ProtoJeb21

As the forecasters at the NHC have said, the incessant East Pacific Hurricane Season continues... Tropical Storm Vicente developed on the 19th, followed by Tropical Storm Willa one day later, exactly three years after Hurricane Patricia formed. That did not bode well, especially since its timing and track was going to be nearly identical to the 2015 storm. While Vicente stayed as a tiny tropical storm small enough to fit inside the state of Connecticut with plenty of room to spare, Willa has wasted no time getting its act together. It almost immediately began rapid intensification, and in the last 24 hours alone, it has gone from a 60 mph tropical storm to a 115 mph Category 3 major hurricane. And it’s not going to stop for another 18-24 hours. It’s looking increasingly likely that Willa will become a Category 5 hurricane and follow in the footsteps of similar hurricanes including the aforementioned Patricia, Hurricane Kenna from 2002, and Hurricane Rick from 2009. Willa has developed a tight ring of very cold (-80 C or colder) cloud tops and a small pinhole eye, indicating that even more potent intensification is starting. Satellite imagery of Willa, updated every minute, can be viewed here: https://www.tropicaltidbits.com/sat/satlooper.php?region=meso1&product=ir

When Invest-99E is forming in the Pacific and a second invest breaks off from it and has a chance to develop as well: https://m.youtube.com/watch?v=lD_ag67tH3I

Last Friday, my AP Physics teacher was using an old Coyote and Roadrunner cartoon as an example for a kinematics problem, which gave me an idea for something to do that weekend: figure out how freakishly fast Wile E. Coyote is going on his Acme rocket skates. Here’s the clip I used: To get results that even mean anything, I needed a way to measure the distance Coyote was traveling. So I decided to use Coyote himself as my ruler for this investigation. Estimating the distance from his head to rump at 0.875 m (between the average length of 0.85 to 0.90 m for a regular coyote) and using pixel measurements, I got his total height of 1.7468 m. Using that, I could find the meter/pixel ratio of the zoomed-out scene showing him and the Roadrunner on that mountainside road and measure the distance Coyote traveled between the final two bushes. This turned out to be 11.4393 meters. Next I had to find the time it took Coyote to travel between those two bushes...which was not easy. I had to slow down the video by 4 times, take over a dozen measurements, and then convert the average time for 25% speed to 100% speed time. The final result was a time of just 0.2925 seconds and a velocity of 39.34 m/s — around 88 mph! I wasn’t finished yet. Sure, Coyote is going fast, but it’s not ridiculously fast. I needed to prove how unrealistic and absurd this scene was, and if you watched the clip, you’ll know what I’m going at: his instant acceleration. When Coyote fires up his Acme rocket skates ($99.99 at your local illegal weapons dealer), he almost immediately accelerates to his top velocity of 39.34 m/s. Once again, I slowed down the clip and tried to time it...but I couldn’t. It was so fast that I could only get a max limit of <0.15 seconds for 25% speed, which is <0.0375 seconds in real time. When that estimate is plugged in with the already calculated velocity, I get Coyote’s acceleration...of at least 1.049 km/s^2. That’s creating G-forces of over 100 gees! And keep in mind, that’s his minimum possible acceleration. I knew it would be ridiculous, but not potentially greater than that of the Roadrunner himself! Wait a minute...I don’t even know the velocity and acceleration of the Roadrunner. ...it looks like I’ve got another mathematical investigation for this weekend.

I forgot to mention this earlier: K2-18b is very similar in mass, radius, and density to GJ 1214b, although it has a greater amount of heavier materials and a lower temperature.

There are two major updates on two different potentially habitable systems to talk about: LHS 1140 and K2-18. First off, the K2-18 system has been re-analyzed again due to the questionable nature of K2-18c. A second study concluded that this planet was a false positive and just an artifact from stellar activity. Howeve, this study did a more careful analysis and found that it is a legitimate planet. It turns out the former accidentally associated K2-18c with the star’s typical activity, when the two signals are shown to be separate after a longer analysis. Not only is K2-18c re-confirmed in this study, but it also kinda kills any hope for life on K2-18b. Why? Because of the Gaia Data Release 2. According to Gaia data, K2-18 is slightly larger than initially expected, which puts K2-18b at 2.711 Re and 8.63 Me. This gives it a density of just 2.4 g/cm^3, too low for a water-rock planet like previous estimates showed. However, K2-18c is actually less massive than previously thought, with a minimum mass of 5.6 Me. It could be primarily rocky with a thick atmosphere and/or a water envelope. The full paper can be read here: https://arxiv.org/pdf/1810.04731.pdf The other system with a major update is LHS 1140. A second, much smaller planet was confirmed, with less than twice the mass of Earth and a little over a quarter larger in radius, giving it a composition similar to TRAPPIST-1b. The paper that it was reported in claims that LHS 1140c has an “Earth-like composition”, which is absolutely not the case — its density implies a rather thin but still significant layer of water. This could be in the form of a very thick, Super-Venus atmosphere, not unlike that of TRAPPIST-1b. However, I have doubts about the radius of LHS 1140c, because it was calculated using new Gaia DR2 parameters for LHS 1140. This also makes LHS 1140b larger and less dense than initially thought, but that isn’t a bad thing. With 7 times the mass of Earth and 1.73 times Earth’s radius, LHS 1140b is, composition wise, a massively scaled-up version of Earth. This makes it by far the largest rocky habitable zone planet yet found, and also puts it in the rare class of rocky planets with radii above the 1.6 Re transition boundary. LHS 1140 is a pretty awesome system with a Super-Venus and a Super-Super-Earth, but it may be ever more complex. The people behind the study that confirmed LHS 1140c noted that it and LHS 1140b have just about the same relative inclination to one another. While at first this may not seem like much, it turns out that this phenomena is only seen with compact multi-planet systems like TRAPPIST-1 and Kepler-186. The authors concluded that LHS 1140 is likely to have more planets that have yet to be detected. While a ~90 day signal was reported by another team a few months ago, this is likely not the only other planet in the system; others likely exist between 1140c and 1140b. Maybe one of them could be in the habitable zone as well! The LHS 1140 paper can be read here: https://arxiv.org/abs/1808.00485

