766
FXUS65 KBOU 011820
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1220 PM 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 /18Z TAFS through 18Z Tuesday/...
Issued at 1220 PM MDT Mon Jul 1 2024

Westerly component winds this afternoon at 08-13 kts. Gusts up to
25 kts are possible through 19/20Z as a result of a weak mountain
wave that extended off the Foothills this morning. Showers this
early this afternoon with scattered thunderstorms possible after
20Z. Brief variable outflow gusts are possible in any
nearby/passing storms with gusts up to 30 kts.

Low coverage showers possible tonight. A weak cold front moves
through early Tuesday morning. Timeframe is low confidence as this
front is weak with no defined boundary/push of northerly winds.
Within in the 08-12Z timeframe, winds transition to north at 07-10
kts. There is potential for low stratus to develop post-front
(10-13Z). Confidence is still on the lower end with models unsure
of how much low level moisture will be available. For now,
messaging this in the TAF as SCT015 until confidence increases.
Tuesday, light winds turn to the WNW in the afternoon. There is a
low chance for isolated showers/storms in the afternoon, mainly
for APA.

&&

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

&&

$$

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