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000
FXUS65 KBOU 150020
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
620 PM MDT Sun Apr 14 2024

.KEY MESSAGES...

- Very warm, dry, and gusty southeast winds to produce Red Flag
  conditions over of the plains and Palmer Divide.

- Critical fire weather conditions over the plains Monday
  afternoon.

- A windy weather system will bring snow to the mountains with
  rain showers likely on the plains late Monday into Tuesday.

- Cooler, windy and unsettled the rest of the week. Occasional
  snow showers in the mountains with a chance of rain showers for
  the plains.

&&

.SHORT TERM /Through Monday/...
Issued at 230 PM MDT Sun Apr 14 2024

Southerly flow aloft will continue to increase tonight and Monday
ahead of an upper level low over California and Nevada. As it
approaches Colorado, surface pressure will lower over Wyoming and
northern Colorado causing southeast winds to increase this
afternoon and evening. On Monday, a surface low forms over
northeast Colorado. In addition this, the strong flow aloft
mixing down will bring gusty south to southwest winds to 45 mph
over the eastern plains. Critical Fire Weather/Red Flag conditons
are expected over the eastern plains because of these gusty winds
and low relative humidities. See the Fire Weather Section for
details.

The upper level low moves into Colorado Monday afternoon. This will
bring rain and mountain snow to western and central Colorado
starting Monday afternoon. A cold front will drop south around the
surface low bringing gusty winds to 50 mph with it. Some showers
will be possible behind it, but downslope flow will make it
difficult for them to form.

&&

.LONG TERM /Monday night through Sunday/...
Issued at 300 PM MDT Sun Apr 14 2024

Models have the upper closed low right over central Colorado at
00Z late Monday afternoon. By 12Z Tuesday morning, its east of the
CWA in northwestern Kansas. Weak to moderate northwesterly flow
aloft is in place Tuesday with 70 to 80 knot zonal flow is
progged at jet level Wednesday night. The synoptic scale energy is
not very significant Monday night through Wednesday night with
shots of both weak upward and downward vertical velocity. It is
noisy with nothing significant either way. The low level wind and
pressure fields now show pretty decent low level downsloping winds
for Monday night. Cross sections on some of the models show the
potential for a downsloping wind set up late Monday night and
Tuesday. Not all agree. I will not go with wind highlights at this
time, but stay tuned.

For moisture, it is deep over the mountains Monday night into
Tuesday morning.  The synoptic scale energy is good early, but not
after 12Z Tuesday morning.  Mountain top wind speeds and directions
are pretty good for orographic enhancement.  We will go with a Winter
Storm Watch for our alpine zones from 21Z Monday to 21Z Tuesday. For
the plains, moisture is not bad and the QPF fields do show some
measurable rainfall over most of the plains Monday evening into
Tuesday afternoon. There is very limited CAPE progged over the far
northeastern CWA Monday night into Tuesday morning. Will leave
the low chances of thunder in and the 50-70% pops going.

For temperatures, models show a cold front move down sometime
Wednesday night.  Highs on both Tuesday and Wednesday look to be
above seasonal normals.

For the later days, Thursday through Sunday, models now have
moderately strong west-southwesterly flow aloft over our CWA through
the period.  The synoptic scale energy is weak and fairly convoluted
all four days. There is a decent amount of moisture progged
Wednesday afternoon into Saturday night. The airmass is still
expected to be cooler than normal Thursday through Saturday, but
nowhere near as cold is models indicated yesterday and the day
before. The trend has certainly been getting warming for the same
period. Will leave the, mainly, "scattered" pops going through
Saturday evening, with a drier Sunday.

&&

.AVIATION /00Z TAFS through 00Z Monday/...
Issued at 543 PM MDT Sun Apr 14 2024

VFR conditions will continue through the TAF period with a 30%
chance of IMC conditions beginning around 03Z on Wednesday at
KDEN. For tonight, gusty south/southeasterly winds will continue
with a lull in gusts for a few hours beginning around 10Z for KAPA
and KDEN. Southwest winds will increase again around 15/16Z with
gusts up to 30 kts possible. A cold frontal passage will shift
winds to the west with a 30% chance of ceilings dropping to 5000`,
bringing light rain showers and winds gusting up 30-35 kts after
23Z Monday.

&&

.FIRE WEATHER...
Issued at 230 PM MDT Sun Apr 14 2024

Southeast winds will remain gusty at times across the eastern
plains through this evening. Winds subside late tonight and Monday
morning, but increase again for late Monday morning and
afternoon. Wind gusts to 45 mph and relative humidities in the 5
to 15 percent range will result in Red Flag conditions through
early Monday evening. A cold front is expected to bring a gusty
wind shift to the west late Monday afternoon into early Monday
evening. Windy conditions are also expected Monday afternoon along
the Urban Corridor, however relative humidities are expected to
stay above 15 percent or fuels are not as susceptible to
ignition.

The weather pattern is cooler with increasing moisture from
Tuesday onward. Although there may be slightly elevated fire weather
conditions over the Palmer Ridge and Lincoln County for a brief time
Wednesday late in the day with humidity levels in the teens.
Otherwise critical fire weather conditions are not expected.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Storm Watch from Monday afternoon through Tuesday
afternoon for COZ031-033-034.

Red Flag Warning until 8 PM MDT this evening for COZ241-245>247-
249.

Red Flag Warning from noon to 8 PM MDT Monday for COZ241-244>251.

&&

$$

SHORT TERM.....Meier
LONG TERM......RJK
AVIATION...Bonner
FIRE WEATHER...Meier/RJK