Tornadoes Are Not All Alike

Not all tornadoes are the same.  There can be very weak tornadoes which produce winds of only around 60 mph, not much stronger than one might fine in a large dust devil.  The strongest tornadoes can produce winds of around 300 mph which are capable of destroying all but specially designed, tornado-proof structures.

The most common tornadoes are nearer to the lower end of this spectrum, with wind speeds ranging between 80 and 120 mph. Such storms are, obviously, capable of doing major damage, but the really violent, top-end tornadoes are truly monstrous by comparison.

Severe thunderstorm winds also vary greatly.  A typical, non-severe thunderstorm might produce brief 20-40 mph wind gusts along its leading gust front.  On occasion, straight line winds from a powerful thunderstorm can reach speeds of more than 120 mph.  Such straight line winds are capable of doing as much damage as the most common tornadoes.

Meteorologist John Wheeler

 

Event Planning and Forecasting

It is a growing trend for events to be cancelled for impending weather and then the weather turns out fine.  People are genuinely more concerned about public safety and more aware of the dangers of bad weather.  But there also seems to be a trend toward calling off events too early based on a forecast without truly understanding the forecast.  A forecast calling for storms, possibly severe, on a certain day, does not mean there will be severe storms everywhere all day long.

There seems to be a growing expectation that forecasters can predict weather precisely hour-by-hour and there must be weather forecasters out there who are willing to make such a forecast.  The commonly used defense is that we are “better safe than sorry” but this is, perhaps, a weak argument.  Cars can be dangerous but we still drive them.  Many people fall on stairs but they are not outlawed.

And likewise, it is possibly better to wait a little longer before cancelling some outdoor events because of a weather forecast.

Meteorologist John Wheeler

 

The Opposite of January

July is the peak summer month and the apex of the average temperature graph here in the Northern Plains.  On average, our hottest time of the year is at the end of July and the beginning of August.  Of course, in any given summer, our hottest weather can happen at any time during the summer owing to the natural random variability of weather.

It is not the same everywhere, however.  Across the deserts of the American Southwest, the hottest temperatures are more often in June, before the hot temperatures begin to draw humidity in from the Gulf of Baja.  In Texas, the hottest days are usually in August, when the ground has become parched a summer’s worth of evaporation.  Along coastal areas of California and Oregon, the so-called Santa Ana winds bring the hottest weather of the year from the deserts up and over the Coast Ranges during September and October.

Meteorologist John Wheeler

 

Complaints About Humidity

It takes a lot for most people to call or email a broadcast meteorologist to complain about the weather.  Everybody knows we don’t actually create the stuff.  Yet people do, from time to time, call with an angry tone to find out when a particular weather pattern will change.

Interestingly enough, it is not our bitter winter wind chills that bring out the worst in the weather complainers.  Even when the Wind Chill factor is down into the minus 40s, people seem to just deal with it.  However, as soon as we get a couple of days of hot and sticky humidity, a lot of people’s inner crabbiness is set free.

I get more complaints about high humidity than any other kind of weather.  “When is this disgusting humidity going away?”  “Can’t you do something about this awful weather, please?”  Unfortunately, our climate has been getting warmer in winter and more humid in summer.  And for a lot of people in our region, this is the worst news possible.

Meteorologist John Wheeler

Senate Bill Would Reduce NWS

South Dakota Senator John Thune has authored a bill on Capitol Hill which proposes to radically change the makeup of the National Weather Service.  The bill would greatly reduce staffing in most offices and create six huge central forecast centers which would issue all the forecast products now issued by the 122 separate forecast offices spread around the country.  Most of these 122 smaller offices would still exist, but would no longer perform forecast duties.  Instead, the local offices would primarily operate the local Doppler radar, issue storm warnings, and provide information for local governments and emergency managers in times of bad weather. Environment Canada, the Canadian equivalent to our National Weather Service, is set up in this way with a small number of regional forecast offices.  The National Weather Service Employees Organization strongly opposes the bill.  A similar bill failed to pass in 2005.

