Alert archive / Colorado / Winter Storm Warnings in 2011

Winter Storm Warning 20, NWS Grand Junction, CO

May 18, 201118 counties in Colorado; Daggett County, Uintah County, Utah

NWS Grand Junction, CO issued this winter storm warning at May 18, 2011, 2:01 PM MDT for 18 counties in Colorado; Daggett County, Uintah County, Utah. It took effect at May 18, 2011, 3:00 PM MDT. It was in force for 57 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
May 18, 2011, 2:01 PM MDT (20:01 UTC)
In effect from
May 18, 2011, 3:00 PM MDT
Expired
May 21, 2011, 12:00 AM MDT
In force
57 hr
Issued by
NWS Grand Junction, CO

Counties Archuleta County, CO, Delta County, CO, Dolores County, CO, Eagle County, CO, Garfield County, CO, Gunnison County, CO, Hinsdale County, CO, La Plata County, CO, Mesa County, CO, Moffat County, CO, Montezuma County, CO, Montrose County, CO, Ouray County, CO, Pitkin County, CO, Rio Blanco County, CO, Routt County, CO, San Juan County, CO, San Miguel County, CO, Daggett County, UT, Uintah County, UT

The radar

The Grand Junction radar (KGJX), 34 km from the middle of the area, began a volume at 20:04 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, 8.0 hours before the alert went out and 421 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 2011-05-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 19 joules per kilogram.LCLLFCEL10008507005003002001001 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, Denver, CO at 12:00Z on 2011-05-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 3 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
19 J/kg
Mixed-layer CIN
-37 J/kg
Mixed-layer LCL
625 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
3 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

What forecasters said that day

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

NWS Grand Junction, CO wrote its last area forecast discussion before this winter storm warning went out at May 18, 8:06 AM MDT, 5 hours 55 minutes earlier.

Area forecast discussion, May 18, 8:06 AM MDT, 5 hours 55 minutes before
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Hazardous weather outlook, May 18, 5:11 AM MDT, 8 hours 50 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
511 AM MDT WED MAY 18 2011

COZ001>014-017>023-UTZ022>025-027>029-191200-
ANIMAS RIVER BASIN-ARCHES/GRAND FLAT-CANYONLANDS/NATURAL BRIDGES-
CENTRAL COLORADO RIVER BASIN-
CENTRAL GUNNISON AND UNCOMPAHGRE RIVER BASIN-
CENTRAL YAMPA RIVER BASIN-DEBEQUE TO SILT CORRIDOR-
EASTERN UINTA BASIN-EASTERN UINTA MOUNTAINS-
ELKHEAD AND PARK MOUNTAINS-FLAT TOPS-
FOUR CORNERS/UPPER DOLORES RIVER-
GORE AND ELK MOUNTAINS/CENTRAL MOUNTAINS-GRAND AND BATTLEMENT MESAS-
GRAND VALLEY-LA SAL AND ABAJO MOUNTAINS-LOWER YAMPA RIVER BASIN-
NORTHWEST SAN JUAN MOUNTAINS-PARADOX VALLEY/LOWER DOLORES RIVER-
ROAN AND TAVAPUTS PLATEAUS-SAN JUAN RIVER BASIN-SOUTHEAST UTAH-
SOUTHWEST SAN JUAN MOUNTAINS-TAVAPUTS PLATEAU-
UNCOMPAHGRE PLATEAU AND DALLAS DIVIDE-UPPER GUNNISON RIVER VALLEY-
UPPER YAMPA RIVER BASIN-WEST ELK AND SAWATCH MOUNTAINS-
511 AM MDT WED MAY 18 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN UTAH AND WESTERN
COLORADO.

.DAY ONE...TODAY AND TONIGHT...

NUMEROUS SHOWERS...WITH SNOW ABOVE ABOUT 7500 TO 8000 FEET...WILL
CONTINUE THIS MORNING.  SNOW AND MIXED RAIN AND SNOW WILL CAUSE
SLUSHY DRIVING CONDITIONS OVER THE HIGHER PASSES.

THE NEXT PHASE OF MOISTURE FROM A STRONG PACIFIC STORM WILL ARRIVE
LATER TODAY. AFTER A BRIEF LULL SHOWERS WILL BECOME NUMEROUS AGAIN
LATE THIS AFTERNOON AND CONTINUE OVERNIGHT. ISOLATED THUNDERSTORMS
ARE ALSO EXPECTED. SEVERAL INCHES OF SNOW ACCUMULATION IS EXPECTED
OVER MOST MOUNTAINS ABOVE 8500 FEET WITH THE SNOW LEVEL DROPPING
BELOW 8000 FEET LATE TONIGHT.

WARM WEATHER WILL CONTINUE THE SIGNIFICANT SNOWMELT AND...ALONG WITH
MORE RAIN AND SNOW...WILL RESULT IN INCREASING RIVER AND STREAM
FLOWS TODAY...ESPECIALLY THE YAMPA...WHITE AND GREEN RIVERS OF
NORTHWEST COLORADO AND NORTHEAST UTAH. SOME OF THE STREAMS IN THE
AREA WILL REMAIN AT OR ABOVE BANKFULL.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY...

THURSDAY THROUGH FRIDAY NIGHT SIGNIFICANT SNOWFALL AMOUNTS ARE
POSSIBLE AS THE PACIFIC STORM SYSTEM MOVES THROUGH THE AREA. MORE
THAN A FOOT OF SNOW ACCUMULATION IS POSSIBLE ACROSS AREAS ABOVE 8500
FEET IN THE NORTHERN AND CENTRAL MOUNTAINS...THOUGH THE NORTHWEST SAN
JUAN MOUNTAINS MAY SEE SIMILAR ACCUMULATIONS.

ANOTHER PACIFIC STORM IS PROJECTED TO AFFECT THE AREA BEGINNING
MONDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED TODAY OR TONIGHT.

CUOCO

The office that day

Everything else NWS Grand Junction, CO issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 18, 6:17 AM MDTWinter Weather AdvisoryGJTArchuleta, Delta, Dolores, Eagle, Garfield, Gunnison and 12 more8 hr

Nearby

Winter Storm Warnings in Colorado, 2011Winter Storm Warnings in Utah, 2011Every winter storm warning in 2011

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.