ATL: ISAIAS - Post-Tropical - Discussion

[Kingarabian]

Power just came back on, after a sweltering day of 95+. Don't know what it topped out at yet, but it definitely picked up power as it was coming on shore. Oak Island took a bad beat, and the riverfront in Southport and 2 marinas did there as well. But tomorrow is another day in paradise.

Everyone up north that is dealing with Isaias, good luck and keep your head down.

Here is the video mentioned earlier of Oak Island.

https://www.facebook.com/watch/?v=318637685845544

Wow that video is pretty intense considering the storms intensity @ landfall. Makes me even more grateful that Douglas missed us last week.

[CrazyC83]

I'd have to guess the damage will be well into the billions.

[Buck]

The good news is that on the coast, it looks like erosion is the biggest problem caused. And while there’s lots of isolation tornado damage, there hasn’t been major, long term flooding.

[SconnieCane]

Isaias made an excellent case to be retired!

Definately very intense for the Ellington, Ct area and my girlfriend. Her parents took shelter in their basement, fortunately they are ok with minimal damage. It seemed like the tornadoes spawned were more intense than the typical tropical cyclone spin ups.

A lot of clean up and damage assessment left for this week.

I think it ends up like Alex, Arthur or Bertha. Rough for some spots, but not overall "catastrophic" enough for retirement. Gotta preserve the "I" names anyway!

*Edit* Unless there was a high death toll in the Bahamas or DR I haven't heard about.

[Craters]

Isaias made an excellent case to be retired!

Definately very intense for the Ellington, Ct area and my girlfriend. Her parents took shelter in their basement, fortunately they are ok with minimal damage. It seemed like the tornadoes spawned were more intense than the typical tropical cyclone spin ups.

A lot of clean up and damage assessment left for this week.

I think it ends up like Alex, Arthur or Bertha. Rough for some spots, but not overall "catastrophic" enough for retirement. Gotta preserve the "I" names anyway!

Yeah, but not THIS "I" name, please...

[TallyTracker]

SUMMARY OF 800 PM EDT...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...43.6N 73.0W
ABOUT 5 MI...10 KM NNW OF RUTLAND VERMONT
MAXIMUM SUSTAINED WINDS...50 MPH...80 KM/H
PRESENT MOVEMENT...NNE OR 20 DEGREES AT 40 MPH...65 KM/H
MINIMUM CENTRAL PRESSURE...997 MB...29.44 INCHES

Rutland, VT is not your typical cyclone point of reference! lol

[CrazyC83]

SUMMARY OF 800 PM EDT...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...43.6N 73.0W
ABOUT 5 MI...10 KM NNW OF RUTLAND VERMONT
MAXIMUM SUSTAINED WINDS...50 MPH...80 KM/H
PRESENT MOVEMENT...NNE OR 20 DEGREES AT 40 MPH...65 KM/H
MINIMUM CENTRAL PRESSURE...997 MB...29.44 INCHES

Rutland, VT is not your typical cyclone point of reference! lol

Next advisory (probably the last as I would have it as extratropical) should have Montreal, QC as the reference point.

[toad strangler]

SUMMARY OF 800 PM EDT...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...43.6N 73.0W
ABOUT 5 MI...10 KM NNW OF RUTLAND VERMONT
MAXIMUM SUSTAINED WINDS...50 MPH...80 KM/H
PRESENT MOVEMENT...NNE OR 20 DEGREES AT 40 MPH...65 KM/H
MINIMUM CENTRAL PRESSURE...997 MB...29.44 INCHES

Rutland, VT is not your typical cyclone point of reference! lol

Next advisory (probably the last as I would have it as extratropical) should have Montreal, QC as the reference point.

Man, talk about hauling ASS! Ahhhh the northern latitudes

[CrazyC83]

The posts in this forum are NOT official forecasts and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K. For official information, please refer to products from the NHC and NWS.

