MESO: Mesoscale Discussion 2158

ACUS11 KWNS 151150
SWOMCD
SPC MCD 151150 COR
MNZ000-SDZ000-151500-

MESOSCALE DISCUSSION 2158
NWS STORM PREDICTION CENTER NORMAN OK
0550 AM CST SAT DEC 15 2012

AREAS AFFECTED...PARTS OF EAST CENTRAL AND NERN SD INTO A SMALL
PORTION OF SWRN-WEST CENTRAL MN

CONCERNING...FREEZING RAIN

VALID 151150Z - 151500Z

CORRECTED FOR TYPOS IN FIRST PARAGRAPH OF DISCUSSION

SUMMARY...FREEZING RAIN RATES OF 0.05 INCH PER 3-HOURS CAN BE
EXPECTED IN A 30-40 MILE WIDE CORRIDOR ORIENTED SW-NE IN NERN SD
/FROM HAND COUNTY TO ROBERTS COUNTY/ AND ADJACENT WRN TRAVERSE/BIG
STONE COUNTIES MN. MEANWHILE...A SMALLER SPATIAL COVERAGE FREEZING
RAIN THREAT EXISTS IN A 25 MILE WIDE CORRIDOR ORIENTED NW-SE FROM
ERN GRANT COUNTY SD TO MML IN SWRN MN...WHERE RATES COULD EXCEED
0.1-0.2 INCH PER 3-HOURS THROUGH 15Z.

DISCUSSION...TRENDS IN OVERNIGHT/EARLY MORNING SURFACE OBSERVATIONS
INDICATED TEMPERATURES REMAINING BELOW 32 F...GENERALLY W-N OF A
LINE FROM 9V9 /CHAMBERLAIN SD/ TO HON TO ATY. ALTHOUGH MOST SURFACE
TEMPERATURES IN CENTRAL AND SRN MN WERE ABOVE 32 F...A SMALL
CORRIDOR EXTENDING FROM MML TO WRN PARTS OF YELLOW MEDICINE/LAC QUI
PARLE COUNTIES MN TO THE MN/SD BORDER AT GRANT COUNTY SD HAD
TEMPERATURES REMAINING IN THE MID-UPPER 20S. REGIONAL RADAR IMAGERY
SUGGESTED A SW-NE DEFORMATION ZONE WAS DEVELOPING IN THE
AFOREMENTIONED SW-NE ORIENTED CORRIDOR IN NERN SD. GIVEN THIS
REGION IS EXPECTED TO REMAIN ON THE NWRN EXTENT OF LOW LEVEL
MOISTURE INFLOW AS THE SURFACE LOW TRACKS NEWD INTO WEST CENTRAL IA
BETWEEN 15-18Z...PRECIPITATION RATES SHOULD TEND TO BE LESS THAN
LOCATIONS FARTHER EAST IN MN.

MEANWHILE...REGIONAL RADAR/SURFACE OBSERVATIONS INDICATED HIGHER
REFLECTIVITY AND RAINFALL RATES...RESPECTIVELY OCCURRING IN NWRN IA
/0.1 TO 0.3 INCH PER HR IN THE 09-10Z OBSERVATIONS/. A BAND OF
CONVECTIVE SHOWERS EXTENDING FROM FAR NWRN IA INTO SWRN MN WILL
CONTINUE TO SHIFT NWWD REACHING LYON COUNTY BY 12Z AND THE REST OF
THE SWRN-WEST CENTRAL MN SUB-FREEZING SURFACE TEMPERATURES BETWEEN
12-15Z. ALTHOUGH TEMPERATURES MAY WARM A FEW DEGREES IN THIS
REGION...MODELS SUGGEST FREEZING RAIN SHOULD BE THE PREDOMINANT
PRECIPITATION-TYPE THROUGH 15Z...WITH RATES EXCEEDING 0.1 INCH IN
1-3 HOURS.

..PETERS.. 12/15/2012

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

ATTN...WFO...MPX...FSD...ABR...

LAT...LON 45839683 45899655 45509643 44999619 44579562 44339579
44649625 45089685 45009733 44389842 44219893 44419935
44809919 45479792 45889730 45839683

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