Weather Chat Megathread

[tater]

Monsoon here in NM. Remember, that's defined by the annual % of rainfall, not the total, so it's still very dry, but each afternoon we get thunderstorms in view somewhere.

Right now it's 26°C (80F), breezy, and a big storm forming over the mountains just to the south of me, and marching off to the SW.

[SaturnianBlue]

Beryl has regenerated as a subtropical storm!

[tater]

Was in quite the deluge at the International Folk Art Market in Santa Fe this afternoon, but while I was gone, this is what it was like very near my house:

 

[ProtoJeb21]

7 hours ago, SaturnianBlue said:

Beryl has regenerated as a subtropical storm!

That was the last thing I was expecting today. It’s been so long since Beryl first dissipated that I assumed its remnants would be unable to reform. 

[ProtoJeb21]

*kicks thread back to life*

Weather in New England has been berserk over the last two weeks, due to an unusual summertime dip in the jet stream. For nearly a week, I had to deal with random on-and-off storms coming from the south, being pulled up by the jet stream. This setup began to slightly change over the next few days. Mercifully, this resulted in some decent days where I could finally get outside. 

For the last week or so, the dramatic jet stream dip has lessened a bit, so now storms are coming at us in a more typical SW to NE or W to E direction. They’ve become more predictable and less frequent, leading to a few nice sunny days. It was especially nice in Plymouth when I visited there Friday and Saturday. However, one major problem remained: the humidity. Temperatures have already been in the mid to high 80’s for days now, and constant 60-80% humidity does not help. Heat index values have been maxing out in the mid to high 90’s since late last week. This can sometimes make even a few minutes outside almost unbearable. Fun. 

It also doesn’t help that the storms over the last two days have been some of the strongest during this two week timeframe. My area was under a Severe Thunderstorm Warning both today and Wednesday, and various flood advisories have been issued as well. Thankfully, no major damage has been reported. 

[tater]

Yet another hellacious rainstorm for NM monsoon season. My arroyo is probably running again.

[ProtoJeb21]

Hurricane Hector has been quite an interesting system to track over the last few days. Being such a small storm, with a tight ring of convection and a wind field less than 100 miles across, it’s been more unpredictable than the other powerful East Pacific storms so far this year. Its small size is likely why it’s gone through two periods of rapid intensification. Hector is currently a high-end Category 3 but will likely become this season’s third Category 4 by later tonight or early tomorrow. I believe it may intensify even further, based on its impressive convective structure and how more models are showing it tracking south of Hawaii into warmer, more favorable waters. Some models are suggesting that Hector may survive its journey through the Central Pacific basin and enter the West Pacific, similar to Hurricane/Typhoon Genevieve in 2014. With Hector still going strong, TD 11-E poised to strengthen, and another tropical system likely to develop, this is quite the time to be watching the East Pacific. 

Meanwhile, the days of rain are finally over where I live. Mostly. With the exception of next Wednesday, there will be NO rainy or stormy days for almost two weeks! The humidity will remain, sure, but otherwise it’ll be quite nice, with mainly or entirely sunny skies and temperatures from the low 80’s to around 90.

[ProtoJeb21]

The East Pacific is going absolutely nuts. 

Hurricane Hector keeps on getting stronger, with winds of 155 mph and a pressure of 936 mbar, just a hair away from being the first EPac Category 5 since Patricia. In fact, it may be a Category 5 already. The latest low-level recon flight (it’s close enough to Hawaii from Hurricane Hunters craft to get into it) found winds of up to 170 mph on one side of Hector’s eyewall. Based on how well organized the system is, with a very tight ring of powerful thunderstorms, I find it likely that Hector will become a Category 5.

There are now two tropical storms off the coast of Mexico, Ileana and John. Both are set to become hurricanes by later today or early tomorrow, and they’re dangerously close together. John is likely going to absorb or destroy Ileana before rapidly intensifying. Some models suggest it could become another Category 4/5. Meanwhile, Ileana probably won’t be anything more than a weak Category 1.

