448
FXUS65 KBOU 102017
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
217 PM MDT Fri Apr 10 2026

.KEY MESSAGES...

- A brief cool down today with scattered rain showers. Isolated
  thunderstorms will also be possible over the higher terrain and
  portions of the I-25 Corridor.

- Scattered showersSaturday with a few thunderstorms. Potential
  for stronger storms in our eastern counties.

- Warm and dry Sunday and Monday, with breezy/windy conditions
  possible along with increasing fire conditions.

&&

.DISCUSSION /Through Friday/...
Issued at 149 PM MDT Fri Apr 10 2026

Cloud cover managed to hold off for much of the morning and
afternoon, allowing for surface heating across much of the area.
This heating has allowed temperatures to warm into the upper 50s to
upper 60s in the urban corridor. The Denver Cyclone has set up
near/north of Denver, putting the convergence zone over the Urban
Corridor for much of the afternoon. This convergences zone could
be a focal point for shower and thunderstorm development this
afternoon. We still have a bit of inhibition out there, but if we
can warm a few more degrees, we could tap into some low end
surface CAPE this afternoon (~500 J/kg). The DCVZ combined with
some surface instability could be enough for a landspout or two to
form along this boundary. A few thunderstorms could develop this
afternoon away from this convergence zone as well. These storms
will be capable of producing dangerous lightning and gusty winds
with any outflows.

Breezy south/southeast winds overnight will bring increased
moisture into the area. A surface low is forecast to develop on
the lee side of the mountains, moving through the plains and out
of Colorado by the late afternoon to early evening. Aloft, we`ll
see a few shortwave impulses in the upper flow ahead of the trough
over the western U.S.. As this surface low moves east, breezy
west winds will move in behind it. There is potential for some
weak surface convergence near the low/lee trough to trigger
scattered showers and thunderstorms. Moisture will be higher
tomorrow, so there is potential for some slightly better rain
amounts under the isolated thunderstorms, with the potential for
localized areas to see a quick couple of tenths. Lapse rates and
instability could support an isolated strong to marginally severe
storm in our east/northeast counties in the afternoon. The main
hazards will be strong winds and dangerous lightning, with a low
potential for small hail.

Above normal temperatures and dry conditions are expected for Sunday
and Monday, leading to critical fire weather conditions for portions
of the area. Minimum RHs will drop into the 10% to 15% range across
the plains both afternoons, with breezy southwest winds. The
strongest winds will be in our southeastern counties. A Fire Weather
Watch has been issued for Sunday afternoon into the early evening
for the Southern Foothills, Palmer Divide, and portions of the
eastern plains.

Precip chances will start to increase late Monday as the upper level
trough over the West Coast moves towards Colorado. While we still
have precip chances, models continue to trend lower with precip
accumulation`s over our area. Models are now showing more of an
open wave versus a few days ago where it was showing a closed low
headed straight for Colorado. Portions of the plains could still
see a few tenths, but most of the area will likely see a few
hundredths of liquid or less. The mountains look a little better
off with this event, with snow accumulations around 1 to 4 inches
for areas above 7,500ft. Precip chances will lower late Tuesday as
the trough moves out of the area. Conditions are expected to be
drier with a warming trend Wednesday through Thursday.

&&

.AVIATION /18Z TAFS through 18Z Saturday/...
Issued at 1205 PM MDT Fri Apr 10 2026

The Denver Convergence Vorticity Zone (DCVZ) is still likely (80%)
to develop near/south of KDEN this afternoon around 18z to 20z.
This is expected to bring E/SE winds to KDEN during that
timeframe. Winds at KAPA are expected to be S/SW. The exact
location of this feature will dictate the wind direction this
afternoon, especially at KDEN and KAPA. As the afternoon
progresses, we expect isolated thunderstorms and scattered
showers to develop for all three TAF sites. The highest likelihood
of showers and thunderstorms (40-50% chance) will be from about
20z to 00z this afternoon, but lower chances will continue through
at least 02z ending from west to east. Therefore, we have -TSRA
included in the TAF with the possibility for sustained winds to be
around 10 to 20 kts and gusts up to 35 kts with any gusty outflow
winds from these showers.

Following the showers and storms this afternoon, stronger than
typical drainage winds will occur at KDEN and KAPA overnight. For
KBJC, we expect lighter winds overnight. These will generally be
NE, but could be VRB for several hours according to the latest hi-
res guidance. For tomorrow afternoon, we again expect another
round of showers and thunderstorms could affect all three sites.
Instability should be slightly lower today and the overall shower
chances are a bit lower than today (30-40%), so we opted for a
TEMPO -SHRA for this package. These chances will likely extend a
few hours after 00z Sunday. There is again the possibility for
sustained winds to be around 10 to 20 kts and gusts up to 35 kts
with any gusty outflow winds from these showers.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Sunday afternoon through Sunday evening
for COZ216-241-246-247-249>251.

&&

$$

DISCUSSION...AP
AVIATION...MV

NWS BOU Office Area Forecast Discussion