377
FXUS65 KBOU 290540
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1140 PM MDT Tue May 28 2024

.KEY MESSAGES...

- Scattered storms mainly over the Front Range and Palmer Divide
  continue until early evening. Storms may produce small hail and
  wind gusts up to 45 mph.

- Higher afternoon thunderstorm potential on Wednesday, when a few
  severe storms will be possible, mainly for the rural plains.

- Slightly cooler Thursday behind a cold front, with isolated to
  scattered afternoon showers/storms each day through at least
  Saturday.

- Drier/warmer conditions favored as we near early next week, but
  details become more murky Sunday onwards.

&&

.UPDATE...
Issued at 847 PM MDT Tue May 28 2024

Active evening in spots across the plains. Radar shows a mix of
sub-severe to severe storms with the severe warned storms being
across east Adams/Arapahoe counties and Washington County.Plenty
of boundaries to go around as well which have helped initiate new
storms. As far as the forecast goes, thunderstorms have extended
into this evening, later than originally anticipated. Adjusted
precipitation probabilities to reflect the storm activity
across mainly the eastern portion of the plains. Over the next few
hours, storms will weaken and move east. Before they do, there
may be a few pulsy strong storms and a chance for severe on the
plains. We`ll have to keep an eye on the less worked over areas
such as the northeast corner where there is instability available.
Hail would be the main threat with up to quarter size possible.

&&

.SHORT TERM /Through Wednesday/...
Issued at 251 PM MDT Tue May 28 2024

Currently, a few showers and storms hover along the southern
foothills and Palmer Divide which can be seen on reflectivity.
Southwest flow aloft remains weak on ACARS soundings. Storms
continue to pulse up and quickly end; this pattern will likely
continue given the marginal amount of instability and shear this
evening. A robust storm or two could produce small hail but
majority of showers and storms should remain non-severe. Models
and soundings indicate large DCAPE values near 1000-1200 J/kg
which could lead to storms producing wind gusts up to 45 mph
through tonight. Low temperatures increase for the lower
elevations sitting a few degrees above normal; normal low
temperatures are expected for the high country. Southwesterly
flow increases aloft as the next shortwave trough arrives to
northeast Colorado early Wednesday morning.

Diurnal thunderstorms and showers are possible once more
Wednesday afternoon across the region. CAMs favor a dryline
initializing slightly east of the I-25 corridor. This set-up
combined with the favorable conditions, bulk shear 30-35kts and
MU CAPE between 700- 1000 J/kg, could lead to a few severe storms
along the eastern plains starting late Wednesday afternoon through
late Wednesday evening.

&&

.LONG TERM /Wednesday night through Tuesday/...
Issued at 251 PM MDT Tue May 28 2024

Thunderstorms will continue to progress eastward across the
plains Wednesday evening and be east of the area by midnight. Then
a cold front will move south across the area towards sunrise
Thursday morning. High temperatures will be cooler Thursday with
readings in to the upper 70s to around 80F over northeast
Colorado. Moisture decreases as well for Thursday behind the
front. In addition to less moisture and instability, soundings
show the airmass will be capped as well. Better moisture and
instability will reside over southeast Colorado where scattered
thunderstorms are expected. The northern extent for showers and
storms Thursday looks to be around or slightly south of I-70.
However, the GFS shows it will be a little warmer than the other
models show, with showers and storms overcoming any capping. Thus,
will keep a slight chance for showers and storms over the
northern parts of the area just in case the GFS is on to
something.

For Friday and the weekend, west to southwest flow aloft will
prevail. Temperatures will slowly climb each day reaching the
upper 80s by Sunday. Better instability and moisture are expected
to be in place Friday for a round of scattered showers and
thunderstorms. Models are hinting at a short wave trough moving
across Colorado on Saturday. Expect an increase in showers and
thunderstorms if this holds true. However, with this system
several days away, timing and track of this wave will likely
change. Models generally agree Sunday will be drier with
subsidence and drying behind the trough.

Upper level ridging begins to build over the Central and Southern
Rockies early next week. This is expected to bring warm and dry
conditions for Monday and Tuesday.

&&

.AVIATION /06Z TAFS through 06Z Thursday/...
Issued at 1140 PM MDT Tue May 28 2024

Storm activity remains north of the terminals. A few VC showers
are possible. Remnant outflow boundaries from those storms may
stay toward the terminal in the next couple of hours.

SE winds at DEN and APA will become more southerly drainage at
08-14 kts around midnight. Confidence in the winds is lower for
Wednesday. This is because of the uncertainty in how the Denver
cyclone sets up toward the afternoon. If the circulation stays
more north, DEN will stay southerly. There is also a chance winds
go NNE or NE. BJC will more likely stay light northerly in either
of these scenarios. There is a low chance for scattered
thunderstorms in the afternoon (< 30%). There will likely be some
shower/storm activity around the terminals (at least DEN). This
will bring the usual threat of brief variable gusts 25-35 kts with
convective showers/storms. Winds return to southerly after 00Z.

&&

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

&&

$$

UPDATE...Mensch
SHORT TERM...AD
LONG TERM...Meier
AVIATION...Mensch