896
FXUS65 KBOU 150057
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
657 PM MDT Wed May 14 2025

.KEY MESSAGES...

- Showers and thunderstorms with strong winds moving across
  northeastern Colorado through early evening. Main threat is
  marginally severe wind gusts.

- Potential for strong winds in the foothills late tonight
  through mid morning on Thursday. Gusts in the 60-70 mph range
  possible in wind prone areas.

- Windy again with increased shower and thunderstorm activity
  expected again starting Sunday.

&&

.UPDATE...
Issued at 513 PM MDT Wed May 14 2025

Updated for higher coverage of rain and slightly higher wind
gusts. Severe gusts aren`t widespread, but there are quite a few
50-60 mph gusts associated with the storms, and some higher. There
hasn`t been much large hail, but the stronger updrafts are
supporting hail near 1 inch in diameter.

&&

.DISCUSSION /Through Wednesday/...
Issued at 308 PM MDT Wed May 14 2025

The expected shower/thunderstorm area has developed nicely, and is
extending south a bit more than expected. This activity will shift
eastward through early evening. The main threat will be strong
winds, and the current organization would suggest an enhanced
threat of an organized wind field developing along this line.
Some convection allowing models today have been really ambitious
with 70-80 mph gusts, but there`s a high bias with these, at least
in the coverage. The idea of widespread 30-40 mph winds with some
places getting gusts up to 65 mph still looks good, perhaps the
probability of severe gusts is looking a little higher than it did
earlier today.

Behind the current shortwave the flow aloft goes more westerly
quickly. There`s a window of opportunity for a mountain wave later
tonight into Thursday morning with about 40 knots of cross barrier
flow, though the wind and temperature profiles aren`t favorable
for much amplification. We think the high wind threat is small,
but we do expect another round of 40-60 mph gusts in wind prone
areas early Thursday. There will still be some wind on Thursday,
especially across the north, but less than this afternoon.

Friday and Saturday look relatively quiet. There will still be a
little wind, and a low level of diurnal shower/thunderstorm
activity. Lower humidities across the southern part of our area
may be near critical thresholds, but fuels are currently green so
the threat is greatly reduced.

There are a couple wrinkles in the forecast from Sunday onward.
Last night`s operational EC kept the large low that develops over
the southwest intact and brought it across Colorado in one piece
on Monday. This is against a trend in most model runs for a
significant shortwave to lift out of the mean trough across
Colorado on Sunday, and the trend in those models is also further
north with that. This could bring a warm, dry, windy day Sunday instead
of a thunderstorm day if that trend continues. But if it`s a
little further south, we could still have a frontal passage with a
transition from warm to stormy.

The NBM seems to track with most of the models on the temperature
and wind fields, but the higher PoPs on Monday are a bit of a
mystery. We`re not sure if it`s due to those EC solutions from
last night, or if it`s that some of the models are producing "day
2" storms on Monday behind the lead trough. It doesn`t seem like
there`s that much precipitation in the model suite that we`ve
seen. There`s probably a better chance on Tuesday as we have more
chance for a plains airmass to settle in and destabilize, and
there may be another piece of the trough or the main trough itself
moving east to the south of us. NBM trend of drier Tuesday is
suspect, we`ll see how model trends continue overnight.

&&

.AVIATION /00Z TAFS through 00Z Friday/...
Issued at 648 PM MDT Wed May 14 2025

VFR is expected for the TAF period. Northerly winds will relax
this evening and will turn toward drainage around midnight. WNW
winds will likely develop tomorrow but may not be as persistent as
the TAFs would indicate. There will likely be some periods where
winds at DEN and APA will be light and variable in-between the
moderate westerly winds. In addition, there may be weak showers in
the afternoon that could create sporadic wind gusts. Winds will
then go back toward drainage Thursday night.

&&

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

&&

$$

UPDATE...Gimmestad
DISCUSSION...Gimmestad
AVIATION...Danielson