742
FXUS65 KBOU 011654
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1054 AM MDT Mon Jul 1 2024

.KEY MESSAGES...

- Isolated to scattered showers and thunderstorms expected today.
  A couple of stronger storms possible in far northeast Colorado
  this afternoon and evening.

- Downward trend in showers and storms beyond Wednesday.

&&

.UPDATE...
Issued at 1053 AM MDT Mon Jul 1 2024

Current radar shows light showers over portions of the high
country. A few storms grazing the NW corner of Jackson County.
Surface observations show hints of a weak mountain wave extending
off the foothills into parts of the west urban corridor. This has
brought gusts 30-45 mph with some locally higher gusts in the wind
prone areas. Cross sections show this mountain wave relaxing over
the next few hours, decreasing winds. For the rest of today`s
forecast didn`t have to make any major adjustments. Refreshed PoP
grids as this has been one of the more lower confidence elements
of the forecast (timing/location). Overall expect scattered
showers and thunderstorms this afternoon across most areas of
northeast CO.

&&

.SHORT TERM /Through tonight/...
Issued at 252 AM MDT Mon Jul 1 2024

A weak disturbance passing through the area overnight produced a
decent rainfall across portions of the eastern plains, with a
couple stronger embedded storms also producing some gusty winds in
Lincoln county. However, radar and satellite imagery show this
convection moving off into Nebraska, with quiet weather across
most of our CWA.

Another active weather day is expected today. The plume of
moisture responsible for this weekend`s showers and storms has
begun to drift a little to the south and east, but there`s still
above normal moisture across the region. Guidance shows a little
more synoptic scale lift today as a trough axis approaches from
the northwest, but widespread cloud cover will limit surface
heating and the resulting instability across the area will likely
be modest. With the broad ascent across the region, most CAMs
develop widely scattered showers and storms this afternoon.
Widespread severe weather is not anticipated, but a couple
stronger storms are possible across far northeastern Colorado
where the parameter space is more impressive.

A few showers will likely continue into the overnight hours, with
a weak cold front arriving late tonight.

&&

.LONG TERM /Tuesday through Sunday/...
Issued at 252 AM MDT Mon Jul 1 2024

A weak upper level shortwave trough will bring isolated to
scattered thunderstorms across our region Tuesday. Zonal flow
should allow development of weak storms and showers west of the
Divide early Tuesday afternoon. Given the lack of instability and
heating, it is possible storms will remain sub-severe through
Tuesday evening while spreading to the eastern plains. Model
soundings indicate dry air throughout the 500-700mb layer thus
expecting storms to lack heavy rainfall. With DCAPE values nearly
1000 J/kg, storms and showers will likely produce gusty winds up
to 45-50 mph. Tuesday temperatures are near normal as partly
cloudy skies should keep us cooler than the past couple days. As
the upper trough pushes east Wednesday, moisture remains limited
over the eastern plains by late afternoon. With the assistance of
upper level forcing, a strong thunderstorms or two could occur for
the far northeast corner. It is possible with the combination of drier
conditions and gusty winds, near critical fire weather conditions
could occur for parts of the high country Wednesday afternoon.

Cold air advection from a cold front will occur by Thursday leading
to cooler temperatures by the afternoon. Afternoon highs range
between 78-86F for the urban corridor and plains. Mountains and
valleys decrease between 58-74F. Northwest flow increases as the
passing trough lifts northeast. While surface winds increase,
relative humidities decrease between 12-18 percent once more for
areas west of the Divide. This pattern may lead to another afternoon
of near critical fire weather conditions. With the holiday occurring,
we`ll have to closely monitor the extent of critical fire weather
conditions especially in areas that have lacked recent rainfall.
Friday and the holiday weekend remains drier with isolated chances
of high based showers and temperatures increasing slightly above
normal.

&&

.AVIATION /12Z TAFS through 12Z Tuesday/...
Issued at 524 AM MDT Mon Jul 1 2024

Drainage flow will weaken this morning, with a brief period of
light/variable winds. Guidance turns winds to a W/WSW direction by
late morning and continues with this direction through the day.

Convection is expected to get started a little sooner than the
past couple of days, with VCTS possible by 18z. Still low
confidence on coverage/timing of storms, but did bump up the start
of the PROB30 group to 19z as it looks like the peak period for
convection will generally be mid-afternoon.

A weak cold front is expected to shift winds out of the north at
the terminals between 06-09z. Forecast guidance hints at enough
low-level moisture for a brief period of stratus, but will likely
be dependent on today`s convective evolution. Have introduced some
FEW/SCT015 for Tuesday AM, but wanted to see this more
consistently before introducing any sort of MVFR cigs.

&&

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

&&

$$

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