AL092020, ISAIAS, 46,
20200727, 0000, , LO, 11.6N, 40.5W, 25, 1014,
20200727, 0600, , LO, 11.8N, 42.6W, 30, 1014,
20200727, 1200, , LO, 11.9N, 44.6W, 30, 1013,
20200727, 1800, , LO, 12.0N, 46.5W, 30, 1013,
20200728, 0000, , LO, 12.2N, 48.7W, 35, 1012,
20200728, 0600, , LO, 12.3N, 51.0W, 35, 1012,
20200728, 1200, , LO, 12.5N, 53.7W, 40, 1011,
20200728, 1800, , LO, 13.1N, 56.2W, 40, 1011,
20200729, 0000, , LO, 13.9N, 58.4W, 40, 1010,
20200729, 0600, , LO, 14.7N, 60.5W, 40, 1009,
20200729, 1200, , LO, 15.3N, 62.7W, 45, 1008,
20200729, 1800, , TS, 15.5N, 64.6W, 45, 1007,
20200730, 0000, , TS, 15.8N, 65.9W, 50, 1005,
20200730, 0600, , TS, 16.6N, 67.2W, 50, 1005,
20200730, 1200, , TS, 17.7N, 68.5W, 55, 1002,
20200730, 1530, L, TS, 18.4N, 69.1W, 60, 1000,
20200730, 1800, , TS, 19.1N, 69.8W, 60, 1000,
20200731, 0000, , HU, 19.9N, 71.2W, 65, 998,
20200731, 0600, , HU, 20.5N, 72.7W, 75, 991,
20200731, 0930, L, HU, 20.9N, 73.5W, 75, 991,
20200731, 1200, , HU, 21.3N, 74.0W, 70, 992,
20200731, 1800, , HU, 22.1N, 75.1W, 70, 992,
20200801, 0000, , HU, 22.9N, 75.3W, 75, 986,
20200801, 0600, , HU, 23.6N, 76.7W, 75, 987,
20200801, 1200, , HU, 24.3N, 77.5W, 65, 990,
20200801, 1400, L, TS, 24.5N, 77.7W, 60, 991,
20200801, 1800, , TS, 24.8N, 78.3W, 55, 993,
20200802, 0000, , TS, 25.3N, 78.9W, 55, 996,
20200802, 0600, , TS, 25.9N, 79.2W, 55, 995,
20200802, 1200, , TS, 26.6N, 79.5W, 60, 994,
20200802, 1800, , HU, 27.4N, 79.6W, 65, 993,
20200803, 0000, , HU, 28.2N, 79.7W, 65, 993,
20200803, 0600, , TS, 29.1N, 79.9W, 60, 996,
20200803, 1200, , TS, 30.2N, 80.0W, 55, 998,
20200803, 1800, , HU, 31.2N, 79.7W, 65, 993,
20200804, 0000, , HU, 32.8N, 79.1W, 75, 988,
20200804, 0310, L, HU, 33.9N, 78.4W, 80, 985,
20200804, 0600, , HU, 35.0N, 78.1W, 65, 989,
20200804, 1200, , TS, 37.7N, 76.9W, 60, 993,
20200804, 1800, , TS, 40.9N, 75.3W, 55, 995,
20200805, 0000, , EX, 44.3N, 73.7W, 45, 998,
20200805, 0600, , EX, 46.5N, 72.0W, 40, 1000,
20200805, 1200, , EX, 48.4N, 71.6W, 35, 1001,
20200805, 1800, , EX, 50.5N, 71.3W, 35, 1001,
20200806, 0000, , EX, 52.8N, 70.7W, 35, 999,
20200806, 0600, , EX, 54.1N, 69.1W, 35, 997,
20200806, 1200, , EX, 54.5N, 68.3W, 35, 995,

This is my thought for the best track of Isaias. I went through all the fixes and data and the changes were generally minor. The main highlights were that I believe there were more fluctuations while off Florida (when it was pulsing up and down) and that its final landfall was at its peak intensity of 80 kt (basis being a blend of the radar observations, SFMR and surface observations, while largely ignoring the flight level winds).

[Steve]

SUMMARY OF 800 PM EDT...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...43.6N 73.0W
ABOUT 5 MI...10 KM NNW OF RUTLAND VERMONT
MAXIMUM SUSTAINED WINDS...50 MPH...80 KM/H
PRESENT MOVEMENT...NNE OR 20 DEGREES AT 40 MPH...65 KM/H
MINIMUM CENTRAL PRESSURE...997 MB...29.44 INCHES

Rutland, VT is not your typical cyclone point of reference! lol

Yeah Tally, haha. And here the center goes rolling SW-NE across the entire Great State of Maine!
https://www.tropicaltidbits.com/sat/sat ... t=vis-swir

And there he goes off to the Maritimes to get absorbed into a broader low pressure. One of the better tropical storms I tracked that I didn't personally experience.

https://weather.gc.ca/satellite/satelli ... &type=1070

[EquusStorm]

Looks like they'll put out advisories despite being post-tropical until warnings are canceled for the US, which should honestly be the next advisory or two given movement speed.

[CrazyC83]

Looks like they'll put out advisories despite being post-tropical until warnings are canceled for the US, which should honestly be the next advisory or two given movement speed.

5 am should be the last advisory, as there are no tropical warnings in Canada right now (as the winds that far east are below tropical storm force and probably felt it wasn't worth issuing for the tidal St. Lawrence).

[jaxfladude]

I for one hope this is retired....hard to pronounce at first but do not need the forecasting headache reminders of 2020's version of Isaias....hopefully the deaths/damages are as low as can be...prayers...please do not return in 2026 thanks...

edit I know many a system can be hard to forecast...

