Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 241306
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
706 AM MDT Sun Mar 24 2024

.KEY MESSAGES...

- A storm system will affect the area today through Monday
  morning. Blizzard conditions will occur over the Palmer Divide
  tonight into Monday morning. In addition blizzard conditions may
  also develop over portions of the eastern plains late this
  evening through Monday morning.

- There is still some uncertainty as to snowfall amounts over the
  plains but gusty north winds from 50 to 60 mph may cause very
  poor visibility despite limited snowfall.

- Heavier snow will occur across the mountains and foothills with
  the highest amounts along the I-70 Mountain Corridor and
  southern Foothills. There will also be snow this evening and
  overnight across the Denver Metro area.

- Travel impacts will increase this evening and continue through
  the Monday morning commute. Roads closures will be possible over
  the Palmer Divide and across portions of the eastern plains.

&&

.UPDATE...
Issued at 703 AM MDT Sun Mar 24 2024

Thick low clouds and fog have spread across much of the far
northeast corner of Colorado this morning. With clouds expected to
continue throughout the day today and with northeasterly winds
increasing and bringing in cooler air, the high temperatures were
lowered drastically today. Holyoke`s forecast high was cut by
about 15 F and highs may stay in the low 40s today. Patchy fog was
also added to the forecast this morning.

&&

.SHORT TERM...(Today and tonight)
Issued at 430 AM MDT Sun Mar 24 2024

Area radars, observations and satellite pictures and web cameras
are showing snow in the mountains at this time with nothing left
out on the plains. The wind field is more relaxed tonight compared
to last night at this time. Temperatures over the plains and
foothills are in the 30s F to lower 40s F currently, with teens
and 20s F in the higher mountains.

Models show an incoming upper trough axis over the Colorado western
border around 18Z today. By 00Z late this afternoon, an upper closed
low is centered anywhere from the far southeastern corner of
Colorado to north central Colorado.  By 12Z Monday morning, the
upper low center is anywhere from the northwestern corner of the
Texas Panhandle to over the southeastern corner of Colorado to south
central Nebraska.  Yesterday at this time, models had this upper
feature well east and northeast of us by 12Z Monday morning. Most
all the models are now slowing this and putting it further south.

The QG Omega field have decent upward vertical velocity today and
tonight for all the CWA.  The low level/surface cyclone is located
over the southeastern corner of Colorado on most of the models by
00Z late this afternoon, so pretty good agreement there. Models have
20-35 mph northeasterly winds for the plains by early afternoon,
becoming 25 to 50 mph north-northeasterly winds by later afternoon. A
decent cold airmass accompanies the surges of upslope, especially
the second one.

The MLCAPE values get as high as 700 j/kg over the plains this
afternoon, so will leave the thunderstorms in.  Lapse rates are
pretty steep as well on the cross sections during the afternoon
hours. Moisture looks fairly deep with this system on the cross
sections, especially from 00Z-12Z tonight.

Model solutions are not becoming clearer with this upper trough the
closer it gets to the CWA. The model discrepancies from one to
another are convoluted enough, however the run to run
inconsistencies are just as complicated with this system. A good
portion of the CWA should receive snow, with some areas
substantial amounts. I won`t swallow the hook, line and sinker
completely for this update, but increased snowfall amounts are a
good bet for much of the CWA. See the watches, warnings and
advisories at the bottom of this discussion.

Concerning the High Wind highlight, the areas that see convection
this afternoon could certainly have outflow gusts to reach high wind
criteria, but overall it look marginal for a high wind warning. Will
leave in go with a High Wind Watch in zones 38, 42, and 47.  Most of
the rest of the eastern plains that were under the High Wind Watch,
now are under a Winter Storm Watch, with strong winds and blizzard
conditions mentioned in that product.

.LONG TERM...(Monday through Saturday)
Issued at 358 AM MDT Sun Mar 24 2024

By 12z Mon, there is an elongated upper low from swrn KS into
central NE which supposedly is to consolidate into one low over
central KS by Mon aftn.  This is not what was shown this time last
night, as the system was supposed to eject quickly northeast out of
the region by 12z Mon.  Naturally with a slower movement, from some
of the models, this would lead to additional snowfall over portions
of the plains and Palmer Divide through midday Monday. However, the
ECMWF basically has most snow ending in the 12z-15z time period
across the plains and Palmer Divide.  Thus there remains a
tremendous amount of uncertainty as to how much additional snowfall
may occur over the plains and Palmer Divide.  One thing that is for
certain is there will continue to be very gusty north winds over
the plains thru at least midday. Thus any lingering snow could
still cause blizzard conditions with very poor visibility.

By Mon night, NW flow will develop as the storm system moves away
from the region.  The NW flow regime will continue thru Tue as well.
Moisture will be embedded in the flow and will combine with decent
lapse rates to produce periods of light orographic snow in the mtns.
Across the plains it will be manly dry, however, can`t rule out a
slight chc of showers Tue aftn/evening.

For Wed, an upper level ridge will begin to shift eastward into the
area.  This will lead to less moisture and a decrease in orographic
snow showers in the mtns.  Across the plains it will be dry with
seasonal temps.

Looking ahead to Thu and Fri, the flow aloft will gradually become
more WSW as a stg storm system approaches the West Coast.  There may
be enough moisture in the flow to produce a chc of snow showers in
the mtns.  Across the plains, it will be dry with warmer
temperatures.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 358 AM MDT Sun Mar 24 2024

A couple of cold fronts/wind shifts are expected today, at DIA.
One around 18Z, the another around 00Z. The second should usher
in northerly winds at 02020G40KT. Will keep some mention of
-TSRA in the this afternoon as well. Will put some variable
 outflow gusts in with the storms up to 45KT. Shortly after 00-01Z
 this evening visiblities and ceilings will range from 1/2-2SM
 with -SN or SN and BKN-OVC003-012.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 6 AM MDT Monday for COZ031-033.

Winter Storm Warning until 6 AM MDT Monday for COZ034.

Winter Weather Advisory from 6 PM this evening to 6 AM MDT
Monday for COZ035.

Winter Storm Warning from 6 PM this evening to 9 AM MDT Monday
for COZ036.

Winter Weather Advisory from 6 PM this evening to 9 AM MDT
Monday for COZ037-039-040-045.

High Wind Watch from 6 PM MDT this evening through Monday
morning for COZ038-042.

Blizzard Warning from 6 PM this evening to 9 AM MDT Monday for
COZ041.

Winter Storm Watch from this evening through Monday morning for
COZ046-048>051.

High Wind Watch from this evening through Monday morning for
COZ047.

&&

$$

UPDATE...Danielson
SHORT TERM...RJK
LONG TERM....RPK
AVIATION.....RJK


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