Snowiest Week of the Year?

Snow lovers in Minnesota can hardly contain themselves as two significant snowstorms, nearly back-to-back, appear headed for the Twin Cities. For some background on the possibilities, check out the video we did with Tom Novak. Happy storm watching!

Probabilistic Thinking

As some of you know, I'm a big fan of probabilistic forecasting and the work of the Capital Weather Gang when it comes to snow forecasts. Here are the high, low and expected snowfall forecasts for MSP as of Friday morning for the Sunday/Monday event.

Did you miss our last video with Novak Weather?

Happy storm track monitoring!

"S" Word Makes Annual Debut (Kinda Early)

If winter's not your thing (in which case what the heck are you living in Minnesota for?), you're probably quaking in your boots. If you're a winter lover, your day is drawing near, possibly much sooner than you dreamed possible.

Several weather outlets are introducing the possibility of a little snow Friday night into Saturday morning. An arresting thought to be sure. Seems like it's almost time to cue up one of our favorite songs.

Here are a few graphics that capture the potentially wintry weather headed our way just days into the official beginning of meteorologic fall.

NWS Forecast

More Cold... and a Little More Snow

Graphic depicting volume of sub-zero cold.

The brutal cold is here for the long haul according to Tom Novak of NovakWeather. We spoke with Tom this evening to learn more about the cold that's in store as well some snow that appears headed our way for Friday.

And how cold has it been? I thought the graphic to the right was particularly instructive, showing a total of almost 20 full days of sub-zero weather. It would appear we're headed to challenge the largest number of sub-zero hours at MSP airport since 1946.

Twitter links: NovakWeather, Minnesota Forecaster.

Facebook links: NovakWeather, Minnesota Forecaster.

Grading Jan. 13-14 Storm (and what was Chris Shaffer thinking?)

It’s been a while since we’ve graded forecasters. In truth that’s because there hasn’t been much interesting weather (i.e., snowstorms) and because there’s been little forecaster variance. This time, however, we feel compelled to highlight the particularly poor forecast by WCCO’s Chris Shaffer.

Here’s an excerpt from Shaffer’s forecast on the 6 p.m. news last night on WCCO. He said that “most of us will see less than an inch.” He went against all others and consistent model data. It seems he looked at one rogue model solution and ran with it. With the 4.4” of snow that fell, we think that most viewers would call this a poor forecast.

Chris Shaffer forecast from 6 p.m. WCCO newscast.

While a bad forecast is one thing, coming out 24 hours later and implying it was just what you expected is harder to swallow. Here’s a video capture from a segment of his 6 p.m. weathercast from Tuesday night. There’s the clear implication that the storm was what he expected (“just a little snow) yet he actually brings forth reported totals that are in excess of the totals he’s trying to validate. And how can he continue to call this “not much snow” when it caused snow emergencies in both major metropolitan cities? The fact is that we received one of the biggest snowfalls of the season with 4.4” and much of the metro received 3-5”. That’s a solid snowstorm in most peoples’ books.

Not surprisingly, we have to give Chris Shaffer’s forecast an F. Here are our grades for the efforts of other local forecasters:

WCCO: F. A poor forecast and an even poorer follow-up self assessment.
KSTP: B. More aggressive than most with a 2-4” forecast, but not aggressive enough. Also emphasized 2-3" with "spots seeing 4".
KMSP: C. Too conservative at 1-3 inches.
KARE: C. Same as KMSP
NWS: B+. They were consistent in forecasting 2-4” and, appropriately, issued an advisory.
Strib: C. Todd Nelson’s 1-3” forecast was too conservative.
MPR: C. While noting forecast volatility, was too conservative at 1-3”
Novak Weather: A. Refer to this video (beginning at 11:45).

Major March Snowstorm Expected by All Forecasters

Yes, it's once again time to stare out the window at falling snow.

