I Knew It Was Cold Here

An article last week in Nature Climate Change identified the few places around the Northern Hemisphere most prone to extreme weather.  Specifically, the study identified those places most likely to have stalled out large-scale jet stream waves as these are the mechanisms for too much rain, snow, cold, heat, etc.  For cold air anomalies, we are in a bad spot.  It turns out, the eastern half of North America is most vulnerable to long-term cold air outbreaks.  The worst flooding occurs in western Asia.  Drought is most prevalent across central North America, Europe, and central Asia.  Heat waves are most likely over western North America and central Asia.   Meteorologist John Wheeler

Good Sun, Bad Sun

Get too much sun and you can get a sunburn, which is painful.  But of greater concern from sun exposure is the risk of skin cancer.  But exposure to sunlight also has known health benefits.  Specifically, exposure to sunlight (and UVB rays in particular) is known to trigger production of vitamin D3, an enzyme which helps our bodies fight cancer.  New research is suggesting that slathering our bodies with the cheapest sunscreen available may actually be a double negative.  Many inexpensive sunscreens block UVB rays (which cause sunburn but also spur vitamin D3 production) but do nothing against UVA rays (which cause melanoma).  Perhaps a common sense approach to sun exposure is called for.  Avoid sunburn by not spending too much time in the sun.  Know your limits and be aware that some people can tolerate less sunlight than others.  Finally, read the labels of sunscreen and use it sensibly.   Meteorologist John Wheeler

Daytime and Nighttime Storms

There are two times of day when thunderstorms are most likely to happen over eastern North Dakota and western Minnesota, and they are related to two distinctly different weather patterns.  During spring, early summer, and early fall, the most likely time for thunderstorms is in the late afternoon and early evening.  Near the hottest time of the day, thermals rising off the warm grounds are at their strongest and this may be just enough to kick off a few thunderstorms.  During July and August, we tend to get more thunderstorms after midnight.  When our weather is at its hottest, the upper levels of the atmosphere are often warm as well, making it harder for just the thermals to initiate storms.  But at night, here in the Northern Plains, storms can get a little boost from something called the Nocturnal Jet Stream; a river of air a few hundred feet above the ground which blows from south to north causing a convergence of air which enhances rising motions in the atmosphere.  Of course, it is possible for a thunderstorm to happen at any time of day.  But suppertime and after midnight are the most common times in our region.   Meteorologist John Wheeler

Wet Year in Minneapolis

Average precipitation (rain and melted snow) in Minneapolis is 30.61 inches.  This is about eight inches more than our average annual precipitation in Fargo Moorhead of 22.58 inches.  Following a four inch rain on Thursday, the official Minneapolis weather station at the main Minneapolis airport has now received over 25 inches of precipitation since the start of the year.  This is more than four inches more (to date) than in any year on record, with records going back to the 1870s.  With half the year still to come, the annual precipitation record of 40.15 inches set in 1911 is in jeopardy of being broken.  Even with all the rain lately, Fargo Moorhead precipitation to date is about eleven and a half inches.  This is about 14 inches less than what has fallen in the Twin Cities.    Meteorologist John Wheeler

Where Does the Water Come From?

When it rains here in the Northern Plains, where does the moisture that makes the rain come from?  Actually, there is enough moisture in the air for rain most of the time.  Storm systems tend to make the most of available moisture because of convergence (air flowing together from different directions).  Also, slow-moving storms are able to generate more rain than ones that quickly pass.  But some weather systems are just better at making rain than others and a lot of this has to do with how much water vapor is available for rain.  If you follow air streamflows into our region, you will see that source regions of that moisture include both the Pacific Ocean and the Gulf of Mexico.  Storm systems really laden with moisture usually have some sort of connection to these regions. A lot of the time, it is the Gulf that brings us the moisture, but sometimes we get very moist air from the tropical regions of the Eastern Pacific.       Meteorologist John Wheeler

Soccer in the Jungle

Manaus, Brazil, is hosting Sunday’s FIFA World Cup match between the teams from the U.S.A. and Portugal.  Manaus is a city of two million people located at the confluence of the Negro and Solimões River, both important tributaries of the Amazon. The city has been populated since the late 1600s, so it is certainly metropolitan.  That being said, Manaus is actually located 900 miles inland from the Atlantic Ocean well within the Amazon rain forest.  One travels to Manaus by plane or boat.  One does not drive there from Rio de Janeiro.  The weather is that of a tropical rain forest.  Temperatures are usually in the 80s with dew points in the 70s. Usually there is very little wind.   There are frequent thunderstorms, often with heavy rain.  The stadium is a brand new, 40,000 seat arena.  It is open to the weather over the pitch but the roof is designed to keep most of the spectators out of any rain.  John Wheeler

More Humidity

For the first time this year, dew point temperatures the past couple of days have been well into the 60s, making the air feel more humid than it has since last summer.  This has not been truly high humidity.  Dew point temperatures in the 70s represent high humidity.  Dew points above 75 degrees are when it is really sticky.  Dew points of 80 degrees or above are uncommon in the Northern Plains but would be considered very high humidity just about any place in the world.  Most of our humid weather happens in July and August.  Over the past two or three decades in our region, the average summertime humidity as well as the number of very humid days has been increasing.  Plainly put, it is more humid around here than it used to be.  An increase in average rainfall has increased humidity as well as soil moisture.  Another reason is increased evapotranspiration from robust soybean and corn crops replacing wheat and barley.    Meteorologist John Wheeler

I’m Sorry, June, For What I Said.

After writing last Sunday in this space about what a lousy month June is, I was promptly treated to two wonderful June days on Monday and Tuesday.  I apologize, June, for the bad things I said about you.  I guess I was mad about all the rainy days and the weekend in particular and I had simply forgotten about just how beautiful June weather can be.  I love the way the blue sky compliments your green grass.  I love your leaves, still young but thick and green and full of life.  I love your rivers and lakes, even if they overflow with emotion from time to time.  We both know how you can be temperamental.  At times, even terrible.  You are never an easy month.  You are just so very, very complicated.  But there is no doubting your beauty, June.  And even if it rains again later today, June, I’ll never be able to get you out of my mind.     Meteorologist John Wheeler

Anniversary of Rare June Heat Wave

This week in 1995, our region was experiencing a rare early summer heat wave.  For eight days, from June 14-21, the high temperature in Fargo Moorhead reached at least 90 degrees.  This included six consecutive days and nights in which the temperature never went lower than 70 degrees even at night.  The hottest day during the stretch was June 17 when it reached 100 degrees.  Temperatures of 100 degrees or warmer are extremely rare in the Fargo area during June.  With records going back to 1881 this has only happened a few times, mostly in the 1930s.  Long stretches of 90 degree days in June are also rare, as are long stretches of nights above 70 degrees.  Such hot weather is much more common in July and August.  Though not something that should be expected every year, mid to late summer temperatures of 100 or higher have happened roughly once every two to three years on average going back to 1881.  Meteorologist John Wheeler

Warm May Globally

In the 35 year globally averaged, satellite-based temperature record, May was the third warmest May recorded.  There are two primary reasons for this.  The first is the ongoing global warming.  Although the warmest point in the satellite record was at the time of the last major El Niño in 1999, the globally averaged temperature has leveled off at a temperature only slightly lower than 1999 and considerably higher than was observed 20 to 35 years ago. The second reason is that another El Niño is developing in the Pacific Ocean.  It remains to be seen if this upcoming El Niño will be a strong one as they usually peak during winter, but this El Nino is starting from a base temperature that is warmer than past El Niños observed by satellite technology.     Meteorologist John Wheeler