Thursday, January 20, 2011

20 January, 2011

TODAY'S TOP WEATHER STORIES
On Weather & Climate Through the Eyes of Mark Vogan

COLDEST NIGHT OF WINTER FOR NORTHERN PLAINS, MIDWEST USA




This morning's WCCO-TV Minneapolis forecast for the Twin Cities

As a polar front sweeps southbound through the N. Plains late this afternoon, the truely bitter cold air is a little further north. It won't be until you've went to bed when temperatures start to fall away sharply through tonight from the Canadian border to Indianapolis as skies clear out and we see -0s and then -10s into Minneapolis, likely around 2 or 3am, falling towards -16 by sunrise, making for the lowest reading since January 10th, 2010. Chicago, is likely to drop towards -4 or -5 by morning. Both Minneapolis and Chicago are not going to make 10 degrees, in fact MSP may be lucky to strike zero degrees! Breezes of only 4 or 6mph will be make air feel more like 25 below, so make sure and cover exposed flesh whilst stepping outside in the morning. This will be the lowest reading of the season, at least it's short lived and temps recover fast!

As for International Falls, Embarrass and Tower, Minnesota, near the Canada border, I wouldn't be surprised to see a -40 reading by morning....

AccuWeather News

BBC


TODAY'S WEATHER ACROSS UK


WEATHER TALK
By Mark Vogan

TODAY MARKED 20TH SUB-FREEZING DAY OF METEOROLOGICAL WINTER, 23RD SINCE LATE NOVEMBER, TALLY OF SUB-FREEZING NIGHTS MOUNTING UP ALSO! 

WHY I WAS SURPRISED THE OVERNIGHT LOW OF 20 DEGREES (-6C) WAS LOWER THAN EXPECTED

I will admit that this morning's low was cooler than I expected and actually, I limited the potential of overnight cooling as I knew the air mass in place wasn't Arctic, it was a mild mid-Atlantic high pressure system which allowed daytime temperatures of mild low 40s, making for a pleasant and relatively warm daytime air under sunshine and light winds for mid-January, however what I failed to remember was that despite the absense of snow on the ground, the conditions were perfect with cloudless skies, light winds and of course it's in the heart of midwinter, so there is a long period of darkness. At this time of year, the atmosphere finds it easiest to cool. I guess another aspect that made me think that mid-20s (around -3C) was more likely was that when mild air is present by day, there's more cooling involved to bring that temperature down to a certain level and with low 40s and not a cold air mass in place, plus clouds and even a light breeze is more likely than within "Arctic high pressure" since there's more moisture within a warmer air mass than cold, I simply put a limit on the cooling potential of the air last night.

Though 20 degrees is not particularly cold by any means, certainly not by this winter's standards nor by other countries which by the way woke to -40C in Siberia, -30C in sections of Canada and across many other northern locales, for Central Lowland Scotland, it was a reminder that it's still a long way till spring and in fact, this is a reading that a few years ago would have been more impressive and in fact would have been a seasonal low back during those particularly warm winters.

Tonight's return to low 20s marks January 2011's 15th sub-freezing night and it would only take 2 more nights to tie last January's number of sub-freezing night's. This is likely to be tied, if not broken!

TODAY'S WEATHER ACROSS AMERICA
From AccuWeather


Watching For a Major Eastern Snowstorm Next Week
AccuWeather

Chilly Temps at NFL Conference Championships
AccuWeather

WHAT'S REACHING TODAY'S BLOGS?

TODAY'S EXTREMES HERE AT MY HOUSE

HIGH: 31 degrees
LOW: 20 degrees

TODAY'S CONDITIONS (LOCALLY)

After what was a full night of clear skies and light winds which allowed sufficient radiational cooling to drive the morning low to 20 degrees which marks the second lowest reading for the month, the morning saw fog form and persist, thus the daytime high struggled to a high of 31 degrees. This marks the 20th sub-freezing day since Dec 1 (now comfortably surpassing last winter's total of just 17). I was surprised at the low being quite as cool and indeed the day as well though conditions were good. Tonight, it's fogbound out there and temps are dropping quickly under the clear skies which remain over top of the thin layer of surface fog, the low may drop into the 10s for only the 2nd night this month (coldest being 16 back on Jan 7th) and it's likely that skies won't be a foggy and temps will rebound back towards the upper 30s, if not 40 degrees. Outside of the fog today and it was nearer 40 degrees...

Thanks for reading.
-Mark

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