072
FXUS65 KBOU 301628
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1028 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.

&&

.UPDATE...
Issued at 1010 AM MDT Sun Jun 30 2024

Temperatures are warming efficiently this morning. It is about
8-11 degrees degrees warmer than it was at this time yesterday in
many locations across the plains/urban corridor. This puts the
forecast well on track for a warmer day with highs in the 90s
across the plains. No adjustments needed to the previous forecast.
High resolution guidance still showing potential for scattered
showers and thunderstorms this afternoon with the highest chances
over the higher terrain. As for the plains, CAMs still show a spread
in timing/location of scattered showers/storms. There`s also still
a split among model guidance in if the low level moisture around
this morning is better maintained this afternoon or efficiently mixed
out (HRRR). If the moisture sticks around, we`ll see a better
chance for showers/storms surviving off the higher terrain late
this afternoon.


&&

.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 /12Z TAFS through 12Z Monday/...
Issued at 531 AM MDT Sun Jun 30 2024

VFR through the TAF period. The stronger push of drainage flow was
slow to develop overnight but is now well established at DEN/APA.
Some uncertainty with how long these stronger winds will last
before becoming light/variable later this morning, but the general
consensus is for this to last a couple more hours.

Mid/high cloud cover should gradually increase this afternoon,
with isolated to scattered convection developing south and west of
the terminals by the early afternoon. This activity should
gradually push across the terminals at some point today.
Confidence in any timing is low though I`d favor something close
to 00z if any TS do reach DEN. Did think about including a PROB30
but confidence in any specific time period is too low. Isolated
showers will likely persist through the first half of the
overnight, with drainage flow redeveloping.

&&

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

&&

$$

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