821
FXUS65 KBOU 300933
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
333 AM MDT Sun Jun 30 2024

.KEY MESSAGES...

- Warmer today, with scattered afternoon storms. A few could be
  strong to severe.

- Continued heat across the region.

- Downward trend in showers and storms beyond Wednesday.

&&

.SHORT TERM /Through tonight/...
Issued at 333 AM MDT Sun Jun 30 2024

Water vapor satellite imagery this morning shows a broad plume of
moisture over the region, wrapping around a upper level ridge
centered near the OK/TX border. A slow moving MCS is evident on
radar along the CO/NM/OK border, with quieter conditions this far
north.

Above normal moisture is expected to remain anchored across the
region, with little change in the overall synoptic pattern. The
mid-level thermal ridge axis should shift east today, along with a
gradual increase in the mid/upper level southwesterly flow.
Temperatures should be 2-4C warmer than yesterday, with highs
generally in the low 90s across most of the metro. Further east,
low cloud cover will likely limit the amount of daytime heating.

Like yesterday, isolated to scattered afternoon showers and
thunderstorms are in the forecast again today. There should be a
bit more instability compared to Saturday, but it`s difficult to
say how much added coverage there will be given a lack of any
synoptic scale ascent. HREF reflectivity paintball plots also show
quite a bit of spread in the timing/location of storms this
afternoon. There are also some concerns about if the better
boundary layer moisture mixes out this afternoon along the I-25
corridor, as some models suggest (HRRR/RAP/ECM). The better PoPs
today are located across the higher elevations where confidence is
greater. If the moist solutions pan out, the parameter space would
favor a couple of stronger storms this afternoon and evening, with
primarily a hail/wind risk.

Guidance also has showers lingering across the northeast plains,
and across portions of the high country overnight, with lower
chances over the Front Range/urban corridor. Overnight lows
tonight will be mild.

&&

.LONG TERM /Monday through Saturday/...
Issued at 333 AM MDT Sun Jun 30 2024

Overall, not many changes to the long-term forecast. A series of
weak shortwave troughs will continue to bring mid-level moisture
to our region. This pattern could produce isolated to scattered
thunderstorms and showers each afternoon Monday through Wednesday.
Monday afternoon appears much more robust in thunderstorm chances
due to the assistance of 90-100kt upper level jet and hefty QPF
fields between 0.20-0.50 inches through southwest flow mainly for
the mountains and foothills. Although there is a lack instability
for majority of the region. Thus if any storms are able to form,
they should remain sub-severe Monday afternoon. A minor threat of
flash flooding could occur for East Troublesome and Cameron Peak
burn areas due to training storms. Afternoon highs on Monday
remain slightly above normal. By Tuesday, another round of
isolated to scattered showers and storms are possible in the
afternoon; Coverage decreases in the lower elevations by Tuesday
evening. By Wednesday, another round of scattered showers and
storms are possible by late afternoon mainly east of the Divide.

There is some uncertainty if another ridge builds in by Thursday.
Models differ in how much moisture lingers between the exiting
trough and western ridge. For now, NBM PoPs seem reasonable with
isolated chances of storms each afternoon starting Thursday
through next weekend. Isolated showers and storms are possible on
4th of July holiday mainly for the eastern plains but this could
change given the cold front late arrival Thursday evening.
Ensembles favor cooler temperatures giving some relief from the
90s on Friday afternoon across the plains.

&&

.AVIATION /06Z TAFS through 06Z Monday/...
Issued at 1134 PM MDT Sat Jun 29 2024

VFR through the TAF period. Still expecting stronger than normal
drainage flow overnight tonight. Starting to see some gustier
southerlies develop at APA with the wind shift line expected to
reach DEN before 07z.

Winds should weaken by late Sunday morning or early Sunday
afternoon, and should attempt to turn to more of an easterly
component. Guidance shows widely scattered convection again, but
no clear timing signal for when storms would be most likely to
affect the terminals. Opted for a long period of VCTS, turning to
VCSH, until there`s more confidence on any sort of timing.

&&

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

&&

$$

SHORT TERM...Hiris
LONG TERM...AD
AVIATION...Hiris