co discuss
Office: BOU
FXUS65 KBOU 110540
AFDBOU
Area Forecast Discussion
National Weather Service Denver/Boulder CO
1140 PM MDT Wed Aug 10 2022
.UPDATE...
Issued at 842 PM MDT Wed Aug 10 2022
No significant updates for tonight's forecast. A 596 dam ridge at
500 mb continues to dominate our weather in terms of heat and
keeping the monsoonal moisture west of our area. GOES-16 water
vapor shows the moisture plume nicely, and it's mostly over the
Great Basin with a little trapped moisture over the western third
of Colorado. The steering flow in western Colorado is actually
out of the northeast, keeping any showers/storms and moisture
away the rest of the evening and overnight. It will be a
beautiful night across the area with mostly clear skies and
seasonally warm lows expected with mid to upper 60s across the
I-25 urban corridor, low to mid 60s elsewhere across the plains,
and upper 40s to low 50s in the mountain valleys and foothills.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 157 PM MDT Wed Aug 10 2022
With a strong ridge of high pressure overhead, there are just
shallow cumulus on visible satellite this afternoon. An inversion
aloft is too strong for showers and storms to form. The only thing
that's noteworthy about the weather today is the heat as it's 88
F in Kremmling and 94 F at DIA at the time of this discussion.
Tonight, there will be relatively warm temperatures as lows will be
in the 60s across the plains. The low temperatures won't be too far
from record warm lows. Winds will be gusty out of the south across
the plains.
The same ridge of high pressure will be over our CWA on Thursday
with almost no change in strength. This will lead to similar
conditions at the surface on Thursday as we saw today. The only
slight change that will happen is a surface low pressure center
will move towards northern Colorado by the afternoon. The lower
pressure and low level convergence associated with this feature
may provide enough lift to create a few showers and storms in the
mountains mainly to the west of the Continental Divide. Across the
plains, conditions will be quite stable so no rain is expected.
The biggest weather concern on Thursday will be heat. With 700 mb
temperatures warming another degree C, highs will increase another
1 or 2 degrees F. The forecast high at DIA is 98 which would break
the daily record high temperature of 97 which was last set in
2020. Other areas along the I-25 corridor may break their daily
record highs as well.
.LONG TERM...(Thursday night through Wednesday)
Issued at 157 PM MDT Wed Aug 10 2022
Thursday night through Saturday, the large upper ridge of high
pressure will be centered over Eastern Colorado. This pattern will
bring a continuation of hot and dry weather across the plains with
max temperatures climbing into the mid to upper 90s. There should
be enough moisture combined with daytime heating to produce
isolated to scattered afternoon and evening afternoon and evening
showers and storms in the high country.
On Sunday, models are showing the upper high weakening and slightly
shifting to the southeast. This may result in an increase in
monsoonal moisture over the western half of colorado which may lead
to a better chance for showers and storms in the mountains.
Northeastern Colorado should remain hot and mostly dry with possibly
a few showers and storms drifting out of the high country onto the
adjacent plains.
Early next week, many of the models are showing the upper high
shifting into the southern plains states with a descent plume of
monsoonal moisture flowing into Colorado from the south and
southwest. This pattern should allow for cooler temperatures along
with better precipitation chances across the forecast area. With
increased PW's and specific humidity, localized heavy rain will be
possible with the storms with the potential for localized flash
flooding especially in and near the burn scars. At this time, the
most active period on the plains looks to be Tuesday afternoon and
evening as an upper level shortwave and associated cold front moves
across Northeastern Colorado.
On Wednesday, models are showing the upper high retrograding
westward over the Four Corners Region as an upper level trough
deepens over the Central and Eastern U.S. This pattern should place
Colorado under the influence of a northwesterly flow aloft which
opens the door to cold fronts to move across Northeastern
Colorado. This should result in below normal temperatures along
with scattered to numerous showers and storms, most numerous over
the high country south of Interstate 70.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1137 PM MDT Wed Aug 10 2022
VFR through period with mainly clear skies. Enhanced south to
southeast winds with gusts up to 25kt at DEN/APA, decreasing
after 10z and becoming more southwest. Winds becoming east and
southeast Thursday afternoon. Any thunderstorms over next 24 hours will
be along and west of the Continental Divide.
