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NWSlogoIt’s been quite a while since I posted much of anything weather-related, but now is as good a time as any! Our middle TN National Weather Service office started a Facebook page a while back, and I’ve been loving the hell out of it. Let’s face it, the weather service has always had a bit of an image problem. I’d be willing to bet that when most people think of the NWS, they think of a boring office with a bunch of crotchety old dudes staring at weather maps & computer screens. But in reality, the meteorologists are dedicated and passionate scientists who truly love what they do, and they enjoy talking about weather on a more conversational level, too! That’s exactly what their Facebook page is for, and it’s filled with tons of interesting factoids, tidbits, and more humanized/conversational information about the forecast. The forecasters are on there quite often, and are very good about responding to comments or questions posted. They also just closed submissions on a summer weather photo contest, and you can browse through the album and vote on your favorites. The photo with the most likes as of June 20th will be declared the winner. So check out their Facebook page and Like it. Even if you’re not as big of a weather nerd as I am, I promise you will learn something interesting if you Like the page and follow their posts!

Speaking of weather, I’m looking forward to the very favorable forecast for this year’s Bonnaroo! I will be there taking photos for the Scene as I have for the last 5 years, and thus I’m issuing my yearly Bonnaroo posting disclaimer: *This will be my last post before Bonnaroo, and posting will resume sometime early next week.* Be sure to follow our coverage and photos over at the Nashville Cream! Also, my girlfriend Lauren will be there with me blogging about the new & improved food options on her blog Old Red Boots, so follow her coverage to see the festival through the eyes of a foodie. But back to the weather- while it’d be nearly impossible to beat last year’s utterly euphoric Bonnaroo weather, this year’s forecast looks very good. Thursday is a little iffy as there’s currently a 30% chance of showers & storms, and the Storm Prediction Center has Manchester right on the edge of their ‘Slight Risk’ area for severe weather in their convective outlook. BUT, that activity should be pretty scattered/isolated so the risk is still pretty low. Friday & Saturday are damn-near perfect, however- sunny skies with mid to upper 80s for highs and low to mid 60s for lows- very similar to last year! That temperature span also suggests lower humidity! Sunday will be a little hotter with highs in the upper 80s and Sunday night brings back a 20% chance of showers. Overall, you really couldn’t ask for a better Bonnaroo weather forecast. See you here next week!

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A combination of technical problems and gusty winds caused Feliz Baumgartner’s record-breaking 23-mile supersonic skydive attempt to be aborted just as the balloon was being inflated today. They had a good window of calm winds to work with, but weren’t able to get the balloon off before a gust of wind came along and blew parts of the partially inflated balloon onto the ground. This is a dicey situation, because the balloon material is so delicate and folded so meticulously that once it’s been unfolded, it cannot be deflated and used again. As far as I can gather from what was said during live webcast, they only have one backup balloon. Since this is the largest balloon of its type ever made or used, it’s REALLY expensive, so they really have to get it right on the next attempt.

The air at the surface, and for roughly the first 1,000 feet off the ground, must be absolutely still for the launch to happen safely. Even a little bit of crosswind can take the balloon off course, dragging the capsule across the ground or smashing it into anything nearby, just as NASA learned first-hand a few years ago during this failed balloon launch in Australia.

Image via Discovery News

From the department of “Is This Guy Totally Insane or Totally Badass or Both?” daredevil Felix Baumgartner is finally ready to attempt the world-record breaking skydive for which he’s been training and planning for many years. The Red Bull sponsored event is scheduled to take place Oct. 8th in New Mexico, weather permitting. Statistically early fall is the best time of year for balloon launches and other such experiments and atmospheric shenanigans. If successful, Baumgartner will become the first human to freefall faster than the speed of sound. He will also set the record for the highest skydive, jumping from an altitude of 120,000 feet. This is high enough that his capsule must be enclosed and pressurized, and his suit must be pressurized as well, all while being able to withstand the stresses of supersonic freefall. Just sit back and let that sink in for a while. The guy is jumping out of a balloon capsule at 120,000 feet and will freefall at roughly 700 mph or even faster.

