274
FXUS65 KBOU 212041
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
241 PM MDT Tue May 21 2024

.KEY MESSAGES...

- Scattered showers and thunderstorms continue through tonight.
  Small hail and gusty winds are possible from these storms but
  they will likely stay below severe limits.

- Ongoing light snow showers may lead to slick travel along
  mountain passes through Wednesday morning.

- Warming/drying trend for the second half of next week with
  elevated fire weather conditions likely Thursday.

&&

.SHORT TERM /Through Wednesday/...
Issued at 241 PM MDT Tue May 21 2024

Radar reflectivity has increased across the foothills and plains
displaying scattered to numerous showers. A few webcams along
mountain passes present flurries for areas above 8,500 feet. This
pattern will continue as the shortwave trough passes through
northeastern Colorado. Snowfall totals for areas above 9 thousand
feet range between 1-4 through Wednesday morning. Showers should
become isolated by midnight tonight. With model soundings along the
plains showing an inversion and low level moisture lingering
through early morning Wednesday, it is possible patchy fog could
occur along I-25 corridor near the Wyoming Colorado border and
along I-76 near Morgan county.

Cross sections indicate drier air throughout the 500-700mb layer
thus limiting any storm development Wednesday afternoon. An isolated
shower or two could occur for the southern foothills and Palmer
Divide but chances are low (10-15%). Wednesday afternoon 700mb
temperatures range between 3-6C along the foothills and plains which
should lead to a slight warm up compared to yesterday. Foothills and
plains range from 60-72F Wednesday afternoon; Additionally, the
mountains and valleys increase near 45-60F. Partly cloud skies will
begin to clear by late Wednesday afternoon.

&&

.LONG TERM /Wednesday night through Tuesday/...
Issued at 241 PM MDT Tue May 21 2024

Colorado will be under the influence of a quasi-zonal flow Wednesday
night through Monday with occasional upper level shortwaves and
cold fronts moving across the Northern and Central Rockies. This
pattern should result in near normal temperatures along with
isolated to scattered afternoon and evening showers and storms
across the forecast area most days. Warm temperatures combined with
breezy conditions and low relative humidity may lead to fire weather
concerns across South Park, the Palmer Divide and much of the
plains Thursday afternoon and evening. A cold front expected to
move across Northeastern Colorado Friday evening may produce wind
gusts up to 35 mph across the northern sections of the plains.
Friday should be the coolest day of the week in the wake of the
front with temperatures only climbing into the upper 60s on the
plains. Most of the showers and storms during this period should
be high based with gusty winds and brief light to moderate rain.
However, there is the potential for some stronger storms across
the plains, mainly east of the Front Range Urban Corridor, both
Thursday and Saturday afternoon/evening due to better available
surface moisture along with increased convergence and lift
associated with the passing shortwaves and cold fronts.

Warmer and drier weather is expected on Tuesday as upper level high
pressure builds over the Rocky Mountain Region.

&&

.AVIATION /18Z TAFS through 18Z Wednesday/...
Issued at 1136 AM MDT Tue May 21 2024

VFR conditions are expected through the TAF period.
Scattered showers and storms are possible starting 20Z-24Z thus
keeping TEMPO in for thunderstorm development. This could increase
winds up to 15-18kts producing gusts up to 30kts. Lingering
showers are likely after thunderstorms exit east but showers seem
spotty with no impact to visibilities. Depending on how much rain
occurs, there could be lower visibilities briefly overnight into
Wednesday morning but that should be short-lived MVFR conditions.
This is a low outcome thus won`t include in this TAF.

&&

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

&&

$$

SHORT TERM...AD
LONG TERM...JK
AVIATION...AD