How Cold Will She Go?

The coldest, most prolonged arctic surge was expected to push through the Twin Cities late Saturday. Here's a graphic we saw issued by WCCO:

Use this space to discuss cold thoughts....

Prospects for Snow Both Sunday and Xmas Eve/Xmas

While it appears that most of the heavy snow from the weekend will fall south and east of Minnesota, there is still potential for accumulating snow on Sunday. And for those who want fresh snow to decorate Christmas Eve and Christmas Day... well, ma nature may just be feeling cooperative. The details are discussed in our latest video with Tom Novak and special guest Daniel Dix.

Daniel Dix, formerly of the Weather Channel, offers thoughts on upcoming snow.

Thursday Night Snow and a Weekend Snowstorm for the Midwest:The Weather Classroom

Some snow appears in the offing for Thursday night and our resident chief meteorologist, Tom Novak from @MinnesotaWeather, says to keep a close eye to the near southeast over the weekend. Here's our latest video.

Also, Tom and I are interested in your feedback on our video. What works for you? What doesn't? We really want you to be honest so we can make it better. Please leave your thoughts in the comment section. Thanks!

Dr. Novak says to keep a watchful eye to the southeast for a storm that's yet to write off the Twin Cities.

Stunning Disparity Among Forecasters in Long Range Forecast

At the Minnesota Forecaster, we love it when forecasters have differences of opinion. When all weather outlets predict the same thing it's boring.

As of this Wednesday evening, we've got a wide range of forecasts for next Wednesday (Dec. 18). The difference in high temperature forecasts between KARE and KSTP is a whopping 21 degrees!

**Update as of Thursday morning** KARE -- and to a lesser extent  WCCO -- have made significant revisions in their extended forecast. Overnight, KARE adjusted its Wednesday forecast from 9 to 29, while WCCO upped the forecast high from 12 to 20. It's obviously still way early, but it appears that KSTP grasped the trend before most other stations.

**Update as of Thursday evening** KARE is BACK to a forecast high of 9 on Wednesday. KSTP now forecasts a high of 20 for Wednesday.

WCCO

KSTP

KARE

Here are the forecast highs for next Wednesday that we gathered late this evening:

WCCO: 12
KSTP: 30
KMSP: not obtained
KARE: 9
NWS: 22
Accuweather: 14
Weather.com: 22

Two to Four Inches is Most Popular Forecast for Sunday Snow

Don't look up. More snow's in the forecast.

Most forecasters were on board with a 2-4" snowfall forecast for Sunday. The exception was KSTP with 1-3". Here's a look at forecasts we picked up on Saturday morning.

WCCO: 2-4" (morning broadcast)
KSTP: 1-3" (KSTP weather blog)
KMSP: 2-4" (KMSP weather blog)
KARE: 2-4" (website video)
MPR: 1-3" (not clear on this forecast; also info from blog post at 5 p.m. Friday)
TWC: "light accumulations" per 60-second video (rather useless for our purposes)
NWS: 2-4". (No advisory posted, at least yet)
Strib: 2-4"

Wide Disparity in Forecast for Dec. 3-4 Snow Event

With winter precipitation expected to begin by midnight, here’s the latest summary from the various forecasters. KSTP has the most aggressive forecast with 6-10” forecast. Accuweather and Minnesota Forecaster in-house forecaster Tom Novak were on the lower side. As we’ve seen fairly often over the last several years, KSTP is at the high end for TV forecast outlets and KARE is at the low end. (It’s been suggested that you can take half the KSTP forecast and arrive at the KARE forecast; that seems to be the case in this instance.)

We were struck by the NWS comment regarding their confidence in the forecast. A tweet at 3:04 p.m. this afternoon stated, “Confidence where that rain/snow line will setup is below average this close to the event.)”

Finally, if you’d like to learn more about the atmospheric dynamics causing the upcoming storm scenario, view our video with forecaster Tom Novak.

The all-important jet stream.

WCCO: 3-6 (5 p.m. news)
KSTP: 6-10” (late afternoon blog update)
KMSP: Either missed it or no totals were mentioned
KARE: Says 2-5” but shows model data depicting 5” (4:57 website video)
MPR: 3-7 per 4:07 blog update
NWS: 4-9” (weather.gov – Minneapolis)
TWC: 5-8 per map on NBC News
Accuweather: 1-3”
Tom Novak: 2-4”
Strib: 2-4” (blog last updated 8:42 a.m.)

