Weather Chat Megathread

[ProtoJeb21]

Overnight, Hurricane Florence has started to undergo an eyewall replacement cycle as predicted, which has taken its toll on the storm’s intensity for now. A new recon flight just did its first pass through the storm and found 120-130 mph winds and a central pressure between 950 and 955 mbar, about 10 mbar higher than last night. However, Florence won’t be like this for long. It looks like the EWRC may be close to finishing and the eye about to start clearing, which will most definitely result in another phase of intensification. The annular appearance of the storm suggests that such a phase is nearing. I’d say there will be about 6-12 hours before Florence begins to strengthen again, maybe a little less. 

[Just Jim]

I talked to my Aunt in South Carolina last night, they're leaving and evacuating down here to Jacksonville sometime this morning.

 

[DarkOwl57]

So this morning was interesting...

I had to go to cross country practice this morning at around 6-ish. It was cold, and, of course, I didn't want to. I went anyways and started running. As I ran, I saw something I never thought I would- steam from my breath. It was cold enough for steam to begin forming. As if that wasn't enough, I walked out of practice after my run and walked over frost. It's only September for crying out loud!

[XB-70A]

Florence, taken 30 minutes ago:

Helene is pretty impressive too...

 

[TheKosanianMethod]

Almost everyone around me is worried about the hurricane barreling toward us. Meanwhile, I'm excited to see a hurricane. It's been a long time since I've been in one, and this may be the first one that doesn't just brush me. Sandy came near us, but wasn't that bad where I was. Something about severe weather just amazes me. 

I'm working on covering the stairs to my basement - the 2 1/2-inch pipe drain won't be enough, so I'm covering the whole thing with plywood. I really can't wait to watch the rain come down and my little project to do it's job. There's always that good feeling of seeing it work.

[razark]

1 hour ago, TheKosanianMethod said:

Meanwhile, I'm excited to see a hurricane. It's been a long time since I've been in one, and this may be the first one that doesn't just brush me.

It looks like this:

Spoiler

Then this:

Spoiler

And, after a while, this:

Spoiler

 

[SaturnianBlue]

Mangkhut is an extremely powerful storm that still has the potential to strengthen, but I don't think it would strengthen like the HWRF predicts...

Is 833 mb even physically possible under current circumstances? 

Edit: I should mention, this model run also had 307 mph winds at the 850 mb level...

Edited September 12, 2018 by SaturnianBlue

[ProtoJeb21]

Some good news and some bad news for anybody in the Carolinas. 

The good news is that Florence has slightly weakened to a high-end Category 3.

The bad news is that it’s about to undergo another eyewall replacement cycle and will maintain 120-130 mph until tomorrow afternoon. Also, places like Wilmington NC will get about 1.5 to 2.5 FEET of rain, which will be absolutely catastrophic. Apparently, Harvey wasn’t enough of a flooding disaster this decade. 

3 minutes ago, SaturnianBlue said:

Mangkhut is an extremely powerful storm that still has the potential to strengthen, but I don't think it would strengthen like the HWRF predicts...

Is 833 mb even physically possible under current circumstances? 

833 mbar...I don’t think that can even happen. It looks like the GFS models were right about Mangkhut becoming a sub-900 mbar Super Typhoon, with a pressure of 898 mbar and maximum 1-minute sustained windspeeds of 180 mph. Mangkhut is starting to remind me of Typhoons Haiyan and Meranti in terms of track and intensity, which is extremely concerning. 

Also, I forgot to mention that Subtropical Storm Joyce just formed in the Atlantic, which was something the GFS predicted for the last several days. 

[ProtoJeb21]

@SaturnianBlue The predictions for Hurricane Florence for the next 36-48 hours are becoming ever worse. AccuWeather is estimating about $60 billion in damage from Florence, and one of its hurricane experts says that an increase to or near Category 5 intensity is not out of the question. This does seem possible for two reasons. First, Florence is well into a second EWRC, so afterwards it should start intensifying again, likely by a little bit but maybe more. Second, in the official NHC Tropical Cyclone Discussion, they say that conditions for the next 36-48 hours will still remain favorable for at least some last-minute strengthening, despite Florence getting closer to land. This is also probable due to the storm’s gradually slowing pace. But whether or not it gets to a Category 4 or 5 or stays a Category 3 tomorrow, this is going to be terrible. How much do you think Florence will strengthen, if at all?

