A shot at 60 Saturday? Records may fall

How high will it go?

My confidence is growing we will challenge or even break records across southern Minnesota Saturday afternoon.

It's a perfect February heat storm combination. An Oct. 15 equivalent sun angle.

There is snow-free ground to absorb and re-radiate the sun's rays to warm the lower atmosphere, and a west wind is one of our warmest wind directions blowing in with slight down-slope off higher terrain near the Buffalo Ridge in western Minnesota.

Put it all together and you have a good shot at seeing some records Saturday.

Saturday's record high at Minneapolis-St. Paul International Airport is 54 degrees. The National Oceanic and Atmospheric Administration's digital forecast database numbers have been trending higher, now cranking out 55 degrees for Saturday in the metro.

My early temperature computations for Saturday's high at MSP yield 58 degrees as of today. We'll see.

Fifties all the way to Fargo Saturday?

Zooming in on the metro, temps look likely to make a run at 60 degrees toward Mankato, Minn.

The European Centre for Medium-Range Weather Forecasts model continues to push the temperature envelope Saturday. Temps near 60 in the metro? It may be optimistic but it could happen it all the weather dominoes fall just right.

60s in southwest Minnesota?

The higher terrain of the Buffalo Ridge in southwest Minnesota can trigger some unusual downslope Chinook-like effects, even at night.

Here's more on how the Buffalo Ridge works on temperatures and winds from the Sioux Falls National Weather Serivce.

Across Lincoln and Lyon counties in southwest Minnesota, the terrain goes from around 1900 feet near Lake Benton, MN to 1200 feet near Marshall, MN.  This decrease in elevation is enough to allow downslope  winds to develop.

Farther south toward Interstate 90, the elevation only decreases 200-300 feet from west of Worthington to Jackson, MN, and is not adequate for downslope winds to typically develop.

When the low level jet and the temperature inversion are near the same level then conditions become favorable for strong winds. - Typically as the sun is setting, temperatures a couple of thousand feet above the surface might be the same or a few degrees warmer than the surface temperatures.

At this time, we see similar temperatures on both sides of the Buffalo Ridge.  Above the surface, the low level jet begins to develop with winds many times over 30 mph.

Back to seasonal reality next week?

After our weekend temperature spike, forecast models differ on details, but agree temps will be closer to season norms next week.

Anatomy of temperature forecasting

Forecasting high temperatures is part science and part seat-of-the-pants weather art.

In my days as an operational forecast meteorologist at Chicago's Weather Command, we applied an old school proprietary technique to temperature forecasts.

In 1946, two World War II veterans John Murray and Dennis Trettel started providing weather sensitive companies with something they had never had before: accurate, site-specific forecasts on a real-time basis.

Fly-by-night weather companies come and go.  It takes long term credibility, commitment and staying power to create a weather company that can thrive for 70 years.

John Murray and Dennis Trettel hired this wide-eyed rookie forecaster in the 1980s. I learned more about weather forecasting at 2 years than I could have any place else. When you write continuously graded hourly temperature forecasts for one of the biggest natural gas companies on the planet, you learn fast.

When you write wind direction forecasts that will be used to evacuate the 3rd largest city in America in the event of an emergency for the nuclear plant 8 miles from your home, details matter.

Welcome to meteorology boot camp.

Without giving away specifics, we used the daily diurnal variation (average temperature change) then applied correction factors for advection (warmer or cooler air blowing in), solar intensity, snow cover, soil conditions, wind speed, lake-effect and any additional factors that could effect temperatures.

In the chaotic universe we call weather forecasting no process is perfect, but the temperature forecasts using this "temperature computation" technique are still the best I have seen to this day.

NOAA forecast models use a similar process with temperature forecasts. The key is knowing how much weight to give to any one factor. The dominant signal from the noise.

That's where the art of weather forecasting comes into play.

Models and forecasters have a hard time pinpointing with extreme temperatures. You local TV meteorologist tends to play it conservative as extreme temp spikes approach. Fear based psychological temperature barriers begin to emerge.

Even if some forecasters believe temps will hit 50+ degrees, you'll often see 49 on the map. Better to under promise for fear of viewers firing off angry emails saying "you said it was going to hit 50 today?"

Forecasting on the 9's is something I have observed in every market I've worked in. The conservative forecast seems "safe" but usually misses the magnitude of the extreme event.

NOAA's Global Forecast System is hinting at the potential for some snow somewhere in southern Minnesota next Tuesday. It's too soon to tell if this is a model hiccup or reality.

Stay tuned.