Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 290340
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
940 PM MDT Wed Jun 28 2017

.UPDATE...
Issued at 940 PM MDT Wed Jun 28 2017

Low level moisture influx on the plains coupled with some jet-
related lift continues to regenerate storms over eastern Colorado.
Still some lift over the mountains as well but much drier air so
just a few weak showers there. Forecast is pretty much on track
so just some minor adjustments for current convective trends
focused more on the area east of Denver and less elsewhere.

&&

.SHORT TERM...(This evening through Thursday)
Issued at 334 PM MDT Wed Jun 28 2017

Isolated high based showers have been developing over the
foothills and to the east and southeast of Denver for the past
hour or so. Gusty winds and light rain have been the main products
of these showers. An upper level jet stream is forecast to move
over northern Colorado through this evening which will help
organize additional showers that are seen developing over
northwest Colorado this evening. Isolated showers should continue
moving off the foothills through the early evening.

Westerly flow aloft will continue over Colorado on Thursday as the
upper jet also lingers overhead. More showers and thunderstorms
are expected through the afternoon hours. Temperatures will be a
few degrees cooler Thursday after weak northerly flow at low
levels prevails overnight. Model soundings for Thursday afternoon
show CAPE values of 1000-1500 j/kg, meaning the atmosphere will be
a little more unstable than this afternoon. Isolated to scattered
showers will suffice.

.LONG TERM...(Thursday night through Wednesday)
Issued at 334 PM MDT Wed Jun 28 2017

Models show fairly strong zonal flow aloft, for this time of
year, over the CWA Thursday night. An upper trough moves across
Friday. Weak northerly flow aloft is progged Friday night followed
by upper ridging Saturday and Saturday night. There is some weak
upward QG vertical velocity Thursday night, then weak downward
motion is progged Friday through Saturday. The boundary layer
winds are progged to be upsloping Thursday night into Friday
evening before more normal diurnal trends kick in Friday overnight
through Saturday night. For moisture there is some progged
Thursday evening, then it dries out a bit more for Friday, and
more still for Saturday. Precipitable water amounts are progged
from a half to a little over one inch Thursday night. The values
are between 0.50 and 1.00 inch Friday, the 0.25 to 0.75 inch
Friday night through Saturday night. There is some CAPE around
Thursday evening, especially over the foothills and adjacent
plains. There is less CAPE around for late day Friday and late day
Saturday. There is limited measurable precipitation Thursday
night into Friday morning, then there is very little through
Saturday night. Best pops will be Thursday evening/night. Pops
will be less both late day Friday and late day Saturday. Will go
with 10-30% pops Thursday night into Friday morning. Ten to 20%
pops will suffice, mainly for the foothills, late day Friday,
then 10-20% pops, mainly for just South Park for late day
Saturday. Temperatures will be 2-5 C cooler on Friday for highs
compared to Thursday. Saturday`s highs will be 4-8 C warmer than
Friday. For the later days, Sunday through Wednesday, models have
a weak upper trough move across Colorado Sunday afternoon and
night. There is northwesterly flow aloft on Monday, then more
upper ridging Tuesday and Wednesday. Moisture is limited.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 940 PM MDT Wed Jun 28 2017

Scattered thunderstorms will continue east of Denver much of the
night, but the impact will likely be limited to approach gates and
east to southeast outflow winds through 08z. VFR conditions are
expected through Thursday. Isolated showers and thunderstorms are
expected again after 21z, with the most likely impact a few hours
of variable winds gusting as high as 40 knots.

&&

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

$$

UPDATE...Gimmestad
SHORT TERM...Dankers
LONG TERM...RJK
AVIATION...Gimmestad



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