August 28: Hotter and Muggier, Tropical Storm Erika, Daily Links


Our weather this week has been nothing short of spectacular…but now it’s back to reality.  Temperatures will warm up to the upper half of the 80s this afternoon:
PAUL RPM 4KM Temperature

The humidity will be increasing as well.  Dew points by this afternoon will climb to the low to mid 60s…that’s not dreadful, but it’s certainly more noticeable than the dry air we’ve enjoyed all week:

On the muggy meter, that’s some where in the “still tolerable” range:
Dew Point Scale Increasing

As the humidity increases, there’s a very slight chance of a couple of showers developing this afternoon in the higher terrain of eastern Middle Tennessee.  Futurecast is unimpressed:

The mugginess will continue to build tonight, so our overnight temperatures won’t be nearly as comfortable (humid air doesn’t cool down as much as dry air).  The humidity will also be the fuel for scattered storms this weekend.  It won’t be an all-day washout, and it’s not a guarantee of rain for everyone in the Midstate, but it’s a high enough chance that you need to be flexible with any outdoor plans…just be ready to adjust to whatever Mother Nature decides to send your way.  Futurecast’s radar simulation for Saturday afternoon shows the scattershot pattern of the showers and storms:

The same pattern will repeat itself on Sunday…the good news is that the storms will be disorganized, so severe weather isn’t likely at any point this weekend:

Back to the lower storm chances early next week, with hotter temperatures (and still plenty of humidity):
7 Day PM

At this point, I’m leaving any influence of Tropical Storm Erika (or the remnants thereof) out of our forecast…but that’s still subject to change, since the path of Erika itself is still subject to change.  The satellite view of Erika this morning shows a glob of clouds to the south of Puerto Rico.  The center of circulation is actually to the northwest of the cloud cover, a sign that the entire system isn’t very organized:

The National Hurricane Center’s latest forecast calls for Erika to track to the northwest over the next 48 hours, directly over the island of Hispanola (the countries of Haiti and the Dominican Republic), then to the north of Cuba.  Hispanola is mountainous, and that terrain will weaken Erika significantly — it’s possible that the sustained winds will drop below 39mph, at which point Erika would be classified as a tropical depression:

That would be temporary though, as the storm moves over warmer water and more favorable atmospheric conditions to the north of Cuba, and as it approaches south Florida.  The NHC forecast calls for Erika to make landfall to the west of Miami late Sunday night, as a strong tropical storm with 60mph winds…but NOT as a hurricane (74mph is the threshold for that):
The distinction between a tropical storm and a category-one hurricane is only related to the strength of the maximum sustained winds — so while it’s tempting to say that Erika will “only” be a tropical storm at landfall, that’s misleading.  Tropical storms are still capable of producing tons of rain, along with coastal erosion, rip currents, and at least some wind damage.

There’s still some uncertainty regarding Erika’s path, which is typical of a disorganized tropical system.  Strong hurricanes are easier for the computer models to “latch onto” and easily project, while these marginal systems can throw some curveballs.  The spaghetti plot of the various model forecasts shows most projections clustered along the NHC’s official forecast, but there are still some outliers on either side:

One last thing about tropical systems…it’s easy to focus in on the projected path and say “okay, that’s where the storm will be.”  But while the path resembles a spaghetti noodle, the storm itself is more of a meatball, traveling along that noodle.  To break away from the metaphor, the effects of Erika (and any other tropical storm) extend hundreds of miles away from the center of circulation represented on the forecast map.  Again, it’s unlikely-but-not-impossible that the remnants of Erika will influence our weather next week…we’ll keep you posted.



Weather, astronomy, particle physics, and animals…the nerd-links are eclectic today.

