Alert archive / Colorado / Winter Storm Warnings in 2012

Winter Storm Warning 8, NWS Denver/Boulder, CO

December 8, 20129 counties in Colorado

NWS Denver/Boulder, CO issued this winter storm warning at Dec 8, 2012, 2:44 PM MST for 9 counties in Colorado. It was in force for 11 hr. 6 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Dec 8, 2012, 2:44 PM MST (21:44 UTC)
Expired
Dec 9, 2012, 1:36 AM MST
In force
11 hr
Issued by
NWS Denver/Boulder, CO

Counties Boulder County, CO, Clear Creek County, CO, Gilpin County, CO, Grand County, CO, Jackson County, CO, Jefferson County, CO, Larimer County, CO, Park County, CO, Summit County, CO

The radar

The Denver radar (KFTG), 102 km from the middle of the area, began a volume at 21:49 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.

What was reported inside it

TimeReportWhereRemark
Dec 8, 4:00 PM MSTSNOW 3.51 Nnw Grand Lake, CO
Dec 8, 4:10 PM MSTSNOW 3.93 W Jamestown, COONE INCH PAST HOUR
Dec 8, 5:07 PM MSTHEAVY SNOW 122 Sse Tabernash, COTWO INCHES OF SNOW SINCE 3 PM
Dec 8, 8:00 PM MSTSNOW 2.92 Sse Breckenridge, CO
Dec 8, 10:00 PM MSTSNOW 1.6N Ken Caryl, CO
Dec 8, 10:25 PM MSTSNOW 0.54 Ene Nederland, CO

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Denver, CO (KDNR), launched 12:00Z, 9.7 hours before the alert went out and 213 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 2012-12-08Temperature 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°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 12:00Z on 2012-12-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -4 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
1398 m above ground
0-6 km bulk shear
70 kt
0-1 km storm-relative helicity
-4 m²/s²
0-3 km storm-relative helicity
296 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

739 
WWUS45 KBOU 082144
WSWBOU

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE DENVER CO
244 PM MST SAT DEC 8 2012

...STRONG WINDS AND SNOW FOR THE MOUNTAINS TODAY AND TONIGHT...

.STRONG WEST TO NORTHWEST WINDS AND PERIODS OF HEAVY SNOW WILL
PRODUCE HAZARDOUS WINTER WEATHER CONDITIONS FOR TRAVELER...
SKIERS AND ANYONE ELSE OUTDOORS IN THE NORTH CENTRAL MOUNTAINS OF
COLORADO THROUGH LATE TONIGHT. SNOWFALL WILL LIKELY INCREASE IN
INTENSITY ABOVE TIMBERLINE AND ON WEST AND NORTHWEST FACING
MOUNTAIN SLOPES THIS AFTERNOON WITH A POWERFUL JET STREAM PASSING 
OVER THE AREA. CONDITIONS SHOULD GRADUALLY IMPROVE LATE TONIGHT
WITH A STEADY REDUCTION IN THE WIND AND SNOWFALL.

COZ031-033-034-090545-
/O.UPG.KBOU.WW.Y.0018.000000T0000Z-121209T1200Z/
/O.NEW.KBOU.WS.W.0008.121208T2144Z-121209T0900Z/
WEST JACKSON AND WEST GRAND COUNTIES ABOVE 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-
INCLUDING THE CITIES OF...
EAST SLOPES PARK AND NORTHERN GORE RANGES...GORE PASS...
RABBIT EARS PASS...CAMERON PASS...
LARAMIE AND MEDICINE BOW MOUNTAINS...RABBIT EARS RANGE...
ROCKY MOUNTAIN NATIONAL PARK...WILLOW CREEK PASS...
BERTHOUD PASS...BRECKENRIDGE...EAST SLOPES MOSQUITO RANGE...
EAST SLOPES SOUTHERN GORE RANGE...EISENHOWER TUNNEL...
INDIAN PEAKS...KENOSHA MOUNTAINS...MOUNT EVANS...
WILLIAMS FORK MOUNTAINS...WINTER PARK
244 PM MST SAT DEC 8 2012

...WINTER STORM WARNING IN EFFECT UNTIL 2 AM MST SUNDAY...

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A WINTER STORM
WARNING FOR THE NORTH CENTRAL MOUNTAINS OF COLORADO...WHICH IS 
IN EFFECT UNTIL 2 AM MST SUNDAY. THE WINTER WEATHER ADVISORY IS
NO LONGER IN EFFECT FOR THIS AREA.

