Alert archive / Nebraska / Mesoscale Discussions in 2011

Mesoscale Discussion 34

January 19, 201110 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Jan 19, 2011, 6:37 AM CST for 10 counties in Nebraska. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Jan 19, 2011, 6:37 AM CST (12:37 UTC)
Expired: Jan 19, 2011, 11:30 AM CST
In force: 5 hr
Issued by: the Storm Prediction Center

Counties Blaine County, NE, Custer County, NE, Garfield County, NE, Greeley County, NE, Howard County, NE, Logan County, NE, Loup County, NE, Sherman County, NE, Thomas County, NE, Valley County, NE

The radar

The North Platte radar (KLNX), 96 km from the middle of the area, began a volume at 12:39 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

N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 0.6 hours before the alert went out and 109 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: 432 m above ground
0-6 km bulk shear: 79 kt
0-1 km storm-relative helicity: 202 m²/s²
0-3 km storm-relative helicity: 290 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.

648 
ACUS11 KWNS 191238
SWOMCD
SPC MCD 191237
NEZ000-191730-

MESOSCALE DISCUSSION 0034
NWS STORM PREDICTION CENTER NORMAN OK
0637 AM CST WED JAN 19 2011

AREAS AFFECTED...PARTS OF CENTRAL NEB

CONCERNING...HEAVY SNOW

VALID 191237Z - 191730Z

SNOW WILL DEVELOP FROM W-E ACROSS CENTRAL NEB THIS MORNING...WITH
THE POTENTIAL FOR RATES TO INCREASE TO 1+ IN/HR BY MID-LATE MORNING
/15-18Z/.  THE AREA OF CONCERN IS 30 MILES EITHER SIDE OF A LINE
FROM KMHN TO 25 N KGRI.

EARLY MORNING WATER VAPOR IMAGERY SHOWED A PRIMARY SHORTWAVE TROUGH
TRACKING SEWD TOWARD THE GREAT BASIN...WHILE A WEAKER LEAD IMPULSE
WAS SHIFTING EWD THROUGH WY.  THE ENTRANCE REGION OF A 50-60 KT WLY
MIDLEVEL JET ATTENDANT TO THIS LEAD WAVE WILL MOVE ACROSS NEB DURING
THE MID-LATE MORNING.  MEANWHILE...WIND PROFILERS/WSR-88D VADS
SHOWED A STRENGTHENING SLY LLJ FROM THE TX PANHANDLE/WRN OK TO WRN
KS IN RESPONSE TO HEIGHT FALLS AHEAD OF THE GREAT BASIN TROUGH AND
LEAD IMPULSE.  INCREASING LOW LEVEL WAA ALONG THE LLJ INTO SRN NEB
JUXTAPOSED BENEATH FORCING FOR ASCENT WITHIN THE ENTRANCE OF THE
LEAD IMPULSE JET STREAK SHOULD SUPPORT AN INCREASE IN UPWARD
VERTICAL MOTION BETWEEN 15-18Z.  FORECAST SOUNDINGS SUGGESTED THE
DENDRITIC SNOW GROWTH LAYER WILL RESIDE WITHIN PART OF THE STRONGER
UVVS...ENHANCING THE SNOWFALL RATES.

RECENT TRENDS IN REGIONAL RADAR IMAGERY SHOWED SEVERAL WNW-ESE
ORIENTED BANDS OF SNOW DEVELOPING OVER SWRN SD INTO THE WRN HALF OF
NEB.  THE EXPECTED WNW-ESE ORIENTATION TO THE GREATER SNOWFALL RATES
PER DETERMINISTIC MODEL CONSENSUS/03Z SREF APPEARS TO BE ASSOCIATED
WITH MIDLEVEL FRONTOGENESIS ALSO ORIENTED WNW-ESE.  GIVEN SURFACE
TEMPERATURES IN THE MID TEENS TODAY RESULTING IN HIGHER SNOW
RATIOS...THE DENDRITIC ENHANCEMENT WILL FURTHER ENHANCE THE SNOWFALL
RATES WITHIN THE DISCUSSION AREA...ESPECIALLY BY 15-18Z.

..PETERS.. 01/19/2011

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

ATTN...WFO...GID...LBF...

LAT...LON   42029900 41839840 41229829 40949866 41169967 41390066
            41940111 42400066 42029900

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jan 19, 10:52 AM CST	Mesoscale Discussion	SPC	Adams, Buffalo, Clay, Custer, Dawson, Fillmore and 26 more	4 hr

Nearby

Mesoscale Discussions in Nebraska, 2011 Every mesoscale discussion 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.