Alert archive / Colorado / Frost Advisories in 2021

Frost Advisory 1, NWS Denver/Boulder, CO

September 21, 20216 counties in Colorado

NWS Denver/Boulder, CO issued this frost advisory at Sep 21, 2021, 2:07 PM MDT for 6 counties in Colorado. It took effect at Sep 22, 2021, 2:00 AM MDT. It was in force for 6 hr.

The area

The counties it named.

The facts

Issued
Sep 21, 2021, 2:07 PM MDT (20:07 UTC)
In effect from
Sep 22, 2021, 2:00 AM MDT
Expired
Sep 22, 2021, 8:00 AM MDT
In force
6 hr
Issued by
NWS Denver/Boulder, CO

Counties Elbert County, CO, Larimer County, CO, Lincoln County, CO, Logan County, CO, Morgan County, CO, Weld County, CO

The radar

The Denver radar (KFTG), 52 km from the middle of the area, began a volume at 20:08 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

Denver, CO (KDNR), launched 12:00Z, 8.1 hours before the alert went out and 75 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, Denver, CO at 12:00Z on 2021-09-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 12:00Z on 2021-09-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -5 square meters per square second.1939587897117Sfc1 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
1008 m above ground
0-6 km bulk shear
81 kt
0-1 km storm-relative helicity
-5 m²/s²
0-3 km storm-relative helicity
99 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

801 
WWUS75 KBOU 212007
NPWBOU

URGENT - WEATHER MESSAGE
National Weather Service Denver/Boulder CO
207 PM MDT Tue Sep 21 2021

COZ038-042-043-046-047-220400-
/O.NEW.KBOU.FR.Y.0001.210922T0800Z-210922T1400Z/
Larimer County Below 6000 Feet/Northwest Weld County-
Northeast Weld County-Central and South Weld County-
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
Including Fort Collins, Hereford, Loveland, Nunn, Briggsdale, 
Grover, Pawnee Buttes, Raymer, Stoneham, Eaton, Fort Lupton, 
Greeley, Roggen, Agate, Hugo, Limon, Matheson, Forder, Karval, 
Kutch, and Punkin Center
207 PM MDT Tue Sep 21 2021

...FROST ADVISORY IN EFFECT FROM 2 AM TO 8 AM MDT WEDNESDAY...

* WHAT...Temperatures expected to drop into the 34 to 36 degree
  range with frost possible.

* WHERE...Weld County and Lincoln County.

* WHEN...From 2 AM to 8 AM MDT Wednesday.

* IMPACTS...Frost could kill sensitive outdoor vegetation if left
  uncovered.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

Rodriguez
3 follow-up statements
172 
WWUS75 KBOU 220341
NPWBOU

URGENT - WEATHER MESSAGE
National Weather Service Denver CO
941 PM MDT Tue Sep 21 2021

COZ038-042-043-046-047-221400-
/O.CON.KBOU.FR.Y.0001.210922T0800Z-210922T1400Z/
Larimer County Below 6000 Feet/Northwest Weld County-Northeast
Weld County-Central and South Weld County-North and Northeast
Elbert County Below 6000 Feet/North Lincoln County-Southeast
Elbert County Below 6000 Feet/South Lincoln County-
Including the cities of Fort Lupton, Pawnee Buttes, Stoneham,
Fort Collins, Greeley, Hugo, Roggen, Matheson, Grover, Loveland,
Limon, Nunn, Eaton, Agate, Briggsdale, Hereford, Forder, Punkin
Center, Kutch, Karval, and Raymer
941 PM MDT Tue Sep 21 2021

...FROST ADVISORY REMAINS IN EFFECT FROM 2 AM TO 8 AM MDT 
WEDNESDAY...

* WHAT...Temperatures as low as 36 will result in frost formation.

* WHERE...North and Northeast Elbert County Below 6000 Feet/North 
  Lincoln County, Southeast Elbert County Below 6000 Feet/South 
  Lincoln County, Larimer County Below 6000 Feet/Northwest Weld 
  County, Central and South Weld County and Northeast Weld County 
  Counties.