The last Invest in the East Pacific isn’t looking as good as it was a few days ago, but most models predict it will develop within the next day. It has the potential to become a hurricane as well, maybe a Category 1 or 2. The GFS model predicts that it will be pulled north by Hurricane John and undergo a Fujiwhara interaction; the same thing happened to hurricanes Hilary and Irwin last July. 

EDIT: The latest NHC forecast for Tropical Storm Ileana says that it will not reach hurricane strength as originally predicted; it won’t have enough time before being absorbed by the recently upgraded Hurricane John. The latter will end up as at least a high-end Category 3 hurricane. 

Edited August 6, 2018 by ProtoJeb21

[cubinator]

Tonight it is not quite cloudy enough to obscure all the sky, but too cloudy to get a proper look out into space. I will have to wait to see Vesta.

[0111narwhalz]

The skies are heavy and gray, but from these clouds no water will come.

[SaturnianBlue]

Hurricane Lane, with winds of 150 mph (as confirmed by aircraft recon), approaching Hawaii... It'll weaken, but the NHC forecast still has it as a hurricane on approach to Hawaii.

[ProtoJeb21]

6 hours ago, SaturnianBlue said:

Hurricane Lane, with winds of 150 mph (as confirmed by aircraft recon), approaching Hawaii... It'll weaken, but the NHC forecast still has it as a hurricane on approach to Hawaii.

6 hours later, and it’s on the brink of being a Category 5 with 155 mph winds. The latest Hurricane Hunters pass has recorded a pressure drop from 940-942 mbar to about 936 mbar. That, and some of the winds in the eyewall are above 157 mph. Lane’s appearance on satellite imagery is also VERY impressive, with an extremely well-defined, deep eye, and a tight ring of powerful convection. I say it’s quite likely that Lane is or will soon become a Category 5 storm, but it won’t be a match for the wind shear in its path by tomorrow. 

[SaturnianBlue]

1 hour ago, ProtoJeb21 said:

6 hours later, and it’s on the brink of being a Category 5 with 155 mph winds. The latest Hurricane Hunters pass has recorded a pressure drop from 940-942 mbar to about 936 mbar. That, and some of the winds in the eyewall are above 157 mph. Lane’s appearance on satellite imagery is also VERY impressive, with an extremely well-defined, deep eye, and a tight ring of powerful convection. I say it’s quite likely that Lane is or will soon become a Category 5 storm, but it won’t be a match for the wind shear in its path by tomorrow. 

925 millibars of pressure recorded on the latest recon pass—that's some very rapid deepening. Very likely a Category 5 at this point.

[ProtoJeb21]

50 minutes ago, SaturnianBlue said:

925 millibars of pressure recorded on the latest recon pass—that's some very rapid deepening. Very likely a Category 5 at this point.

It should be, but it isn’t. Current pressure is about 929 mbar — not too far off from the 925 mbar estimate — but its winds are still at 155 mph. At least, that’s what the Weather Channel (and now Wikipedia) says based on the latest reconnaissance. Lane should be upgraded to a Category 5 during the NHC’s next update; if not, maybe during post-season analysis. 

[ProtoJeb21]

@SaturnianBlue Lane’s latest intensity is up in Tropical Tidbits, and it is...

...still a 155 mph Category 4 hurricane. 

This makes no sense. How can a hurricane have a 12 mbar pressure drop and not result in any increase in winds speed?

[SaturnianBlue]

2 hours ago, ProtoJeb21 said:

@SaturnianBlue Lane’s latest intensity is up in Tropical Tidbits, and it is...

...still a 155 mph Category 4 hurricane. 

This makes no sense. How can a hurricane have a 12 mbar pressure drop and not result in any increase in winds speed?

It is a shocking decision! They might still be relying on the estimates of the Dvorak technique or some other factor to help advise their intensity estimate, but I don't really know. We'll have to see the data from the recon flight which will be flying this night (EDT) into the storm and see if anything is changed.

