Posted at 2:31 PM on January 12, 2010
by Paul Huttner
NOAA GOES visible satellitle image today clearly shows reflective snow covered fields in southern Minnesota and darker coniferous forest in Northern Minnesota and Wisconsin.
This week is climatologically the coldest of the year in Minnesota. In the Twin Cities our average high and low are a frigid 21 and 4. That's climate.
The weather has decided to buck the trend this year bringing the mildest temperatures in weeks. One might think the Twin Cities and southern Minnesota would be the first to expierence the midler temps. Not this time.
Thanks to what we lovingly call "The Pine Tree Effect" many northern Minnesota communities are 10 to 15 degrees warmer than the Twin Cities this afternoon.
Here's how it works:
-The highly reflective snow cover in the prairie and deciduous forests of southern Minnesota reflects roughly 90% of the sun's incoming short wave raditaion back into space.
WEATHER ROUNDUP FOR MINNESOTA
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
200 PM CST TUE JAN 12 2010
TWIN CITIES MOSUNNY 19 11 70 SE13 30.20F WCI 6
ST PAUL MOSUNNY 18 11 74 SE9 30.23F WCI 7
CRYSTAL MOSUNNY 23 14 68 S13 30.17F WCI 11
BLAINE MOSUNNY 21 14 73 S13G18 30.18F WCI 9
EDEN PRAIRIE SUNNY 20 12 71 S14 30.17F WCI 7
LAKEVILLE MOSUNNY 18 12 79 S12 30.20F WCI 5
SOUTH ST PAUL MOSUNNY 19 13 74 S8 30.21F WCI 9
LAKE ELMO FAIR 19 12 73 S14 30.20F WCI 6
-The darker coniferous forest in northern Minnesota absorbs about 90% of incoming short wave raditiaon and convert it to longer wavelengths that are more effective at warming the air near the ground.
ELY PTSUNNY 30 16 55 SW13G21 29.93F WCI 20
INTL FALLS MOSUNNY 33 22 63 SW15 29.89F WCI 23
WASKISH MOSUNNY 34 23 64 S6 29.89F
BIG FORK SUNNY 30 21 69 S15 29.93F WCI 19
CRANE LAKE PTSUNNY 30 19 64 S10G16 29.93F WCI 21
ORR MOSUNNY 34 19 55 S10G17 29.89F WCI 26
COOK MOSUNNY 34 21 60 S15 29.93F WCI 24
It's all about albedo. Snow cover reflects 90%, Coniferous forests absorb and reradiate 90%. That energy is availabe to warm up northern Minnesota. You can create the same effect as a microclimate by planting of pine or spruce on the north side of your home.