On the surface the whole thing seems like a really expensive adrenaline rush, but it’s really much more. The technological advances required to build his dive suit, and the medical knowledge gained by the close monitoring if his body and vital signs during the freefall, all will contribute to future spacesuit designs and other areas of space exploration and human spaceflight. I’m really looking forward to October 8th, and hope the weather is good for them. (Via Discovery News)

Credit: Google/NASA Meteor Watch

California and Nevada residents may have been terrified by the loud sonic boom that shook their houses Sunday morning, but now that we know what caused it, they should feel privileged to have experienced such a rare event. We now know that the cause was a fairly large meteor that entered our atmosphere with the energy equivalent to a 5-kiloton explosion. I’ve read other estimates for the energy, but that is the official number from NASA’s Meteoroid Environments Office. That puts it entering our atmosphere at a blistering speed of over 33,000 mph. This meteor was about the size of a minivan, so it was easily visible during the daylight, and that fact that it caused a massive sonic boom means that it made it all the way down to the troposphere, the lowest level of atmosphere, or the level in which clouds and weather occur. Most meteors are much MUCH smaller, and even if they did cause a sonic boom, they burn up far too high in the atmosphere for us to hear it, not to mention that that the air up there is much thinner and doesn’t carry sound waves as well. Because of this meteor’s size and density there’s a decent chance that some fragments of it may have made it to the ground. Once they hit the ground they’re called meteorites, and there are people who make it their living to hunt for them. The rarity of this event is why I think the people who got to see it or hear it are very lucky. I’d give anything to witness something like that. Meteors of this size only occur about once a year, and the simple fact that earth is about 75% covered in water means that us land-dwellers only have a 25% chance of seeing one when they do hit. (Other sources: Universe Today and Discovery News)

If you’re in Nashville you’re no doubt sitting around waiting for this massive ice-mageddon that is supposed to happen today. Make no mistake, ice storms can be extremely dangerous when they actually happen, but more often than not they end up being far less severe than initially forecast. This is because these types of storms are incredibly complex and the most difficult of all weather phenomena to forecast. Here’s how they work, and why I’m usually skeptical of forecasts involving them:

When an ice storm happens there is always a strong mass of cold air in place (just look at how cold it was yesterday and monday!). Then a low pressure system moves in from the south or southwest, creating a mid-level wind flow from the south or southwest. Mid-level in meteorology is loosely defined as 5,000-10,000 or so feet above sea level. This southerly wind flow brings both warm air and moisture with it, creating a layer of warmer air above the cold air at ground level. This means the precipitation starts out high up as snow or rain, then becomes all rain as it falls through the warmer layer, then refreezes when it gets to the stubborn layer of cold air at the surface. Depending on the thickness of this cold layer, the rain drops will freeze while falling (sleet), or will freeze upon contact with the ground (freezing rain). Usually in these situations, the surface temperature is right at or just below freezing. This freezing precipitation only lasts as long as the cold layer stays below freezing, and that surface layer always eventually warms up. Here’s a graphic I’ve posted on this blog before, to illustrate:

Based on the forecast models, and published forecasts I’ve seen, there’s no doubt Nashville will see some frozen precip today, but I have a feeling that it will change to all rain, and the surface temp will creep up to the mid 30’s by late afternoon or so. The current forecast calls for the ice to remain the longest in the northeastern counties of middle TN, so those folks may see enough accumulation to start downing trees and power lines. I doubt there will be enough accumulation for that to be a major problem in Nashville, and all areas south and west. I’m fairly certain that Nashville’s heat island effect will aid in getting the surface temps up sooner rather than later. Furthermore, most roads have been salted heavily, and even the secondary roads have some salt on them transplanted by car tires, and with the surface temp hovering right around freezing the salt will have no problem preventing ice on the roads. Since the temperature is forecast to continue rising as the night goes on, due to the warmer air in the mid-levels working its way down, there shouldn’t be any problems at all by midnight or so.

PLEASE DON’T THINK THAT I’M TELLING YOU TO DRIVE NORMALLY IN WINTER WEATHER. YOU SHOULD ALWAYS ERR ON THE SIDE OF CAUTION WHEN THERE’S A CHANCE OF WINTRY ROAD CONDITIONS. PLEASE BE CAREFUL, ESPECIALLY IF CROSSING A BRIDGE OR OVERPASS AS THOSE FREEZE MUCH EASIER.

What I’m saying here is that this will NOT be ice-mageddon. For Nashville at least.

