Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 301622
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1022 AM MDT SAT JUL 30 2016

.UPDATE...
Issued at 1021 AM MDT Sat Jul 30 2016

Forecast is on track with drier air aloft working in from the
northwest. Precipitable water (PW) is down nearly a quarter inch
from those observed yesterday per the latest integrated PW from
GPS. It will be hard to spark off any convection with a weakly
subsident and capped atmosphere. However, there is a batch of
moisture on the western slope of Colorado and some of this will
begin to spill eastward late this afternoon and tonight, so at
least isolated late day convection is still anticipated over the
mountains and possibly into the Front Range toward evening. On the
northeast plains, airmass is still more capped so any chance of
stronger storms would likely have to wait until storms or outflow
boundaries arrive from the north/northwest.

&&

.SHORT TERM...(Today and tonight)
Issued at 422 AM MDT Sat Jul 30 2016

Last night`s shortwave is shifting east with the last of the
showers moving out of Colorado around sunrise. The jet will have
shifted further east which should mean less impact from any small
ripples aloft today. A pocket of slightly drier and warmer air
aloft will be moving over northeastern Colorado, though the
persistent easterly low level flow will continue on the plains and
slow the drying at the surface. Between the little bit of warming
and mixing out of the low level moisture, expect pretty good
capping over and just east of the mountains. It could still get
warm enough to pop some late day low CAPE storms, but they should
be isolated and weak. Still a threat of some wetter storms
somewhere out on the plains, though in general I expect there to
be some decreased moisture and mainly capped air out there as
well. By the eastern border dew points could still wind up in the
50s with a weakly capped atmosphere that could be disrupted by
outflows from elsewhere, little ripples in the jet, or the
development of the nocturnal boundary layer jet. Storms in the
richer moisture could still be severe. CAPEs should be under 500
J/kg in and near the mountains, with 1000-2000 J/kg in the richer
moisture over the eastern part of the plains. Large hail still the
main threat, with some wind threat, and still pretty linear shear
so not much of a tornado threat.

Less clouds and the slight warming will translate into warmer
highs today. Forecast temps today and tonight are close to
guidance and look good.

.LONG TERM...(Sunday through Friday)
Issued at 422 AM MDT Sat Jul 30 2016

A flat upper ridge with zonal flow aloft is expected for the CWA
Sunday through Monday night. There is nothing for synoptic scale
energy on the QG Omega fields through the period. The boundary
layer winds will adhere to normal diurnal patterns. Moisture does
increase for the CWA by Sunday afternoon, with plenty around for
late day Monday too. By Sunday evening, precipitable water values
are in the 0.75 to 1.40 inch range from west to east across the
CWA. These numbers continue on Monday. For CAPE, it is fairly
high over the western CWA and far eastern plains late day Sunday.
There is less late day Monday. The QPF fields have fair amounts
of measurable rainfall late day Sunday, with a bit less, and more
so over the high country on Monday afternoon and evening. Will go
with 20-50% pops for late day Sunday, the highest in the mountains,
then 10-40%s on Monday, with the highest over the mountains. For
temperatures, Sunday`s highs are 0-2 C cooler than today`s.
Monday`s highs are 0-2 C warmer than Sunday`s. For the later days,
Tuesday through Friday, models show the upper ridge moving slowly
eastward with the mid and upper level moisture to increase all
four days. Thursday and Friday will be a bit cooler with all the
cloudiness.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1021 AM MDT Sat Jul 30 2016

VFR conditions will persist through Sunday morning.
North/northeast winds will become more easterly through 21Z-00Z
and then southeast to southerly thereafter, with speeds around 10
knots. The chance of thunderstorms is quite low, but still enough
mid level moisture coming over late in the day to provide a low
10-20% threat in the 00Z-04Z time frame.

&&

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

$$

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



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