Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 221618
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1018 AM MDT Sat Apr 22 2017

.UPDATE...
Issued at 1018 AM MDT Sat Apr 22 2017

Showers are coming to an end across the Denver metro area and will
gradually end over the Palmer Divide by noon with large scale
subsidence building in and continued drying. Clouds are beginning
to break and lift with the daytime heating. Shallow instability
will exist this afternoon with isolated showers redeveloping on
portions of the plains, and up to scattered coverage in the
foothills and mountains. Only light precipitation amounts.
Overall forecast is on track through tonight, with only slight
adjustments for the latest trends and maybe a degree or two
cooler. With sufficient clearing, we may see some frost on the
plains tonight into early Sunday morning.

&&

.SHORT TERM...(Today and tonight)
Issued at 343 AM MDT Sat Apr 22 2017

Much of northern Colorado remains under a broad upper trof early
this morning with latest impulse now moving into northwest
Colorado. This coupled with upper jet over central colorado is
creating some enhanced banded precip along eastern portions of the
Front Range urban corridor. Most of the precip on the plains is
rain but some snow over higher terrain with snow level around
6000-6500 feet. With this heavier band of precip could see some
brief mix of rain and snow over the denver area but not expecting
any accumulations with this. Will make some adjustments to focus
on the area of precip over the urban corridor and adjacent eastern
sections early this morning with likely pops.

The back of the trof will slide east of the area this afternoon
with increasing subsident flow with building high pressure over
Colorado tonight. Showers will diminish this afternoon with a
gradual clearing of the skies by later this afternoon and clearing
tonight.

.LONG TERM...(Sunday through Friday)
Issued at 343 AM MDT Sat Apr 22 2017

A shortwave ridge over eastern Colorado Sunday morning will
transition east through the day to allow flow aloft to increase
out of the southwest, as a weak shortwave trough pushes into the
state later that night. A surface low will develop and deepen
over the plains to increase southerly flow over the plains, as
well as help temperatures warm with increasing westerly flow aloft
and warm advection. Above average temperatures are expected
across the area Sunday, with readings in the mid 70s over the
plains. Light moisture from the approaching shortwave trough will
push into the mountains Sunday evening, with a cold front to drop
over the forecast area after midnight, bringing strong winds but
not much in the way of colder temperatures. The eastern slopes of
the Front Range Mountains and foothills will likely see gusts in
the 50 to 60 mph range.

Monday will see a brief break in the precipitation over the
mountains as ridging and drier air moves overhead. Then Monday
evening through the rest of the week will experience faster zonal
flow pushing into the area while several upper disturbances bring
unsettled and cooler conditions to the area. Snow will increase
over the mountains Monday evening into Tuesday to possibly affect
travel. Looking further ahead, models are differing on details,
however it looks like the area will have the highest potential for
widespread precipitation Wednesday night through Friday morning,
and possibly into the weekend as well, if the ECMWF verifies. The
EC and GEM both want to separate the trough pattern into two
distinct troughs, while the GFS wants to keep it one lingering
deeper trough. Expect temperatures to be cooler than average for
the latter half of the week, however differences in models make
confidence in any snow level forecast to be low.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1018 AM MDT Sat Apr 22 2017

Light rain has ended across the Front Range airports, and stratus
deck is beginning to break. It will continue to lift and break
through the afternoon into a broken deck around 3000-4000 feet
AGL through 20Z, and should eventually scatter out 21Z-00Z. Light
east/southeast surface winds returning to normal south/southwest
02Z-06Z tonight.

&&

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

$$

UPDATE...Barjenbruch
SHORT TERM...Entrekin
LONG TERM...Kriederman
AVIATION...Barjenbruch



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