National Weather Service Forecast Discussion

000
FXUS65 KBOU 191024
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
424 AM MDT Mon Aug 19 2019

.SHORT TERM...(Today and tonight)
Issued at 424 AM MDT Mon Aug 19 2019

Today`s forecast of near record highs is looking good. There is
some high cloudiness across the southern half of Colorado and this
may creep northward a bit as the day goes on. However, it`s fairly
thin and should be mainly south and east of Denver through midday,
so it shouldn`t have much impact on temperatures. Moisture near
the eastern border will likely remain capped, although there may
be one or two storms out there and with CAPEs of up to 1000 J/kg
if there is something it could be a strong storm. Further west
over the mountains there should be deep mixing but the air mass is
pretty dry, so isolated virga/sprinkles is about all that`s
expected. For tonight, there will be a bit more cloud cover so
another mild night is expected.  Forecast lows look about right.

.LONG TERM...(Tuesday through Sunday)
Issued at 424 AM MDT Mon Aug 19 2019

An upper level ridge will be be over Colorado on Tue with weak
southwest flow aloft.  At the sfc, a cool front will move into nern
CO during the aftn hours, with northeasterly low level flow
behind the front. Cross-sections show some influx of subtropical
moisture by aftn which may allow for widely sct high based tstms
over portions of the higher terrain.

Meanwhile, over nern CO, there are some major differences as to
where the best focus for tstm development will be late in the aftn
through the evening hours, as a weak disturbance moves across.
The ECMWF continues to focus activity over the far nern plains
while the GFS has convection firing closer to the front range. The
hi res solutions are closer to the ECMWF. At this point have
rather low confidence as to where the best chance of convection
will be. Naturally with weak flow aloft and favorable theta-e
values, in the 850-700 mb layer, advecting into nern CO, there
would be the potential for slow moving tstms that would produce
very heavy rainfall in some areas. Finally as far as highs, it
appears it will be another hot day across most of nern CO with
readings in the 90`s in advance of the cool front.

On Wed, the upper level level ridge will flatten some, however, the
flow aloft will remain weak westerly.  Meanwhile easterly low level
flow will be in place over nern CO behind the front.  Cross-sections
still show some influx of subtropical moisture and with the approach
of a weak upper level jet max should see a good chc of tstms over
the higher terrain and along the front range. Once again, with
weak mid level flow, storms will be slow moving and will produce
heavy rain in some areas, especially from the foothills across
the front range. Highs on Wed will drop into the upper 70s to mid
80s over nern CO.

By Thu, the flow aloft aloft will remain westerly as the low
level flow becomes southeasterly across the plains. There should
still be enough moisture for a chc of tstms over the higher
terrain and across the plains. Highs will be near seasonal
normals.

For Fri, the flow aloft will remain westerly as a weak system
moves across the nrn Rockies. In addition, a weak front may move
across nern CO during the day. There will be some decrease in
moisture, however, with decent MLCAPE over the plains will keep in
a slight chc of storms along the front. As for highs readings
will remain near seasonal levels.

Looking ahead to the weekend, dry northwest flow aloft will be in
place as the upper level ridge shifts westward.  Overall it looks
mainly dry across most of the area.  The only exception might be
over the far nern CO, where decent cape will exist in the
vicinity of the upper level jet. Thus this could lead a few late
afternoon or evening tstms. Temperatures will be above normal both
days.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 424 AM MDT Mon Aug 19 2019

VFR through tonight with light winds.

&&

.FIRE WEATHER...
Issued at 424 AM MDT Mon Aug 19 2019

Near record warmth and very dry low level air will keep fire
danger high to very high across the area. It will be breezy this
afternoon over the mountains, and the lower elevations of Jackson
and Grand counties and the higher foothills of Larimer and Boulder
counties will be near Red Flag criteria for a few hours this
afternoon.

Elevated fire danger will continue on Tuesday, over the higher
terrain and along the front range, due to above normal
temperatures and low humidity values. However, winds will remain
generally light.

&&

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

$$

SHORT TERM...Gimmestad
LONG TERM...RPK
AVIATION...Gimmestad
FIRE WEATHER...Gimmestad/RPK

NWS BOU Office Area Forecast Discussion