Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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000
FXUS65 KBOU 152108
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
308 PM MDT Fri Mar 15 2024

.KEY MESSAGES...

- Low chance (< 30%) for patchy fog across parts of urban
  corridor and plains late tonight and early Saturday morning.

- Cool this weekend with a chance for light snow mountains,
  foothills, and nearby plains.

- Warmer weather next week (Beginning Monday).

&&

.SHORT TERM...(This evening through Saturday)
Issued at 300 PM MDT Fri Mar 15 2024

Satellite imagery shows low clouds continuing to clear this
afternoon. There is still a swatch of lower clouds extending south
from eastern Larimer county into Boulder county with scattering at
the edges. A weak boundary/wind circulation is evident on surface
obs with winds turning northerly in Boulder and Broomfield. This
might be why the clouds are sticking around in/near those areas.
Still some uncertainty on how this boundary moves across the area
with some high-res guidance showing it move across the Denver metro
area early this evening. It may potentially bring in some low-mid
level clouds behind it, but otherwise shouldn`t be impactful.

Tonight expect lows dropping into the 20s across the plains/urban
corridor, teens in the foothills, and single digits to teens for the
mountains and high valleys. There is a low chance (< 30%) for patchy
fog to develop over parts of the plains and urban corridor
overnight. Model soundings show shallow moisture evident late
evening/around midnight. If it does develop, this should erode out
after sunrise. With cooler temperatures tonight and plenty of melted
snow on the roadways, be mindful of icy spots if traveling late
evening/early tomorrow. Tomorrow, expect slightly warmer highs.
Colorado sits between a deep trough over Canada to the east and a
cutoff upper low in the southwest. This is will progress slightly
eastward and bring a period of weak lift across the region. Most of
the upper support will be south, but can`t rule out showers
developing across the mountains mainly south of I-70 and potentially
Palmer Divide in the late afternoon.

.LONG TERM...(Saturday night through Friday)
Issued at 129 PM MDT Fri Mar 15 2024

The stubborn closed low over the SW will nudge ever so slightly
eastward later this weekend, and help reinforce some easterly flow
at mid levels. With above-normal moisture still in place, this may
be sufficient for a few snow showers for the southern
mountains/foothills and Park County Saturday night through Sunday.
Any accumulations should be quite light, generally less than 2".
Cloud cover will linger and, with sustained snow cover across all
but some portions of the eastern plains, temperatures will remain
on the cooler side with highs mainly in the 40`s Sunday.

With a ridging pattern across the PacNW and a longwave trough over
the Great Lakes, northwest flow aloft will prevail early next
week. This subsident pattern will lead to steady warming and
drying. Temperatures look to climb into the 60`s by mid week and
will accelerate snowmelt. The warmest conditions will be found in
the eastern plains, where snow cover is lacking.

The weakened closed low is then progged to finally integrate into
the broader synoptic flow mid week and eject into the plains. As
it does so, periods of light snow showers may impact the high
country, with light accumulations for the higher elevations. These
showers could stick around through Friday as broader troughing
begins to develop west of the region.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1223 PM MDT Fri Mar 15 2024

For a fairly quiet weather day, there are still a couple of
forecast challenges in the TAF period. Winds will be southerly at
10-15 kts with gusts to 20 kts at DEN this afternoon and healthy
southerly at APA as well. This is high confidence. However,
confidence in the wind patterns decreases toward late afternoon-
early evening as there is potential for a boundary that moves
across the terminals briefly shifting winds light WNW/NW 21-01z.
Winds will transition back SW tonight. Winds shift to the NW in
the 16-18z timeframe Saturday at 05-08 kts.

The next challenge is ceilings. Lower cigs have eroded in the
vicinity of the terminals although clouds decks can be seen in
view. Higher clouds move in this afternoon. Where it gets lower
confidence is the chance for lower cigs early this evening as a
boundary moves though. For 00-02z reflected this potential in the
TAF, with SCT010 continuing tonight. VCFG possible for BJC
overnight.

&&

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

$$

SHORT TERM...Mensch
LONG TERM...Rodriguez
AVIATION...Mensch


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