160
FXUS65 KBOU 151727
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1127 AM MDT Sat Jun 15 2024

.KEY MESSAGES...

- A return to hot and mainly dry weather this weekend into early
  next week.

- Snowmelt producing minor impacts from high streams. Gradually
  diminishing flows next week.

- Cooler for Tuesday and Wednesday

&&

.UPDATE...
Issued at 1122 AM MDT Sat Jun 15 2024

Satellite shows cumulus clouds slowly growing across the higher
elevations this morning, though radar is still quiet. Temperatures
have warmed into the 80s across the plains and should continue to
warm to around 90F this afternoon. Isolated/widely scattered
high-based showers remain possible this afternoon, with gusty
outflow winds as the main hazard.

&&

.SHORT TERM /Through tonight/...
Issued at 248 AM MDT Sat Jun 15 2024

An upper level ridge pattern begins over northeastern Colorado.
Westerly flow and weak mid-level moisture will result in isolated
showers mainly west of the Divide. Dry air aloft and low PWATs
hint that these showers could produce little to no rainfall. Model
soundings display decent DCAPE values between 600-800 J/kg
meaning showers could produce wind gusts up to 40 mph. CAMs
suggests a shower or two crossing into the lower elevations
mainly along the Palmer Divide by late afternoon until early
evening. Additionally, warm temperatures return this afternoon.
Areas west of the Divide could reach the upper 60s to upper 70s
this afternoon. Temperatures across the urban corridor and plains
increase above normal reaching the 90s. Tonight, above normal low
temperatures are expected.

&&

.LONG TERM /Sunday through Friday/...
Issued at 248 AM MDT Sat Jun 15 2024

The overall pattern Sunday through Monday will have SW flow aloft
over the area.  At the sfc, it appears nern CO will have to contend
with a boundary associated with convection to the north both days.
Exactly how far south this boundary will be is a big question mark
at this time.  It could stay along the CO-NE border area both days
or end up further south near a Denver to Akron line.  North of this
boundary temps will likely be in the 85-90 degree range while
south of it readings will be in the mid to upper 90s. In addition,
higher dewpoints will be in place north of the boundary with
decent MLCAPE both days. However, with that being said, there is a
decent capping inversion in place both days which will likely
prevent convective development along and north of the boundary. As
a result, have kept pops in the isolated category both days near
the CO-NE border.

By Tue, little change is expected to the overall pattern aloft as
SW flow aloft will continue. A cold front is still expected to
move across nern CO late Mon night thru Tue morning. This will
lead to a more stable airmass across the plains thru the aftn.
Over the higher terrain, there could be some isold high based
tstms in the aftn. As far as highs, readings will drop into the
upper 70s to mid 80s across the plains.

For Tue night into early Wed, there are considerable differences
in the handling of low level moisture across the area. The GFS
has a stronger sfc high pres building into the area with deeper
low level moisture remaining to the south and east. Meanwhile,
the ECMWF has deeper moisture returning by Tue night. As a result,
it has nocturnal convection developing over portions of the plains
overnight into early Wed. At this point, confidence is low in
either solution so have just left a slight chc of storms across
portions of the plains.

As for the rest of Wed, SW flow aloft will remain over the area.
Both the ECMWF and GFS indicate a return of better low moisture
across the higher terrain by Wed aftn with increasing MLCAPE.  As a
result this may lead to sct tstms.  Across the plains, it looks more
stable by aftn so will only keep in a slight chc of storms.  Highs
on Wed will still be slightly below seasonal normals across nern CO.

Looking ahead to Thu and Fri, the flow aloft will remain SW.
Meanwhile, the low level flow across the plains will become
southeast allowing for deeper low level moisture to return.  As a
result, will see increasing MLCAPE with at least a slight chc of
aftn and evening tstms. Finally, highs will rise back above
seasonal levels across nern CO.

&&

.AVIATION /18Z TAFS through 18Z Sunday/...
Issued at 1122 AM MDT Sat Jun 15 2024

VFR through the TAF period. Still a slight chance of a high based
shower or two this afternoon. Main impacts would be from
variable/gusty outflow winds with little precipitation expected.
Winds should remain light through the afternoon hours outside any
outflow. Drainage flow is expected to prevail overnight.

Low confidence in the wind forecast tomorrow as a weak frontal
push, a Denver cyclone, or a well mixed southwest flow are all
possible by midday Sunday. For now have opted to keep a fairly
light northeast in at DEN.

&&

.HYDROLOGY...
Issued at 248 AM MDT Sat Jun 15 2024

Elevated flows continue in the mountain streams, with Flood
Advisories remaining in effect for the streams above Granby and
Grand Lake. Remain alert of the dangers of water that is running
high and cold. Flows are expected to gradually decrease next week
as the peak snowmelt is passing by.

&&

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

&&

$$

UPDATE...Hiris
SHORT TERM...AD
LONG TERM...RPK
AVIATION...Hiris
HYDROLOGY...AD/RPK