360
FXUS65 KBOU 171639
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1039 AM MDT Mon Jun 17 2024

.KEY MESSAGES...

- Hot and dry across most of the area today.

- Critical fire weather conditions expected until this evening.

- Cooler by Tuesday and Wednesday.

- Impacts from snowmelt across the high country will continue to
  diminish through the week.

&&

.UPDATE...
Issued at 1039 AM MDT Mon Jun 17 2024

Day Cloud Phase Satellite imagery shows this morning`s low
stratus gradually eroding out this morning. Still several thicker
areas across the plains that will take another hour or two to see
improvement. How quickly the stratus erodes out will hold a good
amount of weight in today`s forecast and highlights.

Overall, this morning`s stratus event across the plains/urban
corridor took away some heating time. It likely won`t have a large
impact to highs as we have plenty of daylight hours for surface
heating this time of year. Made minor adjustments to today`s
highs, cooling a degree or two in areas. Regardless, it still
looks hot and dry this afternoon.

Despite a delay in heating and mixing, the Red Flag Warning will
be in effect after 11am. It is likely that not all areas in the
Warning will be hitting criteria at that time. Conditions will
warm and dry with gusty winds mixing down from south to north, so
the more north areas might take a bit more time (mid-afternoon)
to hit Red Flag criteria. There is a slight risk for severe
thunderstorms in the far northeast corner this afternoon/evening
with MLCAPE 500-1000 J/kg, low level moisture, and decent shear.
However, this is a low chance (<20%). There is a higher chance
that storms initiate east of Colorado.

&&

.SHORT TERM /Through tonight/...
Issued at 309 AM MDT Mon Jun 17 2024

An upper level trough remains over the west coast. Warm and dry
conditions will occur once more today across northeastern Colorado.
It is possible a weak front will arrive this morning increasing
winds just before mid-day. It seems this front will only result in
southerly flow at the surface for the plains. Given that a few
models such as the GFS and NAM display warm air advection, decided
to increase temperatures this morning and afternoon along the
eastern plains. Expect afternoon highs a few degrees warmer than
yesterday. Generally, 90s for the plains and urban corridor.
Mountains and valleys increase between 65-77F. Not confident in
widespread heat impacts today especially due to widespread wind
gusts up to 25-35 mph where the warmest afternoon temperatures
reside thus no Heat Advisory. Considering widespread wind gusts up
to 35 mph, majority of the forecast region will drop to humidities
as low as 10-16 percent excluding the northeastern corner. The
combination of these winds and low humidities will bring critical
fire weather conditions today for parts of the urban corridor,
plains, Palmer Divide, South Park, and Grand/Summit counties. A
Red Flag Warning is in effect starting 11 AM to 9 PM MDT this
evening. Tonight, as the next upper level system sweeps north of
us, northwesterly winds will increase near the Wyoming Colorado
border. Those traveling across I-25 could experience wind gusts up
to 40-45 mph overnight.

&&

.LONG TERM /Tuesday through Sunday/...
Issued at 309 AM MDT Mon Jun 17 2024

SW flow aloft will remain over the area on Tue. Overall, the
airmass behind a frontal system will be drier and stable thru the
aftn, across much of the area. Still can`t rule out a few higher
based storms over the higher terrain where some instability will
exist. As far as highs, readings will be in the mid 70s to lower
80`s across the plains.

For Tue night, a secondary surge of cooler air will move across the
plains.  There is still quite a bit of uncertainty as to how much
low moisture there will be across the plains.  It still looks to me
like the deeper low level moisture will be to the east and south of
the area.  If that`s the case then best chc of showers and storms
overnight would stay to the east and south.  As a result have kept
pops in the chc category over most of the plains.

On Wed, sfc high pres will be over the area behind the front.  This
would lead to a stable airmass across the plains as highs only reach
the upper 60`s to mid 70`s.  Over the higher terrain,  there will be
some limited MLCAPE so will keep in a chc of aftn tstms.

Looking ahead to Wed night into Thu, sfc high pres will gradually
shift to the east.  This will allow for southeast low level flow to
develop with a return of deeper low level moisture.  In addition,
will begin to see a warm air advection pattern develop, which may
lead to some nocturnal shower and tstm development Wed night over
the plains. Still don`t have high confidence in this scenario so
will keep pops mainly in the chc category. By Thu aftn, should see
better MLCAPE across much of the area so expect sct tstms. As for
highs, readings will rise back to seasonal levels.

For Fri, the flow aloft will continue from the SW.  There still
should be decent instability so will keep in sct tstms with the
highest coverage over the higher terrain. Highs will rise back to
above normal across nern CO.

By next weekend, a flat upper level ridge will begin to build across
the srn Rockies.  This will allow for the flow aloft to become more
westerly.  At this time, there still should be enough moisture and
instability around to keep in a chc of aftn storms both days.

&&

.AVIATION /12Z TAFS through 12Z Tuesday/...
Issued at 500 AM MDT Mon Jun 17 2024

Low clouds are possible at KDEN and KBJC this morning until 16Z.
This afternoon, gusty southwest winds could produce wind gusts up
to 25kts. Wind decrease sometime between 01Z-03Z. shifting
southwest. It is possible remain between 8-10kts overnight through
Tuesday morning.

&&

.FIRE WEATHER...
Issued at 309 AM MDT Mon Jun 17 2024

Critical fire weather conditions are possible this afternoon mainly
for parts of the urban corridor, plains, Palmer Divide, South Park,
and Grand/Summit counties due to humidity as low as 10 percent.
Southwest wind could produce wind gusts up to 35 mph.

Fire conditions will improve from Tuesday into Wednesday as a
couple of cold fronts bring cooler temperatures and higher
humidity to much of the area.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 9 PM MDT this evening for COZ213-214-216-
239>241-244>247-249.

&&

$$

UPDATE...Mensch
SHORT TERM...AD
LONG TERM...RPK
AVIATION...AD
FIRE WEATHER...AD/RPK