979 
FXUS65 KBOU 071740
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1040 AM MST Sun Nov 7 2021

.UPDATE...
Issued at 1030 AM MST Sun Nov 7 2021

Clouds have eroded this morning and sunny skies will be the theme
for the rest of the day today. Temperatures have warmed into the
upper 60s already and we're on our way to another potential 
record high in Denver. Temperatures are maybe a degree cooler 
than this time yesterday, meaning we should have no problems 
getting back into the upper 70s. 

Elsewhere, very dry conditions are already starting to develop, 
with relative humidities below 15% across most of the plains and 
lower Foothills. Continued drying is likely through the afternoon,
with Red Flag conditions developing across South Park due to
the stronger winds forecast there. Elevated fire danger is
expected for the rest of the forecast area.

A few minor adjustments were made to the temperature, wind, and
dew point/humidity grids, but otherwise the forecast remains on 
track.

&&

.SHORT TERM...(Today and tonight)
Issued at 113 AM MST Sun Nov 7 2021

A dry southwesterly flow aloft will be over the region today
resulting in another round of unseasonably warm weather. Record
high temperatures are again possible. The high temperature in
Denver for this date in 78, so expect at least a tie today. The
fire danger will remain high across the region due to very low
relative humidity this afternoon, reference the fire weather
discussion below for those details. Overall, there should be less
wind across the plains, with stronger winds confined to the
elevated terrain. Dry again tonight, with a cold front expected to
bring some relief as it pushes into the northeast plains and urban
corridor Monday morning around 5 am. 

.LONG TERM...(Monday through Saturday)
Issued at 113 AM MST Sun Nov 7 2021

A weak cold front will push across the plains Monday morning,
resulting in cooler (but still at or slightly above normal)
temperatures for Monday. Highs should still be able to make it
into the upper 50s or lower 60s over the plains. Clouds should
gradually increase during the day, but the risk of any
precipitation appears quite limited. ECMWF seems a little more
aggressive with the moisture, but we're not seeing any significant
forcing so maybe just a couple light snow showers at best in the 
northern mountains and isolated sprinkles/very light rain showers
over the northeastern plains by evening. 

We'll then see some short wave ridging and drying for later 
Monday night and Tuesday. Temperatures will rebound a few degrees 
Tuesday, especially from Denver south/east with a little downslope
component off the Palmer Divide. 

For Tuesday night into Wednesday, there has been some change to
model solutions, which would lead to more snow accumulation in the
mountains. The ensembles are now pointing toward more available 
moisture streaming off the Pacific, with 700-500 mb specific 
humidity increasing to around 3 g/kg. In addition, it appears 
we'll be getting into the left exit region of the upper level jet 
Tuesday night into early Wednesday, which will lend itself to 
upward vertical motion. The orographic component will also be 
strengthening, with 30-40 knots of west/northwest flow impinging 
on the mountains. Thus, as long as the moisture and stability 
profile remain consistent over the next couple days, we could be 
looking at several inches of snow and blowing snow in the northern
Colorado mountains, and possible Winter Weather Advisories.

On the plains, we'll have a chance of rain showers starting
Tuesday night, possibly mixed with a little snow into Wednesday 
night. However, by then, we'll probably be settling into a more 
subsident and stronger downslope regime. In fact, we'll probably 
see some gusty downslope winds develop Wednesday afternoon already 
given the signal in the QG fields. Wednesday will likely end up 
being a colder and pretty windy day across the forecast area. 

Snow showers should linger in the high country Thursday, and then
probably end by Friday as long as the upper trough moves
sufficiently eastward. There is pretty decent agreement on the
ensembles that we'll be heading back to gradual ridging and
warming for next weekend, with a return of dry conditions. The
odds of measurable snow in Denver are quite low through at least
the middle of next week. That would put us in line for at least the
top 3 of the latest first measurable snowfalls. Those currently
sit at November 17th, 2016, November 19th, 1931, and November 21st,
1934.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1030 AM MST Sun Nov 7 2021

VFR conditions through the TAF period. Winds will shift to the
north and northeast this afternoon but will be fairly light.
Drainage winds are expected overnight. A cold front will shift
winds back to the north tomorrow morning with light
northeasterlies tomorrow afternoon. No ceiling or visibility
impacts are expected.

&&

.FIRE WEATHER...
Issued at 113 AM MST Sun Nov 7 2021

A Red Flag Warning is in effect for South Park this afternoon. Near-
critical to critical fire danger is expected again this afternoon
with well above normal temperatures. Daytime humidity values will
again drop into 10-15 percent range for the plains, mountain 
valleys and foothills. The winds look to be a little weaker across
much of our forecast area, but elevated fire danger is expected 
this afternoon over the higher terrain. Confidence is highest in 
South Park that the wind will be strong enough for Red Flag 
conditions. Similar conditions will be possible for the valleys of
Jackson and Grand counties, but with slightly less wind and 
shorter duration. 

It will be quite breezy in South Park and the far southern
foothills again on Monday, but humidity levels will be slightly
improved so critical fire thresholds will not be met. 

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 6 PM MST this evening for COZ214.

&&

$$

UPDATE...Hiris
SHORT TERM...Cooper
LONG TERM...Barjenbruch
AVIATION...Hiris
FIRE WEATHER...Cooper/Barjenbruch