  • This weekend marks the 10th anniversary of Hurricane Katrina’s landfall…is New Orleans safer now than it was ten years ago?
  • Those ten years have brought some significant improvements in weather modeling — the difference is startling.
  • Weather is only one part of the Katrina story — there’s also the human element of preparation and response.  This article claims that NO ONE is prepared for the “next Katrina.”
  • Weird stuff in space: a star so powerful, it rivals a black hole.
  • Galaxies go through their own life cycles (over billions of years) — now astronomers have a better understanding of specifically how they change.
  • Some of the new research results from the Large Hadron Collider at CERN could force some changes to the “Standard Model” of physics.
  • I’ve linked to a few articles recently regarding new advances toward achieving sustained nuclear fusion as an energy source — this article does a very good job detailing where things stand now, and some of the methods scientists are using to solve the fusion riddle.
  • Well, this sounds terrifying: “Snake Island.”  No.  Nope.  NONONONONONONONONO.
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August 27: One More Fallish Day, Tropical Storm Erika, Daily Links


You knew this nice weather pattern wasn’t going to last forever…but at least it will last one more day!  That means I get to use one more “corgi flop” GIF…

“Comfortably warm” weather today will give way to increasing heat and increasing humidity tomorrow and Saturday — it will be a gradual process, so at least it won’t hit you all at once:
7 Day PM

The best storm chance that we’ll see for a while will arrive Saturday — at this point I’m leaving the rain chance less than 50-50, but just barely.  I’m unconcerned about severe weather:
Back to summertime heat and humidity next week, as we finish off the month of August and head into early September.

The big national weather story is Tropical Storm Erika, moving through the Leeward Islands this morning with 50 mph sustained winds.  The satellite picture of Erika shows a loosely organized system:

The 3-day track forecast keeps Erika’s center of circulation to the north of Puerto Rico, Hispanola and Cuba — that will allow the storm to slowly strengthen, despite less-than-perfect atmospheric conditions (dry and wind shear, specifically):

The 5-day track forecast is where things get tricky.  (That’s the nature of ALL forecasting, by the way — the farther into the future we try to look, the more uncertainty enters the forecast.)  The National Hurricane Center’s official forecast (the red line) keeps the center of circulation off the east coast of Florida, but the “cone of uncertainty” (where the heart of the storm could go) still includes most of the Florida peninsula.  NHC is also anticipating that Erika will achieve hurricane strength (74+mph sustained winds) by late Sunday night:

Plenty of possibilities still apparent on the “spaghetti plot” of the track forecasts produced by the various weather computer models:

My hunch is that the NHC track will be adjusted even farther to the east as the next few days unfold.  At this point, I don’t anticipate Erika having a direct or even secondary effect on the weather here in Middle Tennessee and southern Kentucky.  Maybe a tertiary effect as the subsidence (sinking air) surrounding the storm helps to suppress storm chances in the southeastern U.S. early next week.

And really, I just wanted to use the word “tertiary.”



Oh-so-much science for you today, on a wide variety of topics…

  • On the subject of Erika, this article from NASA has some tidbits about the satellite technology meteorologists use to evaluate tropical storms.
  • This is pretty cool, and a remarkable feat of engineering: in three years, all trains in the Netherlands will run on wind power.  (That means generating electricity with wind, and storing it in batteries — the trains won’t have sails.)
  • The Mississippi River valley isn’t near a major fault, but the area is a hot spot for earthquakes…why?  The answer might be a hundred miles below the Earth’s surface.
  • I linked to some close-up pictures of a very tall mountain on Ceres, a “protoplanet” in the asteroid belt.  Phil Plait did some analysis of that weird feature…
  • We’re doing more and more exploration of our solar system, but nothing detailed enough to determine whether even very simple life forms exist anywhere other than Earth.  But there are a few spots that could be favorable
  • This gets a little technical, but the upshot is that particle colliders (like the LHC at CERN in Switzerland) might not have to be gargantuan projects in the future.
  • 100 GHz computer processors?  That’s really fast…and might not be far off.
  • How the brain of a selfish person works.
  • What the dust in your house says about you.  (Other than “you really should dust more often.”)
  • How a newborn baby sees the world.
  • Life expectancies worldwide are increasing…but so is the number of years the average person lives with serious illness.
  • Interesting-but-startling animation at the bottom of this article shows every nuclear weapon detonated since 1945.  All 2153 of them.
  • Yesterday was National Dog Day…here are some research projects you can participate in with your dog, if you’re so inclined.
  • 20 things you may not have known about dogs.
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August 26: Autumn Preview Continues, Daily Links


If you liked yesterday, you’ll like today…and if you didn’t like yesterday, seek help.

