Case: March 8, 2003

A fast-moving snow storm passed through Wisconsin on Saturday late morning into the afternoon. Some links to images and information about the storm are presented here, along with forecast ingredient maps. The instability, forcing and moisture of this well-forecasted event was considered by forecasters as much as 30 hours in advance.

Forecast Discussions from NWS Milwaukee/Sullivan:

3:00AM March 7, 2003
Paul Collar

3:15PM March 7, 2003
JJ Wood

3:35AM March 8, 2003
Paul Collar

Satellite images and
surface observations
Not available yet

KMKX Radar
Not Available yet

Ingredient maps and discussion

For more information about the ingredients approach and these diagnostics see http://speedy.meteor.wisc.edu/~swetzel/winter

Sufficient moisture, moderate QG and frontogenetic forcing, and some instability all played important roles in this quick moving system that left up to 4 inches of snow in some areas of WI in less than six hours.

Ingredient maps are shown in the table below from the ETA model forecasts initialized at 00UTC March 7 until 12UTC March 8. Images are grouped by the time the forecasts are valid: 1) 12UTC March 8: Around the time snow was beginning in north central WI, 2) 18UTC March 8: Around the peak of the snow in south central WI, 3) 00UTC March 9: After snow ended in most of WI

1) Snow beginning in NW WI: Ingredient maps valid at 1200UTC 8 March 2003

		Cross Section	850mb	700mb	600mb
12UTC 8 March 2003 ETA Model	00 hour forecast	N/A	Traditional PVQ & PVF	Traditional PVQ & PVF	Traditional PVQ & PVF
00UTC 8 March 2003 ETA Model	12 hour forecast	XC	Traditional PVQ & PVF	Traditional PVQ & PVF	Traditional PVQ & PVF
12UTC 7 March 2003 ETA Model	24 hour forecast	XC	Traditional PVQ & PVF	Traditional PVQ & PVF	Traditional PVQ & PVF
00UTC 7 March 2003 ETA Model	36 hour forecast	XC	Traditional PVQ & PVF	Traditional PVQ & PVF	Traditional PVQ & PVF

2) Snow Underway in WI: Ingredient maps valid at 1800UTC 8 March 2003

		Cross Section	850mb	700mb	600mb
12UTC 8 March 2003 ETA Model	06 hour forecast	N/A	Traditional PVQ & PVF	Traditional PVQ & PVF	Traditional PVQ & PVF
00UTC 8 March 2003 ETA Model	18 hour forecast	XC	Traditional PVQ & PVF	Traditional PVQ & PVF	Traditional PVQ & PVF
12UTC 7 March 2003 ETA Model	30 hour forecast	XC	Traditional PVQ & PVF	Traditional PVQ & PVF	Traditional PVQ & PVF
00UTC 7 March 2003 ETA Model	42 hour forecast	XC	Traditional PVQ & PVF	Traditional PVQ & PVF	Traditional PVQ & PVF

3) After Snow ended in WI: Ingredient maps valid at 000UTC 9 March 2003

		Cross Section	850mb	700mb	600mb
12UTC 8 March 2003 ETA Model	12 hour forecast	N/A	Traditional PVQ & PVF	Traditional PVQ & PVF	Traditional PVQ & PVF
00UTC 8 March 2003 ETA Model	24 hour forecast	XC	Traditional PVQ & PVF	Traditional PVQ & PVF	Traditional PVQ & PVF
12UTC 7 March 2003 ETA Model	36 hour forecast	XC	Traditional PVQ & PVF	Traditional PVQ & PVF	Traditional PVQ & PVF
00UTC 7 March 2003 ETA Model	48 hour forecast	XC	Traditional PVQ & PVF	Traditional PVQ & PVF	Traditional PVQ & PVF

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