At least we’ll still be able to have good Hubble science until the JWST launches...if it ever does. I hope the one-gyro operations won’t be detrimental to any exoplanet studies scientists want to use Hubble for.

The long-lasting storms of the past two weeks are finally coming to a close. Hurricane Sergio has degraded to a remnant low after making landfall in Baja California, and Hurricane Leslie, while still a Category 1, is set to become post-tropical sometime tomorrow. I was hoping Leslie would curve back out into the Atlantic and last even longer, but that doesn’t seem to be the case anymore. It may make an exceptionally rare hurricane-force landfall in the Iberian Peninsula after passing very close to the Canary Islands. Hurricane Michael has also degraded to a rather strong remnant low/post tropical cyclone while passing south of New England. Yesterday it brought heavy rain and flash flood alerts. This morning, the rain had stopped, but the winds were quite high, with gusts up to tropical storm force. By about noon EST, all of Michael’s winds and convection had left, leaving a nearly perfectly clear sky. That would be great for looking at Mars or something, if I didn’t have a club meeting until 9 pm. Hopefully there’s some time afterwards.

I’m still shocked that Hurricane Michael intensified so much all the way up until landfall. Officially, it struck as the second strongest Category 4 in Atlantic history, with 155 mph winds and a pressure of 919 mbar. Its pressure is second only to Hurricane Opal at 916 mbar (which did have lower winds of 150 mph). However, recon data suggests Michael may have gotten to Category 5 status right before landfall, but this will be hard to confirm or deny due to the very short time frame this took place in. If there’s any remotely promising news, it’s that Michael’s eye is (finally) starting to collapse, which should result in rapid degeneration of the storm through Friday. Unfortunately, it’s not weakening fast enough. Winds are still at Category 4 force, with the NHC assessing Michael as a 140 mph storm as of their latest advisory.

Hurricane Michael may now be a Category 5 hurricane. The most recent recon pass has found a pressure as low as 920 mbar and winds around 160 mph. This is an absolute worst-case scenario. To everyone who didn’t evacuate, please stay safe. This is now life or death. EDIT: follow the recon flights here: https://www.tropicaltidbits.com/recon/

Hurricane Michael has rapidly intensified into a 140 mph Category 4 storm, and is expected to get even stronger in the ~12 hours before landfall. As I said last night, if you’re in the path of Michael and have the chance to evacuate, do so immediately. This is nothing to take lightly at all. Don’t risk your life by trying to ride it out.

You beat me to it! Originally I wasn’t too sure that Michael would become a Category 4, but it seems almost certain now. Current recon flights have recorded winds of over 115 kt (130 mph) in some parts of the storm, and its pressure continues to drop by 1 mbar or more for each pass through the center. That ring of -80 C convection is even more concerning. The last time I saw anything like that was with Hurricane Norman when it peaked at 150 mph in late August, but it’s possible it was stronger than initially estimated. If Michael reaches Norman’s intensity, the impacts would be nothing short of catastrophic. To anyone in Michael’s path, take NO chances with this storm. If you have the chance to evacuate, do it. I’m dead serious when I say that this could be worse than Irma’s Florida landfalls.

Tropical Depression 14 has formed near the Yucatán Peninsula and could already be a tropical storm. Current Dvorak estimates suggest an intensity of 35-40 kt (40-45 mph), which will either be confirmed or disproven by an aircraft recon flight heading to investigate the system right now. Future Michael will be limited by horizontal wind shear, but that will weaken by 48 hours and allow thfor system to take advantage of the otherwise favorable conditions in the Gulf of Mexico. Several models are suggesting that Future Michael could rapidly intensify into a Category 2 or maybe even a Category 3 before making landfall on Wednesday. For anybody living on the Gulf Coast, start getting prepared NOW.

