BoB: AMPHAN - Post-Tropical

[mrbagyo]

excerpt from RSMC IMD Bullletin

"AT 0900 UTC OF 19TH MAY, THE BOUY (23092) AT 17.2°N/89.1°E REPORTED MEAN SEA LEVEL PRESSURE OF 987.8 HPA AND WIND DIRECTION AND SPEED 180°/37 KNOTS, BOUY (23459) LOCATED AT 13.6°N/87.0°E REPORTED MEAN SEA LEVEL PRESSURE OF 974.5 HPA AND WIND DIRECTION/SPEED AS 140°/27KNOTS AND ANOTHER BOUY (23094) AT 13.3°N/84.1°E REPORTED MEAN SEA LEVEL PRESSURE OF 996.6 HPA."

[doomhaMwx]

excerpt from RSMC IMD Bullletin

"AT 0900 UTC OF 19TH MAY, THE BOUY (23092) AT 17.2°N/89.1°E REPORTED MEAN SEA LEVEL PRESSURE OF 987.8 HPA AND WIND DIRECTION AND SPEED 180°/37 KNOTS, BOUY (23459) LOCATED AT 13.6°N/87.0°E REPORTED MEAN SEA LEVEL PRESSURE OF 974.5 HPA AND WIND DIRECTION/SPEED AS 140°/27KNOTS AND ANOTHER BOUY (23094) AT 13.3°N/84.1°E REPORTED MEAN SEA LEVEL PRESSURE OF 996.6 HPA."

Whoa 974.5 mb from the buoy at 13.6N ? That's pretty low considering that Amphan was already at/near 17N at 09Z. That's about 380km from the center of Amphan.

[Highteeld]

The easterly shear isn't allowing the outer eyewall to fully contract, thus the inner eyewall remains mostly intact. very interesting

[1900hurricane]

 https://twitter.com/1900hurricane/status/1262819331920052231

[Abdullah]

18Z Best Track is in:

01B AMPHAN 200519 1800 18.3N 86.9E IO 100 950

The pressure is at 950 millibars (down one millibar from 951 six hours ago) and the wind speed is stable at 100 knots (115 mph).

https://www.nrlmry.navy.mil/tcdat/tc2020/IO/IO012020/txt/trackfile.txt

[TheProfessor]

Amphan has veered to the left a bit, which isn't good as it puts the Hooghly river in onshore flow where it will likely get a bad surge.

[1900hurricane]

I'm a little disappointed there wasn't a 12Z Port Blair sounding. Hopefully the 00Z one will be able to reveal the magnitude of the shear.

[Crostorm]

Radar Animation - Paradip

[doomhaMwx]

Please change the thread title. Cyclonic storm is different from extremely severe cyclonic storm on the IMD scale.

[FireRat]

yeah it's weird that its only 'cyclonic storm' on the main s2k tropical weather page, but is extremely severe...here. Thank goodness its not a Cat 4 or 5, but even if it strikes as a 2 or 1 it could be an Ike-like or Sandy-like situation with the surge in a very populated area. I hope the people there took this thing seriously!

[doomhaMwx]

Latest storm surge modelling from the IMD



and for Bangladesh (from the Bangladesh Met Dept BMD):

UNDER THE INFLUENCE OF THE CYCLONE AND THE NEW MOON PHASE, THE LOW-LYING AREAS OF THE COASTAL
DISTRICTS OF SATKHIRA, KHULNA, BAGHERHAT, JHALOKATHI, PIROZPUR, BORGUNA, PATUAKHALI, BHOLA, BARISHAL,
LAXMIPUR, CHANDPUR, NOAKHALI, FENI, CHATTOGRAM AND THEIR OFFSHORE ISLANDS AND CHARS ARE LIKELY TO BE
INUNDATED BY STORM SURGE OF 1.5 METERS to 3 METERS (5-10 FEET) HEIGHT ABOVE NORMAL ASTRONOMICAL TIDE.

[mrbagyo]

[shah83]

That last 0305z microwave image has the look of an eye that is really rather healthy to my inexperienced eyes to be 85 or 95 knots. And even if that strength is true, it all but guarantees a humongous surge.

This is a prime example of why we need worldwide recons, really...

[1900hurricane]

I'd probably estimate Amphan to have an intensity of about 90 kt right now, which is about the Dvorak constraint level I think (and although you shouldn't technically get a DT with a CCC pattern, would also be the embedded center DT). Microwave estimates and SATCON are a little higher, but these estimates sometimes struggle with weaker or concentric core cases, which definitely applies to Amphan since the transition to CCC. However that applies only to the wind estimates; the pressure estimates are typically closer, even in these cases. As an example, you can see how SATCON and its members did in comparison to recon data for Hurricane Maria '17. When I run the 944 mb pressure from the latest SATCON estimate through a background pressure modified AH77 (which I like to use as a loose guide in weak/concentric core cases) also gives me about 90 kt.

[1900hurricane]

Holy bejeezus, 77 kt cloud layer shear in the 00Z Port Blair sounding!

[Jr0d]

While it is a bit of a relief the wind has dropped(but maybe trying to reintensify slightly judging by the latest radar and satellite) the winds are the secondary impact, and the major winds will be localized. Thete still will likely be widespread wind damage.

The primary concern is the storm surge. This area is arguably the most vulnerable region in the world for storm surge because of geography and population. Right now it appears the Sundarban refuge will get the brunt of the surge which is not the worst case scenerio, it will still be high and widespread enough to cause extensive damage.

I really hope those in low lying areas have got the warning and have headed to higher ground.

[mrbagyo]

Latest full color RGB from Elektro L2 satellite

[doomhaMwx]

The eye/center of Amphan has made its closest approach to the Odisha coast. The cyclone is now nearing the coast of the West Bengal. A weather station in Paradip city, Odisha reported sustained winds close to 100kph at 00Z and 03Z. Recorded sustained winds at 06Z were still strong at 87kph.

[Kingarabian]

Prayers for those involved

[doomhaMwx]

The sustained winds at Paradip indeed exceeded 100kph

 https://twitter.com/mcbbsr/status/1262933264345358336



 https://twitter.com/mcbbsr/status/1262939680544301056