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Snowfall Verification for Nov 27

A bit more when right than wrong with this forecast, though there was a decent chunk of the forecast that was in fact wrong. Had the general theme and possible snowfall amounts in the right neighborhood. Big errors can be noted in south-central PA, where lower snowfall rates kept much from accumulating. Northern PA and northern NJ over-performed a bit, especially in northern NJ where better banding set up. Rain/snow line and snowfall amounts in southeastern PA, central NJ and in the NYC area were pretty good.

B- forecast overall.

Snowfall Verification for Nov 7-8

Not a good result for my first forecast of the 2012-13 snow season. Forecast confidence was on the lower side, and it was a difficult forecast, but the difficulty doesn’t changed the fact that I missed the target in a lot of areas. Not a complete failure, though. This forecast gets a D grade.

The storm ended up being a bit weaker and further east than I (and most/all other forecasters) expected, resulting in cooler conditions and heavier snow further east along the coast. Max snowfall reported within the forecast area was a whopping 13.0″ in Freehold, NJ (which was the only report over a foot and got smoothed out in my verification map). In the end, it’s a good thing I left the 4-8″ contour out of the final map as it would have hurt my grade even more.

The stressful, difficult forecasts continue over from last season. I’m hoping for some more straight-forward storms this winter where the storm track isn’t swinging wildly from run to run within 12-48 hours of the event.

Winter 2011-2012 forecast verification

This was an ugly forecast… pretty much the exact opposite of what actually happened. There was virtually no blocking this year (I was relying on blocking for the cold pattern), and a fairly persistent and strong trough over Alaska prevented any sort of real, long-lasting cold from entering the U.S.

DJF temperature forecast: F

December 2011: F

January 2012: F

February 2012: D-

DJF precipitation forecast: D

Snowfall Verification for Feb 19

While my first two maps left much to be desired, I finally got the storm zoned in on my final forecast:

The southern edge of the system did a bit better than expected east of the mountains as the snowfall rates were able to overcome the above freezing surface temperatures. The northern edge of the 4-8 inch contour also did better than expected in central VA, with spotty 8-10 inch reports in the higher elevations. I also overdid some of the snow in the far southern Appalachians.

A solid B+ forecast overall.

Snowfall Verification for Feb 10-11

What a strange storm this was…

The three-part storm that I was expecting to be a two-parter. First, the snow in central MD over-performed Friday night as temperatures were just cool enough to allow snow to accumulate more quickly. The second part, the squall line, went as expected as accumulations of a dusting to a quarter inch (possibly a half inch in a few spots) were reported from that.

The third part that was enhanced by the inverted trough is what really got me. That produced a good 1-2 inches of snow over a good portion of the Delmarva Peninsula and in extreme eastern VA.

Another major failure in the forecast came in eastern PA and NJ as the coastal low and associated precipitation did not come as close to the coast as I had anticipated. Instead, it took a track similar to what the GFS showed and limited most of eastern PA and NJ to under an inch of snow during the first part of the storm. I also missed some of the higher lake-effect totals in northeast OH and northwest PA.

Weighing in the fact that I missed big in some areas, did fairly well in the mountains and the difficulty of the forecast, this was a D+.

Snowfall Verification for Feb 8

Another headache-inducing storm with poor rates, boundary layer issues and overdone QPF amounts:

The verification wasn’t as bad as I thought it would be. I still got the general idea right, but was off in some key areas east of the mountains. The northern extent of 1+ inch accumulation in NJ was a bit surprising, and the OH snow and southern WV/VA snow was a bit lacking compared to my forecast. The southern edge did go down along the mountain ridges a bit more than I expected.

I’m going to give myself another B- for this event. I bit into the hype east of the mountains in VA/MD and put the one inch line further south than I felt comfortable doing, and that backfired. Going conservative is definitely the best option with the snowfall forecasts this winter.

Snowfall Verification for Feb 4-5

The verification on this one was rather interesting… some odd shapes/placements of the snow totals:

The front-end of the system over-produced and the back edge under-produced, with some front-end banding boosting totals in central MD. Lighter rates and above-freezing temperatures kept the totals down elsewhere. Overall, I had the right idea, but with a warm boundary layer and a weak system it’s always difficult to nail the accumulations. I’d give this forecast a B- for getting the general theme right within the oddly-placed snow totals.