Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 08/26/23

Area Forecast Discussion

National Weather Service Denver/Boulder CO

 754 PM MDT Fri Aug 25 2023

.UPDATE...
Issued at 745 PM MDT Fri Aug 25 2023

Shower and thunderstorms coverage has been decreasing
significantly over the past couple of hours as drier mid level
air has intruded from the northeast. Also, cooler afternoon temperatures
and extensive cloud cover significantly inhibited the heavy rain
potential. Consequently we have decided to drop the flash flood
watch that was in effect for the forecast area. The best chance
for localized heavy rain this evening will be confined to the
South Park area, and even that does not justify a flash flood
watch at this time.

&&

.SHORT TERM...(This evening through Saturday)
Issued 221 PM MDT Fri Aug 25 2023

No significant updates to the forecast grids for the rest of the
afternoon and evening, though the threat of heavy rain and flash
flooding continues to decrease along the I-25 corridor. ACARS
soundings at DEN, and a recent radiosonde launched at CSU have a
fully saturated profile, with the CSU sounding showing a 1.36"
PWAT value. However, surface temperatures in the low to mid 60s
have kept instability in check... and have kept precipitation
rates generally under an inch per hour across the metro and
foothills.

Though the metro flood threat has decreased, that can`t be said
for areas west of the divide and across the eastern plains. We`ve
already seen one slow moving/training storm over southeastern
Morgan county, where radar estimated precipitation was roughly
4-5.5 inches and a few road washouts were noted. Isolated heavy
rain and flash flooding will continue to be a threat through the
evening and overnight hours as precipitation slowly sinks
southward.

Scattered showers and thunderstorms will continue through Saturday
with decreasing coverage across most of the forecast area. The
best moisture should exit the region tomorrow as the remnants of
Harold drift east, with upslope flow also diminishing. With
extensive morning cloud cover limiting surface heating (highs in
the 60s to 70s), it will be difficult to get much instability
across most of the area. Most of the precipitation tomorrow should
fall across the Front Range mountains and foothills, with less
coverage off to the east.

.LONG TERM...(Saturday night through Friday)
Issued at 131 PM MDT Fri Aug 25 2023

Saturday night and Sunday, upper level high pressure will be over
the Desert Southwest and Southern Rockies with upper level
troughiness over the Central and Eastern U.S. Colorado will be under
the influence of a weak to moderate northwesterly flow aloft with
some residual tropical moisture caught underneath the ridge.
Scattered showers and a few storms may linger into Saturday evening
across the mountains eastward into the adjacent plains gradually
diminishing by midnight. On Sunday, the lingering moisture
combined with daytime heating and an upper level disturbance
should kick off another round of afternoon and evening showers and
storms, most numerous along the Front Range Urban Mountains and
Foothills. With PW`s up to 0.75" in the mountains and around an
inch on the plains, locally heavy rainfall will still be possible
with the storms.

Another front is expected to push across Northeastern Colorado
Monday morning which should increase precipitation chances and lower
temperatures across the forecast area. The airmass may be somewhat
stable behind the front which may limit thunderstorm activity across
the plains.

Models are showing the upper ridge expanding into the Central Plains
States Tuesday and Wednesday. This pattern would shut off the cool
and somewhat moist northwesterly flow and allow drier air to move
into Colorado from the west. This should result in drier and warmer
weather with temperatures climbing into the low 90s by Wednesday.

By Thursday, we may see an increase in subtropical moisture as the
upper flow becomes southwesterly ahead of an upper level trough
deepening along the west coast of the U.S. Consequently, scattered
afternoon and evening showers and storms may return to the region.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 652 PM MDT Fri Aug 25 2023

MVFR ceiling/visibility restriction tonight, with lingering
showers around overnight, could see higher ceilings and KDEN with
drier mid level air intruding from the northeast. Generally light
rain with some fog restriction possible as well. Light northerly
winds this evening will become more variable overnight. BKN-OVC
ceilings 040-060 will prevail 10-15z, then scatter out by 18z
Saturday. VFR Saturday afternoon, with slight chance of
showers/storms in the afternoon. For now, vcsh will suffice in the
tafs.


&&

.HYDROLOGY...
Issued at 745 PM MDT Fri Aug 25 2023

Flood Watches are no longer in effect as noted in the updated
discussion above, with little to no threat of thunderstorms
expected through midday Saturday, then limited flash flood threat
in the burn areas Saturday afternoon.

Scattered showers and storms will be possible across North Central
and Northeastern Colorado during the afternoon and evening hours
Sunday and Monday. Locally heavy rainfall will be possible across
the mountains, foothills and adjacent plains with a limited
threat for flash flooding in and near the burn scars.

&&

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

$$

UPDATE...Cooper
SHORT TERM...Hiris
LONG TERM...JK
AVIATION...Cooper
HYDROLOGY...Cooper/JK