348
FXUS65 KBOU 120243
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
843 PM MDT Tue Mar 11 2025

.KEY MESSAGES...

- Warm and dry Thursday. Windy as well for eastern Elbert and
  Lincoln counties leading to critical fire weather conditions.

- Potent, quick moving storm system still on schedule for Friday.

- Very windy conditions for the plains Friday.

- Mountain snow Thursday night and Friday with primarily rain for
  the plains.

&&

.UPDATE...
Issued at 843 PM MDT Tue Mar 11 2025

Satellite pictures are showing quite a bit of upper level moisture
over the CWA at present. There is no moisture in the lower levels
and no precipitation over the CWA.

Model data indicates a decent amount of upper level moisture for the
CWA overnight ahead of a weak upper trough that moves across on
Wednesday. Not too much to update in the grids, except to add more
cloudiness as per the current situation and upstream satellite
data. Overnight low temperatures will stay above normal with the
airmass in place and the cloud cover expected. Drainage winds
should be in place in all areas by 06Z.

&&

.SHORT TERM /Through Wednesday/...
Issued at 245 PM MDT Tue Mar 11 2025

A weakening upper level trough will shift across the forecast
area late morning Wednesday, but moisture is very limited and thus
dry conditions will persist with only passing clouds. There`s not
enough moisture to support anything more than a brief sprinkle or
flurry for the higher mountains. Temperatures should trend just a
couple degrees cooler with weak cool advection. Winds will be
lighter as well, given lighter winds aloft and a weak pressure
gradient in place. Thus, any fire weather concerns will be
minimized.

&&

.LONG TERM /Wednesday night through Tuesday/...
Issued at 245 PM MDT Tue Mar 11 2025

Southwest flow aloft will prevail Wednesday night and Thursday
ahead of an upper level trough approaching the region. This will
bring mild and dry conditions to the area. Highs over northeast
Colorado are expected to reach the 70s. A surface trough forms
over eastern Colorado with gusty south winds forming to the east
of it over far eastern Colorado and into Nebraska and Kansas,
which will elevate fire weather conditions. See Fire Weather
Section below for additional details.

Snow moves into the mountains Thursday night as the upper level
trough enters the Central Rockies. Deep cyclogenesis takes place
over southeast Colorado and southwest Kansas Friday morning.
Latest model trends have shifted the near low slightly southward.
Main impact from this strong surface low will be strong winds
across eastern Colorado Friday. Rain showers are expected as well
across plains with temperatures expected to be too warm for snow.
However, where precipitation intensity is heaviest, we could see a
brief period of heavy wet snow. Overall snow impacts are expected
to be minimal over the plains due to the mild temperatures. Can`t
rule out impacts over the higher terrain of the Palmer Divide,
but even there amounts are expected to be less than 2 inches.
Precipitation over the plains is expected to wrap up by late
Friday afternoon with only light snow showers for mountains come
Friday evening.

For this weekend, we will see a broad upper level trough over the
middle part of the country. The storm system that will bring
windy conditions Friday will lift northeast across the Great Lakes
Saturday. Over Colorado, northwest flow aloft will prevail on the
backside of the upper level trough. Enough moisture is expected
to be embedded in the northwest flow aloft to produce snow over
the mountains Saturday and into early Sunday. East of the
mountains, a downslope flow will lead to mostly dry conditions.
The airmass will be slightly unstable along the Front Range, so a
few light rain/snow showers will be possible Saturday afternoon.
Drier conditions are expected for Sunday as ridging starts to move
into the area bringing warmer and drier air. Temperatures
Saturday will be on the cool side, with slightly below normal
highs of mid 40s to lower 50s over northeast Colorado.
Temperatures Sunday climb to near normal with highs in the mid to
upper 50s across northeast Colorado.

For Monday, the upper level ridge slides east of the Colorado
with flow aloft turning to the southwest on the backside of the
ridge and in advance of the next storm system. Temperatures climb
into the mid 60s to lower 70s over northeast Colorado with dry
conditions expected to continue across the area.

The next upper level trough tracks across the Great Basin and
Central Rockies Tuesday and possibly Wednesday. Models in decent
agreement that we will see a trough pass across the region
sometime Tuesday or Wednesday. Strength and timing still needs to
be worked out. Even though the operational runs of the GFS and
ECMWF differ on the timing, they show a closed low forming over
south central to southeast Colorado. This is farther west than
last week`s system and this upcoming system. If this scenario pans
out, the area will see a better chance and higher amounts of rain
and snow than these previous two storm systems that brought more
wind than precipitation.

&&

.AVIATION /00Z TAFS through 00Z Thursday/...
Issued at 644 PM MDT Tue Mar 11 2025

Northwesterly, then westerly winds will prevail at DIA this
evening. Winds speeds should stay fairly light, generally 12 knots
or less.  Most models settle on drainage wind directions by 06Z,
continuing though much of Wednesday morning. There will be no
ceiling issues.

&&

.FIRE WEATHER...
Issued at 245 PM MDT Tue Mar 11 2025

Increasing southwest flow aloft combined with a deepening surface
trough is expected to produce gusty southwest winds to areas
mainly south of I-70 and over far eastern Colorado. Given the warm
temperatures and low dew points, relative humidities in the 10-15
percent range are expected to be common over the plains with some
single digit readings possible. Will issue a Fire Weather Watch
for Eastern Elbert and Lincoln Counties where gusts to 30 mph and
10-15 percent relative humidities will prevail.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Thursday morning through Thursday
evening for COZ246-247.

&&

$$

UPDATE.........rjk
SHORT TERM.....Barjenbruch
LONG TERM......Meier
AVIATION.......rjk
FIRE WEATHER...Meier

NWS BOU Office Area Forecast Discussion