626
FXUS65 KBOU 231140
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
540 AM MDT Thu May 23 2024

.KEY MESSAGES...

 - Warm, dry, & breezy today, with elevated fire weather
   conditions across the urban corridor and plains

 - A cold front tonight should bring some snow showers to the
   mountains with light accumulations possible.

 - Showers expected to impact the region for parts of the end of
   the week and weekend.

-  Summer-like temperatures for next week

&&

.SHORT TERM /Through tonight/...
Issued at 229 AM MDT Thu May 23 2024

Warm and windy is the theme of the day today.

A closed 500mb low is spinning across southern Idaho this morning
and should race across Wyoming into the northern Great Plains by
tonight. The mid/upper level flow is expected to strengthen to the
south of this feature, leading to fairly strong downslope flow
across the forecast area by this afternoon.

The main forecast questions today are "how warm?" and "how much
wind?" - as minimal moisture will keep just some scattered cloud
cover and fairly low chances of any precipitation for most of the
day. In terms of wind, deep mixing should allow for gusts up into
the 25-35 mph range across the lower elevations, with stronger gusts
in the high country where mid-level flow is more impressive. Most
guidance keeps PBL/mixing heights just below the strongest flow at
500mb, but it`s possible we see a few stronger gusts than what the
grids have at this point. In terms of temperatures... model
guidance is in fairly good agreement that we`ll see upper 70s to
low 80s across the I-25 corridor into the eastern plains.

As the trough advances, a cold front is expected to drop into the
region this evening into the overnight hours. Cross-sections show
enough moisture in the high country for a band of rain/snow
showers with light accumulations. Can`t rule out a few showers or
a storm in the plains, but chances are we`ll simply be too dry for
much activity here. Instead, the main impacts for the lower
elevations will likely be another burst of wind along the front,
followed by cooler temperatures for tonight into tomorrow.

&&

.LONG TERM /Friday through Wednesday/...
Issued at 229 AM MDT Thu May 23 2024

As the shortwave trough exits the northern Rockies and heads
eastward into the northern Plains, its associated cold front will
be the cause of cooler temperatures for Friday across the
forecast area. Temperatures will likely be in the upper 50s to
upper 60s across the plains and foothills and 40s to 50s for the
mountains, which will be roughly 5- 10 degrees below the norm for
this time of year. Cross sections show mid and upper level
moisture increasing throughout the afternoon and evening ahead of
the next approaching trough to the west. Instability looks to
increase throughout the day as well, with forecast soundings
indicating nearly DALR Friday afternoon. A few afternoon/evening
thunderstorms and scattered showers can`t be ruled out with a
chance of snow showers for the overnight hours for elevations
above roughly 10,000 ft.

For the holiday weekend, guidance indicates heightened chances for
widespread precipitation as a shortwave trough and cold front bring
enhanced forcings to the region. Daily chances for rain showers are
possible across the area with snow showers likely for the higher
elevations. Forecast soundings show modest CAPE values (between 300-
600 J/kg), which would support a slight chance for some isolated
thunderstorms to develop across the entire forecast area on Saturday
and Sunday. Temperatures will be warmest on Saturday with widespread
upper 70s forecast for the plains with a few locations topping 80
degrees. The foothills are forecast to be in the 60s, and the
mountains high 50s to low 60s for elevations below 9000 feet.
Sunday`s high temps will be slightly cooler behind the cold front,
but still likely manage to make it to the 60s for the plains, and
50s for the foothills and mountains below 9000 feet.

The beginning of next week will bring warmer and drier conditions to
the CWA as models agree on a decent ridge building over the western
CONUS. This looks to be the warmest period seen so far this year
with consecutive days of 80 degrees plus possible across the
plains, bringing us back to above normal temps through mid-week.

&&

.AVIATION /12Z TAFS through 12Z Friday/...
Issued at 531 AM MDT Thu May 23 2024

VFR through the TAF period, with no significant changes from the
previous 06z TAF discussion.

Drainage flow will slowly turn to more of a westerly component
this morning into the early afternoon, with speeds also increasing
this afternoon. General thought is that winds should settle in
some sort of WSW at DEN, then shift a second time later this
afternoon to more of a WNW with some stronger gusts. Still think
there`s potential for a few 25kt gusts during the late afternoon.
A cold front is expected to arrive later this evening with a turn
to a more northerly wind direction, with speeds weakening
overnight. No ceiling/visibility concerns.

&&

.FIRE WEATHER...
Issued at 229 AM MDT Thu May 23 2024

Dry and windy conditions are forecast today, with minimum RH
values near 10-15% across the lower elevations. Wind gusts will
pick up through the day with gusts to 35 mph likely for the plains
with higher gusts across the foothills. Though we are technically
near or at criteria across several zones, we`ll hold off on any
highlights given current fuels status. RAWS-based ERC values are
near or below normal for this time of year with 100/1000-hour fuel
moisture running above normal across most of our region. Still,
today is not a great day to be doing outdoor burning!

&&

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

&&

$$

SHORT TERM...Hiris
LONG TERM...Bonner
AVIATION...Hiris
FIRE WEATHER...Hiris