Edit: To quote the CPHC from 5 PM EDT/11 AM HST:

Quote

Lane remains a powerful hurricane this morning, with a well-
developed warm eye completely surrounded by persistent cold cloud 
tops. Morning visible satellite imagery also depicts a well-defined
eye. The Hurricane Hunter aircraft from the 53rd Weather 
Reconnaissance Squadron is flying through Lane again this morning,
and confirms that the hurricane has intensified further since
their previous visit on Monday evening. The central pressure
has dropped around 10 mb during the past 12 hours, with the most
recent dropsonde in the eye finding 941 mb. Peak SFMR winds measured
so far have been 134 kt, and max flight level winds are 143 kt.
Subjective Dvorak current intensity estimates range from 6.5/127 kt
to 7.0/140 kt, with the latest ADT current intensity at 6.4/125 kt.
Based primarily on the aircraft data, the intial intensity for this
advisory is increased to 135 kt, which makes Lane a high-end
Category 4 hurricane. 

Edit 2: And to quote the CPHC from 11 PM EDT/5 PM HST:

Quote

Lane remains a powerful hurricane this afternoon, with a well-
developed warm eye completely surrounded by persistent cold cloud 
tops. The Hurricane Hunter aircraft from the 53rd Weather 
Reconnaissance Squadron has been flying through Lane during the day,
and has provided invaluable data. The central pressure dropped
around 10 mb between the 18Z and 00Z fixes, with the last eye
dropsonde measuring 930 mb with 16 kt splash wind, yielding a
minimum pressure estimate of 929 mb. Peak SFMR winds during this
mission were 140 kt, and max flight level winds were 146 kt.
Subjective Dvorak current intensity estimates range from 6.5/127 kt
to 7.0/140 kt, with the latest ADT current intensity holding steady
at 6.5/127 kt. Although the central pressure has dropped sharply
during the last 18 hours, it is now about what one would expect for
a hurricane of strong Category 4 intensity in the Central Pacific
basin, and based primarily on the aircraft data the intial intensity
is held at 135 kt for this advisory. 

Personally, I don't think what is usually thought of a Category 4's pressure should be factored into the strength of the storm when data suggests a Category 5, but I digress.

Edited August 22, 2018 by SaturnianBlue

[ProtoJeb21]

Hurricane Lane was officially upgraded to a Category 5 hurricane around midnight to 3 am EST, with 160 mph winds. It already reached its new lowest pressure of 922 mbar — the eleventh or twelfth lowest in the East/Central Pacific — and has now started to weaken. It’s still a Category 5, but the pressure has gone up to 934 mbar, similar to Hurricane Matthew. It should be back to a 150-155 mph Category 4 within the next few hours. 

[Green Baron]

A cool service from where i live:

http://lapalma.hdmeteo.com/

I don't think you'd need translation ...

Edited August 22, 2018 by Green Baron

[ProtoJeb21]

Hurricane Lane is weakening as it encounters wind shear near Hawaii, but it’s  still a Category 4 with winds of 130 mph. How close it gets to Hawaii is partially dependent on how long it can hold itself together. Most models are suggesting that it won’t drop below major hurricane intensity for another 18-36 hours, which would mean it could still be a Category 3/4 storm by late tomorrow EST. However, last night, I noticed something concerning on visible satellite imagery: what appeared to be a second eyewall around the already clouding eye. I’m worried that Lane may be trying to undergo an eyewall replacement cycle, which would help the hurricane strengthen or maintain intensity once it’s finished. Only time will tell. 

[ProtoJeb21]

I didn't think Hurricane Lane could get even more worrying, but apparently I was wrong.

