Alert archive / Nebraska / Mesoscale Discussions in 2012

Mesoscale Discussion 111

February 4, 20126 counties in Iowa; Republic County, Kansas; 19 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Feb 4, 2012, 3:27 AM CST for 6 counties in Iowa; Republic County, Kansas; 19 counties in Nebraska. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Feb 4, 2012, 3:27 AM CST (09:27 UTC)
Expired
Feb 4, 2012, 7:30 AM CST
In force
4 hr
Issued by
the Storm Prediction Center
All 26 counties

Cass County, IA, Fremont County, IA, Mills County, IA, Montgomery County, IA, Page County, IA, Pottawattamie County, IA, Republic County, KS, Butler County, NE, Cass County, NE, Clay County, NE, Douglas County, NE, Fillmore County, NE, Gage County, NE, Jefferson County, NE, Johnson County, NE, Lancaster County, NE, Nemaha County, NE, Nuckolls County, NE, Otoe County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Thayer County, NE, Washington County, NE, York County, NE

The radar

The Omaha radar (KOAX), 48 km from the middle of the area, began a volume at 09:30 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

Omaha, NE (KOAX), launched 00:00Z, 9.5 hours before the alert went out and 48 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, Omaha, NE at 00:00Z on 2012-02-04Temperature 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 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 00:00Z on 2012-02-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 281 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
598 m above ground
0-6 km bulk shear
83 kt
0-1 km storm-relative helicity
281 m²/s²
0-3 km storm-relative helicity
448 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.

812 
ACUS11 KWNS 040928
SWOMCD
SPC MCD 040927
IAZ000-MOZ000-NEZ000-KSZ000-041330-

MESOSCALE DISCUSSION 0111
NWS STORM PREDICTION CENTER NORMAN OK
0327 AM CST SAT FEB 04 2012

AREAS AFFECTED...ERN NEB/WRN IA

CONCERNING...HEAVY SNOW

VALID 040927Z - 041330Z

INCH AN HOUR SNOWFALL RATES /GREATER IN THUNDERSNOW/ WILL GRADUALLY
TAPER OFF LATER THIS MORNING. CESSATION OF HEAVIER RATES IS ALREADY
ONGOING ACROSS CNTRL NEB.

HEAVY SNOWFALL HAS DEVELOPED IN THE FAVORED LEFT EXIT REGION OF A
MID-UPPER LEVEL JET...NOW QUICKLY PROGRESSING NEWD. WITH THE
LESSENING OF MORE SUPPORTIVE VERTICAL MOTION...RATES SHOULD
GRADUALLY BEGIN TO TAPER OFF THIS MORNING. UNTIL THEN...WEAK MID
LEVEL INSTABILITY /ROOTED AT 600-450 MB/ HAS SUPPORTED THE
OCCASIONAL LIGHTNING STRIKE ACROSS SRN NEB. THIS AREA OF ENHANCED
CONVECTIVE SNOWFALL POTENTIAL WILL SHIFT INTO SRN IA OVER THE NEXT
FEW HOURS. BRIEF BURSTS OF HEAVIER SNOW REMAIN POSSIBLE IN
THUNDERSNOW.

..HURLBUT.. 02/04/2012

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

ATTN...WFO...DMX...EAX...OAX...TOP...GID...

LAT...LON   41719543 41339465 40749509 39989670 39829767 40239849
            41049753 41439676 41719543

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 3, 6:36 PM CSTMesoscale DiscussionSPCDecatur, Graham, Jewell, Mitchell, Norton, Osborne and 4 more4 hr

Nearby

Mesoscale Discussions in Nebraska, 2012Mesoscale Discussions in Iowa, 2012Mesoscale Discussions in Kansas, 2012Every 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.