7:00 AM | Warm again today with occasional showers and thunderstorms; weekend looking iffy

6-Day Forecast

Today

Mostly cloudy, warm and humid, occasional showers and thunderstorms, some of the rain can be heavy, highs in the low-to-mid 80’s

Tonight

Mostly cloudy, mild, chance for more showers and thunderstorms, lows by morning in the upper 60’s

Thursday

Partly sunny, warm, slight chance for a shower or thunderstorm, mid 80’s

Thursday Night

Partly cloudy, mild, upper 60’s

Friday

Mostly sunny, warm, mid 80’s

Saturday

Partly sunny, warm, chance for showers and thunderstorms, mid 80’s

Sunday

Partly sunny, warm, chance for showers and thunderstorms, low-to-mid 80’s

Monday

Partly sunny, warm, chance for showers and thunderstorms, mid-to-upper 80’s

Discussion

Showers and thunderstorms are likely today in the Mid-Atlantic region as a frontal system approaches the area and some of the rain can be heavy at times. Weak high pressure will fill in behind the front for Thursday and Friday, but a shower or thunderstorm cannot be completely ruled out for either day. Additional frontal systems will head our way this weekend and the result will be the threat for showers and thunderstorms each day during the upcoming holiday weekend.

Elsewhere, a heat wave continues today across portions of the Plains and Midwest with well above normal temperatures for this time of year. Despite this late season heat wave, there is a preliminary report that indicates that this summer has featured the fewest 100 degree days on a nationwide basis in over a century (using NOAA's Global Historical Climatology Network dataset). The five summers with the highest number of 100 degree days across the nation are as follows: 1936, 1934, 1954, 1980 and 1930.

Video

httpv://youtu.be/Wt_meEjg8sM

3:00 PM | The Carrington Event of 1859 - a solar superstorm

Discussion

It was this time of year 154 years ago when the solar superstorm, now known as the Carrington Event, took place during solar cycle 10. The event has been named for the British astronomer, Richard Carrington, as he observed from his own private observatory the largest solar flare during this event which caused a major coronal mass ejection (CME) to travel directly toward Earth. The 33-year-old astronomer - widely acknowledged at the time to be England’s best - also recorded in detailed fashion the appearance of the sunspot regions that he saw at the time.

From August 28, 1859 to September 2, 1859 numerous sunspots and solar flares were observed on the sun and auroras were being observed in different parts of the world. Just before noon on September 1st, Richard Carrington was using his telescope to project an 11-inch wide image of the sun on a screen and he carefully drew the sunspots that he saw. Suddenly, two brilliant beads of blinding white light appeared over the sunspots and he realized that he was witnessing something unprecedented. He left for about one minute to find another witness and found upon their return that much had already subsided.

Just before dawn the next day, skies all over Earth erupted in red, green and purple auroras - even in tropical locations like Cuba, the Bahamas and Hawaii. The massive solar flare caused a major CME that reached the Earth some 17.6 hours later. Normally such a journey takes 3 or 4 days, but an earlier CME actually cleared the way of the ambient solar plasma for the second blast to move so quickly. The auroras were so bright over the Rocky Mountains that their glow awoke gold miners who began preparing breakfast because they thought it was morning. People in the northeastern US could read a newspaper by the aurora’s light. Telegraph systems all over Europe and North America went haywire and, in some cases, telegraph operators were literally shocked as sparks were flying and telegraph paper was often set on fire. Some systems continued to work despite being disconnected from their power supplies as aurora-induced electric currents still allowed messages to be transmitted.

Now we know that solar flares happen frequently, especially during solar sunspot maximums, but in those days there were no X-ray satellites or radio telescopes and no one knew flares existed until that September morning. “It is rare that one can actually see the brightening of the solar surface which takes a lot of energy to heat up the surface of the sun” says a modern day NASA astronomer. “In the 160-year record of geomagnetic storms, the Carrington event is the biggest.” In fact, going back farther in time by examining Arctic ice (energetic particles leave nitrates in ice cores), it is estimated that this event may have been the biggest in 500 years and nearly twice as big as the runner-up.

