Hail in Colorado, May 16, 2026

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1241 PM MDT Sat May 16 2026

.KEY MESSAGES...

- Scattered showers and thunderstorms through early this evening,
  a few storms will be strong to severe.

- Another active shower/storm day Sunday, although threat of
  severe weather is more uncertain.

- Rain and mountain/foothill snow increases Sunday night through
  Monday with much colder temperatures arriving.

- Accumulating snow (>70% chance of 4-10+ inches) for the
  mountains, and >60% chance of accumulation in the foothills.
  Only a few wet snowflakes possibly mixed in for the I-25
  Corridor.

- One last spring freeze possible on some of the plains Monday
  night.

- Gradually drier with a warming trend through the end of next
  week.

&&

.DISCUSSION /Through Saturday/...
Issued at 1240 PM MDT Sat May 16 2026

Active weather pattern is shaping up through the rest of the
weekend and Monday, potentially lasting into Tuesday.

Satellite shows convection is already starting before the noon
hour as an increase in moisture combines with daytime heating and
growing instability. Low level moisture is also gradually
increasing across the plains this afternoon, with MLCAPE expected
to grow to 600-1200 J/kg over the eastern plains, and less than
600 J/kg along the I-25 Corridor. While those values and low level
moisture is rather marginal, deep layer bulk shear is increasing
to 45-55 kts and low level southeast flow is expected to increase
as well. Low level helicity values are still not terribly strong,
with 0-1 km values mostly under 100 m2/s2 and 0-3km in the
100-200 m2/s2 range. It appears these will be maximized closer to
the decaying weak cyclone and maximized convergence/low level
vorticity from southeast of Denver metro (near Arapahoe/Elbert
County line) eastward into southern Washington county. There is
also potential for stronger low level flow and moisture advection
into early this evening over the far eastern plains. Thus, if we
were to see a brief tornado or two, those would be the most likely
areas. Otherwise the main threat will be large hail and a couple
damaging wind gusts as storms migrate eastward into the higher
instability on the eastern plains late this afternoon and early
evening.

For Sunday, the question remains the severe weather threat. Much
of that will be determined by how far south the front pushes and
whether it actually stalls over/near the Palmer Divide into east
central Colorado. At this point, the far southern and eastern
portions of our forecast area from the crest of the Palmer Divide
eastward to about Limon toward points south and east of Akron
would be most favored for strong/severe storm development with
MLCAPE of 500-1200 J/kg, but again only if that front can stall.
Even if the front does come through, there is still a risk of an
elevated severe storm or two due to sufficient elevated
instability and shear. Hail would be the primary threat from the
stronger elevated storms, while a brief tornado or landspout would
be possible from any convective initiation along the
aforementioned (if stalled) boundary.

The main concern then shifts to Sunday night and Monday with
high potential for accumulating snow in the mountains and higher
foothills. The threat of snowflakes mixing in down into the I-25
Corridor has lowered, as ensembles stepped back from the solution
of one stronger compact shortwave moving across. Now, the first
piece of more organized energy Sunday night and Monday is slightly
weaker/warmer and another piece of energy is held back for
Tuesday. Thus, the chance of any accumulation for the I-25
Corridor is quite low (<10%) and at most we'd expect just a few
wet snowflakes late Monday. Now, only about 20% of ensemble
members are hinting at some snow mixing in for the I-25 Corridor,
versus ~50% yesterday. For the mountains, it will still be cold
enough to support several inches if not close to a foot of snow,
while foothill areas could see anywhere from a trace to 10". Those
heavier amounts would still be favored and mostly confined toward
the north, including the higher foothills above 7,500-8,000 feet
in Larimer County.

The heaviest total liquid equivalent precipitation from this
storm system is still expected along and north of I-70 and I-76 on
the plains. Ensembles have bumped up the lower end a little to our
north, with the 25th-75th percentiles now at 0.70-1.25 inches for
the Denver metro, but a floor (10th percentile) still near 0.25"
as there is some bust potential given Denver will be on the edge
of the more persistent showers/storms. The mean still holds near
0.80-1.0 inch. From those means, add on another 0.3 to 0.4 inch
for locations near the Wyoming border and still take away about
0.5 inch for points farther south along the Palmer Divide.

The weather pattern settles down for much of next week. As this
first trough exits and cold air lingers, some frost/freezing
temperatures can be expected down onto the plains late Monday
night into Tuesday morning. That still depends on how much
clearing and drying we see. The second piece of the main trough
that impacts us on Monday should support higher shower/storm
coverage especially along the Front Range into Tuesday, but some
weak troughiness linger into Wednesday. Temperatures will gradually
moderate those two days, while warming back to normal or above
normal levels by the end of next week as a more zonal flow aloft
develops. Still expect a few showers/storms around with
sufficient heating and afternoon/evening instability which would
be more typical Colorado weather.