The above image was taken just as our Sun belched a Coronal Mass Ejection (CME) in our direction on sunday night. This blob of charged particles are already beginning to interact with the earth’s magentosphere, and will likely result in some spectacular aurorae for the northern latitudes as the brunt of it arrives tonight and tomorrow morning. This is the first large scale activity the Sun has seen in several years, as it has been at the low-point of its 11-year cycle of sunspot activity. Events like this will slowly become more common over the next 3 or 4 years as the sun reaches its next peak in activity around 2012-2013. This is NOT any kind of major disaster, though it may cause a few glitches with satellites, as any CME event is prone to do. Unfortunately TN is way too far south to see any of the auroral activity, but if you’re in the northern US you might be able to see it. It is possible for aurorae to be seen this far south, but it’s very rare and requires a very powerful solar storm, such as the one from April 2001 (the last solar maximum) which made aurorae visible as far south as Texas. Such an event is possible as we head toward this next solar maximum, but I wouldn’t count on it. This upcoming maximum is expected to be about half as intense as the last one. (Via Space.com and Universe Today.

Here’s a video of the current CME when it first erupted sunday night.

If you live in TN, or even the southeast at all, you know damn well that it’s been hot and humid as hell lately. The entire southeast has been a sauna for several weeks in a row. You always hear people say stuff like, “man, it’s 90 degrees and 90% humidity out there!” Anyone with half a brain knows that’s a VAST exaggeration, but honestly the concept of humidity is a rather confusing one, and even some meteorologists don’t explain it very well. I’m not going to attempt to fully explain it because it’s already been done quite well at this Cincinnati meteorologist’s website. Please click through that link if you want a very detailed, but still in layman’s terms, explanation. Read on if you want my extremely condensed version.

Basically, in terms of actually knowing how much water vapor is in the air, relative humidity sucks. In order to really know how humid it is, and how uncomfortable you will be, look at the dew point. The dew point is simply the temperature at which the water vapor in the air will begin to condense. The higher the dew point, the more H2O is in the air. According to most charts that I’ve found, dew points in the 40-50 degree range feel very dry, like you would feel in a desert… Dew points between 50-60 degrees generally feel comfortable, dew points between 60-70 degrees are generally uncomfortable, and dew points 70+ degrees are utterly oppressive. Yesterday afternoon our dew point in Nashville was hovering around 70-72 degrees. Relative humidity takes into account the air temperature as well as the dew point, and the relationship between temperature and RH is inverse. That means that as the air temp goes up, the RH goes down. Of course the relationship between dew point and RH is converse. Again, if you want a really good, albeit long explanation then visit this website. Fortunately, TN is in for a bit of a relief from the oppressive conditions we’ve been enduring. Cold fronts during the summertime aren’t exactly “cold” though they do normally bring slightly cooler temps, but the main thing they usually bring is a drier airmass. The typical summer weather pattern in the southeast US often involves hot and humid air from the Gulf of Mexico being blown northward across the southeastern states, creating the conditions we’ve been experiencing the past few weeks. Sometimes, however, an airmass that originates over the northern US and Canada will make its way southward. That’s exactly what’s happening today, and the dew point is already falling (this morning it was 68, and right now at lunchtime it’s all the way down to 61!). This airmass is drier because it originated over a large area of land, rather than water. All forecast I’ve seen are in agreement that the dry weather will persist for at least a week, if not more, though the temps will creep back up into the 90s by this weekend. But 90 degree temps with a dew point of 60 is hella better than 90/70!

I must mention a couple of science news tidbits that pinged my radar today and yesterday…

The Obama Administration has announced a new national policy for aerospace that supports and guides the plans for NASA that were announced back in February. This is more of an over-arching “this is where we’re headed” type of policy, and it needed to be implemented to be in line with Obama’s NASA plans. Again, I fully agree with his desire to cancel the Constellation program, rely on the private space industry for low-earth orbit, and focus NASA on exploring beyond the moon. With this new policy, NASA basically has no choice but to use the plan unveiled in February. Hopefully this will get some of the opponents of Obama’s plan in Congress to STFU. But that’s probably a pipe dream. (Via Space.com)

The Large Hadron Collider in Geneva continues to creep closer and closer to its final goal of having the most intense proton collisions ever. Right now, Fermilab still holds the record for highest beam intensity, but the LHC just set a new record for overall number of proton collisions. It will be several more years before they have the LHC running at full capacity, but I have no doubt it will pay off. (Via Discovery News)

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