Transition to Winter is Complete

 

Looking out the window, it appears winter has settled in. The transition from summer to winter has been marked with significant moments.  The last time lightning was observed at the airport weather station was during severe early morning thunderstorms back on September 4. The last 80 degree day was September 27.  The last 70 degree day was October 24.  The first frost was October 9. The last measurable rain was November 7.  The last day without measurable snow on the ground and also the last day in the 40s was last Sunday.  Going forward, it is likely the temperature will get back into the 40s during the winter for a few days.  It is also likely we will get a light rain shower or two.  It is possible we will lose our snow cover at some point.  And it is even possible to get lightning during a winter snow shower. But there is no doubt we will consider any of these things as winter occurrences.    Meteorologist John Wheeler

1985: One Cold Start to Winter

Three record low temperatures for Fargo Moorhead set in late November of 1985 still stand.  It was 15 below on November 23 and it was 24 below on November 27 and 28.  This was part of a remarkable severe spell of winter weather the second half of November that year.  Winter started suddenly and seemed to settle in for good.  From November 18 through November 30, a total of 24.2 inches of snow fell, mostly from three heavy snowstorms.  Starting November 20, the last eleven days of the month had subzero morning temperatures.  Seven of those mornings were lower than ten below and four were at least 20 below.  Starting November 27, the temperature remained below zero even in the daytime.  Below average temperatures continued through most of December until it turned mild around Christmas.  The remainder of that winter was much less severe.   Meteorologist John Wheeler

 

Quiet Atlantic Hurricane Season

The Atlantic hurricane season officially comes to an end this weekend.  It was a good year for people and a bad year for hurricanes.  There were just eight named tropical systems (sustained winds of at least 39 mph) in the Atlantic Basin.  Six of them became hurricanes (sustained winds of at least 74 mph).  Only two became major hurricanes (Category 3,4,5 with winds of at least 111 mph).  The relative absence of hurricanes is due to the absence of good hurricane conditions.  Upper level winds over the tropical Atlantic were strong and kept clusters of thunderstorms from becoming organized.  Also, a lot of dry air was in place over the Atlantic. On the other side of the Americas, the eastern Pacific was the most active since 1992.  It is not uncommon for the two oceans to be out of sync like this.  The record year for Atlantic hurricanes, 2006, was a very quiet year across the Pacific.  Meteorologist John Wheeler

Thundersnow!

During last week’s lake effect snowstorms in western New York, there were several instances of thunder and lightning during the heavy snowfall.  Although not something witnessed routinely, thundersnow is not some freak of nature.  I have personally seen lightning during snowfall four or five times in my life.  Lightning is a product of a convective shower. Electrical charge is built up as raindrops and snowflakes bounce around and interact in the rapidly rising air within an updraft.  Most snowfalls come from larger-scale, general rising motions.  Showers are more common in warm weather when the air tends to be more unstable.  Lake effect snows are ideal for thundersnow because the cold air flowing over warmer water can produce the necessary instability.  But sometimes, even out here on the Great Plains, showers form in air cold enough to produce snow, and thundersnow can be the result.      Meteorologist John Wheeler

It Flows North

Running along the Red River recently, I was observing its frozen surface and was struck by its stillness.  Once frozen, the visual motion of the river stops for the winter.  Its hard surface gives the appearance of a thing at rest.  But underneath the frozen river surface, the Red River continues to flow all winter long.  It flows to the north, as we all know.  But this northward motion is not as singular as many of us have led ourselves to believe.  The Red is not the only other river in the United States to flow north.  There are the Kennebec and the Penobscot Rivers in Maine as well as the Willamette River in Oregon.  The only reason most rivers flow south is because the slope of the entire Mississippi watershed is to the south.  This is merely a feature of American geography and not a strange adjustment to any law of physics.  Water flows downhill, whatever direction that happens to be.  Even north.   Meteorologist John Wheeler