The fall-ish weather pattern won’t last forever, though — tomorrow will still be pleasant (just a touch warmer), then the heat and humidity build back into the area Friday through the weekend, complete with a slight storm chance:
7 Day PM

We’re also keeping an eye on Tropical Storm Erika, out in the Atlantic Ocean. It’s a minimal tropical storm right now, with sustained winds around 45 mph (the cutoff between “tropical depression” and “tropical storm” is 39 mph).  Erika is expected to slowly strengthen as it tracks to the west over the next three days, with the National Hurricane Center’s forecast path keeping it just to the north of Puerto Rico, Hispanola, and Cuba:

The tricky part of the forecast is in the 4- and 5-day range…the NHC forecast calls for Erika to strengthen to a Category One hurricane right before it approaches Miami and the rest of south Florida:

But keep in mind that there’s a LOT of uncertainty regarding that level of specificity…the red line is the NHC’s forecast path of the center of Erika, but its impact will spread hundreds of miles away from that center.  And the “cone” surrounding the red line represents the forecast uncertainty — basically, the line is where we think it will go, the cone is where it could go…and 5 days out, that cone is pretty huge.  Another way to represent that uncertainty is to look at the “spaghetti plot” of the various computer model forecasts — each line represents a different computer model’s version of where the center of Erika will track, and the range of possibilities is that Erika tracks all the way to the south of Cuba, or that it curves off east of the Bahamas.

Tropical forecasts have improved a lot in the last 20 years, but the improvements have mostly been to storm tracks, not storm intensity.  Plus, there are a lot of different factors (dry air, wind shear, ocean temperatures, the position of surrounding weather systems) that will keep this forecast complicated.  At this point, I don’t foresee any scenario in which Erika (or the remnants thereof) will have a direct impact on our weather in the Midstate, but of course we’ll keep you updated on Erika’s potential impact on the Caribbean islands, the Bahamas, and Florida.



A mix of weather, space and other nerdy science stuff for you today…

  • This seems particularly relevant, given Erika’s presence in the Atlantic: Climate Change and Hurricane Katrina — What Have We Learned?
  • Ever heard of the “equatorial electrojet“?  I hadn’t either, but it’s a real feature that can cause some problems when the solar wind kicks up.
  • Obviously our weather this week has been spectacular…I’ll be fervently hoping for similar weather on August 21, 2017 — that’s when a solar eclipse will occur, with the path of totality tracking right across the Midstate.
  • An earth science/history crossover story: The Enduring Mysteries of Mount Vesuvius and the Destruction of Pompeii.
  • The Dawn spacecraft orbiting the dwarf planet Ceres sent back some close-up pictures of the huge mountain that dominates Ceres’ landscape.
  • New data suggests that the universe may contain millions of supermassive black holes that are hidden from view.
  • Speaking of black holes, physicist Stephen Hawking has a new theory that melted my brain a little bit.
  • Gettin’ geeky about the upcoming movie The Martian: how would that spinning spacecraft in the trailer actually work?
  • A new art exhibit (and forthcoming app) will let you visualize all of the wireless signals around you.
  • Another sign that a fusion reactor is a little closer to becoming a reality.
  • I didn’t know this disconcerting fact: no one really knows where the nuclear fuel in the melted-down Fukushima reactors went.
  • Staring into someone’s eyes for 10 minutes can cause hallucinations.  I do not plan on testing that theory personally.
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August 25: Autumnal Weather, Tropical Storm Erika, Daily Links


I’m supposed to be impartial…but I really like this weather pattern.  Not only is it pleasant, it’s makes for a really simple, one-sentence forecast: pleasant the next few days, gradually warmer by the weekend.
7 Day PM

