Drought and Heat

The official thermometer for downtown Los Angeles has already recorded four days in the 90s this month.  This is a record for so early in the season.  As California starts its fourth summer of drought conditions, the expectation is there will be a lot of hot days which, in Los Angeles, will mean many summer days in the 100s.  There is a very close relationship between drought and record heat.  Here in Fargo Moorhead, 29 of the 92 summer daily record highs (June 1 through August 31) were set in the 1930s which is by far the driest decade on record here. The connection is simple.  When the soil is dry, it is heated up more efficiently by sunlight, which makes the air hotter.  Summer droughts create dry soil and usually have lots of sunny days. Since 1993, the Red River Valley has been quite rainier than the long-term average, and so summer record highs have been rare in recent years.   Meteorologist John Wheeler

Late Season Snow Likely

After an early spring, threats of snow have rematerialized in our forecasts on a routine basis.  Late-season snows are typical enough that even April carries a monthly snowfall average of three inches.  Last year, Fargo Moorhead got a 2.3 inch snow on March 31 and a 1.5 inch snowfall on April 16.  Two years ago, we got buried by 9.1 inches on April 15-16 followed by another 3.2 inches on April 17-18.  Late season snows usually melt quickly but often provide more shock value than the snowstorms that happen in the middle of winter.  My own interest in meteorology as a lifetime profession was probably triggered by a now famous spring snowstorm that covered southern Wisconsin (and me) in 12-18 inches of snow April 7-8 or 1973.  My family had just moved to the Midwest from Alabama the previous summer and that April snowstorm was my first blizzard.     Meteorologist John Wheeler

Tornado Absence

 

March is typically one of the peak months for tornadoes in the United States.  Though rare so early in our region, it is common for there to be big outbreaks in March across the Southern Plains or the Southeast.  This year, for just the second time since 1950, there were no tornadoes reported across the country from March 1-15.  The other year was 1969. The cause for this year’s absence of twisters is, of course, the jet stream pattern, which has kept the Great Plains extremely dry this month so far.  And although the Southeast has been rainy, the rains have been general soakers.  The pattern just has not favored the development of tornado-producing supercell thunderstorms.  This should not be taken as a sign that our warm season will be free of tornadoes.  Meteorologist John Wheeler

Drought Brings Good With Bad

Since 1993, the weather pattern over the Red River Valley region has been wet.  Dry periods within this time frame have been few and generally brief. Average annual rainfall increased 15-20 per cent starting in 1993.  The weather has been wetter and for a longer period than the dust bowl years were dry.  Eventually this pattern will end but it is not possible to know in advance if the change will take place in another hundred years or if is starting right now.  Weather is difficult that way.  Although drought is hard on our overall economy and water shortages can make life more difficult, drought is a naturally occurring part of nature.  It has a way of rebooting wetlands, leaving them healthier and more productive.  A drought would lower the almost annual flood threat by lowering reservoir levels.  And a drought would lower Devils Lake.   Meteorologist John Wheeler

Prairie Fires

 

Each of the last two spring seasons has been cold, wet, and late.  This one has come in early and dry. This could mean a lot more grass fires this spring.  Pre-historically and historically, prairie fires were common across our region in spring.  As the snow melted each spring, hundreds of square miles of dead grass lay on the ground just waiting to burn on a hot, dry, windy day. All it needed was a bolt of lightning from a light thundershower.  As our terrain has given way to agriculture, grass fires have been reduced to ditches and the few remaining stretches of prairie.  Still, an out-of-control fire is extremely dangerous. It is possible even today for fires to grow large enough to put farmsteads and even whole towns at risk.  And today’s fires are more easily started by careless smokers, trains, or accidental controlled burnings growing out of control.   Meteorologist John Wheeler

Gut Feelings Worth Little/Nothing

 