No A.C. Needed (Yet)

Just a week left of June and I have not even considered installing the three window air-conditioners in the bedrooms of my house.  I prefer to sleep with bedroom windows open in the summer during all but the hottest weather.  So far this summer, our one day of 90 degree weather (92 degrees on June 9) was preceded by as well as followed by nights that cooled into the 50s.  Although this lack of the desire of air-conditioning is lasting a little later into the summer than usual, the summer has not been unusually cool. In fact, the average temperature for June is running slightly above average.  The weather just hasn’t strung together a couple of consecutive hot days yet so we haven’t had a particularly warm night.  Our warmest night so far has been 61 degrees.  Along the Gulf Coast, that would be a record daily low this time of year.

Northern Plains Biggest Outbreak of Tornadoes

Twelve people died from the Fargo tornado on June 20, 1957.  In Fergus Falls, 57 people were killed by twin tornadoes on June 22, 1919.  Thirteen died during the Fridley (Twin Cities) tornado outbreak of May 6, 1965.  But the biggest outbreak of tornadoes on record in this region happened just five years ago on June 17, 2010.  There were 76 tornadoes that day; 22 in North Dakota, 48 in Minnesota, and three each in Iowa and Wisconsin.  The 48 in Minnesota is a record number of tornadoes in a single day.  Wadena, MN, took a direct hit and was heavily damaged. Two were killed and nine injured across the region but the casualty list would have been much higher had the tornadoes formed over more populated territory.  This remains the biggest outbreak of tornadoes on record for the summer months.  Most high-count tornado outbreaks happen in spring.

Meteorologist John Wheeler

 

Not So Stormy (So Far)

The severe thunderstorm season has gotten off to a rather slow start in our region.  Severe storms require a combination of humidity, instability, and upper level wind structure that our region has not had much of so far this spring.  Through the middle of June, there have only been a relatively small number of very brief and local hailstorms and, so far, just one brief tornado touchdown (no damage) in all of eastern North Dakota and northwestern Minnesota.  During May, our weather was very rainy but it was not very stormy.  Further south, severe storms were frequent.  The preliminary national tornado count in May is 414; the most in years.  So far in June, however, the tornado count has fallen off across the Plains.  After two very stormy summers in 2010 and 2011, there has been relatively little severe weather in our region for three summers in a row.  And though 2015 has been calm so far, it is still only the middle of June and our severe storm season here lasts all summer long.

Meteorologist John Wheeler

The Relatively Rare 90s

The temperature reached 92 degrees on Tuesday, June 9.  It was not a record. The record high for June 9 is 95 degrees set in 1976.  It was, however, our first 90 degree day of 2015.  Any time the temperature reaches the 90s in Fargo Moorhead, it is an above average temperature.  But the normal swings of weather give us an average of about 13 or so days in the 90s in a year.  Most of these hot days occur in July and August.  Each of these months reaches the 90s about five or six times on average. May and June together get to the 90s an average of once or twice.  And there is an average of one additional 90 degree day in September.  Of course, in any given year, these numbers vary.  The greatest number of 90 degree days in June is 13 back in 1910 and again in 1988.  The greatest number of 90 degree days in a year is 39 in 1988.   Meteorologist John Wheeler

Red River Flooding: Flat Does Us a Favor

Forecasting floods on the Red River and its tributaries has always been difficult.  The region is so flat that water forms ponds in fields, making it very hard to gauge how fast the rivers will rise.  Fortunately, they usually rise slowly.  Even when the ground is frozen, saturated, or both, daily rises on the Red River in Fargo rarely exceed five or six feet per day. Last month, when the Blanco River in south-central Texas flooded from torrential rainfall on already saturated ground, the Blanco River at Wimberly rose more than 30 feet in just a few hours.  By the time the West Gulf Coast River Forecast Center in Fort Worth issued forecasts for major flooding, people were already chopping holes through their rooftops to avoid drowning.  Twenty-one died.  Flood forecasting is very hard, so this is not intended to be a criticism of the hydrology forecasts.  But at least in our area it happens relatively slowly, giving us some time to react.

Meteorologist John Wheeler