National Weather Service Forecast Discussion

000
FXUS65 KBOU 221032
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
432 AM MDT Mon Apr 22 2019

.SHORT TERM...(Today and tonight)
Issued at 432 AM MDT Mon Apr 22 2019

Colorado will be between systems today. The upper level trough
that brought the showers and thunderstorms to the region has
shifted to the northeast. Also, a closed low will drop south
across the Desert Southwest today. Surface high pressure to the
north of Colorado will produce northeast upslope winds. This
combined with the moist boundary layer will result in low clouds,
fog, and drizzle for parts of the area. The fog and drizzle is
expected to occur this morning, mainly west of I-25 and into the
foothills. It should stay cloudy all day, so temperatures will be
slow to warm. Temperatures are expected to only climb into the
upper 40s to lower 50s this afternoon over northeast Colorado.
Above the cooler and moist airmass, the mountains will be slightly
unstable this afternoon. Expect isolated to scattered showers and
thunderstorms to form, mainly this afternoon. By early evening,
the convection will dissipate. Locally, up to 2 inches of snow
will be possible in the mountains, but most locations will see
little of any snow accumulation.

For tonight clouds should continue through the evening before
they start to dissipate after midnight. Lows are expected to drop
into the 30s across northeast Colorado.

.LONG TERM...(Tuesday through Sunday)
Issued at 432 AM MDT Mon Apr 22 2019

The rest of this week is going to feature warmer temperatures and
mostly dry conditions, with a couple exceptions. On Tuesday
northern Colorado will be under a weak flow pattern on the
northern periphery of a cutoff low moving over southern Arizona.
The chance of rain on the plains will be low, but moisture
lingering over the mountains will be able to feed some afternoon
showers over the high country. Most of these showers will be over
Summit and Park Counties, and should only produce rain for a short
period of time. Snow levels will be up somewhere around 10,000
feet, so any accumulations will be minor. Enough instability will
be present for embedded thunderstorms to develop. Temperatures on
the plains will warm into the lower and mid 60s under mostly sunny
skies while the mountains will warm to the 40s and 50s, depending
on elevation.

Considerable warming will occur on Wednesday as ridging aloft over
Colorado strengthens. The plains will be dry with afternoon
temperatures in the low 70s. Mountain areas may again see
scattered afternoon showers and thunderstorms from mid-level
moisture lingering over the higher terrain.

On Wednesday night and Thursday morning models show a surge of
cooler air coming out of Wyoming which will bring 5 to 10 degrees
of cooling through Thursday afternoon, and will spread the chance
of showers out onto the plains. Through the end of the week, model
moisture field keep Specific Humidity levels over Colorado on the
moist side (3-4 g/kg), which will support the afternoon shower
activity that develops, in spite of the upper level ridging in
place over the state. This is due to the fact that the upper ridge
will be situated just to the south of fairly strong zonal flow
across the northern United States and southern Canada.

After Thursday`s minor cooldown, warmer and drier conditions will
re-develop for Friday through Sunday. High temperatures could
approach 80 degrees as the week comes to an end. The next
indication of precipitation looks like next Monday when an upper
level low is expected to undercut the upper ridge that builds over
the southwestern U.S. over the weekend. Timing for Monday`s system
is still up in the air, and may not acutally reach Colorado until
Tuesday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 432 AM MDT Mon Apr 22 2019

Low clouds will remain over the Denver through today and tonight.
Ceilings should stay under 1000 feet through late morning.
Uncertain if the clouds will be low enough to obstruct visibility
and result in fog. There will be a chance for fog through 16Z with
visibility down to a quarter mile. In addition to the low clouds
and possible fog, drizzle is expected to occur this morning.
Ceilings will slowly lift through the day, but are not expected to
climb above 4000 feet. Dry air slowly moves in tonight with
clouds scattering late tonight or early Tuesday morning.

&&

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

$$

SHORT TERM...Meier
LONG TERM...Dankers
AVIATION...Meier

NWS BOU Office Area Forecast Discussion