Weather forecast for Minneapolis.

[Polaris]

I dare you to do some calculations, polaris. I refused to get my thermo book out.

I do as well. The actual calculations if you want to include boundary conditions and equi-thermal zones is beastly. However, I think we can safely so some "Fermi number" approximations. I think we can assume that if the field has a high percentage of water in it, when we can assign a specific heat for the field of almost 1 in cgs units. If we assume an artificial field, that's lower (prob near the specific heat of rubber) which using Fermi numbers is probably about .75 or so.

[For those that aren't in the hard sciences, Fermi numbers means 'order of magnitude' calculations. They aren't meant to be used to make specific predictions but do serve as a first step to 'sanity check' what results are reasonable.]

Air has a specific heat (in cgs) of about 0.001 approximately. In short, the heat needed to heat 1 gram of water by 1 degree Kelvin would be enough to raise 1000 grams of air by one Kelvin. Now factor in that air has a very low density (when compared with any solid or liquid).

The question now becomes one of boundary conditions: What temperature is the heated field set at. If the field is set at say 5C (or 278 Kelvin) and the starting ambient air temperature is 0F or about -15 C or about 260 Kelvin, then a one degree loss on the surface of the field [or equivalently the energy needed to prevent that loss] could easily heat the air near the field (up to the first meter or so) to near 0C [say -5 C or so which would be in the low twenties].

I admit this is all back-of-envelope approximations, but the idea that a heated field would blunt the cold in calm conditions is not at all outlandish. You see exactly the same effect around a fishing hole in a large lake under very cold conditions.

 

[Polaris]

It's artificial turf.... not soil.

That only changes the calculations slightly. The important part is that even rubber (a reasonable approximation for artificial turf) has a much higher specific heat than air.

 

[Hawks46]

It's artificial turf.... not soil.

That only changes the calculations slightly. The important part is that even rubber (a reasonable approximation for artificial turf) has a much higher specific heat than air.

Most of the field turf fields have a rubber underlay. That said, wouldn't rubber act as an insulate and retain the heat better than say, soil and grass would ?

Plus you could turn the heat up higher underneath it, without worrying about damaging natural grass.

 

[iigakusei]

Couldn't the Vikings just claim the heating coils aren't working today - sorry boys!

 

[Polaris]

It's artificial turf.... not soil.

That only changes the calculations slightly. The important part is that even rubber (a reasonable approximation for artificial turf) has a much higher specific heat than air.

Most of the field turf fields have a rubber underlay. That said, wouldn't rubber act as an insulate and retain the heat better than say, soil and grass would ?

Plus you could turn the heat up higher underneath it, without worrying about damaging natural grass.

How well rubber insulates is irrelevant for this particular calculation because we are assuming the rubber itself is being heated to a specific (mostly) constant temperature. Thus the rubber serves as a thermal boundary condition and the energy is being transferred to the surrounding air by convection and radiation. Since convection is far more efficient than radiation, wind is important since wind could destroy the convection part (by disrupting the local convection currents by blowing away the heated air).

Actually one of the best insulators in nature is a vacuum or failing that *dead* air. [This is why winter clothing and insulation is full of small air bubbles.]

 

[Uncle Si]

Couldn't the Vikings just claim the heating coils aren't working today - sorry boys!

Just because they live here doesn't mean they like it cold. If anything, RW played at Wisconsin, Teddy is from Florida...

This will be the first day in nearly a year to hit single digits. Its a temperate 32 degrees right now and we had a high of 50 not more than three weeks ago.

Cold weather is not going to "help" any team more.

As for the heating coils: I have not been on TCF but have been on similar fields. The surface temps will be at or above freezing. How that translates to actual temperature for the players is another thing. But, they won't "feel" the cold when they hit the ground, if that means anything.

 

[massari]

Better than in Washington goon according to early forecast.....1.5 inches of rain and mid 50 degrees in the afternoon.
That will make the field a slippery slop bowl for potential injuries.

Prefer playing in cold and dry then wet

It's supposed to be -20 with the windchill by kickoff in Minnesota. Either field will be dangerous.

