Longmont, Colorado 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

833
FXUS65 KBOU 261122
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
522 AM MDT Tue May 26 2026

.KEY MESSAGES...

- Today will bring windy conditions to the plains and potential
  for elevated fire weather conditions in areas that see little/no
  rain this afternoon.

- Higher terrain will see a few rounds of fast moving showers and
  thunderstorms this afternoon and evening. There is a marginal
  threat of flooding mainly over the East Troublesome burn acar.

- Wednesday appears to be the most active day with more widespread
  showers and thunderstorm coverage with locally heavy rainfall
  possible due to slow movement of thunderstorms.

- After somewhat of a lull Thursday, thunderstorm potential will
  increase again Friday through the weekend with a chance of
  severe thunderstorms over the plains.

&&

.DISCUSSION /Through Monday/...
Issued at 242 AM MDT Tue May 26 2026

There is a well defined disturbance on satellite which is over nern
AZ early this morning.  This feature will gradually move northward
thru this aftn as abundant mid level moisture moves across the
higher terrain in southerly flow aloft.  Should see showers and
tstms increase over the higher terrain this aftn which will continue
through the evening hours.  The storms will be quick moving,
however, there still could be some locally heavier rainfall if
storms train over the same area.  Across the plains it will be more
stable with gusty SSE winds thru the aftn hours.  At this time, it
appears areas along the I-25 Corridor may see a slight chc of
showers and storms late this aftn thru the evening hours with dry
conditions across the plains.  Highs over nern CO will be in the
upper 70`s to mid 80`s.

On Wed, an upper level low will be over the wrn US as a blocking
upper level high is over the nrn plains.  This will lead to weak
southerly flow aloft across the area.  At the sfc, the low level
flow will be southeast across the plains which may allow for a
Denver cyclone to develop along srn areas of the I-25 Corridor by
aftn.  PWAT`s will increase to around an inch over the plains with
SBCAPE ranging from 500-1000 j/kg by aftn.  Overall, confidence in
where best chc of showers/tstms will be is rather low.  Blended
solutions have rather high pops over most of the CWA by aftn.
Some of the hi res data is focusing best chc for storms in and
near the foothills with outflow boundaries possibly triggering
additional storms across portions of the I-25 Corridor. With weak
flow aloft, storms will be slow moving and may produce locally
heavy rainfall in some areas where storms do occur. Highs on Wed
across the plains will be mainly in the 70`s.

On Thu, the blocking pattern will remain in place as the upper level
low remains over the wrn US.  As a result this will lead to a
continuation of weak flow aloft.  At the lower levels, the flow will
remain southeast with PWAT`s across the plains remaining near an
inch.  Meanwhile, SBCAPE will range from 500-1000 j/kg by aftn.
Overall, believe tstm chances will be lower on Thu, however,
there will still be some potential for sct slow moving storms with
locally heavy rain possible. As for highs, readings be in the mid
70`s to lower 80`s across nern CO.

By Fri, the blocking upper level high begins to shift eastward
allowing for the wrn US low to move into the Great Basin by Fri
aftn.  Across the plains, the low level flow will remain southeast
which will keep deeper low level moisture in place.  In addition,
SBCAPE will rise with values from 1000-1500 j/kg over nern CO.
Meanwhile, mid level flow will become more SW and increase slightly
which will lead to a more favorable shear profile.  Thus expect
stronger storms Fri aftn and evening across portions of the plains.

For Sat, the upper level low over the Great Basin will move
northeast into the nrn Rockies.  As a result, this will lead to
increasing SW flow aloft over the area.  At the sfc, there will be a
lee trough extending from sern WY into ern CO with a pseudo dryline
setting up.  SBCAPE will increase to 1500-2000 j/kg across nern CO
with decent Bulk Shear.  Thus I would expect sct svr storms Sat aftn
into Sat evening across the plains.  Meanwhile, across the higher
terrain, tstm chances will be on the lower side as drier air moves
in.

Looking ahead to Sun, the flow aloft will remain SW.  There will
still be decent low level moisture and SBCAPE across portions of the
plains in the aftn so a few svr storms may still be possible.  Once
again over the higher expect less tstm activity.

&&

.AVIATION /12Z TAFS through 12Z Wednesday/...
Issued at 518 AM MDT Tue May 26 2026

South winds will continue this morning at APA and DIA and
gradually increase by 15z with a few gusts to 25 mph thru 19z.
At BJC winds will be light and variable thru 19z. Winds will
continue to increase at all three sites this afternoon with gusts
up to 35 mph from the south. Winds will slowly decrease by 01z
with gusts up to 25 mph thru 05z.

There is still a slight chance of showers and thunderstorms mainly
between 01z and 05z this evening so have left in a prob30.
Overnight winds will stay mainly from the south.

&&

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

&&

$$

DISCUSSION...RPK
AVIATION...RPK