Alert archive / South Dakota / Mesoscale Discussions in 2009

Mesoscale Discussion 2002

September 8, 20095 states

The Storm Prediction Center issued this mesoscale discussion at Sep 8, 2009, 6:10 PM MDT for 5 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Sep 8, 2009, 6:10 PM MDT (00:10 UTC)
Expired: Sep 8, 2009, 8:15 PM MDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 67 counties

Phillips County, CO, Sedgwick County, CO, Washington County, CO, Yuma County, CO, Big Stone County, MN, Traverse County, MN, Barnes County, ND, Cass County, ND, Dickey County, ND, LaMoure County, ND, Ransom County, ND, Richland County, ND, Sargent County, ND, Arthur County, NE, Blaine County, NE, Boyd County, NE, Brown County, NE, Chase County, NE, Cherry County, NE, Custer County, NE, Deuel County, NE, Dundy County, NE, Frontier County, NE, Garden County, NE, Grant County, NE, Hayes County, NE, Holt County, NE, Hooker County, NE, Keith County, NE, Keya Paha County, NE, Lincoln County, NE, Logan County, NE, Loup County, NE, McPherson County, NE, Morrill County, NE, Perkins County, NE, Rock County, NE, Thomas County, NE, Aurora County, SD, Beadle County, SD, Brown County, SD, Brule County, SD, Buffalo County, SD, Charles Mix County, SD, Clark County, SD, Codington County, SD, Davison County, SD, Day County, SD, Deuel County, SD, Douglas County, SD, Faulk County, SD, Grant County, SD, Gregory County, SD, Hamlin County, SD, Hand County, SD, Hanson County, SD, Hyde County, SD, Jerauld County, SD, Kingsbury County, SD, Lyman County, SD, Marshall County, SD, Miner County, SD, Roberts County, SD, Sanborn County, SD, Spink County, SD, Todd County, SD, Tripp County, SD

The radar

The North Platte radar (KLNX), 153 km from the middle of the area, began a volume at 00:10 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 00:00Z, 0.2 hours before the alert went out and 227 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: 406 J/kg
Mixed-layer CIN: -155 J/kg
Mixed-layer LCL: 1707 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 23 m²/s²
0-3 km storm-relative helicity: 43 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

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

000 
ACUS11 KWNS 090011
SWOMCD
SPC MCD 090010 
MNZ000-SDZ000-NDZ000-NEZ000-KSZ000-COZ000-090215-

MESOSCALE DISCUSSION 2002
NWS STORM PREDICTION CENTER NORMAN OK
0710 PM CDT TUE SEP 08 2009

AREAS AFFECTED...PORTIONS NERN CO...EXTREME NWRN KS...SWRN THROUGH
N-CENTRAL NEB...S-CENTRAL THROUGH NERN SD...SERN ND...EXTREME
W-CENTRAL MN.

CONCERNING...SEVERE THUNDERSTORM WATCH 737...

VALID 090010Z - 090215Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 737
CONTINUES.

PRIMARY/BKN BAND OF CONVECTION CONTINUES INVOF SFC COLD FRONT FROM
NEAR ABR-VTN TO GARDEN COUNTY NEB AS OF 2345Z...THEN SEPARATING FROM
FRONT SWD AND SWWD ACROSS NERN CO...NEAR AKO-APA LINE.  ACTIVITY
SHOULD CONTINUE TO MOVE GENERALLY EWD ACROSS CENTRAL/NRN PORTIONS WW
AND ESEWD ELSEWHERE...WITH STG-SVR GUSTS AND LARGE HAIL POSSIBLE. 
PREDOMINANT MODE SHOULD REMAIN LINEAR GIVEN CHARACTER OF FORCED
ASCENT ALONG FRONTAL/OUTFLOW BOUNDARIES AND NEARLY PARALLEL
ALIGNMENT OF MEAN WIND VECTOR WITH CONVECTIVE CORRIDOR.  ACTIVITY
WILL BE MOVING INTO PROGRESSIVELY GREATER LOW LEVEL MOISTURE...IN
INCREASING PROXIMITY TO SFC MOIST AXES NEAR WRN MN BORDER AND OVER
CENTRAL NEB.  HOWEVER...OFFSETTING FACTOR FOR SFC-BASED CONVECTION
WILL BE DIABATIC COOLING AND INCREASING MLCINH...ESPECIALLY AFTER
ABOUT 03Z.  

MRGL SVR POTENTIAL MAY EXTEND N OF WW ACROSS PORTIONS ERN ND. 
PRIMARILY THIS WOULD TAKE FORM OF HAIL INSTEAD OF WIND...GIVEN
POSTFRONTAL NATURE OF CONVECTION ACROSS THIS REGION AND PRESENCE OF
BOUNDARY LAYER CAA BENEATH.  SAME APPLIES TO POSTFRONTAL CONVECTION
DEVELOPING WITHIN WW ACROSS CENTRAL/NERN SD...AND CARE SHOULD BE
TAKEN CLEARING WW BEHIND MAIN/FRONTAL BAND PENDING TRENDS WITH
POSTFRONTAL ACTIVITY.  EFFECTIVE SHEAR ACTUALLY APPEARS STRONGER
BEHIND FRONT THAN ALONG/AHEAD OF IT...GIVEN SOMEWHAT STRONGER FLOW
ALOFT AND GEOMETRY OF KINEMATIC PROFILE ABOVE STABLE/FRONTAL LAYER. 
HOWEVER INSTABILITY WILL REMAIN RELATIVELY WEAK.

..EDWARDS.. 09/09/2009

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

ATTN...WFO...MPX...FGF...FSD...OAX...ABR...GID...BIS...LBF...
UNR...GLD...BOU...CYS...

LAT...LON   39900381 40340284 40820264 41360304 41690371 42050232
            44159997 45659904 47189881 47369722 46019658 46029629
            45459625 45439608 45199611 45259642 44499651 44519710
            44169716 44199741 43789743 43819758 43479765 43469808
            42829810 42909838 42069835 42059914 41059922 41030020
            40670026 40669996 40409991 40430010 40310006 40330107
            39770176 39900381

Nearby

Mesoscale Discussions in South Dakota, 2009 Mesoscale Discussions in Nebraska, 2009 Mesoscale Discussions in North Dakota, 2009 Every mesoscale discussion in 2009

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.