is more uncertainty in details, but
at the same time good agreement we`ll be getting into a cooler
and more unsettled weather pattern. The first taste of this change
will most likely start Friday or Saturday with an increasing
chance of rain showers for the plains and snow showers for the
mountains. The GEFS hints at these better chances arriving by
Friday, while the ENS would suggest closer to Saturday. While
unsettled, we see little evidence of a big storm, but rather
daily chances of showers with generally light to modest
precipitation amounts. ENS shows about a 70% chance that mountains
receive over 0.5" of liquid water by the end of the weekend, with
a 20-40% chance >0.5" on the plains. The GEFS and GEPS were more
excited as usual, with 80% probabilities in the mountains and
40-60% chance of >0.5" on the plains. Whatever the case, some much
needed precipitation is in the forecast for a change. A quick
look at ensembles show this cooler and somewhat unsettled weather
pattern to stick around into the first week of April which we
certainly need for our drought conditions.

&&

.AVIATION /18Z TAFS through 18Z Monday/...
Issued at 1154 AM MDT Sun Apr 19 2026

Weak winds at 8 knots or less are expected at DIA for the rest of
today with some sort of easterly component to them. For tonight,
the drainage winds at the airport look to be under 10 knots. There
will be no ceiling issues.

&&

.FIRE WEATHER...
Issued at 1125 AM MDT Sun Apr 19 2026

Critical fire weather conditions are likely to develop Wednesday,
as southwest winds increase in an unseasonably warm and dry
airmass. Wind gusts of 35-40 mph can be expected by mid to late
afternoon in most areas. Humidity levels will drop into the 7-11%
range over most of the plains, with minimum RH under 15% in most
of the foothills and high mountain valleys. Those critical
conditions may last well into Wednesday evening with a
continuation of strong, gusty winds.

Cooler temperatures will arrive for Thursday, but it will still
remain dry and breezy (windy northeast plains) with another day
of elevated to critical conditions expected.

Cooler and more moist air arrives for Friday and the weekend with
a daily chance of showers.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

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

NWS BOU Office Area Forecast Discussion