Alert archive / Colorado / Red Flag Warnings in 2025

Red Flag Warning 6, NWS Denver/Boulder, CO

March 17, 202515 counties in Colorado

NWS Denver/Boulder, CO issued this red flag warning at Mar 17, 2025, 7:00 PM MDT for 15 counties in Colorado. It took effect at Mar 18, 2025, 10:00 AM MDT. It was in force for 9 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Mar 17, 2025, 7:00 PM MDT (01:00 UTC)
In effect from
Mar 18, 2025, 10:00 AM MDT
Expired
Mar 18, 2025, 7:00 PM MDT
In force
9 hr
Issued by
NWS Denver/Boulder, CO

Counties Adams County, CO, Arapahoe County, CO, Boulder County, CO, Broomfield County, CO, Clear Creek County, CO, Denver County, CO, Douglas County, CO, Elbert County, CO, Gilpin County, CO, Jefferson County, CO, Lincoln County, CO, Morgan County, CO, Park County, CO, Washington County, CO, Weld County, CO

The radar

The Denver radar (KFTG), 12 km from the middle of the area, began a volume at 01:02 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

N. Platte/Lee Bi, NE (KLBF), launched 00:00Z, 1.0 hours before the alert went out and 378 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, N. Platte/Lee Bi, NE at 00:00Z on 2025-03-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, N. Platte/Lee Bi, NE at 00:00Z on 2025-03-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 127 square meters per square second.1939587897117136Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3239 m above ground
0-6 km bulk shear
58 kt
0-1 km storm-relative helicity
127 m²/s²
0-3 km storm-relative helicity
142 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this red flag warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Denver/Boulder, CO wrote its last area forecast discussion before this red flag warning went out at Mar 17, 4:12 PM MDT, 2 hours 48 minutes earlier.

Area forecast discussion, Mar 17, 4:12 PM MDT, 2 hours 48 minutes before
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Hazardous weather outlook, Mar 17, 11:09 AM MDT, 7 hours 51 minutes before
Hazardous Weather Outlook
National Weather Service Denver/Boulder CO
1109 AM MDT Mon Mar 17 2025

COZ030>051-181715-
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-
1109 AM MDT Mon Mar 17 2025

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

.DAY ONE...This Afternoon and Tonight

Warm, dry, and windy conditions will continue across the forecast
area today. Rad Flag warnings are in effect from 11 AM MDT this
morning through 7 PM MDT this evening for all of the plains, the
southern Front Range Foothills and South Park. Winds gusts will
get up to 60 mph this afternoon over the mountain ridging and
windiest foothills locations. Gusts up to 40 mph are possible over
the rest of the forecast area.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Another storm system will bring snow to the mountains by Tuesday
morning, with rain and snow spreading across the plains Tuesday
afternoon and changing to snow by evening. Strong winds gusting up
to 55 mph are also expected Tuesday night, and some travel
impacts from the snow and wind are likely over the mountain passes
and possible in the foothills near Denver, and in the areas just
south and southeast of Denver. While heavy snow is not expected on
the plains, a combination of light snow and blowing snow is
likely Tuesday evening.

Additional weather systems are expected to bring light to moderate
snow in the mountains and a chance of rain or snow at lower
elevations Thursday night into Friday and again over the weekend.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed today or tonight.

The office that day

Everything else NWS Denver/Boulder, CO issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 18, 3:09 AM MDTHigh Wind WarningBOUElbert, Lincoln, Phillips, Sedgwick, Washington33 hr
Mar 18, 2:12 PM MDTBlizzard WarningBOUArapahoe, Douglas, Elbert, Lincoln, Washington15 hr
Mar 18, 3:58 PM MDTBlowing Dust AdvisoryBOUElbert, Lincoln6 hr

Nearby

Red Flag Warnings in Colorado, 2025Every red flag warning in 2025

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.