EDIT: Whoops, almost forgot the AccuWeather article.

https://m.accuweather.com/en/weather-news/dangerous-category-3-hurricane-florence-to-blast-carolinas-with-perilous-conditions-for-over-24-hours/70006011

Edited September 12, 2018 by ProtoJeb21

[ProtoJeb21]

Both Florence and Mangkhut are weakening, and I find it rather unexpected. The former is suffering from some wind shear and what may be an EWRC, but I didn’t expect it to drop from a Category 4 to a Category 3 so quickly. Mangkhut, on the other hand, is still a Category 5 but now has a higher pressure and 165 mph winds. The problem I’m having is trying to find out why it weakened. It doesn’t look like an EWRC is taking place, SSTs are still extremely favorable, and there are no signs of wind shear. My best guess is that there is an EWRC starting, but it’s hard to notice due to the angle of the sunlight on the storm as seen in visible satellite imagery. 

Edited September 13, 2018 by ProtoJeb21

[tater]

Florence is expected to make landfall as a Cat 2 at this point.

Still, it will be loads of rain.

[Kernel Kraken]

Y'all know what morning Glory clouds are, right? Well, where I'm from it's almost always cloudy. And I was driving and on a stretch of road with no trees I could see a massive morning Glory cloud, like twenty kilos long and mabye five kilos tall there. I've never seen one and it was pretty impressive.

[XB-70A]

On 9/11/2018 at 8:23 PM, TheKosanianMethod said:

Sandy came near us, but wasn't that bad where I was. Something about severe weather just amazes me. 

Florida men actually imagined a solution during the last season, and wished to retry this year:

 

 

Now, I can't be really neutral about the idea of experiencing these natural "monsters". Maybe, if you have nothing to lose ( in term of property)

They are interesting, even passionate at some points, but having loss a lot at three different occasion, I'm suspicious of the cyclones like the plague.

 

p.s: I just love the fact that the shooter needs a laser range finder to aim at the cell.

Edited September 14, 2018 by XB-70A

[Just Jim]

1 hour ago, XB-70A said:

Florida men actually imagined a solution during the last season, and wished to retry this year:

 

 

Now, I can't be really neutral about the idea of experiencing these natural "monsters". Maybe, if you have nothing to lose ( in term of property)

They are interesting, even passionate at some points, but having loss a lot at three different occasion, I'm suspicious of the cyclones like the plague.

 

p.s: I just love the fact that the shooter needs a laser range finder to aim at the cell.

Oh, man...

I seriously hate to admit just where in Florida I actually live...

Hint... it's about an hour north of Tampa... look it up...

then feel free to have a good laugh... 

[ProtoJeb21]

Hurricane Florence has made landfall as quite possibly the strongest Category 1 hurricane ever. Winds were at 90 mph and its pressure was a shockingly low 955 mbar — as low as a high-end Category 3! It’s slightly weakened to 85 mph/958 mbar but the center may be about to go back over open water in a few hours. 

Super Typhoon Mangkhut is very close to a potentially catastrophic Category 5 landfall in the northern Philippines. After completing an EWRC and reaching 175 mph winds again, it’s starting a second cycle and has dropped to 165 mph winds. The JTWC predicts that it will make landfall at this intensity later today. After landfall, it will weaken to a Category 3 equivalent typhoon due to land interaction but is predicted to re-intensify once it gets back into very warm (28-30 C) waters. It may become a Category 4 again and poses a high danger to Hong Kong, as it will likely be a major hurricane at landfall or closest approach. 

[ProtoJeb21]

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. 

[XB-70A]

New options are available at http://rammb-slider.cira.colostate.edu/?sat=goes-16&z=0&im=12&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=0&opacity[0]=1&hidden[0]=0&pause=0&slider=-1&hide_controls=0&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=full_disk&p[0]=16&x=10848&y=10848

 

In the past, only the sight from GOES-R was available, now GOES-S (launched on 2018-03-01) data can also be viewed:

 

Himawari-8 images are now available in color:

 

Finally, JPSS-1 (a.k.a. NOAA-20) was added this week (!):

Being on a 98.7° orbit, fewer images are available, but it's still a nice sight to have.

 

 

 

Edit: @ProtoJeb21 taken 40 minutes ago (16:20 UTC), Trami formation is interesting:

Edited September 21, 2018 by XB-70A

[ProtoJeb21]

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. 

[ProtoJeb21]

@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. 

Edited September 23, 2018 by ProtoJeb21

[ProtoJeb21]

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. 

[ProtoJeb21]

@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).

[YNM]

Anyone knows how to read this ? It's a live rain radar, that reads as dBZ.

http://santanu.sains.lapan.go.id/site/bdg1

[ProtoJeb21]

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. 

[ProtoJeb21]

@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. 

[ProtoJeb21]

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.