In today’s world, electronic technologies have become embedded into everyday life and are, of course, quite vulnerable to solar activity. Power lines, long-distance telephone cables, radar, cell phones, GPS, satellites – all could be significantly affected by an event like this one. The good news is that observations of the sun are a constant in today’s world with a fleet of spacecraft in position to monitor the sun and gather data on solar flares. The bad news is that the Carrington Event occurred during a weak solar cycle (10) which actually resembles rather closely our current solar cycle (24) so we always have to stay on guard for a potential powerful solar storm - even during times of weak solar cycles.

Above: A modern solar flare recorded Dec. 5, 2006, by the X-ray Imager onboard NOAA's GOES-13 satellite. This flare was so intense it actually damaged the instrument that took the picture. Researchers believe Carrington's flare was much more energetic than this one.

7:00 AM | Very warm with unsettled conditions through tomorrow

6-Day Forecast

Today

Partly sunny, very warm and humid, chance for showers and thunderstorms late, highs near 90 degrees

Tonight

Mostly cloudy, mild, chance for showers and thunderstorms, lows by morning in the low 70’s

Wednesday

Partly sunny, warm, humid, showers and thunderstorms possible, upper 80’s

Wednesday Night

Mostly cloudy, mild, still the chance for showers and thunderstorms, low 70’s

Thursday

Mostly sunny, very warm, cannot rule out a shower or thunderstorm, mid-to-upper 80’s

Friday

Mostly sunny, warm, mid 80’s

Saturday

Mostly sunny, warm, mid 80’s

Sunday

Mostly sunny, warm, mid-to-upper 80’s

Discussion

Conditions will remain unsettled through tomorrow as a frontal system hangs around the Mid-Atlantic region, but high pressure will build into the Northeast later this week and then settle to our south this weekend. Temperatures will likely reach their peak today near 90 degrees, but it should remain rather warm for the rest of the week. The highest temperatures relative to normal over the next few days will be across the Plains and Midwest in a reversal of a pattern that brought them cool weather for much of the prior part of August.

Video

httpv://youtu.be/OI27nl-J1KU

2:55 PM | An update on the Yosemite National Park wildfire

Discussion

While the number of wildfires on a nationwide basis has been way down this year near a record low, the one raging right now threatening Yosemite National Park in California is quite intense and still growing. This northern California wildfire called “The Rim Fire” has now devoured more than 149,000 acres which is about the size of the city of Chicago and, as of this morning, it is only about 15% contained. It has been growing eastward in recent hours and is close to a key part of the San Francisco water supply: the Hetch Hetchy Reservoir, which lies within Yosemite National Park. Ash from the fire has been falling on the reservoir, but so far hasn’t sunk far enough into the lake to reach the intake pumps. If ash eventually causes turbidity, the city of San Francisco will begin filtering supplies. San Francisco gets 85% of its water from Hetch Hetchy as well as power for many municipal buildings and the international airport. In addition to the water supply, the fire also threatens the area’s hydroelectric generators which provide much of San Francisco’s electricity. Because of the approaching flames officials have shut down the generators, and the city – more than 120 miles to the west – is temporarily getting power from elsewhere.

As far as Yosemite National Park is concerned, while the “Rim Fire” has consumed at least 12,000 acres in the northwest section of the park, it has had little or no direct impact on Yosemite Valley, a popular spot for tourists and home to many of the famous cliffs and waterfalls in the park. The fire does, however, pose a threat to the giant sequoias inside Yosemite National Park. In particular, the safety of two groves, Tuolumne Grove and the Merced Grove, are of particular concern. The massive trees in these areas are some of the largest living things on Earth and are believed to be more than 2,000 years old in some cases. Sequoia trees are naturally fire resistant due to their thick bark - must be in order to survive this long. Crews have used sprinklers and are lighting fires to clear brush as a protective measure, though the fire is still several miles from the massive trees. The vast majority of the national park remains open at this time.

