Posted on: October 21st, 2020

weather.gov
National Weather Service

Red Flag Warning
URGENT – FIRE WEATHER MESSAGE
National Weather Service Denver/Boulder CO
138 AM MDT Wed Oct 21 2020

…RED FLAG WARNING FOR THE MOUNTAIN VALLEYS THIS AFTERNOON AND
EVENING FOR LOW HUMIDITY AND GUSTY WINDS…
…RED FLAG WARNING FOR THE FRONT RANGE FOOTHILLS THIS AFTERNOON
AND TONIGHT FOR LOW HUMIDITY…GUSTY WINDS…AND POOR RECOVERY
OVERNIGHT…

.Winds will increase today ahead of a weather system that will
pass over Colorado on Thursday. It will also be a little warmer
and drier. As a result, Red Flag conditions are expected in the
mountain valleys and foothills this afternoon. Conditions will
improve in the valleys this evening, but the foothills will have
windy conditions continuing with poor humidity recovery. Overnight
maximum humidity in the foothills will be in the 20 to 30 percent
range while winds increase with gusts of up to 50 mph possible,
mainly in the higher foothills and wind prone lower foothill
locations. The foothills will see a shift to northeast winds with
cooler temperatures and higher humidities behind a cold front
Thursday morning. These winds may also gust up to 30 mph during
the day Thursday.

…RED FLAG WARNING REMAINS IN EFFECT FROM NOON TODAY TO 8 AM MDT
THURSDAY FOR WIND AND LOW RELATIVE HUMIDITY FOR THE NORTHERN
FOOTHILLS…

* Affected Area…Fire Weather Zone 215.

* Timing…From noon Wednesday to 8 AM MDT Thursday.

* Winds…West 15 to 30 mph with gusts up to 50 mph.

* Relative Humidity…As low as 15 percent.

* Impacts…Fires will start easily and spread rapidly.

PRECAUTIONARY/PREPAREDNESS ACTIONS…

A Red Flag Warning means that critical fire weather conditions
are either occurring now….or will shortly. A combination of
strong winds…low relative humidity…and warm temperatures can
contribute to extreme fire behavior.

&&

$$

Gimmestad

Air Quality Alert
COC013-123-001-031-059-035-005-014-069-212200-
Boulder-Weld-Adams-Denver-Jefferson-Douglas-Arapahoe-
Broomfield-Larimer-
910 AM MDT Wed Oct 21 2020

…ACTION DAY FOR PARTICULATES FROM 400 PM TUESDAY UNTIL 400 PM
WEDNESDAY…

The Colorado Department of Public Health and Environment has
issued the following…

WHAT…Action Day for Particulates.

WHERE…Douglas, Jefferson, Denver, western Arapahoe, western
Adams, Broomfield, Boulder, Larimer, and Weld Counties

WHEN…400 PM Tuesday October 20 to 400 PM Wednesday October 21

IMPACTS…Action Day for Particulates is now in effect for the
seven-county Denver-Boulder metropolitan area. Requests to limit
driving of non- ZEV vehicles (i.e., gas or diesel) are now in
effect until at least 4 PM Wednesday, October 21, 2020. Moderate
to heavy smoke can be expected Tuesday afternoon and evening for
locations in Larimer and Boulder counties near the Cameron Peak,
Calwood, and Lefthand Canyon wildfires, along with locations below
the fires in the Front Range Urban Corridor from Ft. Collins
southward to Longmont, Boulder, and Denver. Smoke levels will
likely fluctuate for these areas Tuesday night through Wednesday
afternoon, but the threat for periods of heavy smoke is expected
to continue. CDPHE requests that activities, such as driving non-
ZEV vehicles (i.e., gas or diesel), be reduced to lessen the
impacts on neighboring air quality. Additional air pollution in
this region may directly worsen air quality or contribute to
precursors which may also adversely affect air quality. For
Colorado air quality conditions, forecasts and advisories, visit:
https://www.colorado.gov/airquality/colorado_summary.aspx

HEALTH INFORMATION…If smoke is thick or becomes thick in your
neighborhood you may want to remain indoors. This is especially
true for those with heart disease, respiratory illnesses, the very
young, and the elderly. Consider limiting outdoor activity when
moderate to heavy smoke is present. Consider relocating
temporarily if smoke is present indoors and is making you ill. If
visibility is less than 5 miles in smoke in your neighborhood,
smoke has reached levels that are unhealthy.

$$

Hazardous Weather Outlook
Hazardous Weather Outlook
National Weather Service Denver/Boulder CO
609 AM MDT Wed Oct 21 2020

COZ030>051-221215-
Jackson County Below 9000 Feet-
West Jackson and West Grand Counties Above 9000 Feet-
Grand and Summit Counties Below 9000 Feet-
South and East Jackson/Larimer/North and Northeast Grand/
Northwest Boulder Counties Above 9000 Feet-
South and Southeast Grand/West Central and Southwest Boulder/
Gilpin/Clear Creek/Summit/North and West Park Counties Above
9000 Feet-Larimer and Boulder Counties Between 6000 and 9000 Feet-
Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear
Creek/Northeast Park Counties Below 9000 Feet-
Central and Southeast Park County-
Larimer County Below 6000 Feet/Northwest Weld County-
Boulder And Jefferson Counties Below 6000 Feet/West Broomfield
County-
North Douglas County Below 6000 Feet/Denver/West Adams and
Arapahoe Counties/East Broomfield County-
Elbert/Central and East Douglas Counties Above 6000 Feet-
Northeast Weld County-Central and South Weld County-Morgan County-
Central and East Adams and Arapahoe Counties-
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
Logan County-Washington County-Sedgwick County-Phillips County-
609 AM MDT Wed Oct 21 2020

…VERY HIGH FIRE DANGER IN THE MOUNTAIN VALLEYS AND FOOTHILLS…

This hazardous weather outlook is for northeast and north central
Colorado.

.DAY ONE…Today and Tonight

Winds will be stronger today in the mountains, with another day
of very high fire danger. Wind gusts of 30 to 40 mph will be
common this afternoon, and the higher mountains will have gusts
to 50 mph. The winds will diminish in the mountain valleys this
evening, but it will remain windy with low humidity in the
foothills overnight.

.DAYS TWO THROUGH SEVEN…Thursday through Tuesday

Warm, breezy, and dry conditions will persist over the mountains
and mountain valleys through Saturday. Meanwhile, a cold front
will bring colder temperatures and higher relative humidities to
the Front Range and eastern plains Thursday and continues into
Saturday.

A storm system is still on track to move across the Central
Rockies this weekend. This system will bring a good chance for
snow Saturday night and Sunday along with cold temperatures.

.SPOTTER INFORMATION STATEMENT…

Spotter activation will not be needed today and tonight.

$$

Gimmestad/Meier

U.S. Dept. of Commerce
NOAA National Weather Service
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Silver Spring, MD 20910
E-mail: w-nws.webmaster@nullnoaa.gov
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