Alert archive / Minnesota / Mesoscale Discussions in 2004

Mesoscale Discussion 2549

December 20, 200434 counties in Minnesota; 14 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Dec 20, 2004, 5:28 AM CST for 34 counties in Minnesota; 14 counties in Wisconsin. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Dec 20, 2004, 5:28 AM CST (11:28 UTC)
Expired: Dec 20, 2004, 10:30 AM CST
In force: 5 hr
Issued by: the Storm Prediction Center

All 48 counties

Anoka County, MN, Blue Earth County, MN, Brown County, MN, Carver County, MN, Cottonwood County, MN, Dakota County, MN, Dodge County, MN, Faribault County, MN, Fillmore County, MN, Freeborn County, MN, Goodhue County, MN, Hennepin County, MN, Jackson County, MN, Le Sueur County, MN, Lyon County, MN, Martin County, MN, McLeod County, MN, Mower County, MN, Murray County, MN, Nicollet County, MN, Nobles County, MN, Olmsted County, MN, Ramsey County, MN, Redwood County, MN, Renville County, MN, Rice County, MN, Scott County, MN, Sibley County, MN, Steele County, MN, Wabasha County, MN, Waseca County, MN, Washington County, MN, Watonwan County, MN, Winona County, MN, Buffalo County, WI, Chippewa County, WI, Clark County, WI, Dunn County, WI, Eau Claire County, WI, Jackson County, WI, La Crosse County, WI, Monroe County, WI, Pepin County, WI, Pierce County, WI, Saint Croix County, WI, Taylor County, WI, Trempealeau County, WI, Wood County, WI

The radar

The Minneapolis radar (KMPX), 77 km from the middle of the area, began a volume at 11:29 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.

The nearest sounding before it

Minneapolis, MN (KMPX), launched 00:00Z, 11.5 hours before the alert went out and 79 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: 1873 m above ground
0-6 km bulk shear: 82 kt
0-1 km storm-relative helicity: 258 m²/s²
0-3 km storm-relative helicity: 711 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.

638 
ACUS11 KWNS 201129
SWOMCD
SPC MCD 201128 
WIZ000-MNZ000-IAZ000-201630-

MESOSCALE DISCUSSION 2549
NWS STORM PREDICTION CENTER NORMAN OK
0528 AM CST MON DEC 20 2004

AREAS AFFECTED...NRN IA...SRN MN...WRN WI

CONCERNING...PRECIPITATION TRENDS...WINTER PRECIPITATION 

VALID 201128Z - 201630Z

WINTER WEATHER HAZARDS INCLUDING ICE PELLETS AND MDT TO HVY SNOW ARE
EXPECTED TO INCREASE ACROSS PARTS OF NRN IA...SRN MN...AND WRN WI
FROM LATE MORNING INTO THE AFTERNOON. ICE PELLETS APPEAR TO BE
PRIMARY THREAT OVER WRN MN THIS MORNING WHILE A NARROW AXIS OF
HEAVIER SNOWFALL...WITH RATES APPROACHING 1 INCH PER HOUR...MAY
DEVELOP FROM SERN MN INTO WRN WI BY AFTERNOON.

LATEST IR SATELLITE IMAGERY WAS DEPICTING COOLING CLOUD TOPS WITHIN
A DEVELOPING SMALL-SCALE BAROCLINIC LEAF ACROSS NERN SD AND CNTRL
MN. THIS FEATURE APPEARS TO BE DEVELOPING IN RESPONSE TO STRONG
IMPULSE AND MID/UPPER LEVEL JET STREAK SPREADING EAST FROM ERN WY
THIS MORNING. LATEST RUC AND 06Z ETA ARE IN GOOD AGREEMENT SHOWING
UPWARD VERTICAL MOTION INCREASING FROM ERN SD INTO SRN MN OVER THE
NEXT SEVERAL HOURS. VERY STRONG LOW LEVEL WARM AIR ADVECTION WAS
ALREADY OCCURRING ACROSS THIS AREA WITH INITIAL ROUND OF ISENTROPIC
ASCENT-INDUCED MDT/HVY SNOW NOW MOVING EAST ACROSS WI. CONTINUED
MOISTENING/WARMING WITHIN TRAILING ZONE OF LOW LEVEL ISENTROPIC LIFT
ACROSS SRN MN...COUPLED WITH INTENSIFYING SYNOPTIC SCALE FORCING FOR
DEEP ASCENT...SHOULD RESULT IN AN INCREASE IN WINTER PRECIPITATION
ACROSS THE AREA.

FORECAST THERMODYNAMIC PROFILES SUPPORT SNOW FROM SERN MN ACROSS WI.
HOWEVER...ACROSS WRN MN AND PARTS OF NWRN IA...PRONOUNCED WARM NOSE
WITH 850MB WET BULB TEMPERATURES 4-6C SHOULD RESULT IN A MIXTURE OF
ICE PELLETS ACROSS THESE AREAS...POSSIBLY CHANGING BACK TO SNOW
LATER TODAY.

..CARBIN.. 12/20/2004

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

...NOTICE...
SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A 
SCHEDULED BASIS...FOUR TIMES A DAY...BETWEEN 00-01 UTC...
06-07 UTC...12-13 UTC...AND 18-19 UTC AS SIGNIFICANT SHORT
RANGE WINTER WEATHER EVENTS UNFOLD.  THIS SCHEDULE WILL BE
USED FROM DECEMBER 1 THROUGH FEBRUARY 28.

ATTN...WFO...GRB...ARX...MPX...DMX...FSD...

45379065 44438957 43819044 43379486 43729610 44659604
45299351

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 19, 6:52 PM CST	Mesoscale Discussion	SPC	Becker, Beltrami, Cass, Clay, Clearwater, Crow Wing and 17 more	6 hr
Dec 20, 1:02 AM CST	Mesoscale Discussion	SPC	Carlton, Cook, Lake, Saint Louis	4 hr

Nearby

Mesoscale Discussions in Minnesota, 2004 Mesoscale Discussions in Wisconsin, 2004 Every mesoscale discussion in 2004

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.