The latest updates on the storm as of 18z August 23rd suggest Hawaii is in even more trouble than initially expected, which is concerning for me because I know someone who lived on Oahu. Here's the latest satellite imagery:

Last night through earlier today, wind shear to the west had begun to take its toll on Lane, causing it to become more elongated with an asymmetrical - yet still powerful - core. The eye had collapsed pretty early during this phase, and as I mentioned before, it looked like there may have been another eyewall forming last night, potentially signalling the start of another eyewall replacement cycle (EWRC). The latest satellite imagery of Lane makes me fear that this could be the case. Over the last few hours, Lane's core has become more symmetrical again, and now you can visibly see the eye again. Most of the system's convection is becoming more organized around the core while some of the convection ripped off by wind shear continues to drop heavy rainfall over Hawaii. If Lane was not finishing an EWRC, this should not be happening; the storm should continue to lose its organization and, most importantly, weaken to Category 3 status. It has now maintained low Category 4 winds for longer than forecast for today. This maintaining of intensity and its organizational improvement as seen in visible satellite imagery leads me to believe that Lane has finished or is finishing yet another EWRC, which will help the storm remain strong as it gets closer to Hawaii, which is not good news.

Another concern is Lane's intensity not including the potential EWRC. The latest intensity guidance models predict that Lane will remain as a Major Hurricane (>111 mph winds) for at least 12 hours, likely closer to 18-24 hours. This, along with the possible EWRC, indicate that Lane will still be a powerful storm even when it reaches Hawaii. To make matters worse, some parts of the island chain can get over a FOOT of rain, on top of the foot some areas have already gotten today. Some places may even exceed 24-30 inches of rain total. If that wasn't bad enough, most models (as seen on Tropical Tidbits) are predicting a very close pass (<50 miles) or even a direct landfall before Lane is steered out to the west. All I can hope is that this storm somehow doesn't get even worse.

[tater]

 

Nothing to see here, let's move along.

[SaturnianBlue]

Gone and gone... 

Persisting rainfall is still a major threat, but as a tropical cyclone, Lane has practically gone poof under the 35-40 knot wind shear.

[ProtoJeb21]

Some updates on the latest tropical systems: 

The once formidable Hurricane Lane has, after almost two weeks, finally met its end. Nothing really more to say here. It barely even exists on satellite imagery anyways. 

Tropical Storm Miriam formed in the East Pacific the other day and was initially forecast to rather quickly strengthen into a Category 1 hurricane. However, once it reached windspeeds of 65 mph, it just...stopped. No more intensification for a whole day, then it began to weaken. I have NO idea why this happened. @SaturnianBlue did you notice any inhibiting factors on Miriam that I missed?

Meanwhile, the newly formed Tropical Depression 16-E — now Tropical Storm Norman according to Tropical Tidbits — appears to be doing much better than Miriam. In the last several hours, its connective structure has greatly improved, with an organized cluster of thunderstorms and no exposed circulation. Tropical Tidbits also says that its winds have jumped from 35 mph to 50 mph since the last NHC advisory. If this is true, then Norman may further intensify quicker than expected.

Out in the West Pacific is another relatively  new system, Tropical Storm Jebi (what a very Kerbal name). It already has winds of 60 mph and its current forecast cone predicts it becoming a Category 4 typhoon by late Labor Day weekend. The GFS model says it’ll become a Category 5 Super Typhoon...but seriously, when has any GFS model accurately predicted the formation of a Cat 5 typhoon? It says that for nearly every new soon-to-be-strong West Pacific storm, and 95% of them end up being Category 2’s, 3’s, and 4’s. However, this time may be different, like with Typhoon Maria, because like the latter, Jebi is going to be traveling a pretty long path over very favorable conditions. Maybe it’ll prove the GFS model right, maybe it won’t, but either way it’s going to be a very interesting storm to track. 