&&
.HYDROLOGY...
Issued at 157 PM MDT Wed Aug 10 2022
There will be a few isolated thunderstorms on Thursday mainly to
the west of the Continental Divide. These storms will not be very
strong but they will be almost stationary. This will lead to a
limited threat of flash flooding over the East Troublesome burn
area with the other burn areas seeing almost no threat of
flooding.
Moisture will increase over the mountains and foothills this
weekend leading to an elevated threat for flash flooding over the
burn scars. High levels of moisture will remain through the
middle of next week with continued high chances for showers and
thunderstorms along with an elevated risk for flash flooding in
and near the burn scars.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Schlatter
SHORT TERM...Danielson
LONG TERM...jk
AVIATION...Entrekin
HYDROLOGY...Danielson/jk
Office: PUB
FXUS65 KPUB 110527
AFDPUB
Area Forecast Discussion
National Weather Service Pueblo CO
1127 PM MDT Wed Aug 10 2022
.SHORT TERM...(This evening through Thursday)
Issued at 239 PM MDT Wed Aug 10 2022
Convection has been significantly suppressed across the area under
the upper high as model soundings show a strong capping inversion
over the region. Still watching some CU buildups and can't rule out
an isolated evening thunderstorm over the mountains and Raton Ridge
area but with drier air over the region these should stay pretty
sparse. Have decreased pops a tad. Otherwise, forecast looks on
track with lows dropping into the 40s for the mountains/valleys, and
50s and 60s for the lower elevations.
Not much change expected for Friday. The best chance for
thunderstorms will be along the Continental Divide where the edge of
the monsoon moisture will reside. Will keep generally isolated pops
over the mountains with dry conditions across the plains.
Temperatures will warm a couple more degrees over those of today.
-KT
.LONG TERM...(Thursday night through Wednesday)
Issued at 239 PM MDT Wed Aug 10 2022
Key Messages:
1. High pressure continues to dominate over eastern Colorado
bringing temperatures in the plains close to 100 over the weekend.
2. Cold front will bring cooler daytime high temperatures and
increased convective activity chances early next week.
Friday - Sunday
With high pressure dominating, the warming trend continues, bringing
high temperatures to the 80's in the mountains and close to 100
degrees in the plains by this weekend. Any convective activity will
be restricted to the mountains and mountain valleys and westward
through the weekend. This dome of high pressure will continue
subsidence in the plains east of the mountains, putting a cap on any
convective activity.
Monday - Wednesday
Ensemble models continue to show the high pressure ridge across the
area sliding to the east, allowing the return of monsoonal moisture
in the area which will increase shower and thunderstorm chances.
This could bring moist easterly windflow towards the mountains,
causing orographic building of convective cells, bringing
precipitation and thunderstorms along the I-25 corridor and
eastward. This, along with the passage of a cold front on Tuesday,
will bring a subtle cooling of temperatures, lowering the daytime
highs down to the 60's and 70's in mountains and mountain valleys
and the 80's along the I-25 corridor to the eastern plains by next
Wednesday. Currently, the ensemble models are showing rainfall
amounts of 1 to 3 inches in many areas along the I-25 corridor and
in the mountains and plains, but confidence is not yet high in that
regard.
