Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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812
FXUS65 KBOU 201816
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1216 PM MDT Thu Jun 20 2024

.KEY MESSAGES...

- Warmer today with a good chance of afternoon thunderstorms. A
  few severe storms will be possible mainly across the plains.
  Locally heavy rainfall will occur in some areas as well.

- Scattered to likely showers and thunderstorms on Friday. A few
  could be strong to severe, and also produce locally heavy rain.

- Hotter and drier this weekend into next week.

&&

.UPDATE...
Issued at 1053 AM MDT Thu Jun 20 2024

Minimal sky cover this morning are allowing temperatures to warm
efficiently into the 70s and low 80s across the lower elevations.
The current temperature at the Denver airport is 89, already 9
degrees warmer than the high yesterday. With that being said, it
will be much warmer today than yesterday with highs in mid-upper
80s, approaching 90 in spots on the plains. Made a minor increase
in highs today. Satellite shows cumulus developing in the
mountains, foothills, and the far northeast corner and this will
increase across northeast Colorado as the surface heats more and
the atmosphere becomes more unstable. Scattered thunderstorms are
expected this afternoon into this evening with a few strong to
severe storms. There is potential for another wave of
showers/storms later in the evening, so minor edits to precip.
prob. grids were made to reflect this.

&&

.SHORT TERM /Through tonight/...
Issued at 300 AM MDT Thu Jun 20 2024

A disturbance embedded in SW flow aloft is moving across the area
early this morning.  Most of the shower and tstm activity with this
feature will move across srn areas of CWA thru 12z.

For later today, sfc low pres will develop along the front range
with increasing southerly low level flow across the plains. Deeper
low level moisture has already overspread the plains. Overall,
showers and storms will increase by early aftn over the higher
terrain. Outflow boundaries from this activity will trigger
additional development by mid aftn along the I-25 Corridor which
will then spread across the plains by late aftn into the early
evening hours. MLCAPE over the plains will be in the 1500-2000
j/kg range this aftn with a favorable enough shear profile for a
few svr storms. Meanwhile, storms over the higher terrain may
produce a few wind gusts up to 60 mph as well. Although storms
will be moving, they could produce from 1.00 to 1.5 inches of rain
in a rather short period of time as well. As far as highs today,
readings will be warmer with readings in the 85 to 90 degree range
over nern CO.

For tonight,  there is some indication of a another disturbance
moving across overnight. This feature may allow for the
development of additional shower and tstm development especially
over the higher terrain.

&&

.LONG TERM /Friday through Wednesday/...
Issued at 330 AM MDT Thu Jun 20 2024

Upper ridging returns to dominate the CWA`s weather by Friday.  This
will continue well into next week, at least.  Southwesterly flow
aloft is progged for the forecast area Friday into Saturday,  It
becomes more zonal Saturday afternoon and night.  The QG Omega
fields indicate weak upward synoptic scale energy for the CWA Friday
and Friday evening.  Then weak downward vertical velocity is progged
Saturday and Saturday evening, with benign conditions after that.
There looks to be weak surge of slightly cooler air and upslope
flow on Friday, at least for the plains.

Models continue to show plenty of moisture for the CWA on Friday
with precipitable water values in the 0.80 inch to 1.50 inches range
in the afternoon and evening. Again, there is fairly decent CAPE
progged Friday, especially over the northern and eastern border
areas of the CWA. Moisture looks to decrease on Saturday with the
PWs dropping into the 0.50 to 1.00 inch range. That along with the
weak subsidence should lessen pops from Friday`s numbers.

For temperatures, Friday`s highs look to be close to this
afternoon`s expected highs, perhaps 0-1.5 C cooler.  Saturday`s
highs are 1.5-4.0 C warmer than Friday`s.

For the later days, Sunday through Wednesday, models show upper
ridging over Colorado all four days with the center of the upper
high just sough of the state. The synoptic scale energy is benign
to weak subsident all four days. There is enough moisture for
rounds of late day showers and thunderstorms, with the best
chances in the mountains and foothills. Temperatures look to be
above seasonal normals all four days, with highs in the mid 90s
to 100 degree F for the plains each afternoon.

&&

.AVIATION /18Z TAFS through 18Z Friday/...
Issued at 1216 AM MDT Thu Jun 20 2024

Enhanced southerly winds expected this afternoon with gusts 20-25
kts. Scattered thunderstorms develop and moves eastward this
afternoon, mainly in the 20-00Z timeframe. Any nearby or passing
thunderstorms may bring variable gusty winds up to 40 kts,
potentially closer to 45 kts in any stronger storms. Heavy rain
may also bring reduced visibilities/ceilings for short periods.
After 00Z, there is a chance for another round of lower coverage
scattered showers or storms through midnight. Friday, light and
variable winds in the morning become east in the afternoon.
Scattered thunderstorms develop in the afternoon around the
terminals.


&&

.HYDROLOGY...
Issued at 300 AM MDT Thu Jun 20 2024

Although storms will be moving this afternoon and evening, the
threat of heavy rainfall will be greater with an elevated threat of
flash flooding in the burn scars. Across the plains, where rather
high precipitable water levels will be in place, rainfall amounts
of 1 to 1.5 inches in a short period of time will certainly be
possible with isolated higher amounts.

There could also be decent rainfall late day Friday, and the burn
scars will be most susceptible to flash flooding. Pops will be
lower Saturday and Sunday so the flash flooding threat will be
decreased somewhat those days.

&&

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

&&

$$

UPDATE...Mensch
SHORT TERM...RPK
LONG TERM....RJK
AVIATION...Mensch
HYDROLOGY....RJK/RPK