Severe Mistake in Gamemaster Law

[arakish]

Just recently purchased Gamemaster Law.  While reading in section 19.0 GM Tips, Tricks, and Traps, specifically section 19.7.1 Wind Chill, I noticed the chart in Gamemaster Law is severely wrong.  Investigated on the NOAA internet site and found I was right.  Below are two screen captures showing the comparison.





rmfr

[ob1knorrb]

I believe that the tables in Gamemaster Law were based on older Wind Chill tables, and the table you are showing is a revised table.
There is some additional information on this as well as a calculator that can generate old and new values on this site:
http://www.erh.noaa.gov/er/iln/tables.htm

Here is a copy of the old table (although even this doesn't quite match either):
http://www.eol.ucar.edu/homes/rilling/wc_table.html

Good information to know though.

[Grinnen Baeritt]

Someone has got far too much time on their hands...

The table really isn't that far out... The RM table gives a modifier to the temp, rather than the actual temp (which is what the 2nd chart does). Yes, there are some minor discrepancies between the two but from the point of gaming info I think it does the job just fine..

[arakish]

Someone has got far too much time on their hands...

The table really isn't that far out... The RM table gives a modifier to the temp, rather than the actual temp (which is what the 2nd chart does). Yes, there are some minor discrepancies between the two but from the point of gaming info I think it does the job just fine..

Reading the bolded part above, I went back and read the wind chill section again.  I typed in the section verbatim.

"When the temperature drops below 35° the wind begins to affect the effective temperature. Cross index the low temperature for the day (use the nearest value that is not less than the actual low temperature) with the average wind speed for the day (using the value that does not exceed the actual average wind speed). The result will reveal the modifier for the low temperature (resulting in an effective temperature for the day). Note that wind speeds less than 5 mph have no significant effect on the actual temperature."

And you're right GB.  If you subtract the modifier from the temperature at the top, you get the actual temperature.  My bad, I should have read it more thoroughly.  Thanks for pointing that out.  However, the only modifier that is correct is the very first one in the upper left corner (-2).  After that, as ob1knorrb said, they must have used the old wind chill factor chart.

Here is a spreadsheet I made using the new revised equation.  It carries temperatures down to -80 and winds up to 80mph.  This is in degrees Farenheit and wind speeds are in miles per hour.  I carried this table out this far because the coldest I have ever seen it (when we went on resupply mission to Anuk, Greenland) is an air temp of -70°F and winds up to 40mph, giving a wind chill factor of -126°F.  -126°F is cold enough to cause literal instantaneous frostbite and could freeze diesel fuel solid.

rmfr

[arakish]

And here is spreadsheet calculator for those who want to use.  It is in Excel 97-2003 format (XLS).  It gives temperatures in °F, °C, and Kelvins.  Will create one for OpenOffice later and post it.

Wind Chill Factor Calculator

rmfr

[arakish]

And here is the OpenOffice spreadsheet calculator for those who want to use.

Wind Chill Factor Calculator

rmfr

EDIT: Seems Internet Explorer zips this file for some unknown reason.  Will zip the ods file itself and hope that fixes things.  rmfr

2nd EDIT: Replaced above file with a zip. rmfr

[Dame Eldgeth]

Those of us in northern MN thank you.  Now I don't have to use imprecise phrases like, "I'm freezing my fanny off."
Have you ever tested Jack London's assertion that at -40 F ambient temp, spit freezes with a loud crack before hitting the ground?

[Sorloc]

I've had my breath freeze in my mustache, and steam from my eyeballs freeze in my lashes... it was pretty cold.

[arakish]

Here is a spreadsheet I made using the new revised equation.  It carries temperatures down to -80 and winds up to 80mph.  This is in degrees Farenheit and wind speeds are in miles per hour.  I carried this table out this far because the coldest I have ever seen it (when we went on resupply mission to Anuk, Greenland) is an air temp of -70°F and winds up to 40mph, giving a wind chill factor of -126°F.  -126°F is cold enough to cause literal instantaneous frostbite and could freeze diesel fuel solid.

rmfr

With the above bolded part, I actually smeared a whole tube of Chap Stick on my face.  Went outside and spit.  It went 'dink' off the deck of the ship.  But then again, I was stupid and lucky I didn't get frostbit.

Don't know about -40F though.  I haven't seen it colder than -15F since that resupply mission.

rmfr

[Sloth]

Haven´t tested that, and the coldest i´ve been out all night selling hot-dogs was only -32C(about 0F)
Even then they were just warm-ish.

[Dame Eldgeth]

sloth,
is that right?  'cause I know that Farenheit and centigrade meet at -40.

[Dame Eldgeth]

Oh, OK it's just backward. 
32 F is 0 C.
Never mind.

[cormac_doyle]

the rule of thumb to convert F to C is to subtract 32, then divide by 2

[TJ]

Isn't it actually 1.8?

212f = 100c
32f = 0c
differential = 180f = 100c = 1.8f per c

[cormac_doyle]

I said it was a rough rule of thumb

[Dame Eldgeth]

It's multiply or divide by 7/8, for those of us in the pre-digital age

[arakish]

Actual equations for those who want to know.

°F = (°C × (9 ÷ 5)) + 32

°C = (°F -32) × (5 ÷ 9)

K = °C + 273.15

°F = degrees Farenheit; °C = degrees Celsius (Centigrade); K = Kelvins.

There is no such thing as degrees Kelvin, anymore.  It is only known as Kelvins.  Kelvins are actually a measure of thermodynamic energy.  Basically, Kelvins are a temperature measure of the molecular/atomic energy within a substance.  Kelvins start at 0, or −273.15 °C, −459.67 °F, the point at which there is no longer any molecular/atomic activity in the substance in question.  The greater the number of Kelvins, the greater the molecular/atomic activity the substance has; for example, our sun has a tremendous amount of molecular/atomic activity since it has a surface temperature of ~5780 K, a coronal temperature of ~5×10⁶ K, and a core temperature of ~15.7×10⁶ K.

Of course, more info than y'all'd liked.

rmfr