7:00 AM | Comfortable weekend conditions give way to more warmth and humidity

6-Day Forecast

Today

Partly sunny skies, warmer, highs in the mid 80’s

Tonight

Mostly cloudy, mild, chance for a shower or thunderstorm, lows by morning in the mid-to-upper 60’s

Tuesday

Partly sunny, very warm, humid, scattered showers and thunderstorms, upper 80’s

Tuesday Night

Mostly cloudy, mild, chance for showers and thunderstorms, upper 60’s

Wednesday

Partly sunny, warm, showers and thunderstorms likely, mid-to-upper 80’s

Thursday

Mostly sunny, warm, mid-to-upper 80’s

Friday

Partly sunny, warm, mid-to-upper 80’s

Saturday

Partly sunny, warm, mid-to-upper 80’s

Discussion

High pressure that provided us with a great weekend will drift to our south and east today and this will allow for southwesterly flow of air and a slight warmup over the next few days. An area of moisture this morning across the Great Lakes region will slide in our direction during the day, but while there is the threat for a shower or thunderstorm around here tonight, most of this activity is likely to stay to our north and east. A better chance for showers and thunderstorms may come on Wednesday as a cool front will approach the region.

Video

httpv://youtu.be/dzRGTI-e8mc

7:00 AM | Comfortable conditions for the weekend in the Mid-Atlantic region

6-Day Forecast

Today

Mostly cloudy skies with gradually lowering humidity, still a good chance for showers and thunderstorms, highs in the low 80’s

Tonight

Becoming mostly clear, pleasantly cool, lows by morning in the low 60’s

Saturday

Mostly sunny, comfortable, low 80’s

Saturday Night

Mostly clear, cool, upper 50’s

Sunday

Mostly sunny, nice, low 80’s

Monday

Mostly sunny, comfortably warm, mid 80’s

Tuesday

Partly sunny, more humid, warm, chance for showers and thunderstorms late, mid-to-upper 80’s

Wednesday

Partly sunny, warm, humid, showers and thunderstorms likely, mid 80’s

Discussion

A cool front will sweep off the east coast early today and “Canadian-born” high pressure will fill in on its heels generating great weekend weather in the Mid-Atlantic region with plenty of sunshine, comfortable temperatures and easy-to-take humidity levels. The large high pressure system will drift to our south and east early next week and this will induce a southwesterly flow of air with a slight warm up by Monday afternoon and Tuesday. Following that, it looks like a low pressure system will head our way from the Great Lakes by the middle of next week likely to generate numerous showers and thunderstorms in the Mid-Atlantic region on Tuesday night and Wednesday.

11:00 AM | Interesting activity in recent weeks at both polar regions - North Pole may be experiencing one of its coldest summers ever and the southern hemisphere sea ice areal extent is again at a record high for the date

Discussion

Some interesting activity has been occurring in recent days at both polar regions in terms of cold weather and sea ice areal extent. To begin with, this is turning out to be one of the coldest summers ever recorded in and around the North Pole according to the Danish Meteorological Institute (DMI). Furthermore, on the other side of the globe, the southern hemisphere sea ice areal extent is once again right near a record high for the date and it has a chance to end up near all-time record highs for the region over the next several weeks.

The DMI, Center for Ocean and Ice, estimates the daily mean temperature of the Arctic region north of 80 degrees using analysis data (00 and 12Z) from the European computer forecast model for all model grid points inside that area. The DMI produces a chart plotting this daily mean temperature as a function of the day of the year against the average of the daily mean temperature for the period from 1958 to 2002. In fact, the daily mean temperatures in this Arctic region has remained below the climatological normal for more than 4 months now and it has dropped below freezing far earlier than normal for this area. Normally, the drop below freezing does not occur until the middle part of September. The sea ice areal extent in the northern hemisphere continues to run at well below normal levels, but with the colder-than-normal weather north of 80 degrees this summer, there has been a noticeable uptick in northern hemisphere sea ice areal extent in recent weeks relative to several recent years. The overall northern hemisphere sea ice areal extent has generally been below normal since the mid-1990s at which time the northern Atlantic Ocean developed warmer-than-normal sea surface temperatures which is tracked by meteorologists through an index called the Atlantic Multidecadal Oscillation (AMO). The AMO index switched to a warm or positive phase in the middle 1990s reflective of an oceanic cycle of warmer-than-normal sea surface temperatures. Meanwhile, the southern hemisphere which is moving through their winter season continues to impress with its sea ice areal extent. Indeed, the most recent measurements suggest it is near a record high for the date and may come close to all-time record highs in areal extent over the next several weeks using records that go back to the beginning of the satellite era (1979).