[CrazyC83]

I for one hope this is retired....hard to pronounce at first but do not need the forecasting headache reminders of 2020's version of Isaias....hopefully the deaths/damages are as low as can be...prayers...please do not return in 2026 thanks...

edit I know many a system can be hard to forecast...

Not a lot of names to choose from. Hopefully Ian doesn't get the boot in 2022.

[storminabox]

We’re still without power here in the house I’m staying at near lake Winnipasake in New Hampshire.

[emeraldislenc]

This was a very interesting hurricane to track and to be a part of. I think we were all amazed how fast it intensified off the coast. We experienced very little damage here on Emerald Isle. My thoughts go out to those families who lost loved ones and to those who lost their homes or had damage from the hurricane!

[Steve]

I'd have to guess the damage will be well into the billions.

I couldn’t find anything yet. Low couple billions maybe? I’m not sure how much damage they had in the Bahamas. And with the economy shut down for covid with many parents working remote and people not being in school yet, it’s hard to judge lost productivity. With the erosion, surge, flooding and tornado damage, you’d have to think the range will be roughly 2.5-3.5B.

[Craters]

SUMMARY OF 800 PM EDT...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...43.6N 73.0W
ABOUT 5 MI...10 KM NNW OF RUTLAND VERMONT
MAXIMUM SUSTAINED WINDS...50 MPH...80 KM/H
PRESENT MOVEMENT...NNE OR 20 DEGREES AT 40 MPH...65 KM/H
MINIMUM CENTRAL PRESSURE...997 MB...29.44 INCHES

Rutland, VT is not your typical cyclone point of reference! lol

Yeah Tally, haha. And here the center goes rolling SW-NE across the entire Great State of Maine!
https://www.tropicaltidbits.com/sat/sat ... t=vis-swir

And there he goes off to the Maritimes to get absorbed into a broader low pressure. One of the better tropical storms I tracked that I didn't personally experience.

https://weather.gc.ca/satellite/satelli ... &type=1070

Do you guys think that it might stack back up and reorganize and reach hurricane strength before it gets to Iceland? ( )

[USTropics]

Here is 5pm from Sunday

Isaias is expected to maintain its
current intensity until landfall, and could restrengthen to
hurricane status in 24-36 h when the vertical shear vector is
forecast to switch from westerly to southwesterly which would align
the shear along the direction of storm motion. Some baroclinic
interaction is expected on days 2-3 when Isaias will move into the
right-rear quadrant of an anticyclonically curved jet streak, which
is expected to hold the intensity a little above what would normally
be expected for a post-landfall tropical cyclone. The NHC intensity
forecast is similar to the HFIP corrected consensus model and the
IVCN intensity consensus model, which agree well with the GFS and
ECMWF model intensity forecasts.

^^ That quadrant is an upward motion quadrant (e.g. you drew an x/y access or in other words a plus sign, two of the quadrants tend to inhibit development where 2 provide out flow and upward motion/air evacuation.
http://www.eumetrain.org/satmanu/four_q ... index.html

https://forecast.weather.gov/glossary.p ... 20quadrant

https://pdfs.semanticscholar.org/c6a0/a ... e8bae5.pdf

The physics are mostly too complicated for a semi-idiot like me, but I get the concept. That's why when people scream about shear is going to destroy storm x or y, many long-timers will mention that shear is relative to the position of the storm. While shear can certainly cut the hair of all thunderstorms trying to rise in the atmosphere, it can also provide an evacuation into the upper atmosphere such as what we are seeing with Isaias inland.

Here's a question. I don't think I've ever heard the term "jet streak" as many times as I have with Isaias. Maybe I haven't been paying attention all along. But it's a semi-new term for me that I don't think ever got this much mention.

Ahhh, the good ole 4-Quad Jet Theory and Atmospheric Continuity. Dynamics is fun

The reason Isaias has been able to maintain his strength isn't due to tropical processes, but the baroclinic processes that you guys have outlined in detail. Just to add some visuals to this, here is that 250mb jet streak as Isaias made landfall yesterday in North Carolina:

250mb analysis from Earthnull (https://earth.nullschool.net/):


At this point, you can notice the right entrance region is north of the storm. As Steve's post illustrated, this allows for evacuation of air south of the jet streak entrance region. The increased divergence at the 250/200mb level means increased evacuation of air away in the upper levels from the center of the storm, which therefore increases surface inflow. Here is a great product on TropicalTidbits, I've outlined the axis in cyan. The orange is the 850mb vort where divergence has increased.

TropicalTidbits 200-400mb Q-Div, Streamfunc., 850mb vort, 200mb Irrotational Wind (https://www.tropicaltidbits.com/analysi ... 500&fh=-24):

[Hybridstorm_November2001]

A band of heavy showers is passing through and it is breezy but otherwise we dodged a bullet here (it has been very calm thus far in my area all day) as earlier tracks had the storm center passing directly through the area.

Stay safe everyone.