I’m not too sure about that. Kepler-1625b-i is probably too close to its giant parent planet for any moons to exist in stable orbits around it. But it’s not out of the realm of possibility that other, much smaller moons orbit further out — maybe some captured asteroids or dwarf planets.

The Dvorak estimates I was using earlier were slight overestimates; as of their latest advisories, Kong-Rey is a 155 mph Super Typhoon, and Walaka has winds of 150 mph. The site where I got the estimates from has revised their Dvorak numbers down to T#6.7-7.0, which are more compatible with the latest data from the NHC and JTWC. However, the cyclone intensities have remained the same — 175 mph and 908 mbar for Kong-Rey, and 160 mph and 925 mbar for Walaka. Both storms should end up around these intensity estimates by the 11 pm EST advisories.

@SaturnianBlue Super Typhoon Kong-Rey and Hurricane Walaka are undergoing explosive intensification. As of the most recent Dvorak estimate updates, Kong-Rey is as intense as Hurricane Maria (T#7.3, 175 mph, 908 mbar), while Walaka is at least a strong Category 4 (T#6.5, 145-150 mph, 939-935 mbar), although I feel that its intensity is slightly underestimated. Just look at its appearance on satellite imagery.

Nope. I have my own names I would like for the TRAPPIST-1 system, all named after minor seasonal deities.

As Hurricane Rosa weakens and Tropical Storm Kirk falls apart, Subtropical Storm Leslie regains suptropical Characteristics after spending some time as an enormous hurricane-strength post tropical cyclone. Although it has shrunk a bit, Leslie is still huge — its diameter of tropical storm force winds are 550 miles across, nearly 200 miles wider than Florence’s max size. It’s going to slowly move south over the next five days and become fully tropical in 3-4 days before strengthening and slowing down. It could end up becoming a hurricane next week.

@SaturnianBlue Have you seen how fast Hurricane Rosa has intensified? It’s gone from an 85 mph Category 1 to a 125 mph Category 3 hurricane between the 5 am and 5 pm EST advisories, and according to Tropical Tidbits, it has hosted reached winds of 145 mph. Rosa is an absolute beast of a storm, and it shows no signs of slowing down anytime soon (at least in terms of intensification, it actually is slowing down speed wise).

Typhoon Trami maxed out at 140 mph before starting an eyewall replacement cycle a few hours ago. Already, it seems to be almost finished, and should begin intensifying tonight. What’s concerning is how Trami is expected to stall on Tuesday for about twelve hours, which will allow for extreme intensification.

@SaturnianBlue @XB-70A Typhoon Trami has developed the dreaded Pinhole Eye. This means one thing: it is going to explode in intensity today. Already, it’s jumped from a 110 mph Category 2 to a 130 mph Category 4 in barely six hours according to Tropical Tidbits. If this continues, Trami will absolutely surpass the peak intensity of Super Typhoon Mangkhut, especially since it’s expected to slow down over very warm waters in a few days.

Tropical Depression 11 has formed near the Lesser Antilles and should dissipate within the next 24-36 hours. Meanwhile, Invest 99L has just been upgraded to Tropical Storm Kirk, and is at a surprisingly low latitude for a tropical cyclone. It should keep moving west at around the same latitude and gain some strength, maybe becoming a hurricane, before increasing wind shear takes its toll in 4-6 days.

Activity in the tropics stalled after Florence and Mangkhut dissipated last week, but that won’t be the case for long. A new tropical storm in the West Pacific bears close watching, as it’s forecast to undergo rapid intensification late this weekend. It has a good shot of becoming another Category 5 Super Typhoon and may pose a threat to Japan afterwards. Meanwhile, the Atlantic is about to stir into activity again, with four areas of interest being watched, two of which could end up as this season’s next named storms. - A weak tropical wave a few hundred miles east of the Lesser Antilles has been watched for a few days, but dry air and wind shear are close to destroying it. - This area of low pressure associated with the remnant low of Florence is meandering near Bermuda. On visible satellite imagery, a displaced but pretty well defined center can be seen. The NHC gives it a low chance of development due to nearby dry air and shear. - A tropical wave just emerged off the coast of Africa early today and is predicted to be in an environment favorable for gradual development. The NHC currently gives it a 60% chance of developing during the next five days, but I believe this system will become a tropical cyclone by early next week. If so, it will be another long-lasting Cape Verde storm to keep an eye on. - Finally, the most likely to develop area of interest hasn’t even formed yet. A low pressure system is expected to develop later today in the North Atlantic, and most models are in good agreement that this will become a subtropical or tropical cyclone this weekend. Some models are suggesting it could meander in the north or central Atlantic for about a week or more. Since it will definitely be the first area of interest to develop into a cyclone, it would get the name Kirk if it reaches tropical storm status.

Here’s a new paper on Pi Mensae c. It turns out that the planet is slightly smaller and denser than reported in the first paper, at about 4.5 Earth masses and just under 1.9 Earth radii with a density around 4 g/cm^3. It is at least 50% silicates by mass, either with a water envelope or a thick gaseous atmosphere above a water mantle. https://arxiv.org/pdf/1809.07573.pdf