 

[johnnyfever]

I dare you to do some calculations, polaris. I refused to get my thermo book out.

I do as well. The actual calculations if you want to include boundary conditions and equi-thermal zones is beastly. However, I think we can safely so some "Fermi number" approximations. I think we can assume that if the field has a high percentage of water in it, when we can assign a specific heat for the field of almost 1 in cgs units. If we assume an artificial field, that's lower (prob near the specific heat of rubber) which using Fermi numbers is probably about .75 or so.

[For those that aren't in the hard sciences, Fermi numbers means 'order of magnitude' calculations. They aren't meant to be used to make specific predictions but do serve as a first step to 'sanity check' what results are reasonable.]

Air has a specific heat (in cgs) of about 0.001 approximately. In short, the heat needed to heat 1 gram of water by 1 degree Kelvin would be enough to raise 1000 grams of air by one Kelvin. Now factor in that air has a very low density (when compared with any solid or liquid).

The question now becomes one of boundary conditions: What temperature is the heated field set at. If the field is set at say 5C (or 278 Kelvin) and the starting ambient air temperature is 0F or about -15 C or about 260 Kelvin, then a one degree loss on the surface of the field [or equivalently the energy needed to prevent that loss] could easily heat the air near the field (up to the first meter or so) to near 0C [say -5 C or so which would be in the low twenties].

I admit this is all back-of-envelope approximations, but the idea that a heated field would blunt the cold in calm conditions is not at all outlandish. You see exactly the same effect around a fishing hole in a large lake under very cold conditions.

It looks like you are pretty well versed in this area Polaris. If the temp is zero, winds are between 5 and 10, and with the stadium being a wide open college field, how much do you think it would raise the temp from ground level to say 6'?

I know there are all sorts of important variables we dont know like heating coil temps, how far under the turf they are, make-up of turf for convection etc, but I would think they are probably 2" down, some sort of rubber for convection, and maybe 160 on the coils. I'm trying to remember what temp radiant runs at in houses, and I thought it was around 150 or 160, so figured that might be close.

Whaddya think?

 

[rideaducati]

Anyone going to the game should take a pitcher full of hot water outside and throw the water into the air...it comes down as snow. I lived in Minnesota as a kid and used to do that for fun. At that temp, a gallon of water will freeze in 20 minutes. Did that one too. I don't miss the cold.

 

[CPHawk]

It will be so much fun for the Viking players to tackle beast mode, while their hands are frozen.

 

[DavidSeven]

Wilson played very well in his year at Wisconsin.

This narrative might be a little overstated in terms of weather.

The coldest game Russ ever played for Wisconsin was 43 degrees.

 

[Uncle Si]

Wilson played very well in his year at Wisconsin.

This narrative might be a little overstated in terms of weather.

The coldest game Russ ever played for Wisconsin was 43 degrees.

just a bit...

I think we might be overemphasizing the weather in general to be honest..

but.. on a positive.. the predicted temp went up 1 degree this afternoon!

 

[bmorepunk]

Anyone going to the game should take a pitcher full of hot water outside and throw the water into the air...it comes down as snow. I lived in Minnesota as a kid and used to do that for fun. At that temp, a gallon of water will freeze in 20 minutes. Did that one too. I don't miss the cold.

It's not going to be cold enough to do that, nor would the water stay hot enough in a pitcher taken to a game to do it.

 

[Boiler]

Saw this and I thought it was interesting. I was at both the 2000 and 2006 games, and I remember the 2000 game being much more uncomfortable than the 2006 game. The 2000 game was pretty high-scoring.

Extreme temps: The Seahawks defeated the Broncos 23-20 Dec. 3, 2006 at Denver when the temperature was 16 degrees, Seattle’s coldest game. The Seahawks and Broncos also played in 22 degrees Dec. 10, 2000 and in 27 degrees Dec. 19, 1999. The teams also met on an 85-degree day Sept. 13, 1987.

http://sportspressnw.com/2176993/2014/s ... -scrapbook

 

[CodeWarrior]

Is it supposed to be cold for this game?

