Severe Thunderstorm Warning 342, NWS Denver/Boulder, CO

Area Forecast Discussion
National Weather Service Denver/Boulder CO
604 PM MDT Wed Aug 19 2026

.KEY MESSAGES...

- Isolated to scattered storms into the evening, with a couple
  severe storms still possible mainly Palmer Divide area into
  southern Lincoln County.

- Summer heat and drier Thursday into Friday, although isolated
  showers/storms in the mountains.

- Monsoon moisture returns this weekend and holds into early next
  week, with increasing chance of storms.

&&

.DISCUSSION /Through Wednesday/...
Issued at 1242 PM MDT Wed Aug 19 2026

Main concern in the short term is development and strength of
convection this afternoon into early evening. We are seeing drying
in the mid and upper levels spread southward across the forecast
area, but low level moisture is hanging on across the plains. Best
MLCAPE is developing pretty much as expected over the Palmer
Divide through Lincoln County, where MLCAPE has grown to 1000-1500
J/kg. Farther north, the drying will limit overall MLCAPE to just
a few hundred J/kg. Thus, the main threat of any severe weather
would be from the crest of the Palmer Divide through central/
southern Lincoln County through early evening. Farther north,
mainly isolated and less intense storms are expected as there is
still some weak support/instability along and south of the upper
level jet axis.

Convection is expected to end latest over the far southern portion
of our forecast area by mid to late evening, with clearing skies
and temperatures a few degrees above normal overnight.

Thursday and Friday will feature very warm and mostly dry weather
as the upper level ridge starts to amplify and a drier northwest
flow aloft holds over the forecast area. The amplification of the
ridge will support a return of full summer heat, with highs
pushing into the lower to mid 90s across all of the plains and
I-25 Corridor on Thursday. Friday will see even further warming,
with mid to upper 90s well agreed upon by guidance.

Looking into this weekend, ensembles were still in good agreement
that monsoonal moisture arrives as the upper level ridge migrates
ever so slowly eastward. That would put the forecast area in
southwest flow aloft and increased moisture advection. Precipitable
water (PW) values climb to around 150% of normal on average. That
will support scattered to numerous storm coverage in the
mountains each day, at least once the ridge axis shifts slightly
eastward - which should be by Sunday at the latest. That's when a
shortwave moves over the northern U.S./Canada border area,
leading to a little more westerly component aloft. That component
would also aid an increase in showers/storms drifting eastward
onto the plains.

That same relative weather pattern holds through early next week,
which supports daily chances of showers and storms along with
slightly cooler (but still above normal) temperatures. A couple
weak backdoor fronts are possible during this period, which means
a day or two should see highs settle back into the mid to upper
80s across the plains and I-25 Corridor.

&&

.AVIATION /00Z TAFS through 00Z Friday/...
Issued at 547 PM MDT Wed Aug 19 2026

VFR conditions expected through the TAF period. Current radar
imagery still shows showers around all TAF sites so have kept the
PROB30 till 01Z, but most convection should be out of the area by
before 02Z. Winds are currently transitioning to the east and
should gradually turn southeast this evening before returning to
drainage flow by 06/07Z. For tomorrow, expect a typical diurnal
wind pattern. No precipitation or ceiling issues expected.

&&

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

&&

DISCUSSION...20
AVIATION...MAI

Preliminary Local Storm Report
National Weather Service Denver CO
701 PM MDT Wed Aug 19 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0621 PM     Hail             8 SW Deer Trail         39.53N 104.14W
08/19/2026  M1.00 Inch       Elbert             CO   Trained Spotter

            Time estimated based on radar data.

&&

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