A Forecast in Flux

As of late Monday night, predictions for a possible snow event Tuesday night into Wednesday was, as MPR’s Paul Huttner put it, “a forecast in flux.” Although the National Weather Service issued a Winter Storm Watch mid-afternoon Monday, there was a sense that many forecasters were not quite buying into such lofty possibilities. However, there was also a sense that the storm was taking a more southerly route, which would bring heavier accumulations closer to the Twin Cities from the north.

Here’s our recap of forecasts gathered late Monday night for snow possibilities Tuesday night into Wednesday.

WCCO: 1-3” but more possible later on Wed.

KSTP: 3-5” (10:40 p.m. on news)

KMSP: No specific amounts mentioned in 10 p.m. news

KARE: 2” (10:40 video posting on website)

NWS: 3-6”

MPR: “Early hunch” 1-6” from south to north (Updraft blog 10:46 p.m.)

Strib/Paul Douglas: 2-4” (11:21 p.m. update)

Accuweather: 1.67” (we added the 12-hour amounts posted on the site)
The Weather Channel: <1” (weather.com)

Side note: We did want to bring attention to what we consider one of the better weather blogs for a Twin Cities television forecaster (i.e., excepting MPR and Strib weather columns). KMSP's Cody Matz provided some nice graphics and an accompanying explanation of how and why the expected heavier snow accumulations have moved south in this blog.

Finally, a reminder that you can find us on Twitter and Facebook.

KARE11

WCCO

NWS

Weather Channel (weather.com)

A Test of Mid-Range Forecasts: Forecasters Calling for Arctic Air Next Weekend

With unusual unanimity for a forecast so far out, local meteorologists warned upper midwesterners to gird for some arctic temps NEXT weekend. As of Friday night, some forecasters were warning of sub-zero low temps and single digit high temps. We were surprised to see that old-school forecaster Craig Edwards, who typically doesn't discuss weather beyond 5-7 days out, noted the model forecasts for next weekend. Here's a sampling of what we could find.

Accuweather

Weather Channel (weather.com)

Paul Douglas/Strib

Most Forecasts Expecting Little More Than Coating for Thursday Night

Here’s a recap of forecasts for Thursday night’s possible snow. As much as possible, we’re using forecasts closest to 24 hours before onset as the forecast of record. Several forecasters have told us that 24 hours before snow onset is the time when you can best separate the men from the boys.

That said, for Thursday night’s forecast, there’s really not a lot of separation. As best we could determine, the NWS was the most liberal with snow forecasts (mentioning 3” on the top end of the range) while WCCO and KSTP seemed to poo poo the possible snow the most.

Herewith, the less than staggering snow forecast for the evening of Thursday, November 21, 2013:

WCCO: Coating to an inch (5 p.m. news)

KSTP: Coating to an inch

KMSP: Total accumulations look very light with around an inch in the metro and generally 2 inches or so for southern Minnesota. (Source: website post at 5:04 p.m.)

KARE: Said 1-2”. Showed 2” for MSP on graphic (6 p.m. news)

MPR: Coating to 2” (blog post at 5:01 p.m.)

NWS: 1-3” (Source: weather.gov/55111, zipcode for MSP airport)

Star Tribune: 1” possible (from blog with posting date of 12:17 a.m. on Nov. 20)

AccuWeather: 1.06” (Source: accuweather.com for zipcode 55111)

Harnessing the Power of Wind – In Minnesota and Beyond

Several weeks ago on the way to Joshua Tree National Park from Los Angeles, I passed through the largest field of wind turbines I’d ever seen. And, as if on cue, strong gusty winds suddenly whipped through the San Gorgonio Pass, buffeting my lightweight rental car. I was inspired by the sight of wind turbines extending out to the horizon, and wondered what goes into decisions on where to build these icons of green energy.

Wind turbines in Southern California's San Gorgonio Pass. (Bill Stein)

Fortunately, I didn’t have to wait long. Just weeks later, Kate Mullin, resource modeling analyst from WindLogics, a St. Paul-based company that provides forecasting and optimization solutions for sustainable power, gave a most informative talk to the Twin Cities Meteorological Society. She talked about the process by which wind power developers estimate the future energy production of a wind farm. While the following is by no means a complete summary of Kate’s presentation, I thought I’d share some of the facts we learned that I found interesting.

There are highly detailed maps that depict wind across the United States, providing a basis for determining locations that may be best suited for the construction of wind turbines. These maps display average annual wind in meters per second. You can multiply meters per second by 2.2 to get an approximate miles-per-hour measurement.

