441
FXUS65 KBOU 162248
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
448 PM MDT Thu Jul 16 2026

.KEY MESSAGES...

- Hot weather continues with the heat now expected to last through
  Monday. The highest temperatures will occur Sunday and Monday
  with a Heat Advisory for the urban corridor possible.

- Scattered afternoon/early evening storms in the mountains
  expected through Sunday with the plains remaining dry.

- Significant monsoonal moisture and cooler temperatures will
  arrive on Tuesday of next week. The thunderstorms that develop
  will be capable of producing locally heavy rainfall.

&&

.DISCUSSION /Through Thursday/...
Issued at 1200 PM MDT Thu Jul 16 2026

Water vapor imagery shows a very weak shortwave trough over
northeast Colorado moving southwestward with plenty of dry air
aloft. At the surface, there are warm temperatures and decently
high moisture values given the warmth. With very steep lapse rates
and most-unstable CAPE approaching 1,000 j/kg over the mountains,
widespread thunderstorms are expected in Park County with
scattered coverage in Grand and Summit Counties. Some storms could
have nickel size hail in South and Middle Parks. In addition,
multiple rounds of storms could lead to rainfall totals around an
inch in Park County. Otherwise, some isolated showers or storms
could develop in the southern foothills. It is unlikely but
possible that a storm or two moves onto the adjacent plains in the
southwest Denver metro which could produce some wind gusts up to
35 mph this evening.

Slightly warmer temperatures aloft with less moisture will lead to
an increase in surface temperatures by a degree or two on Friday
with less coverage of showers and storms over the mountains.

A ridge of high pressure aloft will strengthen on Saturday and
Sunday and place itself directly over Colorado. 500 mb heights
will increase to around 594 dm over our CWA on Saturday and up to
596 dm on Sunday. High temperatures will increase as a result and
highs will be 96-98 in the downtown areas of Denver, Fort Collins,
and Greeley on Saturday. The warmest day of the 7-day forecast
appears to be Sunday as highs in the downtown areas of those three
cities will be between 99-101. The latest HeatRisk forecast value
for Sunday shows most of the urban areas will have a value of 3.
If models continue to show this level of heat tomorrow, a Heat
Advisory may be issued for the urban corridor for Sunday.

One of the bigger forecast changes over the past 24 hours is the
delay in the arrival of the monsoonal moisture and cooler
temperatures. The ECMWF ensembles now have a much tighter range of
forecast high values with the 25th percentile in Denver of 97.
This is likely due to a slight shift with the center of the upper
level ridge to the northwest throughout the forecast runs. If this
trend continues, it is possible that high temperatures will be
around 100 degrees again in urban areas with a HeatRisk value
at 3 on Monday. That means, a Heat Advisory will again be
considered for Monday.

Showers and storms will increase in coverage over the higher
terrain on Monday as more monsoonal moisture makes its way
northward. But it is not until Tuesday that the plains will begin
to see better coverage of showers and storms. With the upper level
ridge shifting to the south, there will be light westerly flow
aloft which will allow storms to move off the higher terrain and
onto lower elevations. The storms Tuesday night and into Wednesday
will have ample moisture and moderate instability. It does look
like the first couple of days that this monsoonal moisture
arrives will have a flash flooding concern due to heavy rainfall.

&&

.AVIATION /00Z TAFS through 00Z Saturday/...
Issued at 444 PM MDT Thu Jul 16 2026

VFR conditions will prevail for all terminals through the TAF
period. ESE winds will continue to persist at the terminals
through early this evening with gusts generally in the 19-25 kt
range. Latest guidance has accelerated the rotation to southerly
drainage flow this evening, so the TAFs reflect this quicker
transition. Ongoing convection across Park County could induce
some sw-erly outflows after ~01Z, with corresponding impacts to
KAPA in the form of occasional gusts 25-30 kts, however confidence
is low. This potential is notably lower for the other two
terminals.

Tomorrow, expect very similar diurnal wind patterns with
development of robust E/ESE flow by early afternoon. An isolated
high-based shower and associated outflow wouldn`t be out of the
question later in the day, but neither confidence nor projected
coverage are high enough to warrant any explicit inclusion in the
TAFs.

&&

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

&&

$$

DISCUSSION...Danielson
AVIATION...BRQ

NWS BOU Office Area Forecast Discussion