-Riser
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1122 PM MDT Wed Aug 10 2022
VFR at all taf sites the next 24 hrs. E-SE winds at KCOS and KPUB
will gust to around 20 kts Thu afternoon, then diminish in the
evening. At KALS, very low risk of some brief gusty/erratic
outflow winds from 20z-02z, as a few model solutions move some
weak convection off the Sangres and through the nrn San Luis
Valley, though chance looks too low to include in the taf at this
point.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KT
LONG TERM...RISER
AVIATION...PETERSEN
Office: GJT
FXUS65 KGJT 110833
AFDGJT
Area Forecast Discussion
National Weather Service Grand Junction CO
233 AM MDT Thu Aug 11 2022
.SHORT TERM...(Today through Friday)
Issued at 228 AM MDT Thu Aug 11 2022
High pressure remains located just to our northeast, which means
today will be similar to yesterday. There are subtle changes with
regards to the moisture though. Models indicate a slight increase
that should support an increase in storm coverage this afternoon
and evening. There are also signs of more cape, which could boost
the intensity of the convection. Expect storms to develop across
most of the high terrain early this afternoon. Steering flow
remains out of the southeast so storms will general drift to the
northwest. Like yesterday, heavy rainfall, gusty outflow winds,
small hail and frequent lightning are all possible. By late
afternoon outflows keep the convection going in addition to no
midlevel cap, which has eroded away. Expect convection will
continue into the overnight hours especially across the western
half of the forecast area. Tomorrow the high pressure drifts to
the southeast as a low pressure system impacts the Pacific
Northwest. This should result in steering flow more out of the
south across the north and southeast across the south. Despite
this there will be very little change to the monsoon moisture
plume currently in place. Expect convective development around mid
day across most of the higher terrain with expansion taking place
during the afternoon. The same hazards that are in play today
apply to tomorrow. Temperatures over the next two days stay above
normal, but will be slightly cooler than yesterday with the
increased cloud cover and the high shifting away from the region.
.LONG TERM...(Friday night through Wednesday)
Issued at 228 AM MDT Thu Aug 11 2022
A nearly stationary ridge of high pressure focused over the central
plains will maintain a repetitive forecast for the beginning of the
long term. The CWA will be sandwiched between a dry airmass directly
under the center of high pressure to the east and anomalously high
precipitable water (PW) values in excess of 200 percent of normal
stretched across western Utah. Areas west of the Divide should
continue to fall under the anomalously moist category, however, some
dry air seeping into southwest Colorado may carve the moisture
gradient further west. Besides the far southeast clip of the CWA,
the rest of the region maintains PW values of 0.8 to 1.0 in. As a
result, daily recurrence of showers and thunderstorms develop each
afternoon/evening through the weekend. Perturbations rippling around
the high's center may also support nocturnal convection Saturday and
Sunday night, as well.
By Monday, a wave lifting inland along the PacNW begins to suppress
the ridge of high pressure, shift the high's center to the south and
east. This synoptic regime will knock high temperatures back a few
degrees, as higher height contours sag to the south. In terms of
moisture, the monsoonal plume will be shunted across the north with
a sharp moisture gradient settled just north of the CWA. Timing of
the southern extent of the plume between models leaves a level of
uncertainty of storm coverage on Monday, however, PW in excess of
200 percent of normal fills in over most of the West Slope by
Tuesday afternoon. Ridging begins to reestablish itself over the
Western CONUS by the later half of the week, as troughing becomes
more prominent over the Great Lakes. Despite this shift in synoptic
pattern, moisture continues to refuel and recycle under the ridge,
reinvigorating storms each afternoon across the West. Of note, the
GFS maintains a sharp moisture gradient across the north and east of
the CWA. Any southern or easterly shift of this gradient may limit
storm activity across portions of the CWA. However, the ECMWF keeps
us on juicy side and current NBM guidance weighs heavier on the
Euro, keeping PoPs within the likely category across northwest
Colorado.
In summary, monsoonal moisture doesn't want to budge. Heavy rainfall
will likely lead to localized flooding concerns, especially as the
forecast progresses and soils become (if not already) saturated.
Keep an eye on the sky next week, especially folks nestled in steep
terrain, near/downstream burn scars, arroyos and other flood-prone
areas.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1103 PM MDT Wed Aug 10 2022
Storms will lingering around KVEL and KCNY for the next few hours.
Another round of scattered storms are expected tomorrow afternoon
and evening. Brief heavy rainfall and gusty outflow winds are
possible.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&
$$
SHORT TERM...KJS
LONG TERM...ERW
AVIATION...TGJT
