Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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246
FXUS65 KBOU 301653
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1053 AM MDT MON MAY 30 2016

.UPDATE...
Issued at 1053 AM MDT Mon May 30 2016

No need for any changes to the forecast at this time. Satellite
imagery shows a short wave over northwest Colorado at the present
time that will be moving out over the northeast plains during the
afternoon hours. We should start seeing showers develop over the
mountains in the next hour or so. Model soundings are showing
around 1000-2000 j/kg of CAPE this afternoon, with higher values
further to the east. With the higher CAPE values on the far
eastern plains, the strongest storms will develop out there, later
in the evening.

&&

.SHORT TERM...(Today and tonight)
Issued at 403 AM MDT Mon May 30 2016

The forecast area is in between weak short waves at the present
time with mostly clear skies in place. However, the next short
wave moving across Utah will arrive by this afternoon with
increasing clouds and convection. Q-G fields show only slight if
any lift, and most of that skirting by to our North and South.
Nonetheless, satellite data would suggest at least an increase in
mid level moisture so the higher PoPs in the forecast for today
seem reasonable. Should see scattered shower and thunderstorm
coverage develop first in the mountains by late morning and then
spread/develop east across the plains shortly after noon.

Low level moisture appears rather thin early this morning, so
CAPE will likely erode along the Front Range to around 500 J/kg,
while farther east on the plains toward Sterling, Akron, and Limon
CAPE should hold closer to 1000 to perhaps 1500 J/kg keeping
potential for one or two severe storms there. SPC outlook seems to
depict this potential well. Strong gusty winds will be the main
threat due to relatively high based storms and increasing mid
level wind field, along with isolated large hail reports possible
in areas of higher CAPE.

For tonight, cold front will push south across the plains late
this evening. Behind that, shallow and moist upslope regime should
result in areas of stratus along with patchy drizzle or light showers,
and areas of fog where stratus deck runs into the ground - namely
the foothills.

.LONG TERM...(Tuesday through Sunday)
Issued at 403 AM MDT Mon May 30 2016

Upper level trough dropping in from the northwest and moist
post-frontal anticyclonic upslope flow on the plains promises a
cooler...cloudy and wet day Tuesday esply for areas east of the
Continental Divide. Upslope flow on the plains is progged to
be relatively shallow during the day...generally no more than
7000-8000 ft at its greatest depth Tuesday morning. Models show
this shallow upslope flow becoming nearly saturated up against
the Front Range during the morning hours. Without much forcing
aloft or instability...the heavy deck of low clouds pushed up
against the Front Range will probably produce not much more than
light rain and/or drizzle...and even areas of fog during the
morning hours. The fog should be concentrated in the foothills
where visibilities may lower below a mile at times during the
morning. Farther out on the plains the low cloud cover will not as
thick nor as extensive and the chance of precip not as great. High
country areas generally west of the Continental Divide should see
less cloud cover and warmer temperatures on Tuesday...and with
more sunshine a slight chance of t-storms by afternoon. Highs on
the plains expected to be only in the 60s.

Tuesday night and Wednesday...the upper trough shifts east
by nighttime placing the forecast area under northwest flow
aloft. Models show a weak mid-level disturbance embedded in this
flow passing over the CWA during the evening hours. Could see some
enhancement in shower activity including a few t-storms as a
result. After midnight should see drier air spreading down from
Wyoming resulting in gradual clearing from north-to-south by early
Wednesday morning. During the day Wednesday...low-level flow on
the plains turns sely as per models which could lead to isolated
shower/t-storm development over and near the Front Range and
across South Park by early to mid-afternoon. Temps on Wednesday
should be a few degs warmer with the return of sunshine.

Thursday through Sunday...the upper ridge building over the Great
Plains will slowly migrate eastward during the period bringing
warmer temperatures and drier air to the forecast area. The chance
of t-storms should significantly drop off as daytime temperatures
climb several degs above average. Temperature guidance gives highs
in the low to mid-80s for the plains. Can`t see any reason to go
against that.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1053 AM MDT Mon May 30 2016

Will hold onto the forecast of a round of thunderstorms moving
across the Denver area late this afternoon. With a weak upper
level disturbance moving across the area this afternoon, it will
be difficult for thunderstorms to not develop. The storms will be
high-based after moving off the foothills. Gusty winds and brief
rain will be the main threats at the airports.

&&

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

$$

UPDATE...Dankers
SHORT TERM...Barjenbruch
LONG TERM...Baker
AVIATION...Dankers



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