Rainy Opinion

Either it rains or it doesn’t.  Nature has no opinion.  But when the weather forecaster is talking about an upcoming chance for rain, it is almost impossible to do so without offering some sense of whether the outcome will be a good thing or a bad thing.

And this time of year, especially, the perceived status of the thing can become a problem. Late summer rainfall tends to be sporadic but evaporation is uniform so those places that have been missed by the better rains in July could use a drink of water.  Many row crops are getting pretty thirsty but small grain harvest is underway and those doing combining like it dry.  Cabin and resort owners like it sunny.  Those planning outdoor events like it sunny.  But when brown patches show up in homeowner’s front yards, those homeowners want it to rain, but not on the days they’re going to the lake.

Everyone knows the weatherman doesn’t make the rain, but many people like to remind the weatherman whenever each one of these various needs is underrepresented in the weather program.

Meteorologist John Wheeler

One Wet May

 

The Monitoring Branch of NOAA’s National Centers for Environmental Information has declared this past month as the wettest May in the United States over 121 years of record-keeping.  Although many parts of the West Coast region as well as most of the Southeast region were significantly drier than average, the wet spots won out.  The wettest region, relative to average, was the Great Plains from Texas to North Dakota, with rainfall in May about 200 to 300 per cent of normal.  The states of North Dakota and Texas had their wettest May months on record.  Across North Dakota, the month of May was rainy enough to turn a very dry March and April into the 37th wettest spring since 1895.  Weather was also wet in the Great Basin, Arizona, and New Mexico.

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

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

May Rain a Record

May rainfall totaled 7.85 inches, which is the wettest May since records began in 1881.  There had only been 2.25 inches of precipitation (almost all of it rain) this year prior to May.  In fact, you would have to go back to August 4 and total all the precipitation that fell into the gauge at Hector Airport to add up to our May total.  In other words, we got as much precipitation in May as we had over the previous nine months.  A part of this is due to timing.  Our dry spell started at the end of last summer and lasted through April.  On average, 53 per cent of our annual precipitation falls in May, June, July, and August.  Our dry weather happened during the drier part of the year, anyway.  Hopefully, the rainfall this summer will be closer to average and not one of the extremes.

Meteorologist John Wheeler

Sea Levels

A new orbiting weather satellite scheduled to launch July 22 is designed to monitor the level of the ocean.  Jason-3, the latest in a joint U.S. and European mission designed to monitor sea level, will use the latest and most sophisticated radar altimeter to send a series of microwave pulses to the ocean’s surface so it can time the reflection.  Jason-3’s predecessors have measured a 2.4 inch average rise in the past 23 years.  But the rise is nor universal.  Most people think of the sea-level as being the same all over, but it is not.  Regions of the oceans that are relatively warm compared to their surroundings swell due to thermal expansion whereas colder regions contract.  These hills and valleys can vary by as much as six feet. By monitoring the height of the ocean around the world, we will be better able to track changing ocean currents as well as improve storm surge forecasts during hurricanes and other coastal storms.   Meteorologist John Wheeler

Texas Floods

Flooding in Texas the past two weeks has become symbolic of the concern that the warming climate is contributing to more extreme weather.  Yes AND no.  Yes, it does make sense that a warmer atmosphere will contribute to increased volatility; more heat in heat waves, more rain in wet patterns.  However, it is also the very nature of Texas weather to go from drought to flood.  Texas is uniquely positioned geographically for huge swings in precipitation.  Western Texas is arid, nestled up against the southern Rocky Mountains which catch whatever is left of any moisture coming across from the Pacific on the subtropical jet stream.  Southeast Texas is wet, straddled against the warm and humid Gulf of Mexico.  A stalled out weather pattern tends to favor one extreme or the other.  That being said, the potential contribution of the warming climate should not be ignored.  Nor should it be considered the only factor.  Meteorologist John Wheeler

Where’s the Flood?

In the space of thirteen days, from May 6 to May 18, Fargo Moorhead’s annual precipitation total to the date went from the 17th driest on record to the 15th wettest .  The 5.82 inches of rain that fell those thirteen days alone would rank in 8th place on the list of wettest Mays.  And yet there was hardly any river flooding in the entire region.  Sure there has been some minor lowland flooding in the typical flood prone areas, the sort of flooding that is common after heavy rain.  But nowhere in our region has there been any of the significant flooding one would expect following such a rain.  Most of the fields that had standing water for a few days have dried nicely, suggesting additional water storage capacity if needed.  We can thank the fall-winter-early spring drought for this.        Meteorologist John Wheeler

Rain and Heavy Rain

Rainfall and heavy rainfall go together.  That is, when there is a pattern of above-average and more frequent rainfall, it is also more likely that there will be a downpour.  Warm weather and heavy rainfall also go together.  When the atmosphere is warmer, there is more capacity to hold moisture in the air, which increases the potential for downpours.  As the average temperature in our region has risen since the middle of the 1900s, so has the frequency of heavy rains.  Also, as the average annual precipitation began to rise in the 1990s, the downpours have been increasing.  The flooding problem across our region the past 20 years can be tied to both of these trends.  The future of flooding in our region is likely going to be tied to both of these trends.  Additional warming appears likely but a further increase in annual precipitation is probably less likely.   Meteorologist John Wheeler

Rising Seas?

Although the interior of the Antarctic continent is getting colder, one of the most rapidly warming locations on Earth the past few decades is along the Antarctic Peninsula.  An ice shelf known as Larsen C, the fourth largest ice shelf in the world at more than 20,000 square miles, adjoins the Antarctic Peninsula and has been discovered to be melting at a rapid rate due to the warmer air temperatures and the warmer seas underneath.  A research team from the British Antarctic Survey has reported a growing crack in the shelf which could cause it to break up some time in the next 100 years.  This would not lead directly to a rise in sea levels because this ice is already floating in the ocean.  However, if the region continues to warm, the loss of the ice shelf could allow glaciers presently land locked to melt into the ocean faster.  Sea-level rise is one of the greatest concerns associated with Global Warming.   John Wheeler