The off-again, on-again winter storm for the Twin Cities is most definitely on again according to virtually all local forecasters as of Sunday evening.. While there's remarkable consensus in the forecast, some forecasters were late to the party. For a look at anecdotal comments regarding the evolution of this  now-bullish forecast, visit our previous blog entry. It's worth noting that Novak Weather was the most steadfast in forecasting a major storm.

Six to ten inches of snow seems to be the magic phrase. The Star Tribune blog (Paul Douglas), last updated shortly before noon, details 5-8" of snow, a bit lower than the consensus. The KMSP (Fox) forecast was a hair above the consensus at 7 to 11 inches.

WCCO: 6-10 (5 p.m. news)
KSTP: 6-10 (5:30 p.m. news)
KMSP: 7-11 (5:30 p.m. news)
KARE: 6-10 (5 p.m. news)
NWS: 6-10 (weather.gov)
Strib/Paul Douglas: 5-8
MPR: (no original entry; cited NWS info)
Accuweather: 6-10
TWC: 6-10
Novak Weather: 8-10 (but warns conservative)
Chase the Plains: 8-9
Shakopee Weather: 6-9
Note: The NWS in La Crosse has MSP in the 9-13 inch range.

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Analysis of Forecaster Performance for Dec. 9 Storm

The final total for this weekend’s snowstorm was 10.5 at the official MSP airport recording station. The core metro area snowfall ranged from 9 to 14 inches with an even foot of snow a common observation, including here at TMF headquarters in St. Paul.

No forecaster anticipated the possibly of a truly major snowfall until late Saturday afternoon. Even then, most forecasts did not fully capture the extent of the burgeoning snowstorm. (Note, for weather geeks looking to get a meteorological explanation for the late-changing forecast, MPR provides a good analysis here.)

Rather than provide forecaster grades as we have in the past, we’ll focus on a few general observations. Given that we don’t capture forecast activity in a truly systematic, day-by-day manner, we feel that the assignment of grades suggests a level of authority and exactness we simply don’t have. Still, we believe we monitor the forecasts enough to offer reasonable opinions. As always, take them for what they’re worth. We invite readers to provide grades and thoughts in the comment section to this post.

Our observations:

The best performers for this storm were the National Weather Service (NWS) and Novak Weather. Most other forecast outlets did not distinguish themselves.

Virtually all forecasters eyed this storm for the better part of a week. However, several minimized the storm as recently as Thursday. On Thursday, KMSP tweeted, “Winter returns the next few days, flurries late Fri afternoon, flurries Sat and wicked cold by Mon.” On Thursday evening, the Star Tribune noted the possibility of 1-3 inches of “oatmeal-like slush,” jokingly suggesting it would be cause to contact MnDOT and the National Guard. Likewise, the Weather Channel noted the possibility of mere “snow showers” over the weekend. At the same time, however, other forecasters were not ready to conclude the storm would be a minimal, back-page item.

KMSP was Jekyll & Hyde on this one. After the overly minimizing tweet on Thursday, they had the best standing prediction on Friday night with a forecast of 6-8 inches. But by Saturday, they’d revised it downward to 4.1 inches (the “snow meter.”)

The NWS consistently predicted higher amounts than the majority of forecasters 36 hours prior to the storm’s arrival. Some readers/viewers may have wondered whether a winter storm warning for MSP would prove to be warranted; clearly, it was.

Novak Weather also lead the way on this forecast, staying the course of a forecast of 6+ inches for MSP from early on. On Saturday afternoon, Novak Weather was also the first to communicate the possibility that accumulations could “get out of hand quickly for MSP” on Sunday as they ultimately did.

The separation of men from boys on this forecast took place Saturday afternoon and evening. Some forecasters picked up on the late-developing possibility of a truly significant snowfall while others did not. As detailed in the previous post, forecasts by KSTP (Jonathan Yuhas) and KMSP (Steve Frazier) missed the boat in not noting the late change in the storm’s evolution (though it should be noted that other members of the KSTP forecasting team tweeted 5-8 inch forecasts at the same time Yuhas was on air forecasting 3-6 inches).