Alert archive / Colorado / Winter Storm Watches in 2018

Winter Storm Watch 2, NWS Denver/Boulder, CO

February 17, 2018Grand County, Jackson County, Colorado

NWS Denver/Boulder, CO issued this winter storm watch at Feb 17, 2018, 3:26 PM MST for Grand County, Jackson County, Colorado. It took effect at Feb 18, 2018, 9:00 PM MST. It was in force for .

The area

The counties it named.

The facts

Issued
Feb 17, 2018, 3:26 PM MST (22:26 UTC)
In effect from
Feb 18, 2018, 9:00 PM MST
Expired
Feb 18, 2018, 2:01 PM MST
In force
Issued by
NWS Denver/Boulder, CO

Counties Grand County, CO, Jackson County, CO

The radar

The Cheyenne radar (KCYS), 147 km from the middle of the area, began a volume at 22:27 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

Grand Junction, CO (KGJT), launched 12:00Z, 10.4 hours before the alert went out and 239 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, Grand Junction, CO at 12:00Z on 2018-02-17Temperature 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 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Grand Junction, CO at 12:00Z on 2018-02-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 75 square meters per square second.1939587897Sfc1 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
1598 m above ground
0-6 km bulk shear
68 kt
0-1 km storm-relative helicity
75 m²/s²
0-3 km storm-relative helicity
342 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 winter storm watch 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 winter storm watch went out at Feb 17, 3:24 PM MST, 2 minutes earlier.

Area forecast discussion, Feb 17, 3:24 PM MST, 2 minutes before
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Hazardous weather outlook, Feb 17, 10:59 AM MST, 4 hours 27 minutes before
Hazardous Weather Outlook
National Weather Service Denver/Boulder CO
1059 AM MST Sat Feb 17 2018

COZ030>051-181800-
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-
1059 AM MST Sat Feb 17 2018

...HIGH WIND WARNING FOR THE FRONT RANGE MOUNTAINS AND FOOTHILLS
WITH HIGH WINDS REDEVELOPING TONIGHT...
...FIRE WEATHER WATCH OVER THE PALMER DIVIDE SUNDAY AFTERNOON...

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

.DAY ONE...Today and Tonight

Strong and gusty west winds of 40 to 55 mph will continue in the
mountains and higher Front Range foothills today. Northwest winds
of 20 to 35 mph can also be expected on the plains near the
foothills and along the Wyoming border. Tonight, chinook winds are
likely to become quite strong and gusty in the Front Range
mountains and foothills with gusts of 55 to 85 mph possible in
areas prone to high winds. A High Wind Warning remains in effect
for the the mountains and foothills due to the expected increase
in winds this evening.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

The strong winds in the Front Range mountains and foothills will
continue through Sunday morning and then decrease by afternoon.
Wind gusts from 65 to 80 mph will be possible in areas prone to
high winds, such as open terrain above timberline and east slopes
of the Front Range generally above 7000 feet.  Elevated fire
danger is expected over the Palmer Divide Sunday afternoon with
low humidities and gusty southwest winds.

After a dry and warm Sunday, another Pacific storm system is
expected to bring snow and much colder temperatures to the outlook
area Monday and Tuesday. It's possible that temperatures on the
plains Tuesday may not reach the 20 degree mark. Snow amounts with
this storm still remain uncertain at this time, but it appears
several inches of snow can be anticipated in the mountains, with
lighter snow accumulations over most of the plains. Dry and
warmer weather should then return to the outlook area Wednesday
and Thursday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed today or tonight. However,
reports of strong winds will be appreciated.

The office that day

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

IssuedProductOfficeCountiesLasted
Feb 17, 4:04 AM MSTFire Weather WatchBOUArapahoe, Douglas, Elbert, Lincoln11 hr
Feb 17, 3:15 PM MSTRed Flag WarningBOUArapahoe, Douglas, Elbert, Lincoln26 hr

Nearby

Winter Storm Watches in Colorado, 2018Every winter storm watch in 2018

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.