* WHEN...From 2 AM to 8 AM MDT Wednesday.

$$

For more information from the National Weather Service, visit 
https://weather.gov/bou

Direnzo
936 
WWUS75 KBOU 220847
NPWBOU

URGENT - WEATHER MESSAGE
National Weather Service Denver CO
247 AM MDT Wed Sep 22 2021

COZ044-048-221400-
/O.EXA.KBOU.FR.Y.0001.000000T0000Z-210922T1400Z/
Morgan County-Logan County-
Including the cities of Sterling, Wiggins, Goodrich, Fort Morgan,
Peetz, Crook, Brush, and Merino
247 AM MDT Wed Sep 22 2021

...FROST ADVISORY IN EFFECT UNTIL 8 AM MDT THIS MORNING...

* WHAT...Temperatures as low as 35 will result in frost formation.

* WHERE...Logan County and Morgan County Counties.

* WHEN...Until 8 AM MDT this morning.

* IMPACTS...Frost could harm sensitive outdoor vegetation. Sensitive 
  outdoor plants may be killed if left uncovered.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

COZ038-042-043-046-047-221400-
/O.CON.KBOU.FR.Y.0001.000000T0000Z-210922T1400Z/
Larimer County Below 6000 Feet/Northwest Weld County-Northeast
Weld County-Central and South Weld County-North and Northeast
Elbert County Below 6000 Feet/North Lincoln County-Southeast
Elbert County Below 6000 Feet/South Lincoln County-
Including the cities of Fort Lupton, Pawnee Buttes, Stoneham,
Fort Collins, Greeley, Hugo, Roggen, Matheson, Grover, Loveland,
Limon, Nunn, Eaton, Agate, Briggsdale, Hereford, Forder, Punkin
Center, Kutch, Karval, and Raymer
247 AM MDT Wed Sep 22 2021

...FROST ADVISORY REMAINS IN EFFECT UNTIL 8 AM MDT THIS MORNING...

* WHAT...Temperatures as low as 34 will result in frost formation.

* WHERE...North and Northeast Elbert County Below 6000 Feet/North 
  Lincoln County, Southeast Elbert County Below 6000 Feet/South 
  Lincoln County, Larimer County Below 6000 Feet/Northwest Weld 
  County, Central and South Weld County and Northeast Weld County 
  Counties.

* WHEN...Until 8 AM MDT this morning.

* IMPACTS...Frost could harm sensitive outdoor vegetation. Sensitive 
  outdoor plants may be killed if left uncovered.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

For more information from the National Weather Service, visit 
https://weather.gov/bou

Direnzo
491 
WWUS75 KBOU 221346
NPWBOU

URGENT - WEATHER MESSAGE
National Weather Service Denver CO
746 AM MDT Wed Sep 22 2021

COZ038-042>044-046>048-221500-
/O.EXP.KBOU.FR.Y.0001.000000T0000Z-210922T1400Z/
Larimer County Below 6000 Feet/Northwest Weld County-Northeast
Weld County-Central and South Weld County-Morgan County-North and
Northeast Elbert County Below 6000 Feet/North Lincoln County-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
Logan County-
Including the cities of Wiggins, Fort Morgan, Hugo, Roggen,
Forder, Briggsdale, Sterling, Pawnee Buttes, Crook, Raymer, Fort
Lupton, Matheson, Loveland, Peetz, Grover, Eaton, Agate, Kutch,
Goodrich, Stoneham, Fort Collins, Greeley, Punkin Center, Nunn,
Brush, Karval, Limon, Hereford, and Merino
746 AM MDT Wed Sep 22 2021

...FROST ADVISORY WILL EXPIRE AT 8 AM MDT THIS MORNING...

The threat has ended.

$$

For more information from the National Weather Service, visit 
https://weather.gov/bou

Rodriguez

Nearby

Frost Advisories in Colorado, 2021Every frost advisory in 2021

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.