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

 

 

What the Polar Vortex Is… and Isn’t

 

The Polar Vortex is an actual thing, although the term has been badly misused in recent months.  Most cold air outbreaks are caused by high-pressure areas dropping south from the Arctic regions, displacing cold air into the mid-latitudes.  Usually, some part of the Arctic such as Alaska or The Yukon has an accompanying mild spell of weather.  The Polar Vortex, on the other hand, is a circumpolar wind at the Jet Stream level of the atmosphere.  It is not a high-pressure area nor is it a cold front.  The Polar Vortex circulation grows stronger during winter and tends to keep the coldest weather in the hemisphere bottled up over the Polar Regions where it is perpetually dark and bitterly cold in winter.  Sometimes, however, the Polar Vortex weakens or is bent out of shape.  These episodes cause the weather over the Poles to become relatively mild while displacing Polar southward into the mid-latitudes.   Meteorologist John Wheeler

 

It’s Just a Forecast

 

Even as technology improves, weather forecasting is still forecasting.  We are almost never exactly right.  Our goal on a daily basis is to be close enough to be useful, and most of the time, we are.  Sometimes, however, we do miss by a lot, like Monday’s snow storm. Most Twin Cities forecasts on the previous Friday had the heavy snow going south of the Twin Cities.  Over the weekend, most forecasts changed to having it go right through the Twin cities.  But Monday came and snowfall was an inch or two at Bloomington and Inver Grove Heights to six inches in Coon Rapids and Lino Lakes on the north side.  The heavy snow (12-17 inches) fell from St. Cloud to Cambridge.  As a forecaster, myself, I can say that the Twin Cities forecasters did pretty well with the storm.  They got the amounts right and were off by a only hundred miles. That is not bad for a highly energetic fluid dynamics problem covering an area the size of several states.   Meteorologist John Wheeler

 

 

 

Another Cold Winter Looms

The weather will be cold next week.  The coldest of this fall so far.  Below average for the time of year.  Granted, this is only one week and not even really winter yet, but what does this mean for the Climate Prediction Center’s forecast of a warmer than average winter for our region?  Well, this one cold week means nothing.  Many of our warmest winters on record were preceded by cold November weather.  However, there are two big reasons to think this winter might be another cold one.  The snow pack over the higher latitudes of North America, including Siberia, is the most extensive since satellite records began in the 1960s.  This correlates to the winter becoming a very cold one.  Also, there are signs on the Pacific that the expected El Nino is falling apart.  The cold weather this week could just be a harbinger of another very cold winter.   Meteorologist John Wheeler

Already Bitter About Wind Chill

Wind is the element that defines our winter more than any other.  The flat terrain of the Red River Valley is not conducive to extremely cold low temperatures.  We do not experience cold-air drainage on calm nights so we do not get the 50 and 60 below temperatures which occasionally occur in northern Minnesota or (more rarely) central North Dakota.  Fargo Moorhead will almost never make national news for having the coldest temperature in the nation on any particular morning.  Naturally, when it is 50 below in International Falls and just a paltry 25 below here in Fargo Moorhead, it is International Falls that makes the national news.  But those mornings are rarely anything other than calm in International Falls whereas here in the Valley, the wind chill is most certainly a factor.  But wind chill is not the same as temperature, so the sexier temperature gets the notoriety, and we are left feeling bitter in the bitter cold.    Meteorologist John Wheeler

Forecast For Winter

The Climate Prediction Center (CPC) issued its winter prediction this week and, based largely on the forecast of a weak El Nino developing, have given our area an increased likelihood of above normal temperatures for averaged from December through February.  This means they think it is more likely to be warmer than normal than near-normal or below-normal.   When it comes to long range winter forecasting, there is hardly a better indicator than the presence of El Nino or La Nina.  Unfortunately, even these are not as reliable as we would like them to be.  Conditions in the Pacific Ocean are neutral at the moment, but there are signs of a weak El Nino forming early in this winter.  The CPC has had more trouble than usual with winter forecasts lately because factors other than El Nino/La Nina have been trumping the winter weather regime.  The past few weeks, widespread, substantial snow cover has spread across most of Siberia, often a sign of a colder winter in our region.  In other words, we really do not know what the winter will bring.  Long range forecasting is not quite the same as guessing wildly, but it isn’t much better.   Meteorologist John Wheeler

Memorable Early October Snow

On October 7, 1985, the Fargo Moorhead area just missed out on a major early season snowstorm.  Grand Forks got six inches from the storm, Roseau received eight inches, and Langdon got ten inches.  The heaviest snow fell in north-central North Dakota where Minot got a foot of snow and Velva received 17 inches.  The autumn of 1985 was much colder than average and, although most of that early snowfall melted within a few days, several major November snowstorms blanketed our entire region to a depth of one to three feet by Thanksgiving.  Here in Fargo Moorhead, the last five days in November were all below zero day and night.  Such a cold snap before December is unusual.  And though the weather remained cold until just before Christmas, most of January, February, and March brought above-average temperatures.  That was my first winter at WDAY and I remember it well.  The early snow and cold was exciting professionally, but a bit of a shock personally.   Meteorologist John Wheeler

Winter Forecast (NOT!)

If you want to be both amused and annoyed, do an internet search of “winter forecast” and see what comes up.  You will read about El Nino and what it means this winter.  You will later stumble across other ideas about what it means which will severely contradict the earlier meanings.  You will read personal rants in various comments sections from people who know little about long-range forecasting but know a lot about how to shout when writing.  You will read about how last winter’s forecasts were right in some places and wrong in others.  You will stumble across the Old Farmer’s Almanac and recall how their forecast is almost never correct despite its claim that it is right 80 per cent of the time.  You will read their forecast and tell yourself you do not believe it but you will believe it a little.  After a while, you will get bored and find something else to look at.  In the end, you will have no idea how the upcoming winter will be.   Meteorologist John Wheeler

First Hard Freeze

The first hard freeze of fall is one of those truly great moments of the year.  So many things change that one morning.  So much of what had been growing and green turns dead, brown, and black and there is no way back from the first freeze in the fall.  Most years, the first hard freeze happens in October although occasionally it comes early, in September.  There are, of course, places on Earth that do not freeze in our present climate. In Key West, the vines and the palms just keep growing and people have to work to keep the jungle out of their yard. Southern California will get a killing freeze now and again.  But a northern killing freeze is a dependable, once-a-year, life-changing event.  It is a milestone and a harbinger and in that sense, some hate what it stands for.  But it always comes and it will come one morning soon and I will find comfort in not having to worry about my garden any more.    Meteorologist John Wheeler

 

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