Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 232105
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
305 PM MDT MON MAY 23 2016

.SHORT TERM...(This evening through Tuesday)
Issued at 305 PM MDT Mon May 23 2016

A jet max that pushed into southwestern Colorado earlier today
continues to push northeast, firing off convection over the
forecast area this afternoon. A shortwave ridge will be pushing
overhead tonight, however convection will spread northeast for
the rest of the afternoon and evening as a theta-e ridge advects
into the area from the south. The chance of showers and
thunderstorms will mainly confine itself overnight over the far
northeastern corner of the state. Skies will be clearing overnight
with winds becoming light, but at this time am not expecting any
fog to form. Minimum temperatures will be right around average
for this time of year.

More thunderstorms are expected Tuesday as a fast moving shortwave
ejected from an upper trough over California pushes over the area.
At the same time, a surface low should push into central Colorado,
with southeasterly surface winds helping to advect in higher
theta-e values. CAPE values between 1000-3300 J/kg are progged,
with the highest values over the far northern to northeastern
plains. Shear and instability is enough to prompt SPC to cover the
northeastern plains with an Enhanced Risk of severe storms. Large
hail and strong damaging winds are likely from the stronger
storms, but cannot rule out a tornado forming with good turning in
the winds from the surface upwards. Temperatures will warm about 5
to 10 degrees over todays readings.

.LONG TERM...(Tuesday night through Monday)
Issued at 305 PM MDT Mon May 23 2016

Models continue to indicate the passage of a couple of weak mid-
level instability axes/shortwave troughs over the forecast area
during the afternoon and evening hours Tuesday and Wednesday. The
stronger of these disturbances appears to pass over the area late
on Tuesday impacting mainly the northeast corner of the CWA
during the evening. Could see t-storms forming along a wind
shift/dry line which slowly translates northeast with the
shortwave during the evening. Best sfc based capes and instability
east of this boundary where gusty sely sfc winds continue to
advect in lower 60s wetbulb temps. A few storms may produce hail...
stg gusty winds and brief moderate to heavy rainfall rates. Cannot
rule out a severe storm east of a Briggsdale-to-Akron line. The
late Wednesday disturbance being carried along by strengthening
swly flow aloft appears weaker and not as moist. Yet may still see
isolated to widely scattered showers and t-storms produce gusty
winds and light to moderate rainfall over and along the Front
Range during the late afternoon and evening hours.

During the Thursday-Friday time period...the poorly organized long
wave upper trough over the Great Basin is still progged to migrate
eastward across the Rocky Mountain region during this period.
Models now in better agreement as they all show this open wave
trough bringing cooler air and a decent amount of moisture to the
state. Should see an increase in shower and t-storm coverage
both days. Thursday afternoon and evening appears to be the
optimum time for shower and t-storm development along and east of
the Front Range with the upper low passing to south and a moist post-
frontal low-level upslope flow on the plains. CAPES off interactive
soundings not terribly great due largely to cooler temps and
increasing cloud cover. However cannot rule out a couple of t-storms
producing locally heavy rainfall and hail. By Friday...models
show the CWA on the back side of the upper trough...but a weak
upr air disturbance swinging out of the nrn Colorado mtns and srn
Wyoming during the afternoon could generate additional showers and
perhaps a few t-storms. Although their intensity should not be
not as great as the day before. Temps Thursday and Friday expected
to drop 10 deg f or so from those on Wednesday.

Saturday through Monday...trough moves east and washes out over
the northern Great Basins placing the fcst area under a gentle
near zonal flow aloft on Saturday. Sunday and Monday the area
comes under the influence of a warmer south-southwesterly flow
with just a slight chance of heat driven afternoon and evening
t-storms each day.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 305 PM MDT Mon May 23 2016

VFR conditions are expected through Tuesday afternoon. Scattered
thunderstorms across the Denver area airports will last through
about 00z before the main activity pushes east over the plains.
Wind gusts to 30 knots and brief heavy rain are possible with the
storms over the urban corridor...with stronger winds and small
hail possible over the eastern plains. Easterly winds at 15 to 25
knots will become variable with the convection, then trend
northeasterly early this evening before trending toward light drainage
tonight. At this time, no widespread fog is expected, however
there could be some patchy areas along the South Platte River
valley. More convective activity is expected tomorrow, especially
over the far northeastern plains where strong winds and hail are
expected.

&&

.BOU Watches/Warnings/Advisories...
None.
&&

$$

SHORT TERM...Kriederman
LONG TERM...Baker
AVIATION...Kriederman


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