Enjoy!  Go outside and frolic…



A few weather-related links this morning, and a sampling of other science news…

  • There’s a new tropical storm in the Atlantic Ocean…Tropical Storm Erika will slowly strengthen over the next several days — the National Hurricane Center’s official forecast calls for it to be a Category One hurricane by this weekend:
  • Remember, the red line on that map is where the NHC thinks the center of Erika’s circulation will go, the “cone” surrounding the red line is where it could go.  So, anything you see on social media (or regular media, for that matter) regarding potential impacts from Erika along the East Coast of the U.S. is vastly premature…there’s plenty of time for things to evolve, so be patient, and we’ll keep you updated.
  • Sunday is the 10th anniversary of Hurricane Katrina’s landfall along the Gulf Coast.  Here’s how some historic neighborhoods in New Orleans have bounced back…
  • …but while much of the physical damage has been repaired, the psychological scars from Katrina remain.
  • 2015 also marks the 200th anniversary of the eruption of Mount Tambora in Indonesia — an eruption that worldwide effects.
  • Clear skies at night this week will make for good stargazing weather…if that’s your thing, here’s what to look for.
  • You won’t see this with a backyard telescope, though…a glimpse into the center of our galaxy, the Milky Way.
  • This would be very good news — seasonal flu shots may soon be a thing of the past.
  • More proof that the canine sense of smell is amazing: dogs are now being trained to sniff out criminal electronics.
  • Despite the autumnal weather this week, it’s still mosquito season.  Good luck dodging them…it’s pretty much impossible.
  • The neurological and evolutionary reasons why teenagers are so difficult to deal with.
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August 24: Pleasant Weather, Daily Links


Mother Nature threw a few curveballs over the weekend, as the more widespread shower and thunderstorm activity developed Saturday (as the humidity returned to the Midstate) rather than Sunday (when a cold front approached from the northwest).  Unusual, unexpected…but yet another reminder that the weather around here is rarely dull.

This week’s weather is looking spectacular, beginning already today.  Humidity levels have been dropping all morning, and here’s where dew points will stand this afternoon:

For reference, that’s great on the “muggy meter”:
Dew Point Scale Increasing

Temperatures will be warm, but several degrees below normal…”comfortably warm” considering it’s still August:
PAUL RPM 4KM Temperature

And the best news of all…this kind of weather will stick around all week!
7 Day PM

Those low temperatures in the 50s are well below normal for late August (tomorrow morning will be our first journey into the 50s in Nashville since early June), but not record-setting:

To summarize:



Some good stuff in the science world from over the weekend…

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August 21: Nice Today, Stormy Sunday, Daily Links


We started off this morning at 61 degrees in Nashville, just 5 degrees above this morning’s record low temperature…plenty of locations outside of Nashville dipped into the mid to upper 50s — not bad at all for mid-August!  We’ll warm up today, but the humidity will remain low…so these high temperatures in the 80s will be “comfortably warm”:
PAUL RPM 4KM Temperature

There’s a very slight chance that a shower or two will drift up from the south and visit our southern counties this afternoon — Futurecast is unimpressed with the rain chances:

Another cool night tonight, then slightly warmer Saturday with highs in the upper 80s.  Another very slight storm chance Saturday afternoon, this time on the western edge of the Midstate…once again, Futurecast is unimpressed:

The better chance of storms will arrive for the second half of the weekend:

It’s still an uncertain-enough scenario that I won’t post any computer-model data on it at this point…the best bet right now is for one round of showers and non-severe storms to move in late Saturday night and early Sunday morning, with another round of scattered storms Sunday afternoon.  The Sunday afternoon storms could be a little stronger, and the Storm Prediction Center has included the northwest corner of the Midstate in a “Marginal Risk” (level 1 out of 5) of severe storms:

But the SPC’s own model data (from the SREF model data) doesn’t really support that theory — it shows the best chance of stronger storms farther off to our northwest:

For now, my level of concern is firmly set to “meh”:

Once that system moves through, lower-humidity air will settle right back into the Midstate for the majority of next week!
7 Day PM



Just a handful of nerd-links for you today…the internets were not in a giving mood over the last 24 hours when it comes to geek catnip.

