ATL: GRACE - Remnants - Discussion

[Iceresistance]

The eye is likely embedded inside the CDO of Grace . . .

[ElectricStorm]

With that big of a dry slot I don't think it's going to be able to wrap that convection all the way around before landfall, so my 100kt prediction might bust. Still will likely end up with a Cat 2 out of this.

[kevin]

I present to you, hurricane croissant.

[aspen]

I present to you, hurricane croissant.

https://i.imgur.com/hjmWihR.jpg

Too bad this didn’t end up as Henri, because the French name would’ve been perfect.

[tolakram]

saved loop

[kevin]

While still assymetric (as noted by my previous post ), ADT based wind data does indicate that the SW and SE quadrants of Grace have grown significantly in the last few hours as can be seen by the jump from 60 to 90 miles for the 34 kt radius in those quadrants. Still far from symmetric as NW and NE have a radius of 120 miles, but ADT at least seems to notice an improved organization compared to the last recon visit.

[cheezyWXguy]

From what I can gather looking at vis loops, the center is not within the dry slot making this look like a croissant. It looks more like it’s tucked under -70 cloud tops further northeast. That dry slot is also making gradual progress in closing up. Not sure what intensity this will end up at, but if it does close off that dry slot before landfall it’s all systems go

[ThetaE]

Think y'all are overemphasizing this "dry slot" a bit much. Recon showing that winds have increased on the SW quadrant in the past two hours.

To me, the croissant shape looks like an overlay of two feeder bands (or their remnants) plus a slight northerly shear (as analyzed by CIMSS) that favors pushing the CDO to the south. I see no plausible path for a significant amount of dry air to have worked its way into the circulation.

Attached is an earlier WV frame that shows the feeder bands (annotated) better.



CIMSS shear: http://tropic.ssec.wisc.edu/real-time/windmain.php?&basin=atlantic&sat=wg8&prod=shr&zoom=&time=

[Sciencerocks]

[cheezyWXguy]

Mid level eye starting to show through

[ThetaE]

Recon dropsondes have shown a fairly steady pressure the last few hours, but I have to say that Grace has really symmetrized since the first pass. SW and NE quadrants had a difference of maybe 10 kts at flight level, and less in SFMR (at the cost of the eye-catching 92 kt flight level winds in the NE quadrant). IMO, this is a big checkbox for further intensification to commence heading forward.

[ElectricStorm]

Dry slot starting to close up a bit. Once that convection wraps around there's no holding it back. It will be interesting to see what the NHC will have for landfall intensity on the upcoming advisory.

[cheezyWXguy]

When is the next recon pass?

[kevin]

R50 almost symmetric at the moment 50/40/40/50 miles. Once the dry slot closes this could intensify at a very rapid pace, kind of similar to HWRF and HMON this morning which strenghtened Grace from 990 to 960 mbar in the last 12 hours before landfall.

[FireRat]

I present to you, hurricane croissant.

https://i.imgur.com/hjmWihR.jpg

Dam u Grace, now u made me wanna get my croissant sandwich from dunkin donuts (trying to lose weight here)

[Blinhart]

Is this going to hit any large populated areas or mostly unpopulated area? Looks like this could end up being a major at landfall which wouldn't be good for anyone in the path of this system. Looks like it will have plenty of energy involved with her to make it all the way across the Mountains which is very shocking. Hoping there is not many loss of lives as this system goes all the way across Mexico.

[ElectricStorm]

BULLETIN
Hurricane Grace Advisory Number 29
NWS National Hurricane Center Miami FL AL072021
1000 AM CDT Fri Aug 20 2021

...GRACE EXPECTED TO CONTINUE STRENGTHENING...
...PREPARATIONS TO PROTECT LIFE AND PROPERTY SHOULD BE RUSHED TO
COMPLETION IN THE HURRICANE WARNING AREA...


SUMMARY OF 1000 AM CDT...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...20.6N 94.3W
ABOUT 200 MI...325 KM E OF TUXPAN MEXICO
ABOUT 155 MI...250 KM NE OF VERACRUZ MEXICO
MAXIMUM SUSTAINED WINDS...85 MPH...140 KM/H
PRESENT MOVEMENT...W OR 265 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...982 MB...29.00 INCHES

[ElectricStorm]

FORECAST POSITIONS AND MAX WINDS

INIT 20/1500Z 20.6N 94.3W 75 KT 85 MPH
12H 21/0000Z 20.4N 95.9W 90 KT 105 MPH
24H 21/1200Z 20.0N 98.2W 55 KT 65 MPH...INLAND
36H 22/0000Z 19.4N 101.1W 35 KT 40 MPH...INLAND
48H 22/1200Z...DISSIPATED

[kevin]

Dry slot starting to close up a bit. Once that convection wraps around there's no holding it back. It will be interesting to see what the NHC will have for landfall intensity on the upcoming advisory.

They went with a 90 kt Cat 2. However that's at 00z while landfall will most likely be 3 to 6 hours afterwards so it's reasonable to assume that a low-end Cat 3 is within their uncertainty margin.

FORECAST POSITIONS AND MAX WINDS

INIT 20/1500Z 20.6N 94.3W 75 KT 85 MPH
12H 21/0000Z 20.4N 95.9W 90 KT 105 MPH
24H 21/1200Z 20.0N 98.2W 55 KT 65 MPH...INLAND
36H 22/0000Z 19.4N 101.1W 35 KT 40 MPH...INLAND
48H 22/1200Z...DISSIPATED

[kevin]

Is this going to hit any large populated areas or mostly unpopulated area? Looks like this could end up being a major at landfall which wouldn't be good for anyone in the path of this system. Looks like it will have plenty of energy involved with her to make it all the way across the Mountains which is very shocking. Hoping there is not many loss of lives as this system goes all the way across Mexico.

This is the expected landfall location. So near Poza Rica (200k population) and Papantla (150k population). Multiple small villages (1k - 5k population each) are within a few miles of the expected landfall location.