I Only Have Ice For You

As of late Tuesday night, the Twin Cities enjoyed a veritable ice storm, with seemingly considerable more ice accumulation than virtually all forecasters anticipated. Here are a few pictures taken from TMF headquarters in St. Paul.

 

And the morning after

What will Wednesday bring? And, in the end, which forecaster will have come the closest to predicting the storm?

Capricious Models Blamed for Changing Snow Forecast

As of late Monday night, nearly all weather outlets were minimizing snow forecasts. The primary exception was KSTP, which was still calling for 4-8 inches and the NWS, which was calling for 3-6 inches. Most other outlets had followed MPR's lead from earlier in the evening and were in the general 1-2 or 1-3 inch range, with most snow expected to fall on Wednesday. The latest comparative forecasts appear here.

The much-talked about major Tuesday/Wednesday snowstorm now seems to be in doubt for the Twin Cities as many forecasters began changing their forecasts late this morning. Most weather outlets predicted an increasing likelihood that mixed precipitation would bring snow accumulation down considerably. We're trying to keep track of the various and fast-changing forecasts here.

Given that so many snow forecasts have gone south (or north) this winter, TMF conducted its own investigation into why weather models are behaving so erratically. With a little digging, we found the cause. Using a well-placed spy camera we determined how the models were being guided and captured the picture below.

We'll continue to track the models, ehrrr forecasters, as the storm -- in whatever form it takes -- arrives in the Twin Cities.

A Friendly Challenge to Local Forecasters

We challenge local Twin Cities forecasters to get creative and more informative in their forecast presentation as we get closer to a potential big storm on Tuesday/Wednesday. We’d love to see them take a page from the Capital Weather Gang book and paint a storm scenario in simple probabilities, something along the lines of this: 

• 10% 1 inch or less
• 25% 1-3 inches
• 30% 3-6 inches
• 25% 6-12 inches
• 10% >12 inches

This seems to be a very logical way of recognizing the possibilities of a given storm scenario while implicitly incorporating the uncertainty that comes with distance (in time) to the event. And just as the cone of a possible land-falling hurricane gets narrowed as time elapses, so too, could the probabilities of various outcomes.

Forecasters, what are your thoughts with this kind of presentation? Consumers/weather watchers, is this a presentation you'd like to see?

Sunday “Storm” On Deck, Larger Storm in the Hole

If a nation once turned its lonely eyes to Joe DiMaggio, then a snow-starved metro area turns its wishful eyes to Tuesday and Wednesday, when the latest possibility of significant snow seems to exist. While Sunday’s storm is about to take its expected weak at bat (think Drew Butera), the midweek storm that sits in the dugout has shown indications – at least to some forecasters – of having some Ruthian potential.

Cue up the national anthem fellas and let’s start keeping score.

Portion of forecast discussion page from the NWS in Chanhassen.

 

 

This image was issued by The Weather Channel at 3:45 p.m. Saturday. The use of the "accumulation potential" wording is unusual for this year.