273
FXUS65 KBOU 101043
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
443 AM MDT Mon Jun 10 2024

.KEY MESSAGES...

- Scattered thunderstorms expected this afternoon with a few
  strong to severe storms possible and a risk of heavy rain,
  localized flooding with some storms.

- Snowmelt producing minor impacts from high streams, mainly in
  Grand County.

- Hot and mainly dry weather towards the middle to end of next
  week. There is potential for a day or two to need a Heat
  Advisory, most likely Thursday.

- Cooler conditions will arrive Friday and Saturday with scattered
  showers and storms. Some of these storms could be strong to
  severe with heavy rain.

&&

.SHORT TERM /Through tonight/...
Issued at 412 AM MDT Mon Jun 10 2024

The region remains under an upper level ridge today. Flow aloft is
still on the weaker side out of the WNW, but perhaps not as weak as
yesterday. A mid-level shortwave trough moves through the flow later
this afternoon. The stronger synoptic support is further north of
Colorado; however, it should provide sufficient ascent out ahead
of it aligning with peak heating. Current Mid-Level Water Vapor
satellite imagery depicts rich moisture transporting from the
south, wrapping around the upper ridge over CO this morning. This
correlates well with ensemble guidance keeping above normal
moisture in the area today around 140-175% of normal. Precipitable
water values rise to around 0.4-0.6" for the higher elevations
and 0.8-1.1" across the plains/urban corridor. MLCAPE values range
from 600-1500 J/kg. High level clouds will be around for the day,
but shouldn`t limit instability as much as lower clouds would.
With weaker upper level winds, 0-6km shear will be on the weaker
side with some slightly better values closer to the northeast
corner(20-30kts). Overall, this environment should support
scattered thunderstorms with a couple strong to severe storms.

Thunderstorms develop over the high terrain by early afternoon
moving east onto the adjacent plains. The suite of high-res CAMs
generally show a broken line/wave of storms pushing off of the
higher terrain then filling in more as it moves across the east
plains where the richer moisture and instability are. Hail 1-1.5"
and strong gusts are possible with any severe storms. Storm
motions should be a bit higher today, but can`t rule out a few
strong storms capable of producing heavy rain for a period of
time. This could still result in minor impacts in prone areas if
a storm stays over an area long enough. Storms move east across
the plains through the late afternoon-early evening hours. For
temperatures today, highs rise into the 80s for the plains/urban
corridor, 70s for the foothills, and 50s/60s for the mountains.

&&

.LONG TERM /Tuesday through Sunday/...
Issued at 412 AM MDT Mon Jun 10 2024

Little change to the extended forecast this morning. It does look
like the drying aloft from the northwest on Tuesday is coming
along towards the faster end of what we`d been thinking, and we`ve
backed off a bit more on PoPs for Tuesday afternoon and evening.
There should still be enough moisture and instability for a few
storms, mainly over the Front Range.

Temperatures rebound sharply for Wednesday and Thursday as an
upper ridge pokes northward across the Rockies. There will
probably be some late day cloud development drifting from the
mountains onto the plains, but that`s about it. Thursday probably
has the warmest air aloft, but there is a puff of northerly winds
from the tail end of a shortwave that`s focused up on the Canadian
border. There may also be a bit of cloud cover and attempted
showers along the northern border in the afternoon. We`ll also be
hot enough to generate some high based weak convection away from
that forcing near the end of the day. All of that may take a
couple of degrees off of the highs if there`s enough of it.

There continues to be some vacillation about the details for
Friday and Saturday, chiefly how strong the push of cooler air
into the plains will be. There`s also been a trend towards a bit
more mid level moisture drifting up from the south. The variations
don`t really change the story though, of decent thunderstorm
coverage and highs dropping back into the 80s for Friday. The
upper trough coming out of the southwest will provide some lift in
a favorable atmosphere, but timing varies on this from Friday
night into Saturday. After that passes, we should have warming and
drying again for less activity, but still some moisture east of
the mountains.

&&

.AVIATION /06Z TAFS through 06Z Tuesday/...
Issued at 1149 PM MDT Sun Jun 9 2024

Enhanced southerly component flow overnight at 10-15 kts. Winds
weaken after 12z, becoming light and variable by 15z Monday.
Light and variable winds transition easterly by the afternoon.
Scattered showers and thunderstorms are possible after 21z, with
the threat continuing through around 01z. Gusty outflow winds up
to 35 kts are possible with any passing/nearby storms as well as
wind dir/speed changes from outflow boundaries from other storms.

&&

.HYDROLOGY...
Issued at 412 AM MDT Mon Jun 10 2024

Remaining runoff from last night`s rain in Douglas county is
reaching the downstream reservoirs this morning and remaining
lowland flooding should be ending within the next few hours.

Elevated flows continue across the upper Colorado River basin and
additional rainfall could lead to further increase in the flows.
Remain cognizant of the dangers of these cold flows, and be aware
of any Flood Advisories and Warnings.

Winds aloft remain on the weaker side today, leading to slower
storm motions, but a bit faster than Sunday. There is a minor
threat for burn area flash flooding on Cameron Peak today. Periods
of heavy rain are possible in storms today which may lead to
localized flood impacts if a storm stays over a prone area long
enough.

Warmer and drier weather will follow, with the next threat of
heavy rain on Friday and Saturday. Snowmelt may peak on the
hottest days at the end of this week.

&&

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

&&

$$

SHORT TERM...Mensch
LONG TERM...Gimmestad
AVIATION...Mensch
HYDROLOGY...Gimmestad/Mensch