* TIMING...SNOW WILL INCREASE THIS LATE THIS AFTERNOON AND
  CONTINUE HEAVY AT TIMES THROUGH THIS EVENING. CONDITIONS WILL
  IMPROVE LATE TONIGHT.

* SNOW ACCUMULATIONS...ANOTHER 5 TO 12 INCHES...WITH THE HIGHER
  AMOUNTS ON WEST AND NORTHWEST FACING SLOPES IN JACKSON...GRAND
  AND SUMMIT COUNTIES.

* MAIN IMPACT...WEST WINDS OF 40 TO 60 MPH WILL LIKELY PRODUCE
  CONSIDERABLE BLOWING AND DRIFTING SNOW IN OPEN AREAS ABOVE 10
  THOUSAND FEET. HIGHER GUSTS ABOVE TIMBERLINE WILL PRODUCE
  DANGEROUS WHITEOUT CONDITIONS AND WIND CHILLS AS LOW AS 25
  DEGREES BELOW ZERO. THE STRONG WINDS AND REDUCED VISIBILITIES
  DUE TO BLOWING SNOW WILL CREATE HAZARDOUS DRIVING CONDITIONS...
  PARTICULARLY ON THE HIGH MOUNTAIN PASSES. 

* OTHER IMPACTS...TIRE CHAINS AND OR ADEQUATE SNOW TIRES WILL
  LIKELY BE REQUIRED ON MANY HIGH MOUNTAIN ROADS. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WARNING FOR HEAVY SNOW MEANS SEVERE WINTER WEATHER
CONDITIONS ARE EXPECTED OR OCCURRING. SIGNIFICANT AMOUNTS OF SNOW
ARE FORECAST THAT WILL MAKE TRAVEL DANGEROUS. ONLY TRAVEL IN AN
EMERGENCY. IF YOU MUST TRAVEL...KEEP AN EXTRA FLASHLIGHT...
FOOD...AND WATER IN YOUR VEHICLE IN CASE OF AN EMERGENCY.

&&

$$
BAKER
2 follow-up statements
020 
WWUS45 KBOU 090325
WSWBOU

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE DENVER CO
825 PM MST SAT DEC 8 2012

...WINDY AND SNOWY CONDITIONS IN THE MOUNTAINS TONIGHT...

.CONTINUING WEST TO NORTHWEST WINDS AND PERIODS OF HEAVY SNOW
WILL PRODUCE HAZARDOUS WINTER WEATHER CONDITIONS FOR TRAVELERS IN
THE NORTH CENTRAL MOUNTAINS OF COLORADO TONIGHT. SNOWFALL...HEAVY
AT TIMES...IS EXPECTED TO CONTINUE OVER THE I-70 CORRIDOR THROUGH
ABOUT MIDNIGHT. CONDITIONS SHOULD GRADUALLY IMPROVE DURING THE
PRE-DAWN HOURS WITH A STEADY REDUCTION IN THE WIND AND SNOWFALL.

COZ031-033-034-090900-
/O.CON.KBOU.WS.W.0008.000000T0000Z-121209T0900Z/
WEST JACKSON AND WEST GRAND COUNTIES ABOVE 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-
INCLUDING THE CITIES OF...
EAST SLOPES PARK AND NORTHERN GORE RANGES...GORE PASS...
RABBIT EARS PASS...CAMERON PASS...
LARAMIE AND MEDICINE BOW MOUNTAINS...RABBIT EARS RANGE...
ROCKY MOUNTAIN NATIONAL PARK...WILLOW CREEK PASS...
BERTHOUD PASS...BRECKENRIDGE...EAST SLOPES MOSQUITO RANGE...
EAST SLOPES SOUTHERN GORE RANGE...EISENHOWER TUNNEL...
INDIAN PEAKS...KENOSHA MOUNTAINS...MOUNT EVANS...
WILLIAMS FORK MOUNTAINS...WINTER PARK
825 PM MST SAT DEC 8 2012

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 2 AM MST SUNDAY...

* TIMING...SNOW WILL BE HEAVY AT TIMES THROUGH MIDNIGHT.
  CONDITIONS WILL IMPROVE AFTER MIDNIGHT.

* SNOW ACCUMULATIONS...ANOTHER 4 TO 8 INCHES OVERNIGHT...WITH THE
  HIGHER AMOUNTS ON WEST AND NORTHWEST FACING SLOPES IN GRAND AND
  SUMMIT COUNTIES.