Minnesota is just northeast of the nation's strongest average winds.

Although there are several small and isolated pockets of high winds in western parts of the country, the majority of larger-scale strong winds occur in the central part of the United States. Minnesota is among the windiest parts of the country with southwestern Minnesota – owing in part to the Buffalo Ridge formation – experiencing the strongest average winds.

Areas of southwestern Minnesota average winds of nearly 20 mph.

An analysis of potential sites for wind farms includes mesoscale weather forecast model data, such as the Weather Research & Forecasting Model (WRF), as well as terrain-based models that take a closer look at smaller geographic grids (1km and 50m resolution).

Meteorological towers (“met” towers) are used to capture hourly data such as wind speed, wind direction and temperature at heights of up to 100 meters. Wind flow models incorporate the data and produce forecasts of wind conditions for an extended period of time, such as 30 years. Ultimately, the data generated will determine if a project is financially viable during the pre-construction phase.

The actual design of a wind farm incorporates a variety of factors. First, it’s a function of where land can be obtained and if it’s subject to any land use restrictions. Additional considerations include the form of power transmission, whether the site is close to housing and development, and environmental restrictions.

(Kate noted that regulations for wind farms in Canada are particularly stringent given environmental and other concerns. In the United States, Iowa and Texas are among states considered the most “wind-friendly.”)

After the potential energy production from a wind farm is calculated, other factors that can cause production losses must be considered. One of these factors is wake, a concept we might think of when it comes to a cyclist drafting behind another cyclist in a velodrome or a car following closely behind a large truck on the highway. In wind circles, it refers to the effect that one turbine has on additional turbines that follow down the line. Kate shared a particularly interesting graphic depicting wake that most everyone in the wind industry has seen. It’s an image of the Horns Rev offshore wind farm in Europe’s North Sea.

Clouds form in the wake of the front row of wind turbines at the Horns Rev wind farm in the North Sea. (Aeolus)

Some of the other factors that can reduce the productivity of wind turbines include the availability of the proper turbine model (different models are built to maximize different wind environments) and curtailment, which occurs when wind conditions are favorable, but for one reason or another the wind energy is not sent to the power grid.

Weather can also cause wind turbines to become unproductive. For example, icing is a particular concern for wind turbines in our part of the country. And, interesting enough, there are some parts of the country where wind turbines must be turned off when bats are most active so they don’t get caught in them.

So the next time you see a wind turbine, whether in the California desert or on the snow-covered prairie in southwestern Minnesota, take pleasure in knowing that energy is being captured from resources that are continually replenished, but also know that a ton of work – including complex wind forecasts – go into the building of them.

Follow the Minnesota Forecaster on Twitter and Facebook.

An Open Letter to Twin Cities TV Forecasters

Dear Beloved Twin Cities Television Forecasters,

It’s snow time, and a winter-obsessed populace turns its blue eyes to you. If you’ll follow a few of our pointers, we’ll get through this season with a healthy appreciation for meteorology and a minimal amount of misunderstandings.

Ditch the Snow Meter

It’s certainly tempting to use all the tools that WSI and other weather providers give you to wow us. But remember, we’re generally lazy, literal simpletons who glob on to whatever we see on the screen (especially if we’re not listening closely). If we see you point to a graphic showing 7.5 inches of snow in Mankato, 11.6 in Maple Grove, and 5.1 in Rochester, we’ll take it to the bank.

Here’s the problem. The snow meter suggests a level of preciseness that the science can’t yet support. It’s hard enough to get snowfall forecasts right to within an inch or two; why make it more complicated by displaying forecast amounts to the tenth of an inch?

Go Barry ZeVan on Us

Sometimes, old school is the best way to go. There’s nothing wrong with hand-drawn general estimates of snowfall amounts presented in colored gradation bands (just proof them to make sure no bands are missing, something that happens surprisingly often). Yes, this may be more time consuming than simply slapping up a pre-programmed depiction, but it’s worth it. Knock yourself out by using fancy colors but keep the presentation simple.

Keep Model Data Behind the Green Screen

These days there’s no shortage of weather models, whether proprietary or public. And access to the information is equally unprecedented. But please keep the model data to yourself. And never, NEVER, display the one outlier model that shows gargantuan amounts designed to make us drool. We’ll take it the bank and that’s no good for anyone. Ultimately, model data is your domain and should be kept under control of those who know how to interpret it.

