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Boundary Waters Quetico Forum Winter Camping and Activities temp adjustments |
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02/09/2015 12:41PM
I'm curious for planning purposes. When typical weather forecasts predict a given temp, it is not based upon temps experienced when standing/traveling on a large frozen body of water. What generically could someone expect in terms of a temp adjustment from standard weather forecast temp data and actual on top of some frozen lake in the boundary waters?
Dale
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02/09/2015 01:52PM
If it's a low lying area you can always expect it to be colder. By how much I wouldn't know. To me wind is a killer when it comes to tolerance for the cold. Wind and cold will find every chink in your armor.
The best part of this journey here is further knowing yourself - Alan Kay
02/09/2015 03:18PM
Be interesting to see what our resident weather expert says.......I'll guess that it doesn't make much if any difference, if we're talking about frozen, snow covered ground and frozen snow covered lakes. However, wind chill will have a big impact.
I don't think the ice affects the air temperature as much as the air temperature affects the ice.
I don't think the ice affects the air temperature as much as the air temperature affects the ice.
I set a goal of losing 10 lbs. this year. I only have 15 left to lose.
02/10/2015 12:12PM
quote SevenofNine: "If it's a low lying area you can always expect it to be colder. By how much I wouldn't know. To me wind is a killer when it comes to tolerance for the cold. Wind and cold will find every chink in your armor."
This...is my opinion too.
I'm just here to give my opinion...If you don't like it, ignore it.
02/11/2015 02:01AM
quote spirit2189: "I'm curious for planning purposes. When typical weather forecasts predict a given temp, it is not based upon temps experienced when standing/traveling on a large frozen body of water. What generically could someone expect in terms of a temp adjustment from standard weather forecast temp data and actual on top of some frozen lake in the boundary waters?"
Great question! Official temperature measured at many sites across the US (sadly many at airports-- that is for another time) is taken at the 5-6' level-- more commonly called the 2M temp. Temperature forecasts by NOAA/NWS are made for the 2 meter level-- nearly all forecasts issued by Noaa/NWS in and around large cities are made for the actual temperature sensor located at the nearest airport so their forecast can verify or .. bust.
As far as a "real feel" under your conditions above- those above pretty much nailed it. Obviously as mentioned-- wind chill is huge. Many on here likely remember the "old" wind chill chart that was replaced in 2001 with the "new wind chill chart. The reason??? Wind is "officially" measured at the 10 meter level (at airports again). 10 meters because of the effect that height has on the aviation community (take off and landing). The old wind chill used the 10 meter level-- which due to frictional effect of the earth -- is usually several knots or mph higher then at human face level. So a algorthim was developed that converts the 10 meter wind speed to a more representable speed at human face level -- hence the new wind chill chart. I have always thought that dampness affects us also with the wind chill-- by how much I don't know-- but a wind driven cold rain at 35F to myself is much more miserable then the same wind with snow at 28F. Probably has something to do with the specific heat of water. old/new wind chill calculator
As far as the actual temperature being different in your ?-- not much. Maybe a few degrees cooler at most as mentioned by oldfingers. This mainly due to being away from concrete/buildings etc-- but it can work the other way also. However, as mentioned -- cold air is more dense then warm air and sinks. On calm,clear skies/cold nights-- lower lying areas will get colder/faster then surrounding- higher terrain. I have seen 10F+ changes both ways (actually just a few nights ago--- -17F to -7F within one valley-- less then 50' drop/rise. It doesn't take much for cold air to funnel-- but the winds must be very light to calm otherwise the wind "mixes" the air column and and then little change will be noticed-- if at all. This is also partly explains why snow can accumulate with 2 meter temps above 0C -- say 34F. On Super Bowl weekend-- here in Des Moines we received 11.6" of snowfall--- 85% occurred with a 2 meter temp of 34F-- but 1" above the ground (frozen) the temps was just barely colder then 0C-- and the falling snow was allowed to accumulate.
I hope this helps.
The two loudest sounds known to man: a gun that goes bang when it is supposed to go click and a gun that goes click when it is supposed to go bang.
02/11/2015 10:56AM
Thanks, O Great Weather Kahuna........
Not that it means a lot in the BWCA, because it is basically low humidity winter location, but I've always experienced feeling colder with higher humidity.
I lived in Germany when I was in the Army. The winter temperature rarely got below the 20's, but it was a humid cold. It would chill you to the bone.
Not that it means a lot in the BWCA, because it is basically low humidity winter location, but I've always experienced feeling colder with higher humidity.
I lived in Germany when I was in the Army. The winter temperature rarely got below the 20's, but it was a humid cold. It would chill you to the bone.
I set a goal of losing 10 lbs. this year. I only have 15 left to lose.
02/11/2015 11:03AM
i agree that dampness or humidity is a critical factor in the 'feel' of cold tempts. -10f in alaska and the west is much different than the feel of -10f in the midwest. that's just based on experience, no science.
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