&&

.AVIATION /18Z TAFS through 18Z Sunday/...
Issued at 1210 PM MDT Sat May 16 2026

Latest radar and satellite imagery shows showers developing over
the mountains. Currently watching a cyclone located over central
Arapahoe county near Byers. This feature is expected to continue
moving south this afternoon providing the easterly winds at KDEN
and KAPA this afternoon.

For this afternoon, there is a 30-40% of showers and
thunderstorms at all three TAF sites. Any of these storms could
intensify rather quickly and produce variable gusty wind gusts of
at least 30 kts. Rainfall chances decrease after 00z, but there is
still a low (20%) chance of showers after then. Have kept in the
TEMPO and Prob30 groups between 20z today and 03z this evening for
this threat. Winds will be vrb for a brief period tonight or may
turn to NNW for a few hours. MOS guidance is showing increasing
confidence in a bkn stratus deck developing after at about 08z
Sunday around 5000 to 6000 feet AGL and lasting throughout Sunday.

A cold front will move through all three TAF sites between 12z
and 14z Sunday turning winds to be N or NE for most of Sunday
afternoon. By 18-19z, -SHRA can be expected. Ceilings should lower
to 2000 ft or so with any persistent showers. IMC and local MVFR
conditions are forecast for tomorrow afternoon, especially closer
to KDEN. Have added in a tempo group for -TSRA and visibility as
low as 5sm for tomorrow afternoon. This will be reliant on where
exactly the cold front stalls out and thus the location of the
greatest CAPE/instability.

&&

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

&&

DISCUSSION...20
AVIATION...MV

Special Weather Statement
National Weather Service Denver CO
129 PM MDT Sat May 16 2026

COZ041-046-162015-
Elbert/Central and East Douglas Counties Above 6000 Feet CO-North
and Northeast Elbert County Below 6000 Feet/North Lincoln County
CO-
129 PM MDT Sat May 16 2026

...A STRONG THUNDERSTORM WILL IMPACT CENTRAL ELBERT COUNTY UNTIL 215
PM MDT...

At 129 PM MDT, Doppler radar was tracking a strong thunderstorm 8
miles west of Simla, or 29 miles west of Limon, moving northeast at
20 mph.

HAZARD...Landspouts, wind gusts up to 40 mph, and half inch size
         hail.

SOURCE...Radar indicated.

IMPACT...Minor damage to outdoor objects is possible. Gusty winds
         could knock down tree limbs and blow around unsecured
         objects.

Locations impacted include...
  Simla and Matheson.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

If a tornado is spotted seek shelter inside a sturdy building.

&&

LAT...LON 3913 10426 3919 10431 3941 10406 3914 10386
      3913 10405
TIME...MOT...LOC 1929Z 235DEG 17KT 3917 10422

LANDSPOUT...POSSIBLE
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

Hiris

Special Weather Statement
National Weather Service Denver CO
208 PM MDT Sat May 16 2026

COZ041-046-047-162045-
Elbert/Central and East Douglas Counties Above 6000 Feet CO-
Southeast Elbert County Below 6000 Feet/South Lincoln County CO-
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County CO-
208 PM MDT Sat May 16 2026

...A STRONG THUNDERSTORM WILL IMPACT EAST CENTRAL ELBERT COUNTY UNTIL
245 PM MDT...

At 208 PM MDT, Doppler radar was tracking a strong thunderstorm near
Matheson, or 16 miles southwest of Limon, moving east at 20 mph.

HAZARD...Wind gusts up to 50 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible. Hail may accumulate on roadways causing hazardous
         travel.

Locations impacted include...
  Matheson.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the weather situation closely and be alert for threatening
weather conditions.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 3909 10403 3919 10403 3926 10373 3903 10374
TIME...MOT...LOC 2008Z 266DEG 16KT 3915 10395

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...50 MPH

Hiris

Special Weather Statement
National Weather Service Denver CO
313 PM MDT Sat May 16 2026

COZ046-047-162145-
Southeast Elbert County Below 6000 Feet/South Lincoln County CO-
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County CO-
313 PM MDT Sat May 16 2026

...A LINE OF STRONG THUNDERSTORMS WILL IMPACT NORTHEASTERN LINCOLN
COUNTY UNTIL 345 PM MDT...

At 313 PM MDT, Doppler radar was tracking a line of strong
thunderstorms extending from 5 miles northeast of Limon to near Hugo,
or extending from 5 miles northeast of Limon to 13 miles southeast of
Limon, moving east at 20 mph.

HAZARD...Wind gusts up to 50 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
  Hugo and Genoa.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the weather situation closely and be alert for threatening
weather conditions.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 3910 10362 3924 10363 3931 10369 3945 10349
      3928 10333 3903 10328
TIME...MOT...LOC 2113Z 258DEG 18KT 3931 10361 3923 10354 3914 10352

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...50 MPH

Hiris