Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 240920

Area Forecast Discussion
National Weather Service Denver/Boulder CO
320 AM MDT TUE MAY 24 2016

.SHORT TERM...(Today and tonight)
Issued at 320 AM MDT Tue May 24 2016

Southwest flow aloft will prevail around an upper level trough
over California. A weak short wave trough embedded in the flow
aloft and a surface low will move across the state today.
Southerly flow around the low will bring drier air to southern
Colorado while southeast to east winds farther north will
transport moisture into northeast Colorado. Expect an east/west
boundary/dry line to set up this afternoon. The southerly flow
will also likely cause a Denver Cyclone to form. As the airmass
moistens...low clouds are expected to spread across parts of
northeast Colorado early this morning. They may be slow to burn
off and thus lowered highs a few degrees, especially across
northern parts of northeast Colorado.

The HiRes models are in general agreement that convection will
initiate over/near the Denver metro area 2-3pm. Likely due to
convergence along the Denver Cyclone and the east/west boundary.
Storms will spread northeast through afternoon and evening hours.
Greatest threat for severe thunderstorms will be northeast of the
Denver area where CAPES will be 1000-2500 J/kg. Main threat will
be large hail. Damaging winds and a couple of tornadoes will also
be possible.

Drier air will spread across northeast Colorado overnight.
Convection is expected to exit the area by midnight and by
Wednesday morning mostly clear skies will prevail.

.LONG TERM...(Wednesday through Monday)
Issued at 320 AM MDT Tue May 24 2016

On Wednesday...the upper level trough will remain to the west with
a dry southwesterly flow aloft over north central and northeast
CO. The models show weak subsidence over the cwa through the day
...with the best low level moisture flushed out to the east into
western NE and northwestern KS. The models generate some QPF in
the aftn but it is mainly over the mountains. Wednesday night...
...a little surge is progged to push into the northeast corner of
CO. This boundary could act as a focus for nocturnal tstms around
06Z Wednesday night. Thursday through will be cooler
and wetter across the cwa. The models have the next system near
the Four Corners region by 18z Thursday then move into western
NE/KS by Friday evening. As a result...there appears to be a
prolonged period of light to moderate rainfall over the region. The
models all show moderate QG ascent over the cwa Thursday
aftn/evng...with decreasing QG ascent late Thursday night and
Friday as the trough starts to shift to the east of CO. Highest
pops will be Thursday night...but still a good chance of showers
especially from the Front Range Foothills eastward on Friday.
There is a marginal threat for severe thunderstorms closer to the
KS border on Thursday aftn. It will also be a little cooler and
this may help to minimize the threat of severe thunderstorms. Over
the weekend...a drier westerly flow aloft will be over the state
on Saturday. It will be warmer with enough moisture around to keep
a slight chance of aftn/evng thunderstorms both days. By Sunday...
another trough in the Pacific Northwest will produce a southwesterly
flow aloft over CO.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 320 AM MDT Tue May 24 2016

Southeast winds will increase low level moisture and is expected
to produce low clouds across eastern Colorado. Ceilings of 1000 to
3000 feet are expected at the Denver airports from 11 to 15z, low
clouds may linger through the late morning, until 18z. Scattered
thunderstorms are expected to form after 20z. The best chance for
thunderstorms in the Denver area will be 20-23Z. Wind gusts to 40
knots, hail, and heavy rain will be possible with the
thunderstorms. Drier air will move into the area after 00z and
bring mostly clear skies by 06z.


.BOU Watches/Warnings/Advisories...


LONG TERM...Cooper
AVIATION...Meier is the U.S. government's official web portal to all federal, state and local government web resources and services.