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000
FXUS65 KBOU 190236
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
836 PM MDT Thu Apr 18 2024

.KEY MESSAGES...

- Cool and cloudy with rounds of snow through Saturday morning.

- Best chance of accumulating snow Friday afternoon into Saturday
  morning.

- Drier and warmer early next week.

&&

.UPDATE...
Issued at 830 PM MDT Thu Apr 18 2024

The low clouds will be here to stay throughout the night tonight
across the plains and foothills. There will continue to be mist
and flurries as well. Roads may become slick and icy especially
in the foothills where there is colder temperatures. Across the
Denver metro, bridges may become very icy by morning so the
morning commute could have more crashes than normal.

Tomorrow, clouds may clear over the plains to the south of I-70.
This may allow for a bit warmer conditions than today but highs
were lowered a couple of degrees in this update.

&&

.SHORT TERM...(This evening through Saturday)
Issued at 242 PM MDT Thu Apr 18 2024

Post frontal upslope flow continues which will lock stratus in
across the plain as periods of overrunning associated with passing
disturbances move through westerly flow aloft. Snow bands
redevelop overnight across the front range and spreads eastward
bringing some additional light snow through early Fri morning. A
stronger round of upper lift associated with the next wave in
westerly flow spreads in late Friday through Saturday morning.
This will bring another more widespread snow event to the region,
with HREF probabilities of 3 inches in the 40-60% range across a
large portion of NE CO through early Saturday morning, though
warmth of ground and pavement surfaces may mitigate impacts to
some degree across the lower elevations. Probabilities for 6" or
more really tail back quickly across the lower elevations though
some HREF probs do show an area of 50% probs along front range
mountains. Some light snow continues into Saturday morning before
drying spreads in behind the wave through the day. Stratus may
hang in most of the day across the plains as focus for
precipitation shifts southward. Temperatures will remain below
normal through the period.

.LONG TERM...(Saturday night through Thursday)
Issued at 242 PM MDT Thu Apr 18 2024

Upper ridge builds in then flattens as the next closed low passes to
the north on Monday. Temperatures rebound back into the 60s to
around 70 across the plains for Sunday and into the 40s and 50s for
the mountain communities.  This wave brings another brief round of
snow Sunday night across the mountains but accumulations stay light.
Monday gets windy and warm again which could bring some near
critical fire weather conditions to portions of the plains.  For now
RH values stay above the 15 percent critical thresholds. A minor
drop in temperatures expected for Tuesday behind another front
which drops through the region Monday night. Post frontal upslope
flow may generate some mountain showers across the region Tuesday
afternoon and evening.

Timing of the next system in southwest flow for mid to late week is
still in question among the models/ensembles.  For now it looks like
we enter another dry and windy southwest flow pattern with another
uptick in mountain precipitation late week.

&&

.LONG TERM...(Saturday night through Thursday)
Issued at 242 PM MDT Thu Apr 18 2024

Upper ridge builds in then flattens as the next closed low passes to
the north on Monday. Temperatures rebound back into the 60s to
around 70 across the plains for Sunday and into the 40s and 50s for
the mountain communities.  This wave brings another brief round of
snow Sunday night across the mountains but accumulations stay light.
Monday gets windy and warm again which could bring some near
critical fire weather conditions to portions of the plains.  For now
RH values stay above the 15 percent critical thresholds. A minor
drop in temperatures expected for Tuesday behind another front
which drops through the region Monday night. Post frontal upslope
flow may generate some mountain showers across the region Tuesday
afternoon and evening.

Timing of the next system in southwest flow for mid to late week is
still in question among the models/ensembles.  For now it looks like
we enter another dry and windy southwest flow pattern with another
uptick in mountain precipitation late week.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday afternoon)
Issued at 242 PM MDT Thu Apr 18 2024

Active pattern with low ceilings, periodic drizzle or light rain,
with eventually snow returning to the TAF sites at the every end of
the forecast period Friday evening.

Latest radar imagery depicting continued drizzle and light rain
across all of the terminals, with observational data indicating any
snow remaining confined to the higher terrain. While coverage of the
drizzle or light rain should decrease this evening, still think it
will be occasionally observed for much of the night. Some guidance
showing a possibility for a small window of snow very late tonight
into early Friday morning, but think there is a very low chance of
this occurring at this time. Vis under this precip should be 6 miles
or more but by late evening, will see vis begin to fall, with vis 3-
5sm appearing likely under additional BR development later tonight
into Friday morning. The improvement to higher end MVFR ceilings
this afternoon should be the last of any improvement, as a slow
downward trend is likely once again tonight into Friday morning.
While can`t completely rule out a return to IFR ceilings, think a
more likely solution at this point is MVFR ceilings in the 1kft to
2kft range. A general light easterly wind component looks to remain
in place into this evening, however, more variable winds are
possible later tonight before shifting to the north Friday morning.

Drizzle or rain chances look low Friday morning at this point, but
if lower ceilings are in place than currently forecast, would not be
surprised to see continued development. A slow improving trend with
ceilings and vis is likely through early to mid afternoon Friday, as
northerly winds steadily increase. Rain will return to the terminals
by mid to late afternoon and will assist with lowering ceilings
during that time, with this trend continuing into the evening as
snow becomes more likely.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

UPDATE...Danielson
SHORT TERM...099
LONG TERM...099
AVIATION...099