  • New data came out yesterday showing that July 2015 was the warmest on record in the “modern” record-keeping era.  Basically, it was the warmest month for the planet in the last 136 years.
  • That record-setting July pushes 2015 closer to being the warmest year on record (99% certainty now, with El Nino tipping the scales).
  • It’s hard to quantify the impact that climate change is having on existing weather patterns, but the data here is pretty solid — the drought in California is anywhere from 8% to 27% worse because of the warming climate.
  • It’s not all bad news, though — a chemist has come up with a way to extract carbon dioxide from the atmosphere to produce carbon fiber.
  • The Cassini mission orbiting Saturn (and its moons) will wrap up in 2017, but it already is concluding some of its research — including a last fly-by of Saturn’s moon Dione.  The images are fantastic.
  • Physicists still aren’t sure what “dark energy” really is, but at least they’re narrowing down what it isn’t.
  • Scientists are always looking for theoretical explanations that are not only accurate, but also “elegant” — that is, capable of incorporating what came before and what will come after.  But some elegant theories end up being scrapped…here are a few of the “beautiful losers.”
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August 20: Drying Out, Daily Links


We got through yesterday’s storms with very little in the way of damage — just a few reports of minor tree damage, and of course plenty of rain.  But the showers are moving off to the east this morning, and skies are clearing from west to east.  Partly cloudy skies this afternoon will allow the August sunshine to heat us up:
PAUL RPM 4KM Temperature 1

But the humidity is dropping!  Check out where dew points will be late this afternoon:

Again, for reference, here’s where those dew points rank on the “muggy meter”:
Dew Point Scale Increasing

Dry air, clear skies, and light winds are the ideal ingredients for cool nighttime temperatures, and we’ve got some genuine windows-open weather in store late tonight and early Friday morning:
PAUL RPM 4KM Temperature 2

Pleasantly warm on Friday (due to the lack of humidity), and I’m leaving rain out of the forecast as well.  I will hedge that bet a tiny bit though, and mention that a couple of the weather computers are trying to bring a few showers back into southern Middle Tennessee early Friday morning…but I don’t think that’s a very likely scenario.  Futurecast agrees with me, and keeps the rain chances well down to our south:

The weekend will bring warmer temperatures and a gradual return of the mugginess.  Just a very slight storm chance on Saturday (mostly near the Tennessee River), with scattered storms possible on Sunday.  After that, the weather turns pleasant again next week!
7 Day PM



All sorts of geeky topics to cover today: weather, space, physics…movies???

  • We showed this video on the air yesterday, but it’s worth checking out again — a huge firenado that formed in Idaho.  Firenados (or “fire ropes”) are pretty common, but usually not captured on video, because they’re most common in a “firestorm” scenario.  So if you’re seeing them, you’re either a firefighter who’s pretty busy fighting the fire, or you’re REALLY in the wrong place and the odds of your surviving to share the video are pretty low.  (Fire ropes were very common in the firestorm aftermath of the Hiroshima atomic bombing, as well as the conventional bombings of Tokyo and Dresden.)
  • The wind energy industry is booming, but extreme weather events (like El Nino) could complicate its continued growth.
  • We’re familiar with cloud-to-ground lightning, but how about cloud-to-SPACE lightning?
  • Once again, a rumor-gone-viral on social media has prompted a response from people who actually know what they’re talking about: NASA has confirmed that an asteroid is NOT going to hit Earth next month.
  • Jupiter and Saturn are huge…but they formed out of mere pebbles.  Here’s how.
  • New evidence shows the sky might be a bit more crowded than previously thought.
  • The internet in space?  It could happen soon.
  • Think my bosses will go for this?  One key to lowering your risk of stroke could be as simple as a shorter work-week.
  • It would be nice to avoid Nashville traffic and just teleport to work (like in Star Trek)…here’s a look at the science of teleportation.
  • I loved this book, and I can’t wait for the movie…a new trailer for The Martian was released earlier this week.
  • I’m not the only one looking forward to that movie — NASA scientists are excited about it as well.


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