Alert archive / Colorado / Mesoscale Discussions in 2012

Mesoscale Discussion 97

February 3, 201211 counties in Colorado; Cheyenne County, Kansas; Chase County, Dundy County, Perkins County, Nebraska

The Storm Prediction Center issued this mesoscale discussion at Feb 3, 2012, 2:45 AM MST for 11 counties in Colorado; Cheyenne County, Kansas; Chase County, Dundy County, Perkins County, Nebraska. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued: Feb 3, 2012, 2:45 AM MST (09:45 UTC)
Expired: Feb 3, 2012, 6:45 AM MST
In force: 4 hr
Issued by: the Storm Prediction Center

Counties Adams County, CO, Arapahoe County, CO, Douglas County, CO, El Paso County, CO, Elbert County, CO, Kit Carson County, CO, Lincoln County, CO, Phillips County, CO, Sedgwick County, CO, Washington County, CO, Yuma County, CO, Cheyenne County, KS, Chase County, NE, Dundy County, NE, Perkins County, NE

The radar

The Goodland radar (KGLD), 117 km from the middle of the area, began a volume at 09:49 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.

The nearest sounding before it

Denver, CO (KDNR), launched 00:00Z, 9.8 hours before the alert went out and 27 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 2009 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: -41 m²/s²
0-3 km storm-relative helicity: 58 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.

658 
ACUS11 KWNS 030945
SWOMCD
SPC MCD 030945 
NEZ000-KSZ000-COZ000-031345-

MESOSCALE DISCUSSION 0097
NWS STORM PREDICTION CENTER NORMAN OK
0345 AM CST FRI FEB 03 2012

AREAS AFFECTED...FRONT RANGE OF THE ROCKIES INTO NERN CO...NWRN
KS...SWRN NEB

CONCERNING...HEAVY SNOW 

VALID 030945Z - 031345Z

HEAVY SNOW WITH RATES NEAR 1-3 INCH AN HOUR WILL CONTINUE ALONG THE
FRONT RANGE IN CO. HEAVIER SNOW WILL GRADUALLY DEVELOP EWD INTO THE
ADJACENT PLAINS THROUGH THE MORNING. NEAR-BLIZZARD CONDITIONS MAY BE
POSSIBLE AS NELY LOW LEVEL WINDS STRENGTHEN SLIGHTLY.

ENHANCED SNOWFALL RATES HAVE BEEN ONGOING ALONG THE FRONT RANGE AND
IMMEDIATE UPSLOPE AREAS WHERE MULTI CLOUD LAYER PRECIPITATION HAS
LED TO AN AMALGAMATION OF SNOWFLAKES. WITH THE UPPER LOW REMAINING
RATHER STATIONARY...FAVORABLE UPPER DIVERGENCE SHOULD CONTINUE TO
MAINTAIN ENHANCED SNOWFALL RATES IN THIS AREA IN CONCERT WITH
PERSISTENT NELY/UPSLOPE LOW LEVEL FLOW. DETERMINISTIC MODELS DO SHOW
A SLIGHT EWD SHIFT IN THE LOW...RESULTING IN A GRADUAL INCREASE IN
PRECIPITATION ACROSS THE ADJACENT PLAINS THIS MORNING. 0915Z RADAR
IMAGERY IS SHOWING A BAND DEVELOPING FROM NEAR PUB NEWD TO
LBF...WHERE RATES ARE EXPECTED TO CONTINUE TO INCREASE. ALTHOUGH
TEMPERATURE PROFILES ARE TOO WARM FOR SNOW AS OF 0930Z ACROSS SWRN
NEB AND NWRN KS...WEB BULB EFFECTS MAY ALLOW FOR SOME LOW LEVEL
COOLING...WITH TEMPERATURES HOVERING AROUND FREEZING IN A FEW HOURS.
WINDS ARE EXPECTED TO INCREASE SLIGHTLY BY SUNRISE...LEADING TO
NEAR-BLIZZARD CONDITIONS IN BLOWING SNOW. DETERMINISTIC MODEL SPREAD
REMAINS HIGH EVEN WITH THE EVENT ONGOING...LEADING TO CONSIDERABLE
UNCERTAINTY IN SNOWFALL ACCUMULATIONS. QPF TOTALS THUS FAR HAVE BEEN
OVERDONE COMPARED TO OBSERVATIONAL DATA. NONETHELESS...SNOWFALL
RATES MAY BE INTENSE AT TIMES...ESPECIALLY ALONG THE FRONT RANGE.

..HURLBUT.. 02/03/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...LBF...GLD...PUB...BOU...

LAT...LON   39600156 39050307 38540428 38400451 38780504 39630499
            39980410 40840247 41060181 40850129 40330109 39600156

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 2, 5:08 PM MST	Mesoscale Discussion	SPC	Adams, Arapahoe, Boulder, Broomfield, Cheyenne, Denver and 13 more	4 hr
Feb 2, 8:48 PM MST	Mesoscale Discussion	SPC	Barber, Comanche	117 min
Feb 2, 10:44 PM MST	Mesoscale Discussion	SPC	Barber, Harper, Kingman	91 min
Feb 3, 1:00 AM MST	Mesoscale Discussion	SPC	Sumner	60 min

Nearby

Mesoscale Discussions in Colorado, 2012 Mesoscale Discussions in Nebraska, 2012 Mesoscale Discussions in Kansas, 2012 Every mesoscale discussion 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.