The sun is currently featuring one lonely visible sunspot region and this relatively blank look is becoming more and more common as solar cycle 24 heads towards the next solar minimum. In fact, there have been 42 days in 2017 with a completely blank sun – already ten more days than all of last year – and this makes up almost one-quarter of the time for this year. Solar cycle 24 has turned out to be historically weak with the lowest number of sunspots since cycle 14 peaked more than a century ago in 1906. In fact, by one measure, the current solar cycle is the third weakest since record keeping began in 1755 and it continues a weakening trend since solar cycle 21 peaked in 1980. One of the natural impacts of decreasing solar activity is the increase of cosmic rays that can penetrate into the Earth’s upper atmosphere and this can have many important consequences.
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A weak El Nino instead of a moderate-to-strong one would allow for a more active tropical season in the Atlantic Basin. In addition, should a weak El Nino persist into the upcoming winter season and be concentrated in the central tropical Pacific Ocean (Modoki), it could increase the chances for a snowy winter in the eastern US. Earlier this year, it looked as though a moderate-to-strong El Nino was a sure bet as sea surface temperatures shot up to well above normal levels just off the west coast of South America. In addition, numerous computer forecast models at that time supported the idea of a moderate-to-strong El Nino in the tropical Pacific for the summer and fall seasons. Recent actual observations, however, indicate El Nino is sputtering and many computer forecast models have now backed away from a moderate-to-strong El Nino and this potential change could indeed have some important implications.
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This could very well be just a temporary blip, but Arctic sea ice extent has actually crossed into territory in recent days that it hasn’t seen too often in many months. Specifically, Arctic sea ice extent as measured by the European global operational satellite agency (EUMETSAT) has moved into the relatively “normal” range of +/- 2 standard deviations – albeit on the very low side of “normal” for this particular time of year. Arctic temperatures have dropped to below-normal levels in recent weeks after running consistently above-normal for the first four months of the year and this has slowed down the normal springtime melting in that region.
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Earlier this year, it looked as though El Nino was beginning to form in the tropical Pacific Ocean with warmer-than-normal sea surface temperatures becoming more evident off the west coast of South America. In addition, numerous computer forecast models were predicting moderate-to-strong El Nino conditions for the summer and fall seasons in the equatorial region of the Pacific Ocean. While this can still happen, recent actual observations have raised some questions about those predictions. One of the reasons it is necessary to closely follow the changes in the tropical Pacific Ocean is the fact that it can have an important consequence on the rapidly approaching Atlantic Basin tropical season. In an El Nino year, for example, there is a tendency for less tropical activity in the Atlantic Basin as El Nino-induced vertical wind shear is typically higher-than-normal and this tends to inhibit the growth of tropical storms.
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It is not often that “severe”, “extreme” or “exceptional” drought conditions are limited to only 1.58 percent of the continental US, but that is exactly what we have right now across the country. We know that these good times will not last for too much longer; nonetheless, it is worth noting that this is about as good as it gets for the US regarding drought. In fact, going back to the year 2000, only the early part of 2010 featured somewhat similar limited drought conditions on a nationwide basis to what we are enjoying today. Just under five years ago in August of 2012, the nation was at a real dry point and nearly 25 percent of the country was classified with “extreme” drought.
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Today marks the 6th day in a row that the sun is blank and the 36th time this year - already more spotless days than all of 2016. In what has turned out to be a historically weak solar cycle (#24), the sun continues to transition away from its solar maximum phase and towards the next solar minimum. In April 2010, the sun was emerging from the last solar minimum which was historically long and deep. The blank look to the sun will increase in frequency over the next couple of years leading up to the next solar minimum - probably to be reached in late 2019 or 2020. By one measure, the current solar cycle is the third weakest since record keeping began in 1755 and it continues a weakening trend since solar cycle 21 peaked in 1980. One of the impacts of low solar activity is the increase of cosmic rays that can penetrate into the Earth’s upper atmosphere and this can have many important consequences.
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The overall numbers are likely to be near normal this year in terms of the number of Atlantic Basin (includes the Caribbean Sea and Gulf of Mexico) tropical storms and the sea surface temperature pattern in the western Atlantic and Caribbean Sea makes the southern and eastern US somewhat vulnerable to “home-grown” tropical hits. The major factors involved with this year’s tropical outlook include an unfolding weak El Nino in the equatorial Pacific and a mixed picture of warmer-than-normal and colder-than-normal patches of water across the Atlantic Basin.
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Europe had an extended period of colder-than-normal weather in April accompanied by lots of snow and now much of the US is experiencing an extended period of colder-than-normal weather as we transition from early-to-mid May. Snowfall has been running at above normal levels this winter across the Northern Hemisphere and continues at those higher-than-normal levels as we heads towards the middle of May. In addition, temperatures in the Arctic region - which have been generally running at above-normal levels in recent weeks - have actually dropped to below-normal in recent days and, if this trend continues, it should prevent any chance for sea ice extent to reach record lows up there this summer. One of the main factors contributing to this late season cold across much of the Northern Hemisphere is a blocking pattern in the upper part of the atmosphere centered over Greenland and Iceland and this tends to contribute to cold air outbreaks into the land mass areas on both sides of the Atlantic Ocean.
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A cold wave has hit Europe and it looks like much of the continent will stay well below normal right through the rest of the month of April. In addition to the unusual cold, heavy snow accumulations are likely over the next ten days in many higher elevation locations (e.g., Alps) and accumulating snow is probable as far south as southern Italy and Greece.
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It is not often that “severe”, “extreme” or “exceptional” drought conditions are limited to only 1.6% of the continental US, but that is exactly what is currently taking place. Going back to the year 2000, only February and March of 2010 had similar limited drought conditions on a nationwide basis that we are enjoying today. In fact, the news may actually get better with the next “drought monitor” update as the numbers cited in today’s posting reflect only precipitation data registered through last Tuesday, April 4th and does not include the substantial rainfall that fell late last week in California and across the southern and eastern US.
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