The sun has been completely spotless on 21 days in 2016 and it is currently featuring just one lonely sunspot region. In fact, on June 4th of this year, the sun went completely spotless for the first time since 2011 and that quiet spell lasted for about four days. Sunspot regions then reappeared for the next few weeks on a sporadic basis, but that was followed by several more completely spotless days on the surface of the sun. The increasingly frequent blank sun is a sign that the next solar minimum is approaching and there will be an even greater number of spotless days over the next few years. At first, the blankness will stretch for just a few days at a time, then it’ll continue for weeks at a time, and finally it should last for months at a time when the sunspot cycle reaches its nadir. The next solar minimum phase is expected to take place around 2019 or 2020. The current solar cycle is the 24th since 1755 when extensive recording of solar sunspot activity began and is the weakest in more than a century with the fewest sunspots since cycle 14 peaked in February 1906. One other note, the weak solar cycle and the expectation for continued low solar activity this upcoming winter is an important factor in this year’s colder-than-normal Winter Outlook for the Mid-Atlantic region.
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Last winter was one in which significantly warmer-than-normal temperatures prevailed in the Mid-Atlantic region largely as a result of a strong El Nino event in the tropical Pacific Ocean, but it also featured a blockbuster blizzard that boosted seasonal values to well above normal levels in the DC-to-Philly-to-New York City corridor. It looks like the Mid-Atlantic region is going to experience a much different winter this year with respect to temperatures as it should turn out to be colder-than-normal as weak La Nina conditions in the tropical Pacific Ocean have replaced the strong El Nino. As far as snowfall is concerned, total amounts this winter are likely to reach near normal to slightly above normal levels in the I-95 corridor. In addition to the big change in temperatures, another big difference this year should be a much quicker start to winter-like weather conditions. The last couple of winters featured quite warm Decembers compared to normal, but that is not likely this year as a big flip in the overall temperature pattern to colder should take place during the middle or latter part of November.
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Arctic sea ice extent has seemingly just passed its low point of the melting season with a rather sharp uptick in recent days (circled region). Arctic sea ice generally shrinks every year during the spring and summer seasons until it reaches its minimum yearly extent around this time. Sea ice then typically regrows during the frigid fall and winter seasons when the sun is below the horizon in the Arctic. The apparent end to this year’s melting season in the Arctic around September 10th was actually a bit sooner than in some recent years and perhaps the earliest turnaround since the late 1990s. For example, in the record low year of 2012 for Arctic sea ice extent, the turning point marking the end of the melting season took place around September 16th.
While Arctic sea ice extent appeared to be headed for record lows earlier this year, the melting rate changed pace and actually slowed down in the summer months. The low point just reached is clearly still below the normal value for the 1981-2000 time period, but it is actually quite comparable to the minimums seen during each of the last three years - and safely above the record low seen in 2012. The Arctic sea ice extent has been generally below normal since the middle 1990’s at which time the northern Atlantic Ocean switched sea surface temperature phases from cold-to-warm and it is likely to return to pre-mid 1990’s levels when the ocean cycle flips back to cold. Meteorologists track oceanic temperature cycles in the northern Atlantic Ocean with an index value known as the Atlantic Multidecadal Oscillation (AMO). The AMO flipped from negative-to-positive in the mid 1990's signaling an important long-term sea surface temperature phase shift from cold-to-warm and it has stayed positive ever since. Typically, oceanic temperature cycles in the Atlantic Ocean have lasted for about 20 to 30 years.
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It has long been widely accepted that the sun is absolutely critical to all weather and climate here on Earth and yet there are still some aspects of this connection that are not too well understood and even controversial. For example, there has been the belief by many atmospheric scientists that cosmic rays which penetrate the Earth’s atmosphere from outer space can play a significant role in the formation of clouds which, in turn, has a direct impact on climate. Solar activity has a direct impact on the ability of cosmic rays to actually reach the Earth’s atmosphere. A just published study has confirmed the notion that cosmic rays can indeed be an important player in Earth’s weather and climate and the role of the sun is critical.
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Amazingly, the state of Florida has not had a hurricane of any intensity since Wilma came ashore in southwestern Florida during late October of 2005. Hurricane Wilma was also the last major hurricane (i.e., category 3, 4 or 5) to strike US soil in what has turned out to be another amazing streak. As the climatological peak of the Atlantic Basin hurricane season approaches (mid-September), we now have quite an active scene with three different tropical systems. Tropical Depression Fiona is in a weakening state (at least for now) and it should have little or no impact on the US over the next couple of days. Tropical Storm Gaston is situated in the far eastern Atlantic Ocean and it will likely strengthen significantly over the next few days as it heads in a general northwest fashion, but it is likely to never reach the US coastline before it curves towards the northern Atlantic. And then there is the third system - which is yet to be named - currently sitting a few hundred miles east of the Leeward Islands. It is this system that has a good chance of intensification over the next few days (would become named Hermine), and it has a chance to end the hurricane drought in Florida by the early part of next week.
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The climatological peak of the Atlantic Basin tropical season is around the middle of September with a usual ramp up of activity during the second half of the month of August. It looks like the atmosphere will be behaving as expected this year with an active period likely during the next six weeks or so and there are early signs for an important coastal threat as we approach the end of August or begin the month of September.
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Torrential rainfall will inundate Florida and other sections of the Gulf coast over the next several days with some areas likely to receive more than a foot of rain. Tropical moisture associated with a slow-moving tropical wave is causing rain today from Louisiana to Florida and much more rainfall is on the way. There is little doubt that with this kind of excessive rainfall, standing water will become an increasing problem in the next several days and this can eventually lead to higher numbers of the type of mosquito that is known to spread the Zika virus. The tropical wave contributing to the excessive rainfall could reach "named tropical-storm" status as it moves over the very warm waters of the Gulf of Mexico; however, even if it does not do that, it’ll still have the ability to dump bucket loads of water on Florida and other parts of the Gulf coast.
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The usually brownish-green North Atlantic has turned blue-green in recent weeks due to a combination of atmospheric conditions and it now seemingly resembles the Caribbean Sea. The uncharacteristically blue-green hue of the North Atlantic is the result of phytoplankton and has been around for at least ten days or so – but is likely to not last much longer.
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The forecast for the high temperature in Death Valley, California for the next couple of days is a rather pedestrian 108 degrees or so. One hundred and three years ago – on July 10th, 1913 - the weather observer at Greenland Ranch in Death Valley recorded a high temperature of 134 degrees. This is the highest air temperature ever reliably recorded on Earth, but it didn’t get that distinction until just recently. The Greenland Ranch weather station was located across the street from what is known today as the Furnace Creek Ranch and it is about 180 feet below sea level.
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The Atlantic Basin hurricane season is now well underway and there has been somewhat of an active start to the season with one hurricane (Alex) already in the books which formed way back in January and three recent tropical storms (Bonnie, Colin and Danielle). While there is not a significant statistical correlation between early season activity and the tropical season as a whole, there are reasons to believe that this year may end up being more active than recent years which have been relatively quiet for the US mainland. In fact, the Atlantic Basin is in the midst of an unprecedented streak with no major (i.e., categories 3, 4 and 5) hurricane strikes in the US since 2005. In fact, this is the longest streak of that nature since record-keeping began in 1851 and there are some meteorological factors involved. The closest major hurricane drought to that of the present was the smaller 8-year record of 1861-1868. Just as a point of comparison, in 1954 the US was hit by 3 major hurricanes in less than 10 weeks (plot below).
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