Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 170321

Area Forecast Discussion
National Weather Service Denver/Boulder CO
921 PM MDT Wed Aug 16 2017

Issued at 920 PM MDT Wed Aug 16 2017

Showers diminishing a little earlier than forecast. Only minor
changes to cloud cover and ending the showers a couple hours


.SHORT TERM...(This evening through Thursday)
Issued at 110 PM MDT Wed Aug 16 2017

The flow aloft will remain northwesterly tonight. Strongest mid
level qg descent will occur around 00z this evening. Best lift and
instability across the northeast plains will be this aftn, with
the airmass stabilizing fairly quickly this evening. CAPES across
the region best through mid afternoon, then they drop off as drier
airmass mixes in from the northwest. On Thursday, the flow aloft
will remain northwesterly. Mid level subsidence will continue in
the morning. Weak qg ascent will occur in the afternoon as short
wave trough embedded in the flow aloft brushes across the cwa in
the afternoon. CAPES Thursday aftn will range from around 400 j/kg
at Denver to 1000 j/kg along the eastern border. Timing of deep
convection will be linked to the passage of this system which
appears to be during the aftn. Should see improving conditions
behind that trough axis. Warmer on Thursday with highs back in
the mid 80s.

.LONG TERM...(Thursday night through Wednesday)
Issued at 110 PM MDT Wed Aug 16 2017

Upper level NW flow returns with the ridge building over the West
coast. A surface low pressure will build in Thursday night into
Friday morning that will increase westerly flow over the
Foothills. This will help to stabilize and dry the lower levels
and end storms early. Friday will see a 1-2 C increase at 700 mb
temps with lower 90s possible. Conditions will be dry with drier
flow moving in from the NW in the mid levels. Some isolated
orographic storms may be possible over the higher terrain by the
late afternoon hours but elsewhere QG subsidence will help to
detour storm development.

For the weekend upper flow will turn more SW and allow for some
waves to move through. Moisture will move up from the south and
increase instability over the plains. This will bring another
round of showers and thunderstorms to the region. Highs will
continue to be in the upper 80s to lower 90s.

Monday upper flow will turn more zonal. QG fields show subsidence
over the region with some drier air moving over the region keeping
storms weak and isolated to the higher terrain. As for sky cover
current GFS models showing some drier air in the mid levels with
the possibility of just some upper scattered clouds for the
eclipse. Could be partly cloudy in the morning then increase in
coverage later in the evening. This could change however as
models update between now and Monday. Temperatures for the start
of the week will start to decrease slightly and become closer to
seasonal normals with increased chances of afternoon convection
through Wednesday.


.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 920 PM MDT Wed Aug 16 2017

VFR conditions through Thursday. Isolated storms expected Thursday
afternoon with little or no impact to the Denver area terminals.




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