Alert archive / Arkansas / Mesoscale Discussions in 2011
Mesoscale Discussion 92
The Storm Prediction Center issued this mesoscale discussion at Feb 6, 2011, 10:13 PM CST for 15 counties in Arkansas. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Feb 6, 2011, 10:13 PM CST (04:13 UTC)
- Expired
- Feb 7, 2011, 2:15 AM CST
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
Counties Cleburne County, AR, Conway County, AR, Faulkner County, AR, Independence County, AR, Izard County, AR, Jackson County, AR, Lawrence County, AR, Perry County, AR, Pope County, AR, Searcy County, AR, Sharp County, AR, Stone County, AR, Van Buren County, AR, White County, AR, Yell County, AR
The radar
The Little Rock radar (KLZK), 67 km from the middle of the area, began a volume at 04:15 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
Springfield, MO (KSGF), launched 00:00Z, 4.2 hours before the alert went out and 206 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 521 m above ground
- 0-6 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- -22 m²/s²
- 0-3 km storm-relative helicity
- 10 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
810
ACUS11 KWNS 070414
SWOMCD
SPC MCD 070413
ARZ000-070815-
MESOSCALE DISCUSSION 0092
NWS STORM PREDICTION CENTER NORMAN OK
1013 PM CST SUN FEB 06 2011
AREAS AFFECTED...NRN AND CNTRL AR
CONCERNING...HEAVY SNOW
VALID 070413Z - 070815Z
HEAVY SNOW APPEARS POSSIBLE ACROSS PARTS OF NORTH CENTRAL ARKANSAS
OVERNIGHT...NORTHWEST THROUGH NORTHEAST OF LITTLE ROCK ...PERHAPS
INCLUDING THE LITTLE ROCK AREA.
AN AREA OF ENHANCED MID-LEVEL FORCING FOR UPWARD VERTICAL MOTION
...ASSOCIATED WITH AN INITIAL SHORT WAVE IMPULSE LIFTING NORTHEAST
OF THE ARKLATEX...APPEARS LIKELY TO CONTRIBUTE TO INCREASING
PRECIPITATION ACROSS MUCH OF NORTHERN AND CENTRAL ARKANSAS DURING
THE NEXT FEW HOURS. AS THIS OCCURS...MODELS SUGGEST EVAPORATION
WILL GRADUALLY SATURATE AND COOL LOW-LEVEL THERMODYNAMIC PROFILES
TOWARD FREEZING. COOLING WILL PROBABLY BE ENHANCED BY WEAK COLD
ADVECTION...AS A WEAK SURFACE LOW MIGRATES EASTWARD NEAR THE
SOUTHERN ARKANSAS BORDER...AND A CHANGEOVER FROM RAIN TO SNOW AT THE
SURFACE IS EXPECTED OVERNIGHT.
WITH THE APPROACH OF ANOTHER VIGOROUS IMPULSE...LIFTING OUT OF THE
BASE OF THE BROADER SCALE UPPER TROUGH OVER TEXAS DURING THE 06-09Z
TIME FRAME...LATEST RUC GUIDANCE SUGGESTS STRENGTHENING LIFT IN THE
MIXED PHASE LAYER FAVORABLE FOR LARGE DENDRITIC ICE CRYSTAL GROWTH.
IN THE PRESENCE OF PRECIPITABLE WATER IN EXCESS OF 0.5
INCHES...CONDITIONS SEEM LIKELY TO BECOME SUPPORTIVE OF 1+ INCH PER
HOUR SNOW RATES BY 09Z...PARTICULARLY WITH CONVECTION POSSIBLE AS
STEEPENING MID-LEVEL LAPSE RATES CONTRIBUTE TO WEAK DESTABILIZATION.
SNOW RATES AND TOTALS MAY BE ENHANCED FURTHER BY OROGRAPHIC FORCING
ACROSS THE BOSTON AND OUACHITA MOUNTAINS.
..KERR.. 02/07/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...MEG...LZK...
LAT...LON 35179368 36129298 36189141 35999091 35819077 34849213
34759267 34849335 35179368Nearby
Mesoscale Discussions in Arkansas, 2011Every 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.