Video

httpv://youtu.be/R6t2j415vg0

7:00 AM | Sticky with scattered showers and storms today and then comfortable weather returns on Friday and lasts right through the upcoming weekend

6-Day Forecast

Today

Partly sunny, very warm, humid, scattered showers and thunderstorms, some of the rain can be heavy at times, upper 80’s

Tonight

Mostly cloudy, mild, muggy, chance for early evening showers and thunderstorms, upper 60’s

Friday

Becoming mostly sunny with gradually lowering humidity, warm, mid 80’s

Friday Night

Mostly clear, pleasantly cool, low 60’s

Saturday

Mostly sunny, comfortable, near 80

Sunday

Mostly sunny, pleasant, low 80’s

Monday

Mostly sunny, nice, low 80’s

Tuesday

Partly sunny, warm, chance for a shower or thunderstorm, mid 80’s

Discussion

A cool front will bring us scattered showers and thunderstorms right into the evening hours as it closes in on the east coast from the Upper Midwest and while much of the time today will be rain-free, any rain that falls can be heavy at times. This front will push off the coast on Friday and this will set the stage for another nice and comfortable weekend in the Mid-Atlantic region. High pressure will follow the frontal passage and will control the weather throughout the Northeast, Mid-Atlantic and Midwest for several days beginning on Friday.

Video

httpv://youtu.be/27iZS0aq5CA

7:00 AM | Still very warm and humid today, but cool frontal passage brings nice weather back for the weekend

6-Day Forecast

Today

Mostly sunny, very warm, humid, chance for showers and thunderstorms late in the afternoon, highs in the upper 80’s

Tonight

Mostly cloudy, mild, muggy, showers and thunderstorms likely, some of the rain can be heavy, lows by morning in the low 70’s

Thursday

Partly sunny, warm, humid, showers and thunderstorms likely, some of the rain can be heavy, upper 80’s

Thursday Night

Mostly cloudy, mild, muggy, chance for evening showers and thunderstorms, upper 60’s

Friday

Becoming partlysunny, still the chance for a shower or thunderstorm, gradually lowering humidity, mid 80’s

Saturday

Mostly sunny, comfortable, low 80’s

Sunday

Mostly sunny, pleasant, low 80’s

Monday

Mostly sunny, continued nice, low-to-mid 80’s

Discussion

Summer-like weather has returned to the region and will continue through Thursday with highs not far from 90 degrees this afternoon and then in the mid-to-upper 80’s on Thursday afternoon along with uncomfortable humidity levels. A cool front will approach the region later tomorrow resulting in an increased chance for showers and thunderstorms, but once that front passes, the humidity will drop later Friday and the weekend looks quite comfortable throughout the Mid-Atlantic.

1:20 PM | Suddenly, the sun has become quite active; Coronal Mass Ejection on the farside of the sun and a small comet plunges to its demise early today (both captured on video) at the same time sunspot activity increases dramatically

Discussion

There has suddenly been an uptick in action on the sun as sunspot activity has increased dramatically in recent days from a rather quiet picture just a few days ago to one with numerous sunspots now facing the Earth. In addition to the increasing sunspot activity, there was a coronal mass ejection (CME) early this morning on the far-side of the sun. It is likely that this CME will not have an impact on the Earth’s upper atmosphere since it took place in a “non-Earth facing” direction. Finally, a small comet plunged into the sun early this morning at just about the same time the sun expelled the CME. Not surprisingly, the comet did not survive its encounter with the sun as it vaporized furiously upon approach. The comet was still millions of kilometers away from the sun when the explosion got underway. Amazingly, NASA’s Solar and Heliospheric Observatory (SOHO) captured on video both the CME and the small comet disintegration from earlier today. We’ll continue to monitor the sun over the next several days to see if the uptick in sunspot activity produces any Earth-facing CMEs.

Video

httpv://youtu.be/xRw-CvTpkUs