(Major Exception: Weather Bloggers)

It makes more sense for weather bloggers to show model data, though even they might want to be careful as well. Just as true foodies might like to hide out in the chef’s kitchen, weather enthusiasts might enjoy a little inside baseball when it comes to weather. Weather bloggers also have the luxury you don’t: unlimited time. They can educate us to their heart’s delight and update essentially continuously.

Use Snowfall Probabilities to Communicate Uncertainty

There’s no such thing as a sure bet in snowfall forecasts, so why not communicate uncertainty? Tell us there’s a 20% chance of 4+ inches of snow, a 60” chance of 2-4 inches, and a 20% chance of less than 2 inches. This may threaten your inner macho, but it’s all about communication. When it comes down to it, it’s your communication abilities that we judge, almost as much or more than your actual knowledge of meteorology. The Capital Weather Gang, a weather blog produced by the Washington Post, sets the standard for communicating uncertainty.

Stand Up to the News Director Who Wants to Play Up A Storm

OK, this may tread on job security, but if you’re honest with yourself you know you’ll be doing the right thing. We know that snow sells almost as much as sex. You’ve probably been asked at some point to “play up the snow possibility” either explicitly or subtly. When the anchor leads with, “Hey Eddie, big snow coming our way, eh?” nip the hype in the bud with, “Ginger, this one will barely cover the grass!” Viewers will appreciate the straightforward approach.

Post-Storm Evaluation

Here’s where you can earn gobs of credibility. If the storm didn’t pan out as forecast, as often happens, come out and say so directly. A simple phrase like, “It was less than we expected and here’s why,” is all that’s needed. Better yet, if you communicated storm uncertainty with pre-storm probabilities, you can say, “the concern we had that thunderstorms in Iowa would steal the system’s energy materialized.”

By following these tips, you can become a truly trusted resource in this mother of all Minnesota seasons.

P.S. – Go easy on the non-weather tweets or consider setting up a separate Twitter account for non-weather tweets. The more extraneous stuff you throw in, the harder it is for us to sift through the important stuff.

If you're a meteorologist or consumer, what are your thoughts? Agree? Disagree?

First Measurable Snow Forecast for Nov. 5-6

Twenty-four hours before the approximate onset of MSP's first measurable snow, most forecaster were expecting roughly 3 inches of snow to fall in the urban core. The following information was what we were able to gather online at 7:30 p.m. on Monday night.

WCCO: Snow on yards. Roads mainly wet. Showed urban core of MSP split between 1-3” band and 3-6” band.

KSTP (kstp.com) Here in the Twin Cities we'll probably end up with 2 to 4 inches of snow before it winds down early Wednesday.  This should make the roads slick, especially the side streets, for the Wednesday morning commute. 

KSTP. No recent information or video posted on website.

KARE11 (kare11.com/weather/) Potential of 3-5 for Twin Cities.

MPR (http://blogs.mprnews.org/updraft/) 5:25 p.m. posting. Most of the metro will probably end up in the 1 inch to 4 inch range for snowfall by Wednesday a.m.

Paul Douglas/Star Tribune. (Update at 2:01 p.m.) Note the sharp gradient from north to south, maybe 1-2" for the northern suburbs, as much as 3-6" in the central core of the metro, with some 5-8" amounts not out of the question far southern suburbs,

NWS: 3-5” per graphic posted on Facebook

Storm Setup Next Week Reminiscent of '91 Halloween Blizzard But Great Uncertainty Exists

The National Weather Service has been closing eyeing a storm next week that could bring anything from rain to snow to nada. For the snowstorm-starved (obsessed?), this represents the first "interesting" set up of the season.

Source: NWS website, Oct. 24, 2013

The NWS discussion includes the following:

THIS IS ONCE AGAIN CLOSE TO THE SAME WINTER STORM THAT BROUGHT HEAVY SNOWFALL TO EC MN ON HALLOWEEN 1991. THE MAIN DIFFERENCE WITH THE 1991 STORM IS A MUCH COOLER THERMAL PROFILE ACROSS THE UPPER MIDWEST.

HOWEVER...VERY DYNAMICAL SYSTEMS CAN DEVELOP IT/S OWN TYPE OF

THERMAL PROFILE ONCE IT BEGINS TO TAP ENERGY FROM THE UPPER

TROPOSPHERIC LEVELS OF THE ATMOSPHERE. AGAIN...THIS SYSTEM NEEDS TO BE WATCHED VERY CLOSELY ON ALL TYPES OF HAZARDOUS WX.

Professional meteorologists and weather enthusiasts, alike, please share your thoughts.