Finally, I get to talk about the Atlantic for the first time since Beryl reformed back in mid-July. The NHC and other meteorologists have noted that tropical activity could return to the Atlantic basin for the peak of the hurricane season this September, and it looks like the next named system may be upon us. A tropical wave is expected to emerge off of the coast of Africa south of the Cape Verde islands late Thursday/early Friday, and just about every model on Tropical Tidbits suggests the wave will develop pretty quickly. These predictions could easily change, but because of the short time frame they’re covering (no more than four days), I’d say they’re rather reliable. The same cannot be said about their predictions for a system developing near Florida by early-mid next week, or the possibility of another tropical wave behind the first one developing next week. For right now, the first tropical wave has the highest forecast confidence to be considered worthy for observation. 

[SaturnianBlue]

@ProtoJeb21 Tropical Storm Miriam is gradually strengthening again, so it has some chance of becoming a Hurricane. The cause for weakening for this storm was wind shear, which is still affecting the storm, according to the NHC Forecast Discussion. The storm has now had a burst of convection, so they have upgraded the storm slightly.

Norman is already forecast to reach high-end Category 3 status in the coming days. Apparently this is one to watch for in the long-term, because it may pass near Hawaii, which would make it the third in the set of long-track hurricanes, following Hector and Lane.

The current GFS has an unfortunate tendency to have storms—especially in the subtropics—intensify into super typhoons. This is the reason the GFS predicts super typhoon strikes on Japan constantly, despite this being very unlikely.

Regarding the Atlantic, I do agree that the tropical wave is quite likely to form something—considering the NHC now gives it a 50% chance of tropical cyclone development in the next five days! If I recall correctly, the Florida system is expected to enter the Gulf of Mexico, which is a rather concerning storm track, with the high SSTs. 

The official death toll estimate for last year's Hurricane Maria has been raised to 3,057.

Edited August 29, 2018 by SaturnianBlue

[ProtoJeb21]

2 hours ago, SaturnianBlue said:

 

@ProtoJeb21 Tropical Storm Miriam is gradually strengthening again, so it has some chance of becoming a Hurricane. The cause for weakening for this storm was wind shear, which is still affecting the storm, according to the NHC Forecast Discussion. The storm has now had a burst of convection, so they have upgraded the storm slightly.

 

I didn’t know about the wind shear Miriam was facing, although I assumed it was the cause of its weakening. Do you know of any online sources that map wind shear in the tropics?

2 hours ago, SaturnianBlue said:

Norman is already forecast to reach high-end Category 3 status in the coming days. Apparently this is one to watch for in the long-term, because it may pass near Hawaii, which would make it the third in the set of long-track hurricanes, following Hector and Lane.

Norman looks to be different than Hector and Lane if it does end up heading towards Hawaii because, while the latter two approached or passed to the south, Norman will be coming from the east-northeast of the islands. If this is the case, it may end up like 2016’s Hurricane Darby or 2014’s Hurricane Iselle, although a landfall on the Big Island is quite unlikely. The fact that Norman is going to be a long-lasting powerful storm will make it very interesting to track. 

3 hours ago, SaturnianBlue said:

Regarding the Atlantic, I do agree that the tropical wave is quite likely to form something—considering the NHC now gives it a 50% chance of tropical cyclone development in the next five days! If I recall correctly, the Florida system is expected to enter the Gulf of Mexico, which is a rather concerning storm track, with the high SSTs. 

I’d say that tropical wave is just about guaranteed to develop into Tropical Storm Florence by Friday or Saturday — nearly every model is predicting it doing so. The GFS model has it becoming a Category 3 hurricane by early next week, which I’m a bit skeptical about, mainly due to a patch of below-normal SSTs just north of the MDR. Future Florence is likely to pass through this patch, but how much of it the storm goes through depends on its exact track. For now, it looks to be one of those typical long-lasting open-ocean major Cape Verde hurricanes like 2011’s Katia. 

You’re right, the other area of interest is going to move into the Gulf of Mexico. However, even though that would be concerning for Texas as it’ll be heading into very warm (29-31 C) waters, I don’t anticipate anything major. It’ll likely stay too close to land to become anything more than a tropical storm...I hope.