Since this warm spell began, many people have asked me about “gut feelings” (theirs or mine), as to how much winter weather remains. The premise being that a number of people “have a feeling” we have seen the last of snow and cold.  A good weather forecaster does not use “gut feelings” to make a forecast because such a premonition would be baseless.  Colder weather and even snowstorms could happen with a change in the Jet Stream.  The physics models we use to make our seven-day-forecasts actually run out to more than two weeks.  It’s just that they are terrible at such a range.  Other forecasting tools, such as circulation anomalies, are sending mixed signals as they often do in spring.  So this meteorologist is comfortable saying any spring/summer forecast is as good as anyone’s gut feeling, which is essentially worthless. So enjoy the mild weekend weather.  It might last but it might not.   Meteorologist John Wheeler

 

Drought Talk Premature

Any discussion of drought in our region is March is probably premature.  It has been dry all around eastern North Dakota and northwestern Minnesota since the middle of fall but all our water needs are being met at the moment.  This all changes if the dry weather lingers past planting season.  After planting, crops will need rainfall to germinate. But a timely rain or two will get regional growers through.  By summer, the effects a continued lack of rain will depend on the temperatures.  If it is hot, evaporation rates will be greater and crops will need more rain.  If it is cool, crops can get by with less.  Reservoirs upstream are relatively full so unless the drought is severe, rivers should not drop to low.  But again, a combination of severe drought and high temperatures could cause municipal and other water shortages.  Of course, none of this has happened, yet.  Thus, any discussion of drought in March is probably premature.     Meteorologist John Wheeler

March Blizzards

 

It is a myth that there are always huge blizzards in March.  In the distant past as well as in recent years, March and April pass without any blizzards at all.  Of course, it is also true that some of our most severe blizzards in history have happened in March.  Across North Dakota, the benchmark for blizzards may well be the monster blizzard of March 3-6, 1966, when one to three feet of snow with winds 50 to 100 mph built drifts 30 feet high.  But March is not the only month with a tendency to produce memorable winter storms.  All of the cold months from October through April have produced at least a few severe blizzards.  Interestingly, the big ones are most common in three of the months; November, January, and March.  November and March provide the greatest proximity of warm and cold as the seasons change.  January is the king month for hybrid Alberta Clipper storms connecting with super strong Arctic high pressure systems.   John Wheeler

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Average is Average

 

Average March snowfall is 9.1 inches.  Average April snowfall is 3.0 inches. This does not mean we are for sure in for a foot of snow before spring.  Nor does this mean we should expect around a foot of snow unless something goes wrong with the weather.  What is average implies nothing about what is supposed to happen.  Average is derived by taking an average.  Almost all of the time, weather is above or below average and the average is just the middle of all the samples.  We usually use the average of the three most recent complete decades to calculate the average.  At present, we are using 1981-2010 to compute our averages.  Each new decade the averages change.  This is so what we refer to as average keeps up with the gradual changes in our climate without overreacting to sudden swings in year-to-year weather.  We might get very little snow during March and April.  Or the storm track could change and we might get a lot.  That’s weather.  That’s all.    John Wheeler

 

If You Want a Big Spring Blizzard…

 

In order for us to get socked by a blizzard this spring, the pattern will need to change.  At present, the Polar Jet Stream is too weak and to far north to be a threat.  The far more active Subtropical Jet Stream could shift northward and bring snow, but a real blizzard would not be likely from such a set up.  The few near-blizzards we have had this winter have been brief rounds of blowing snow in the open areas of the Red River Valley.  And with limited snow cover and very little falling snow, conditions have been marginal at best as blizzards go.  Serious Great Plains blizzards are born along a fast and active Polar Jet Stream.  Some ripple in the wind field out over the Pacific Ocean grows into a full-fledged kink in the Jet Stream.  As it crosses the Rocky Mountains, the differences within the system widen and the low pressure deepens.  As the system closes into a circle throughout the lower and middle atmosphere, fierce winds and heavy snows develop and woe is he who gets in the way.   Meteorologist John Wheeler