* MAIN IMPACT...WEST WINDS OF 40 TO 50 MPH WILL LIKELY PRODUCE
  CONSIDERABLE BLOWING AND DRIFTING SNOW IN OPEN AREAS ABOVE 10
  THOUSAND FEET. HIGHER GUSTS ABOVE TIMBERLINE WILL PRODUCE
  DANGEROUS WHITEOUT CONDITIONS AND WIND CHILLS AS LOW AS 25
  DEGREES BELOW ZERO. THE STRONG WINDS AND REDUCED VISIBILITIES
  DUE TO BLOWING SNOW WILL CREATE HAZARDOUS DRIVING CONDITIONS...
  PARTICULARLY ON THE HIGH MOUNTAIN PASSES.

* OTHER IMPACTS...TIRE CHAINS AND/OR ADEQUATE SNOW TIRES WILL
  LIKELY BE REQUIRED ON MANY HIGH MOUNTAIN ROADS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WARNING FOR HEAVY SNOW MEANS SEVERE WINTER WEATHER
CONDITIONS ARE EXPECTED OR OCCURRING. SIGNIFICANT AMOUNTS OF SNOW
ARE FORECAST THAT WILL MAKE TRAVEL DANGEROUS. ONLY TRAVEL IN AN
EMERGENCY. IF YOU MUST TRAVEL...KEEP AN EXTRA FLASHLIGHT...
FOOD...AND WATER IN YOUR VEHICLE IN CASE OF AN EMERGENCY.

&&

$$

COZ037-090900-
/O.NEW.KBOU.WW.Y.0019.121209T0325Z-121209T0900Z/
CENTRAL AND SOUTHEAST PARK COUNTY-
INCLUDING THE CITIES OF...FAIRPLAY...HARTSEL...LAKE GEORGE...
SOUTH PARK
825 PM MST SAT DEC 8 2012

...WINTER WEATHER ADVISORY IN EFFECT UNTIL 2 AM MST SUNDAY...

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A WINTER
WEATHER ADVISORY FOR SNOW AND BLOWING SNOW...WHICH IS IN EFFECT
UNTIL 2 AM MST SUNDAY.

* TIMING...SNOW...HEAVY AT TIMES...IS EXPECTED TO SPREAD ACROSS
  PARK COUNTY THROUGH THIS EVENING AND CONTINUE THROUGH ABOUT 2
  AM. 

* SNOW ACCUMULATIONS...3 TO 6 INCHES OVERNIGHT...WITH QUITE A BIT
  OF DRIFTING.

* MAIN IMPACT...WEST TO NORTHWEST WINDS AT 40 TO 50 MPH WILL CAUSE
  WIDESPREAD BLOWING AND DRIFTING SNOW. VISIBILITIES WILL BE POOR
  FOR MOTORISTS ALONG HIGHWAY 285.  

* OTHER IMPACTS...WIND CHILL VALUES COULD DROP AS LOW AS 25
  DEGREES BELOW ZERO.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW MEANS THAT
PERIODS OF SNOW WILL CAUSE PRIMARILY TRAVEL DIFFICULTIES. BE
PREPARED FOR SNOW COVERED ROADS AND LIMITED VISIBILITIES...AND USE
CAUTION WHILE DRIVING.

&&

$$
466 
WWUS45 KBOU 090836
WSWBOU

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE DENVER CO
136 AM MST SUN DEC 9 2012

...SNOW SHIFTING TO THE CENTRAL COLORADO MOUNTAINS...

.SNOW WAS DIMINISHING IN THE NORTHERN COLORADO MOUNTAINS EARLY
THIS MORNING...BUT AN AREA OF MODERATE TO HEAVY SNOW CONTINUED
ACROSS THE CENTRAL MOUNTAINS FROM THE ASPEN AREA EAST TO PARK
COUNTY. SNOWFALL WILL GRADUALLY DIMINISH ACROSS SUMMIT COUNTY
DURING THE EARLY MORNING HOURS...BUT WILL CONTINUE IN PARK COUNTY
UNTIL LATER THIS MORNING. WINDS WILL ALSO GRADUALLY DIMINISH...BUT
THERE WILL STILL BE AREAS OF BLOWING AND DRIFTING SNOW AT LEAST
THROUGH SUNRISE.

COZ034-091600-
/O.CAN.KBOU.WS.W.0008.000000T0000Z-121209T0900Z/
/O.EXB.KBOU.WW.Y.0019.000000T0000Z-121209T1600Z/
SOUTH AND SOUTHEAST GRAND/WEST CENTRAL AND SOUTHWEST BOULDER/
GILPIN/CLEAR CREEK/SUMMIT/NORTH AND WEST PARK COUNTIES ABOVE
9000 FEET-
INCLUDING THE CITIES OF...BERTHOUD PASS...BRECKENRIDGE...
EAST SLOPES MOSQUITO RANGE...EAST SLOPES SOUTHERN GORE RANGE...
EISENHOWER TUNNEL...INDIAN PEAKS...KENOSHA MOUNTAINS...
MOUNT EVANS...WILLIAMS FORK MOUNTAINS...WINTER PARK
136 AM MST SUN DEC 9 2012

...WINTER WEATHER ADVISORY IN EFFECT UNTIL 9 AM MST THIS
MORNING...
...WINTER STORM WARNING IS CANCELLED...

