391
FXUS65 KBOU 072009
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
209 PM MDT Tue May 7 2024

.KEY MESSAGES...

- Freeze warning for the Palmer Divide early Wednesday morning

- Continued snowfall with blustery conditions across the high
  terrain this evening.

- Cool and unsettled pattern Wednesday through Friday.

- Warming Saturday through Tuesday with more normal late day
  shower and storm chances

&&

.SHORT TERM /Through Wednesday/...
Issued at 1201 PM MDT Tue May 7 2024
Remainder of Today and Tonight...Still windy and quite frankly we`re
over it! Elongated trough axis and perpendicular jet streak
careening into the Continental Divide continues to create pockets of
heavier snow combining with stronger winds will drop visibilities to
a mile or less. As mentioned earlier, lapse rates are still very
steep so we`re looking at convective snow showers, so impacts will
vary greatly within a small amount of real estate. The Winter
Weather Advisory continues through 6 PM MDT for the high country.

Across the foothills and plains, winds, virga, virga driven winds,
maybe a hundredth or two of rain (right along the foothills),
otherwise no big sensible weather concerns...did we mention wind!?

We continue the Red Flag Warning across southern Lincoln County as
numerous gusts 30-40 MPH are expected the remainder of the afternoon
with relative humidity values hovering right around 15% at this time.

Overnight we really don`t lose the winds, though we remove a
majority of the stronger gusts outside of the high terrain. While
the skies do clear and the airmass is rather dry, we should cool
enough to get close to the freezing mark in a lot of places early
Wednesday morning. The highest confidence we have in a harder freeze
is across the Palmer Divide where we expect shelter temperatures to
drop into the upper-20s. DESI viewer shows nearly a 100% chance of
being below freezing in this area...chances drop off quickly outside
of the Palmer to around 30% of being below freezing. The warmer
overnight temperatures and the addition of the winds is the main
reason why we canceled the Freeze Watch tonight.

Wednesday...Much the same, though a tad less wind...finally! 700mb
low pulls further to the east-southeast so winds should back more
towards the northwest throughout the day. Lapse rates aren`t as
steep as today but a little bit of heating during the afternoon we
could see some pop-up showers, 20% chance, across the northern
plains counties.

&&

.LONG TERM /Wednesday night through Tuesday/...
Issued at 200 PM MDT Tue May 7 2024

A more tranquil (and less windy!!) pattern will dominate our
weather through early next week. There will still be a few showers
or isolated thunderstorms around in typical spring fashion, but no
big storms are in the works.

For Wednesday night into Thursday, the elongating upper level
trough will sink slowly southward into Colorado and the Great
Basin. Moisture will increase, leading to scattered but mostly
light showers. It`s quite a chilly system with 700 mb temperatures
near -6C along the Front Range by early Thursday morning, perhaps
leading to a little rain/snow mix all the way down to Denver`s
elevation, if we see precipitation Thursday morning. Then daytime
heating would lift any snow levels closer to 7000 feet by the
afternoon hours. That said, any accumulation in the higher
elevations will still be light given weak dynamics and
orographics. We may be hard pressed to push far into the 50s for
highs considering the additional moisture and cooler airmass
overhead.

For Thursday night, most showers are expected to come to an end as
the best lift settles into the Great Basin, leaving a weak col
but somewhat drier air over our forecast area. If it clears out
sufficiently we could be looking at frost/freeze conditions again.
For Friday, enough instability would still exist though to keep a
few convective afternoon and evening showers in the forecast,
mainly over the higher terrain. Some drying should allow for more
solar insolation, pushing highs into the 60s.

For Saturday through Monday, there is still uncertainty and no
clear solutions for the forecast in this period. Ensembles are
coming into a little better agreement, but it all depends on how
far north the low kicks to the east, and the timing of said
feature. For now, there`s not much confidence in any one
particular solution, as there`s a relatively even split between
lifting the upper low back up across Colorado at some point next
weekend, or keeping it sufficiently to our south for mostly dry
weather and warmer temperatures. There`s still no clear solution
at this point, so we`ll go with the consensus model blends showing
the warmer temperatures but also a chance of showers/isolated
storms most days. This pattern would not favor any threats of
significant weather or strong thunderstorms.

&&

.AVIATION /18Z TAFS through 18Z Wednesday/...
Issued at 1156 AM MDT Tue May 7 2024

Today...VFR. Complicated wind forecast with predominant WSW surface
flow. Issues come with any enhanced showery/virga activity that push
the winds more directly west, especially for KDEN, for an hour or
two this afternoon. Winds should begin to decrease by late afternoon
and back slightly WNW. Medium confidence overall.

Tonight - Wednesday...VFR. Winds still on the decrease with a
predominant WNW flow and some continued gustiness. Thinking gusts
top out around 25 knots for our terminals. Medium confidence.

&&

.FIRE WEATHER...
Issued at 1201 PM MDT Tue May 7 2024

Critical fire conditions will be in place into the early evening
across southeastern Elbert and southern Lincoln counties due to
very windy conditions and low humidity. Across the rest of the
plains there will be elevated fire conditions.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 6 PM MDT this evening for COZ031-
033-034.

Freeze Watch from midnight MDT tonight through Wednesday morning
for COZ038>040-042>049.

Freeze Warning from midnight tonight to 8 AM MDT Wednesday for
COZ041.

Red Flag Warning until 7 PM MDT this evening for COZ247.

&&

$$

SHORT TERM...Heavener
LONG TERM...Barjenbruch
AVIATION...Heavener
FIRE WEATHER...Heavener