615 
FXUS65 KBOU 062020
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
220 PM MDT Mon Sep 6 2021

.SHORT TERM...(This evening through Tuesday)
Issued at 220 PM MDT Mon Sep 6 2021

The strong upper level high will remain over the Great Basin and 
only shift slightly eastward through Tuesday. Weak northwest flow 
around the high will continue to bring warm and dry conditions to 
the Central Rockies. It will be a cool night in the low lying 
areas again due to the dry airmass and light winds. An upper level
trough will pass well north of Colorado and over the Northern 
Plains. A weak cold front associated with this system will push 
south through Colorado tonight and bring slightly cooler 
temperatures for Tuesday. Highs across northeast Colorado will be 
about 4-7F cooler than today. This will put highs in the mid to 
upper 80s. Looking at satellite and the HRRR model, appears smoke 
will increase over the region tonight and Tuesday. This may 
limited afternoon heating by a couple of degrees.

.LONG TERM...(Tuesday night through Monday)
Issued at 220 PM MDT Mon Sep 6 2021

Hot and dry is the main headline for the period. There is good 
consensus among ensemble and deterministic guidance that an upper 
level ridge slowly progresses eastward over the region through 
the week. This will promote unseasonably warm temperatures and dry
conditions. The mentioned conditions will increase fire weather 
concerns; however, winds may likely keep us below criteria for 
red flag headlines. 

An upper level ridge will dominate the pattern for much of this 
week. Weds., the main axis remains to the west and gradually moves 
eastward. This will support below normal moisture and unseasonably 
warm temperatures. Temperatures trend warmer into Thurs. marked 
by a bump in 700mb temperatures. There is increasing potential for
the Denver area to break records Thurs/Fri (94/93) with highs 
forecasted to be in the mid to upper 90s. Slightly cooler 
temperatures expected for the weekend in the low 90s at the lower 
elevations and 70s over the higher elevations. In regards to
moisture this week, relative humidities drop into the teens in 
many areas through Fri. increasing fire weather concerns. Weaker 
winds will help keep conditions below red flag criteria. Ensemble 
guidance shows the jet max to stay north of the region which will 
limit high wind potential. Fri/Sat afternoon may warrant 
monitoring as ensemble guidance has members with gusts above 20 
mph over parts of North Park, but confidence is not high at this 
time.

Deterministic guidance continues to show potential for the passage 
of a few embedded shortwave troughs in the NW flow aloft this 
weekend. Details still remain uncertain with differing solutions, 
but general consensus exhibits them to be fairly weak. A signal for 
gradual moisture return combined with weak QG forcing for ascent 
will bring back chances for afternoon showers and thunderstorms 
Sat/Sun over the higher terrain. Limited instability and average 
precipitable water amounts should keep coverage scattered. May see 
increased winds over the higher terrain Monday with increased 
WNW flow aloft.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 220 PM MDT Mon Sep 6 2021

VFR conditions will prevail through Tuesday with little to no 
clouds. Winds will remain light through the afternoon and trend a 
northerly direction. During the early evening hours winds will 
gradually go west and then transition to drainage by midnight. 
Smoke is expected to slowly increase over the next 24 hours. By 
Tuesday morning, slantwise visibility may become reduced and 
impact arrivals. 

&&

.HYDROLOGY...
Issued at 220 PM MDT Mon Sep 6 2021

Hot and dry conditions will limit flash flood potential for much
of the week. Moisture gradually increases over the weekend
resulting in scattered showers and thunderstorms over the higher
terrain. Instability appears to be limited and precipitable water
values are closer to average which will keep flash flood potential
low. 

&&

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

$$

SHORT TERM...Meier
LONG TERM...Mensch
AVIATION...Meier
HYDROLOGY...Mensch