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A WINTER
WEATHER ADVISORY FOR SNOW AND BLOWING SNOW...WHICH IS IN EFFECT
UNTIL 9 AM MST THIS MORNING. THE WINTER STORM WARNING HAS BEEN
CANCELLED.

* TIMING...SNOW AND WINDS WILL GRADUALLY DIMINISH THIS MORNING.

* SNOW ACCUMULATIONS...ANOTHER 3 TO 6 INCHES BY LATE THIS MORNING.

* MAIN IMPACT...WEST TO NORTHWEST WINDS AT 20 TO 30 MPH WITH GUSTS
  TO 50 MPH WILL CAUSE BLOWING AND DRIFTING SNOW IN EXPOSED AREAS.

* OTHER IMPACTS...WIND CHILL VALUES COULD DROP AS LOW AS 25 
  DEGREES BELOW ZERO. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW MEANS THAT
PERIODS OF SNOW WILL CAUSE PRIMARILY TRAVEL DIFFICULTIES. BE
PREPARED FOR SNOW COVERED ROADS AND LIMITED VISIBILITIES...AND
USE CAUTION WHILE DRIVING.

&&

$$

COZ031-033-090945-
/O.CAN.KBOU.WS.W.0008.000000T0000Z-121209T0900Z/
WEST JACKSON AND WEST GRAND COUNTIES ABOVE 9000 FEET-
SOUTH AND EAST JACKSON/LARIMER/NORTH AND NORTHEAST GRAND/
NORTHWEST BOULDER COUNTIES ABOVE 9000 FEET-
INCLUDING THE CITIES OF...
EAST SLOPES PARK AND NORTHERN GORE RANGES...GORE PASS...
RABBIT EARS PASS...CAMERON PASS...
LARAMIE AND MEDICINE BOW MOUNTAINS...RABBIT EARS RANGE...
ROCKY MOUNTAIN NATIONAL PARK...WILLOW CREEK PASS
136 AM MST SUN DEC 9 2012

...WINTER STORM WARNING IS CANCELLED...

SNOW WILL CONTINUE TO DIMINISH THIS MORNING. ADDITIONAL
ACCUMULATIONS OF 2 TO 4 INCHES ARE EXPECTED THROUGH LATE THIS
MORNING.

$$

COZ037-091600-
/O.EXT.KBOU.WW.Y.0019.000000T0000Z-121209T1600Z/
CENTRAL AND SOUTHEAST PARK COUNTY-
INCLUDING THE CITIES OF...FAIRPLAY...HARTSEL...LAKE GEORGE...
SOUTH PARK
136 AM MST SUN DEC 9 2012

...WINTER WEATHER ADVISORY NOW IN EFFECT UNTIL 9 AM MST THIS
MORNING...

* TIMING...SNOW WILL CONTINUE THIS MORNING AND MAY BE HEAVY AT
  TIMES. 

* SNOW ACCUMULATIONS...STORM TOTALS OF 3 TO 6 INCHES BY LATE THIS
  MORNING.

* MAIN IMPACT...WEST TO NORTHWEST WINDS AT 15 TO 30 MPH WITH GUSTS
  TO 40 MPH WILL CAUSE WIDESPREAD BLOWING AND DRIFTING SNOW.
  VISIBILITIES WILL BE POOR FOR MOTORISTS ALONG HIGHWAY 285.

* OTHER IMPACTS...WIND CHILL VALUES COULD DROP AS LOW AS 25 
  DEGREES BELOW ZERO. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW MEANS THAT
PERIODS OF SNOW WILL CAUSE PRIMARILY TRAVEL DIFFICULTIES. BE
PREPARED FOR SNOW COVERED ROADS AND LIMITED VISIBILITIES...AND
USE CAUTION WHILE DRIVING.

&&

$$

GIMMESTAD

The office that day

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

IssuedProductOfficeCountiesLasted
Dec 7, 9:25 PM MSTWinter Weather AdvisoryBOUBoulder, Clear Creek, Gilpin, Grand, Jackson, Jefferson and 3 more17 hr

Nearby

Winter Storm Warnings in Colorado, 2012Every winter storm warning in 2012

Sources

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