028
FXUS65 KBOU 300619
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1219 AM MDT Mon Sep 30 2024

.KEY MESSAGES...

- Warm and dry for the foreseeable future with very limited
  chances of precipitation.

- Front to bring slightly cooler conditions Monday into Tuesday.

- Periods of elevated to critical fire weather conditions expected
  through the week.

&&

.UPDATE...
Issued at 850 PM MDT Sun Sep 29 2024

The alpine convective cloudiness continues to decrease this
evening.  There is isolated convection over the west slope still.
Temperatures are in the mid and upper 60s F over the plains.
There are fairly decent drainage winds going over the plains as
well. Will make a few minor grid adjustments to winds, sky and
temperatures.

&&

.SHORT TERM /Through Monday/...
Issued at 1247 PM MDT Sun Sep 29 2024

Days like today go to show why the weather enterprise favors
meteorological seasons as opposed to astronomical ones - another
summerlike day across the board, with the thermometer climbing into
the low 90`s across part of the Denver metro and plains. As of 130
PM, Denver had reached 91F, just one degree shy of the daily record.
Our morning low temperature of 61F may also tie the daily record for
highest minimum temperature, assuming we don`t drop below that by
midnight (unlikely).

As expected, scattered cumulus is dotting the higher terrain, with
localized virga apparent on radar and webcams mainly encircling Park
and Clear Creek Counties. Measurable precipitation is not
anticipated given the very dry low levels.

A modest cold front remains on tap for tomorrow, descending north to
south after sunrise and reaching the Denver metro shortly before
noon based on model consensus. It will be just early enough to
prevent another unseasonably warm day, with highs in the 70`s for
the mountain valleys and northern plains, and low 80`s for the
southern plains and urban corridor owing to the front`s later
arrival. Breezy north/northeast winds will follow the frontal
passage with gusts 20-30 mph. Speeds should relax slightly later
in the day when humidity is lowest, thus limiting the fire danger
severity, but elevated fire weather conditions will be in place
nonetheless. There`s a slim (15%) chance of squeezing out a light
sprinkle in the southern foothills/mountains, but most areas will
remain mostly sunny.

&&

.LONG TERM /Monday night through Sunday/...
Issued at 1247 PM MDT Sun Sep 29 2024

Monday night and Tuesday, an upper level trough of low pressure will
be over the Upper Midwest with upper level high pressure stretching
from off the California coast into Texas. Colorado will be in
between these systems under the influence of a dry west-northwesterly
flow aloft. This pattern will dominate the forecast area through
Thursday with a large upper level ridge of high pressure building
over the Rocky Mountain Region by late in the work week. These two
weather patterns should result in unseasonably warm temperatures
and dry weather across North Central and Northeastern Colorado
through the forecast period.

Occasional upper level shortwaves moving across the Northern
Rockies may push a couple of dry cold fronts across Northeastern
Colorado. These fronts should lower temperatures by 5 to 10
degrees Thursday, Friday and again on Sunday. Despite the cool
down, max temperatures are expected to be 8 to 18 degrees above
normal through this period with max temperatures approaching
record values on some days. Wednesday and Saturday look to be the
warmest days of the week due to some downsloping flow and
prefrontal warming. Max temperatures are forecasted to climb into
the upper 80s both days with the potential for some new max
temperature records to be set.

&&

.AVIATION /06Z TAFS through 06Z Tuesday/...
Issued at 1217 AM MDT Mon Sep 30 2024

VFR through Monday. A cold front will move through the Denver area
around 16z-17z with northeast winds gusting to 25 knots behind it
through 20-22z, then more easterly winds at 10-15 knots through
early evening.

&&

.FIRE WEATHER...
Issued at 1247 PM MDT Sun Sep 29 2024

Widespread elevated to locally near-critical fire weather
conditions expected Monday as a cold front brings a surge of
breezier north/northeast winds, which will produce gusts 20-30
mph. Winds in most areas will likely peak before early afternoon
and thus not coincident with the lowest humidity (13-19%),
limiting the severity of fire weather concerns compared to future
days.

Near critical to critical fire weather conditions are expected
across North Park and Park Range Tuesday afternoon and evening due
to very low relative humidity (11-15%) and gusty westerly winds
to 28 mph. Therefore, have issued a fire weather watch from Noon
to 7 pm Tuesday for zones 211 and 217. On Wednesday the westerly
winds are expected to increase somewhat across the high country
and spread eastward into the Cheyenne Ridge with continued very
low relative humidity. As a result, the fire weather threat may
worsen and expand across the high country in areas below 9000 feet
and east across the Cheyenne Ridge. Conditions are expected to
improve Thursday and Friday due to higher humidity and lighter
winds. Fire weather concerns may return by Saturday due to
strengthening westerly winds and lowering humidity.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Tuesday afternoon through Tuesday
evening for COZ211-217.

&&

$$

UPDATE.........RJK
SHORT TERM.....Rodriguez
LONG TERM......JK
AVIATION...Gimmestad
FIRE WEATHER...Rodriguez/JK