 

[Polaris]

I dare you to do some calculations, polaris. I refused to get my thermo book out.

I do as well. The actual calculations if you want to include boundary conditions and equi-thermal zones is beastly. However, I think we can safely so some "Fermi number" approximations. I think we can assume that if the field has a high percentage of water in it, when we can assign a specific heat for the field of almost 1 in cgs units. If we assume an artificial field, that's lower (prob near the specific heat of rubber) which using Fermi numbers is probably about .75 or so.

[For those that aren't in the hard sciences, Fermi numbers means 'order of magnitude' calculations. They aren't meant to be used to make specific predictions but do serve as a first step to 'sanity check' what results are reasonable.]

Air has a specific heat (in cgs) of about 0.001 approximately. In short, the heat needed to heat 1 gram of water by 1 degree Kelvin would be enough to raise 1000 grams of air by one Kelvin. Now factor in that air has a very low density (when compared with any solid or liquid).

The question now becomes one of boundary conditions: What temperature is the heated field set at. If the field is set at say 5C (or 278 Kelvin) and the starting ambient air temperature is 0F or about -15 C or about 260 Kelvin, then a one degree loss on the surface of the field [or equivalently the energy needed to prevent that loss] could easily heat the air near the field (up to the first meter or so) to near 0C [say -5 C or so which would be in the low twenties].

I admit this is all back-of-envelope approximations, but the idea that a heated field would blunt the cold in calm conditions is not at all outlandish. You see exactly the same effect around a fishing hole in a large lake under very cold conditions.

It looks like you are pretty well versed in this area Polaris. If the temp is zero, winds are between 5 and 10, and with the stadium being a wide open college field, how much do you think it would raise the temp from ground level to say 6'?

I know there are all sorts of important variables we dont know like heating coil temps, how far under the turf they are, make-up of turf for convection etc, but I would think they are probably 2" down, some sort of rubber for convection, and maybe 160 on the coils. I'm trying to remember what temp radiant runs at in houses, and I thought it was around 150 or 160, so figured that might be close.

Whaddya think?

Best on my estimates which I have to emphasize are order-of-magnitude GUESSES only, and based on my own experience around water in such temperatures ('lake effect'), I would say that in still conditions, the ambient air temperature over a heated field could be as much as thirty degrees (Fahrenheit) over the normative temperatures immediately above the field. Of course this would diminish rapidly to ambient temperature (0 Fahrenheit) as you went from 0 meters to 2 meters with the most drastic drop happening in the first meter (it won't be linear). Basically using these very BASIC and COARSE assumptions, the air at head level would be really cold while the air (and field) at the playing surface would be more moderate (as in below freezing but not 0 Fahrenheit). Also the field itself would be above freezing which should help the injury situation on both sides. It also means the ball won't be *quite* as hard as one might expect (but still no fun).

Of course if you have a stiff breeze then the fall off happens much more rapidly and the air would approach ambient (0 Fahrenheit) within a meter above the field or perhaps less. Bundle up.

 

[johnnyfever]

Atleast the turf wont be frozen

 

[rideaducati]

Anyone going to the game should take a pitcher full of hot water outside and throw the water into the air...it comes down as snow. I lived in Minnesota as a kid and used to do that for fun. At that temp, a gallon of water will freeze in 20 minutes. Did that one too. I don't miss the cold.

It's not going to be cold enough to do that, nor would the water stay hot enough in a pitcher taken to a game to do it.

Just take the water outside...not to the game...although it is wise to drink a lot of water in cold temps. You don't notice being dehydrated easily when its cold.

 

[dadof3]

Why do they even put cities in places like that? It's hard to believe they can find that many people dumb enough to live in that crap

 

[MizzouHawkGal]

Predicting weather this many days out is about as statistically significant as a random process. Things may change significantly over the week.

Winter here in mnpls is not hard to predict though.

You can bet that prediction is going to be fairly accurate. I'd bet temps in the teens by kickoff, little wind, maybe some sun

Same thing in Kansas City they are spot on with the weather here. Weather is serious business in the breadbasket of the nation.