Alert archive / Colorado / Frost Advisories in 2019

Frost Advisory 5, NWS Denver/Boulder, CO

October 2, 201912 counties in Colorado

NWS Denver/Boulder, CO issued this frost advisory at Oct 2, 2019, 2:26 AM MDT for 12 counties in Colorado. It took effect at Oct 3, 2019, 2:00 AM MDT. It was in force for 6 hr.

The area

The counties it named.

The facts

Issued
Oct 2, 2019, 2:26 AM MDT (08:26 UTC)
In effect from
Oct 3, 2019, 2:00 AM MDT
Expired
Oct 3, 2019, 8:00 AM MDT
In force
6 hr
Issued by
NWS Denver/Boulder, CO

Counties Adams County, CO, Arapahoe County, CO, Douglas County, CO, Elbert County, CO, Larimer County, CO, Lincoln County, CO, Logan County, CO, Morgan County, CO, Phillips County, CO, Sedgwick County, CO, Washington County, CO, Weld County, CO

The radar

The Denver radar (KFTG), 69 km from the middle of the area, began a volume at 08:25 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, 8.4 hours before the alert went out and 297 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 2019-10-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCLEL10008507005003002001001 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 2019-10-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 27 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
615 m above ground
0-6 km bulk shear
54 kt
0-1 km storm-relative helicity
27 m²/s²
0-3 km storm-relative helicity
202 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 frost advisory 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 frost advisory went out at Oct 1, 4:04 PM MDT, 10 hours 22 minutes earlier.

Area forecast discussion, Oct 1, 4:04 PM MDT, 10 hours 22 minutes before
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Hazardous weather outlook, Oct 1, 11:10 AM MDT, 15 hours 16 minutes before
Hazardous Weather Outlook
National Weather Service Denver/Boulder CO
1110 AM MDT Tue Oct 1 2019

COZ030>051-021715-
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-
1110 AM MDT Tue Oct 1 2019

...RED FLAG WARNING FOR THE HIGH MOUNTAIN VALLEYS AND PORTIONS OF
THE NORTH CENTRAL MOUNTAINS INCLUDING SUMMIT COUNTY...

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

.DAY ONE...Today and Tonight

The wind and humidities int he mountains and high valleys are
already showing critical fire danger conditions late this morning.
The areas included are North Park, Middle Park, Summit County,
and South Park. Winds will gust to around 35 mph this afternoon
with minimum humidities dropping to less than 10 percent on valley
floors. Conditions will improve by sunset.

A distinctly different airmass will prevail across the plains and
foothills with cool and moist conditions. There will be a chance
of light rain or rain showers over the plains later this
afternoon well into the overnight period.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

Fire danger will remain high over the mountain valleys on Tuesday
and Wednesday due to gusty and dry southwest winds. Meanwhile,
fire danger will decrease significantly across the plains as a
cool and moist airmass filters in. Scattered light rain showers
can also be expected into Wednesday.

Fire danger will likely remain elevated in the mountains through
the end of the week with breezy conditions and low humidity.

.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
Oct 2, 1:58 PM MDTFire Weather WatchBOUBoulder, Clear Creek, Douglas, Gilpin, Grand, Jackson and 4 more39 hr

Nearby

Frost Advisories in Colorado, 2019Every frost advisory in 2019

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.