Mesoscale Discussion 247

Issued

Mar 22, 2011, 2:25 PM CDT (19:25 UTC)

Expired

Mar 22, 2011, 6:30 PM CDT

In force

4 hr

Issued by

the Storm Prediction Center

The Aberdeen radar (KABR), 93 km from the middle of the area, began a volume at 19:29 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.

348 
ACUS11 KWNS 221926
SWOMCD
SPC MCD 221925
MNZ000-SDZ000-NDZ000-222330-

MESOSCALE DISCUSSION 0247
NWS STORM PREDICTION CENTER NORMAN OK
0225 PM CDT TUE MAR 22 2011

AREAS AFFECTED...NERN SD/SERN ND/W-CNTRL MN

CONCERNING...WINTER MIXED PRECIPITATION

VALID 221925Z - 222330Z

A MIX OF WINTRY PRECIPITATION TYPES IS EXPECTED TO OVERSPREAD NERN
SD...SERN ND...AND W-CNTRL MN THIS AFTERNOON AND CONTINUE THROUGH
THIS EVENING. LIQUID-EQUIVALENT RATES TO 0.10 INCH/HR WILL BE
POSSIBLE.

DEEP-LAYER LOW PRESSURE OVER THE NRN ROCKIES IS TRANSLATING
EWD...WITH AN 850-MB BAROCLINIC TROUGH EXTENDING FROM NW TO SE
ACROSS SD. NORTH OF THE TROUGH AXIS...RUC OBJECTIVE ANALYSIS DEPICTS
AN 850-MB JET CHARACTERIZED BY E-SELY FLOW OF 50 TO 55 KT.
CONVERGENCE AT THE NOSE OF THIS JET IS DRIVING WIDESPREAD
PRECIPITATION ACROSS CNTRL AND SWRN ND. ADDITIONALLY...AN ARCING
BAND OF CONVECTION...INCLUDING THUNDERSTORMS...CONTINUES TO
MATERIALIZE FROM S-CNTRL ND INTO N-CNTRL SD. ALL OF THIS
PRECIPITATION IS FORECAST TO SHIFT EWD ACROSS THE DISCUSSION AREA IN
TANDEM WITH THE EWD MOTION OF THE AFOREMENTIONED 850-MB FEATURES.

ACROSS S-CNTRL ND...FAR N-CNTRL SD...AND PORTIONS OF W-CNTRL
MN...FORECAST SOUNDINGS INDICATE THAT SNOW WILL BE THE PREDOMINANT
PRECIP TYPE WITH GENERALLY SUB-FREEZING TEMPERATURES ALOFT. SNOWFALL
RATES OF 1 IN/HR WILL BE POSSIBLE...DUE TO APPRECIABLE ISENTROPIC
ASCENT IN THE 300-310-K LAYER. FARTHER SOUTH...SURFACE TEMPERATURES
ARE INITIALLY FORECAST TO BE ABOVE FREEZING IN MANY AREAS...YIELDING
RAIN. HOWEVER...NAM/RUC MODELS SUGGEST THAT SUB-FREEZING LOW-LEVEL
TEMPERATURES WILL MATERIALIZE AS LOW-LEVEL COLD AIR ADVECTION AND
EVAPORATIVE COOLING EFFECTS OCCUR. THIS COULD SUPPORT SLEET AND
FREEZING RAIN...ESPECIALLY AFTER 22Z. FREEZING RAIN RATES OF 0.05 TO
0.10 INCH PER HOUR WILL BE A CONCERN...ESPECIALLY GIVEN THE
CONVECTIVE NATURE OF THE PRECIPITATION SUGGESTED BY THE NAM/RUC
MODELS INDICATING MUCAPE VALUES AOA 200 J/KG. THE PRECIPITATION IS
EXPECTED TO CONTINUE THROUGH THE EVENING HOURS...WITH THE
PRECIPITATION TYPE EXPECTED TO BE ALL SNOW BY LATE EVENING.

..COHEN.. 03/22/2011

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

ATTN...WFO...MPX...FGF...ABR...BIS...

LAT...LON   46139465 45529464 45069551 44889713 44979875 45380008
            46080137 46750047 46749575 46139465

Mesoscale Discussions in Minnesota, 2011Mesoscale Discussions in South Dakota, 2011Mesoscale Discussions in North Dakota, 2011Every mesoscale discussion in 2011

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.