846 
FXUS65 KBOU 051130
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
530 AM MDT Mon Oct 5 2026

.KEY MESSAGES...

- Dry and unseasonably warm through at least Saturday, with
  record/near record warmth on Monday.

- Isolated showers possible (15-30% chance) most afternoons for
  the higher elevations, highest Tue. Precipitation, if any, will
  be highly localized.

&&

.DISCUSSION /Through Sunday/...
Issued at 1019 PM MDT Sun Oct 4 2026

An upper level high over the Great Basin will weaken a bit on 
Mon. Once again there is some mid level moisture embedded in weak 
NW flow aloft. As a result, can't rule out isold high based 
showers over the high terrain. Meanwhile, with rising 850-700 mb 
temps along with downslope low level flow, highs may tie or break 
records, as readings reach the mid 80's to around 90 over the 
plains.

On Tue, a weak disturbance will affect the area with some increase 
in mid level moisture.  Thus may see a slightly better chc of high 
based showers/isold tstms over the higher terrain in the aftn. 
Some of this activity may affect portions of the I-25 Corridor by 
late aftn or early evening. Over the rest of nern CO, it will 
remain dry with highs remaining 10 to 15 degrees above normal.

By Wed, the flow aloft will remain weak WNW. There will still be 
some lingering mid level moisture over the higher terrain. Overall, 
will keep in a slight chc of high based showers/isold tstms. Once 
again highs will be 10 to 15 degrees above normal.

For Thu and Fri, the flow aloft will gradually become more zonal by 
Fri.  Still expect mainly dry conditions both days.  The GFS tries 
to backdoor a cool front into nern CO on Fri while the ECMWF has 
downslope low level flow as a sfc lee trough is over nern CO. 
Overall, still believe highs will remain 10 to 15 degrees above 
normal across the plains both days.

By next weekend, the flow aloft will increase from the WSW as an 
upper level trough develops over the Pacific NW on Sat.  Should see 
another day of warm and dry conditions over the area on Sat. 
Meanwhile, both the ECMWF and GFS keep the upper level trough to the 
NW of the area thru Sun. Both models show some subtropical 
moisture embedded in the flow aloft which may lead to a slight chc
of showers over portions of the higher terrain by aftn. Across 
the plains, it looks dry with another day of above normal 
temperatures.

For late Sun through Mon, there are varying solutions as to how fast 
or slow the upper level trough will be as it moves eastward. The GFS 
is faster while the ECMWF is slower by at least 24 hours. Naturally, 
depending on the timing and how much it amplifies will have a 
significant impact on weather for next Mon and Tue. 

&&

.AVIATION /12Z TAFS through 12Z Tuesday/...
Issued at 441 AM MDT Mon Oct 5 2026

VFR conditions expected through the TAF period. South-
southwesterly winds are expected to become light and variable by
17Z-18Z at KDEN/KAPA, slightly sooner at KBJC (15Z-16Z). Light 
easterly winds are then expected for a few hours before turning 
clockwise towards drainage at KDEN/KAPA. A period of light and 
variable winds are expected at KBJC this evening (~0Z) before 
becoming westerly for the overnight hours. South-southwesterly 
winds should persist through Tuesday morning at KDEN/KAPA, with a 
few hours of light and variable winds expected to return by late 
morning (~16Z). 

&&

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

&&

$$

DISCUSSION...RPK
AVIATION...9