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
The high temperature this past Wednesday of 96 degrees was the warmest of the year.If that holds, it would continue our trend in recent years of our maximum yearly temperature being below the historical average.From 1900 through 1990 the average yearly maximum temperature was 99 degrees.
Since 1990 the average maximum has been 96 degrees.The abundant moisture since the early 1990s and the corresponding wetter soils tend to lower the potential air temperature.Plus, atmospheric patterns have rarely been conducive to high heat in the past two decades as well.That average maximum of just 96 in the past 20 years is even colder than the average maximum high in the 1880s.That decade, which is overall the coldest decade on record, had an average maximum yearly temperature of 98 degrees.
The only time frame which experienced cooler maximum temperatures then what has been recorded in recent years was in the first decade of the 1900s when the average yearly maximum was 94 degrees.
Often times during my public speaking appearances, I talk about the concept of climate utopia. It is a reference to how common it is for people to think that what they see today will be the way things will always be. Put another way, the future will be a perfect utopia with no changes.
Although it has occurred numerous times during the past few thousands years, no one would have likely guessed the change that occurred to Devils Lake from 1993-1996 that continues to be a problem today and will likely be for years to come. When you buy a new lake cabin you always imagine the shoreline will be static, but lake rises and falls are and always will be a natural progression over time. In recent years it seems no matter what the weather, it is reported as extreme or unusual, when in fact it all a normal part of our highly dynamic, ever varying atmosphere.
Change is often difficult, but that does not mean it is unusual or unique.
Many people tend to write down and keep track of certain annual events.These events may include the sighting of the first robin of spring, or if you live on a lake, the ice out date.For me in recent years, I have tended to keep track of when my crabapple trees bloom.Although I have moved, I still find myself every spring driving by those crabapple trees to continue my dating when they bloom each spring.
This recording of the timing of natural events is referred to as Phenology.My former crabapple trees finally went into full bloom on Tuesday, May 28.That is latest bloom date in the 12 years I have been keeping track.Although, that may not surprised anyone based on the cold weather this spring, it is only one day later than the springs of 2002 and 2008 when the trees bloomed on May 27.
This means at least to the flowering trees, this spring has been similar to a couple of other springs in the past decade.
One of the most common questions that come into the weather center deals with correlation.We are often asked if because this season is – insert hot, cold, dry or wet – does that mean the next season will be – insert hot, cold, dry or wet—and usually the reference is that the next season will be the opposite of what is currently occurring.
In other words, is there a correlation between what is occurring now and what we can expect in the future?Our cold spring have many people inquiring if a hot summer is coming as that would then “balance” the weather.There can be some correlation between seasons, especially when dealing with El Nino or La Nina events, yet even in those instances the relationship is no where near 100% accurate. Therefore, as a general rule a pattern from one season, does not correlate very well with future seasons.
Meaning, this summer will not necessarily continue to be cold, or end up extremely warm based on what has been occurring these past few months.
Bank thermometers will often show erroneous temperatures. It is not so much that the sensor being used is inaccurate, but instead, the sensor is often placed in a poor position. To accurately measure the air temperature, official thermometers have historically been placed in a white shelter box referred to as a Stevenson screen and more recently in a white enclosed ventilated plastic cover.
Often a thermometer used by a business is directly in the Sun part of the day, plus the thermometers are often placed over parking lots that are black and absorb much of the incoming solar radiation and make the surrounding air much warmer. That dark surface influence has been particularly noticeable in recent days as the strong early Spring sunshine has a lot of potential to warm, but our snow pack has been limiting the area from reaching our temperature potential.
So if you see a bank thermometer flashing 50 degrees on a sunny day, the reality is, it would likely really be 50 degrees if it was not for our deep snow cover.
Back on June 24, 2012 a tornado, associated with Tropical Storm Debby, moved through Highland County, Florida. Very tragically, a young mother was killed protecting her baby from the violent wind that struck her house. The baby still wrapped in her mother’s arms suffered broken ribs, cuts and bruises, but did make a full recovery.
That tornado death was the last one reported in the United States until last Wednesday’s severe weather that hit northern Georgia particularly hard. An EF-3 rated tornado moved through Adairsville, Georgia killing a man when a tree fell on a shed he happened to be seeking shelter in. That stretch of 220 days was the longest stretch between tornado deaths in the country since such records have been kept in 1950.
The previous record was 197 days which occurred from late 1986 through early 1987. That period many of you will recall was also a period of drought and the corresponding lack of thunderstorms in the United States.
Last year Fargo Moorhead recorded a brown Christmas. Other recent brown Christmas’ included 2006, 1999 and 1994. Our historic average for having a white Christmas is 84%, meaning that approximately once every decade we have no snow on the ground on this morning. This year we are experiencing a white Christmas.
You may remember that a year ago today, I forecasted a white Christmas in 2012. It was based on the fact that the odds favored me being right and that locally there has never been two brown December 25ths in a row since such records have been kept. Although we do not have a lot of snow on the ground, it is close to the historic average of 4 inches for this date.
The extremely snowy Decembers from 2007 to 2010 tended to skew our perception of how white the ground usually is this time of year. Yet, both the amount of snow on the ground and our total for the season are pretty close to the average.
In the Atlantic Ocean they are called hurricanes. In the western Pacific they are referred to as typhoons. In the southern Pacific and in the Indian Ocean they are referenced as tropical cyclones. The tropical cyclone season is just beginning and already one has brought devastation.
Somoa and neighboring American Somoa were hit last week by Tropical Cyclone Evan. Evan was a Category 2 Tropical Cyclone when it made a direct hit on Upolu, the eastern of the two principle islands of Somoa. It then moved northeast with the eye wall just missing American Somoa and then it stalled and moved back toward Somoa with the eye wall barely missing them again. That track kept high wind and torrential rainfall over the area for a few days. Tragically at least three deaths were attributed to Evan with two of those deaths being young children.
The storm then intensified into a Category 4 storm and headed southwest and had major impacts on Fiji on Monday.
Rivers flood. We know that all too well here in the Red River Valley. But there is another kind of river that has been causing flooding in California that you may not have heard about, an atmospheric river. Atmospheric rivers are narrow regions in the atmosphere, often one to three hundred miles in width that contain high concentrations of water vapor.
Like real rivers, they come in all shapes and sizes and often contain meanders. Using specialized satellite data (water vapor imagery) these rivers of concentrated water vapor are often easily detected. One type of atmospheric river is the so called “Pineapple Express”. This references times when tropical moisture near Hawaii is transported into the west coast, but these narrow flows of moisture can also come from non tropical sources and that has been the case with the heavy rain that has been impacting northern California in recent days.
Although these atmospheric rivers can cause flooding, more often they just bring beneficial moisture to the west coast.