Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 170945
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
345 AM MDT Thu Aug 17 2017

.SHORT TERM...(Today and tonight)
Issued at 340 AM MDT Thu Aug 17 2017

Colorado will be under a moderate northwest flow aloft through
tonight. Water vapor imagery showing a disturbance in the flow
along with 60kt jet streak now over Idaho which will clip the far
northeast plains later today with some weak upward ascent.
Meanwhile there is another jet streak across southeast colorado
which is creating scattered showers and a few thunderstorms over
southern Lincoln county early this morning.

Overall moisture values are less today as integrated precipitable
water values from GPS are running .10-25 inches less than this
time yesterday. Best chance of storms today will be over
mountains, higher terrain areas and over far Eastern Colorado
where moisture and instability will be greatest. Surface trof over
the plains will create some convergence this afternoon over the
far plains with surface based CAPES of 1000-1500j/kg. Marginal
severe weather threat give instability and marginal shear profile.
Further west towards the Front range, much of the low level
moisture will mix out with CAPE values generally under 500j/kg
and the main threat will be gusty winds but only brief light rain.
Storms will diminish rapidly this evening with weak subsidence
and drying behind the trof.

.LONG TERM...(Friday through Wednesday)
Issued at 241 AM MDT Thu Aug 17 2017

On Fri the flow aloft will become more wly with a drier airmass
across the area.  However there will still be enough moisture for
isold-wdly sct aftn tstms over the higher terrain generally south of
I-70.  Elsewhere no tstms are expected.  Highs on Fri will be near
seasonal normals.

For the weekend the flow aloft will become more wsw on sat and then
swly on Sun.  Both the GFS and ECMWF shows a gradual increase in
subtropical moisture through the weekend. Thus will see a better chc
of sct storms over the higher terrain.  Outflow boundaries fm these
storms will probably trigger isold-wdly sct storms along the urban
corridor and over portions of the plains in the late aftn/early
evening hours.  As for highs readings across the plains will be
mostly in the upper 80s to lower 90s both days.

By early next week little change is expected as there will still be
an influx of subtropical moisture in weak flow aloft.  Thus will
continue to see a chc of aftn tstms over the higher terrain with a
slight chc of storms elsewhere.  Highs will continue in the upper
80s to lower 90s over nern CO on Mon.  On Tue there could be a wk
fnt affecting portions of the plains which may keep readings in the
80s.  For Wed current data still shows some subtropical moisture
affecting the area so expect sct storms over the higher terrain with
wdly sct activity over the plains.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 241 AM MDT Thu Aug 17 2017

Storm coverage will be isolated today with main threat of gusty
outflow winds but only brief rain. With low coverage will not
include in TAF. Southerly surface winds will shift west and
northwest from mid morning through the afternoon.

&&

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

$$

SHORT TERM...Entrekin
LONG TERM...RPK
AVIATION...Entrekin



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