Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 160255
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
855 PM MDT Wed Aug 15 2018

.UPDATE...
Issued at 850 PM MDT Wed Aug 15 2018

Last of the t-storms in Lincoln County have moved out and will
likely be the last of the storminess tonight. Earlier storms along
the Douglas/Elbert/El Paso County line generated gusty outflow
which has spread northward across the Denver Metro Area and points
to the east-southeast of the metro area. Wind gusts south of this
boundary generally in the 12-22kt range. Have also noticed a push
of slightly more humid northeasterly winds into northeast Colorado
in the past couple of hours, the product of strong/severe
supercells that blew up overwest-central Nebraska late this
afternoon. Not sure if the southerlies will wash out this upslope
flow, or if the northeasterlies will dominate with a reinforcing
shot of rain cooled air later tonight. At any rates speeds
will be on the light side and chance of fog should be low and
confined to the far northeast corner of the CWA late. Otherwise,
rest of the forecast remains on track.


&&

.SHORT TERM...(This evening through Thursday)
Issued at 645 PM MDT Wed Aug 15 2018

Updated evening PoP and weather grids for the t-storm taking aim
on sern corner of the forecast area. The t-storm in El Paso
County has had a history of producing 0.75 inch diameter hail and
heavy rainfall. Could see nearly similar weather conditions as
this storm tracks southeast across Elbert and lincoln counties
during the next 1-2 hours. Also added a bit more sky cover this
evening acrs the southwest one-half of the CWA to account for the
influx of mid and high clouds spreading up from the southwest.
Not seeing much if any precip from this rather high cloud cover,
and don`t expect to see any overnight. Otherwise, rest of the
forecast appears to be on track. Oh, forgot to mention, smoke
eminating from the Silver Creek wildfire in northwest Grand County
has reached the Front Range. Could see a modest reduction in
ground level visibility overnight due to this new batch of smoke.
If nothing else, this evening`s sunset will be colorful.


.LONG TERM...(Thursday night through Wednesday)
Issued at 319 PM MDT Wed Aug 15 2018

Showers and storms over the high terrain and over the Palmer
Divide will be weakening Thursday night. Northeastern plains
should still be under a stable cap so not expecting activity out
that way. Easterly winds from the surface high pressure over the
Great Plains will advect in higher dewpoints for areas of fog to
likely develop after midnight across the eastern plains.

On Friday, a weak shortwave will move over the plains to take
advantage of the increase in moisture over the northeastern
plains. Expect the normal diurnal cycle of thunderstorms starting
over the high terrain, then pushing out over the plains and
lasting over the eastern plains through the evening.

On Saturday, a much larger and stronger upper trough will move
from the Northern Rockies and into the Northern Great Plains. MLCAPE
values will likely be up near 2000 J/kg or more along and east of
a line from Sterling down to the Palmer Divide. PW values of
1.1-1.4 inches are progged for that area, likely at or above the
90th percentile for the date. Therefore there will be a good
chance for stronger storms with some reaching severe criteria.
Storms will take a while to diminish overnight, and may last into
the morning over the far eastern plains.

Sunday will be cooler in the post trough and frontal airmass, with
strong northerly winds pushing over the area. The airmass should
dry out quite quickly with almost no precip expected in the stable
airmass.

Yet another shortwave diving down along the Great Plains will
bring back diurnal thunderstorms across the area Monday, then
high pressure will build back over the southwestern US. However
moisture will be trapped under this ridge, so continue to expect
diurnal storms each afternoon and evening for Tuesday and
Wednesday with temperatures starting to warm again.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 850 PM MDT Wed Aug 15 2018

Hazy VFR conditions on tap tonight with lingering wildfire smoke
in the area. Southerly winds of 7-15kts this evening may briefly
become northeasterly around 06z with a push of slightly cooler
and more humid air originating from t-storms up in Nebraska
earlier this afternoon. Then look for a gradual shift to a light
west-northwest wind towards sunrise under a clear to partly
cloudy sky.


&&

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

$$

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


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