The North Wind Doth Blow

It has been a windy fall.  Very windy compared to last year.  Through September, October, and the first 21 days of November, there have been wind gusts of at least 20 mph on 56 of the 82 days and gusts of at least 30 mph on 19 of those 82 days.  In the fall of 2013, the same period produced just 49 days with gusts of at least 20 mph and just eight days with wind gusts of at least 30 mph.  The reason for the wind is a high frequency of storm systems which have produced a lot of changes in air pressure.  Interestingly, those same storm systems have not generated much precipitation.  Fargo Moorhead has only received 3.27 inches since September 1, and most of that came on two days.  We received 1.99 inches in a thunderstorm September 4 and 0.40 inches in a rain shower November 5.  The remaining 0.88 inches has come from occasional rain or snow showers.  To be fair, there was a significant snow storm which passed just south of the Fargo Moorhead area November 10.

I am reminded of a very old English nursery rhyme.    Meteorologist John Wheeler

The north wind doth blow,
And we shall have snow,
And what will poor robin do then?
Poor thing.

He’ll sit in a barn,
And keep himself warm,
And hide his head under his wing,
Poor thing.

 

It’s All Relative. Even Winter

Winter got a bit of an early start this year, causing many of us to think about migrating south for the winter, or at least going south for a few days.  But think about this. Some of the backyard birds we see during winter are actually migratory birds that have flown south to the Fargo Moorhead area for the winter. Pine grosbeaks, white-winged crossbills, and red crossbills; all hail from the Boreal forests of northern Manitoba and Saskatchewan.  And they actually come here for winter because it suits their needs.  Lapland longspurs and the common redpoll fly here from the High Arctic Tundra for our relatively mild winters.  A few years ago, I spent some time in Churchill, Manitoba, on a polar assignment for WDAY-TV.  I learned that many of the Churchill locals will spend a midwinter month or so “down south” in Winnipeg.  As they say, “It’s all relative.”   Meteorologist  John Wheeler

How Cold is Cold?

Last winter, the average temperature in Fargo Moorhead over the three primary winter months (December through February) was 1.1 degrees, which ranks as the eighth coldest winter on the record back to 1881.  The coldest winter on record is the winter of 1886-87, with an average temperature of 4.5 degrees below zero.  A difference of 5.6 degrees, averaged over an entire winter, is a powerful statement that the winter of 1886-87 was remarkable colder than what we experienced last winter.  The oldest weather record in our region comes from Fort Snelling near Minneapolis. This record is complete back to 1867 and sporadic back to 1820. At Fort Snelling, the winter of 1874-75 was significantly colder (by about three degrees) than the winter of 1886-87.  Last winter was a cold one.  But it can get a whole lot colder than that around here.   Meteorologist John Wheeler

Cold Weather Marathon or Sprint?

 

Is our present cold snap temporary or the start of another cold winter?  Many times, an early weather pattern which sends the Jet Stream so far north of Alaska and then so far south into the southern states is one which has trouble holding its place.  True, last winter brought a similar Jet Stream pattern and it lasted from early December right through into early May.  So not only was the winter cold, but the spring was mostly a continuation of the winter.  And while a continuation of the cold is certainly possible, it is probably slightly more likely that the pattern will break down in a week or so.  The break might be temporary, but it also might not.  Obviously, this is not intended to be a forecast.  Rather, this is just to point out that a cold spell in November is not a guarantee that the rest of the winter will be cold.    Meteorologist John Wheeler

Snow Means Cold

 

Most of the time, snow means colder weather. Snow cover does two things to temperature.  It reflects sunlight and it radiates Earth heat very well.  By reflecting sunlight efficiently, a lot of the potential energy coming into the air from the sun is reflected back into space.  Radiating Earth heat simply means the white color of snow allows the snow, itself, and also the air near the snow, to lose heat into space, particularly at night.  So when the ground is covered with snow, it is colder in the daytime and also in the nighttime but for different reasons.  Snow also creates a lagging effect on cold weather.  It takes energy to melt snow into liquid water.  So the process of melting snow robs the air of warmth.  Snow helps the weather get cold and also helps it stay cold. When snow covers the ground, it is possible for the weather to get warmer, but it is a lot harder than without snow.     Meteorologist John Wheeler