533
FXUS65 KBOU 052104
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
304 PM MDT Wed Jun 5 2024

.KEY MESSAGES...

- Summer heat through the rest of this week, with Friday the
  hottest day.

- Increasing chances for showers and thunderstorms this weekend
  into early next week, along with slightly cooler temperatures.

- Gradual trend towards warmer/drier weather towards the middle of
  next week.

&&

.SHORT TERM /Through Thursday/...
Issued at 246 PM MDT Wed Jun 5 2024

There are a few weak convective clouds around the CWA early this
afternoon but no precipitation. Cloud coverage over the CWA is
about 1% at present. Most of the CWA has southwesterly to
northwesterly winds currently.  Gusts up to 35 mph have been
recorded this afternoon. It did hit 90 F at DIA a few minutes ago
for Denver`s first 90 degree reading of 2024.

Models show the upper ridge to push eastward into the CWA by
Thursday.  The flow aloft will be west and northwesterly overnight
and Thursday.  The QG Omega fields have benign synoptic scale motion
for the CWA the first two periods. A cold front is still expected
to push southward across the plains late this evening with weak
upslope flow behind it for a few hours. Southeasterly low level
winds are progged for the plains and lower foothills on Thursday.
For moisture, the precipitable water values are progged in the
0.50 to 0.90 range for the CWA tonight and Thursday. There is some
CAPE around on Thursday, mainly over the foothills and southern
CWA. The QPF fields are dry, with a tad of measurable rainfall
over the far southwest/south central CWA late day Thursday. Will
keep the minor late day pops going for south central CWA. For
temperatures, Thursday`s highs will be a tad cooler than today`s
highs.

&&

.LONG TERM /Thursday night through Wednesday/...
Issued at 246 PM MDT Wed Jun 5 2024

Main story of the long term forecast is a period of increased
moisture and increased precipitation chances across most of the
forecast area.

Mid-level moisture is expected to increase on Friday on the edge
of a thermal ridge axis centered over Colorado. 700mb temperatures
are quite warm and deterministic models would support low/mid-90s
across the plains, though the increasing moisture and a subtle
shortwave on the periphery of the upper ridge would support cloud
cover that may limit temperatures. The increasing moisture aloft
will also support some widely scattered showers and thunderstorms
by the afternoon hours with modest instability.

The better low-level moisture arrives this weekend, and will lead
to increased precipitation chances. Ensemble guidance continues to
support a broad moist airmass across the region (PWATs >150% of
normal) with roughly 500-1000 J/kg of CAPE each afternoon. Main
question is if we get any strong forcing mechanism for organized
convection or if things stay a bit less organized and dependent on
more subtle boundary collisions to drive storms in the afternoon.
Guidance does pick up on a few weak shortwaves embedded in the
flow but disagree on the timing of most of these features. At some
point, a weak cold front may also push into the region either late
this weekend or sometime Monday.

Moisture may linger into early next week, but guidance largely
agrees on a broad ridge axis building back across the Four Corners
region as we get towards mid-week. Timing and strength of the
upper ridge is up in the air (pun somewhat intended), but a
warming/drying trend is likely by the end of the forecast period.

&&

.AVIATION /18Z TAFS through 18Z Thursday/...
Issued at 1120 AM MDT Wed Jun 5 2024

Models have west, then northwesterly winds at DIA through about
06z, then a cold front with northeasterly winds moves in. Most of
the models never show drainage winds at DIA overnight.
Southeasterlies are indicated by late Thursday morning. There
will be no ceiling issues.

&&

.HYDROLOGY...
Issued at 246 PM MDT Wed Jun 5 2024

Snow melt is continuing across the higher elevations, with
elevated flows across a few creeks/rivers over the high country.
Main area of concern is across the upper Colorado River basin.

In addition, there is a limited threat of burn area
flash flooding this weekend into early next week, as an
anomalously moist airmass advects into the region. Scattered
showers and thunderstorms are forecast most afternoon, which would
be capable of brief heavy downpours. However, mean cloud-layer
flow should be strong enough (15-25kt) to keep the overall chances
of heavy rain/flash flooding low.

&&

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

&&

$$

SHORT TERM...RJK
LONG TERM...Hiris
AVIATION.....RJK
HYDROLOGY...Hiris