ATL: GRACE - Remnants - Discussion

[ChrisH-UK]

(From earlier, i posted it to the wrong thread)

Belize Radar have it coming ashore south of Cozumel.

Source - http://nms.gov.bz/sensors/radar-imagery/

https://nms.gov.bz/images/radar/400/latest_400kmpic.gif?t=1629365860

Seems like you posted the original image instead of saving it and re-uploading to an external site (like imgur). As a result, this image shows Grace further inland than when you first posted it, and in a few days people who look at this post will see nothing.

Refer to this post for how to post images.

Thanks fixed it now.

[NXStumpy_Robothing]

https://twitter.com/iCyclone/status/1428297175956664321

iCyclone’s MSLP of 983 mb is a bit lower than the NHC’s official value of 986 mb at landfall, so I would expect the TCR to make adjustments.

It seems like that the minimum central pressure was even lower, as Morgerman tweeted out. NHC will probably have to revise further, though the fact that there is a relative lack of reliable surface OBS in the area will certainly hamper efforts. There's a good chance Grace may have come quite close to reaching Cat 2 status this morning, with the drop of 7-8 mb (if iCyclone's readings are accurate) after recon left 5 hours before landfall.

 https://twitter.com/iCyclone/status/1428332562125004801

[Hypercane_Kyle]

I don't think Josh is going to be nearly 10mb off. I'm pretty confident Grace tightened up a bit right before landfall based on IR images from this morning.

[kevin]

I don't think Josh is going to be nearly 10mb off. I'm pretty confident Grace tightened up a bit right before landfall based on IR images from this morning.

If I recall correctly HWRF also showed deepening to a pressure in the upper 970s mbar before landfall. While HWRF tends to blow up storms in the long-term it's often quite good with short-term structure and intensity and combined with the surface obs I'm also fairly confident that Grace tightened up in the last hours before landfall.

[TallyTracker]

Grace appears to be almost halfway across the Yucatán. Holding together pretty well this far.

[aspen]

The 11am discussion mentioned Josh Morgerman’s measurement of 983mb at landfall, but not his 978mb measurement. They also state how the environment up ahead is very conductive, but it should take Grace time to build up an inner core again, and that most of the intensification could be in the last 12 hours before landfall like the HWRF and HMON show.

[aspen]

At this rate, Grace will be back over water around the 5pm advisory. It will then have roughly 30 hours over the BoC.

[ThetaE]

The 11am discussion mentioned Josh Morgerman’s measurement of 983mb at landfall, but not his 978mb measurement. They also state how the environment up ahead is very conductive, but it should take Grace time to build up an inner core again, and that most of the intensification could be in the last 12 hours before landfall like the HWRF and HMON show.

I agree with this. Think this is also the main explanation for Grace’s steady (not rapid) intensification the past few days. Many insisted that Jamaica isn’t a storm killer like it’s neighbors— which it isn’t! But it’s still a sizable mountainous island that really widened Grace’s windfield, even if pressure dropped while crossing it.

[cheezyWXguy]

The 11am discussion mentioned Josh Morgerman’s measurement of 983mb at landfall, but not his 978mb measurement. They also state how the environment up ahead is very conductive, but it should take Grace time to build up an inner core again, and that most of the intensification could be in the last 12 hours before landfall like the HWRF and HMON show.

I agree with this. Think this is also the main explanation for Grace’s steady (not rapid) intensification the past few days. Many insisted that Jamaica isn’t a storm killer like it’s neighbors— which it isn’t! But it’s still a sizable mountainous island that really widened Grace’s windfield, even if pressure dropped while crossing it.

I think it’s a fair assessment to say Jamaica isn’t a storm killer on its own. If conditions were otherwise favorable, the core probably wouldn’t need as much time to tighten. It seems to me that there were two main factors here that limited intensification, Jamaica and the pv steamer that induced some shear. Neither one seems like it would have slowed the intensification rate this much, but I suspect the land interaction provided an opportunity for shear and any attendant dry air to make it to the core more easily.

[Sciencerocks]

[GCANE]

CONUS dodged a bullet on this one due in large part to the heat wave over the CONUS.
This kept the ARWB far enough north of Grace to limit intensification and curve her north.
As temps cool in a few weeks, we won't be so lucky.
Rossby Waves will be dipping more south and allowing associated ARWB's to settle into the GOM.
As most are well aware, GFS has be advertising a major coming out of the CAG.
September may be a rough month. Stay tuned.

[kevin]

https://imagizer.imageshack.com/img924/4180/zo67aW.gif

Haven't seen IR, but at least on visual it looks surprisingly healthy considering it's over land.

[zeehag]

so this grace is supposed to make it all the way across the mexican landmass including mountains to get jiggy with us here on pacific coast? this is going to be an interesting watch.

[Astromanía]

65 MPH sustained winds with gusts to 84 MPH at Cozumel.
Pretty solid storm there.
00z models showing stronger storm at landfall south of Tampico possibly near Túxpam.
We don't have any storm2k members from there do we?

I actually think I'm the only active mexican member for now

[Astromanía]

so this grace is supposed to make it all the way across the mexican landmass including mountains to get jiggy with us here on pacific coast? this is going to be an interesting watch.

I doubt it will survive, but we will see

[ElectricStorm]

This isn't looking as bad as I hoped it would...

[psyclone]

Once again the Yucatan demonstrates it is an ideal landmass for a TC to transit intact.

[AlphaToOmega]

ZCZC MIATWOEP ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 AM PDT Thu Aug 19 2021

For the eastern North Pacific...east of 140 degrees west longitude:

The National Hurricane Center is issuing advisories on recently
downgraded Tropical Storm Linda, located approximately 1100 miles
east of Hilo, Hawaii.

1. Tropical Storm Grace, located over the Yucatan Peninsula,
is forecast to move inland over mainland Mexico Friday night and
dissipate over Mexico by late Saturday. However, Grace's remnants
are expected to continue westward and emerge over the eastern
Pacific Ocean off the west-central coast of Mexico early Sunday.
Environmental conditions are forecast to be conducive for
development, and a tropical depression could form late this weekend
or early next week while the system moves westward at 10 to 15 mph
away from the coast of Mexico.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...medium...60 percent.

Forecaster Cangialosi/Papin

[cheezyWXguy]

This isn't looking as bad as I hoped it would...

I’m not convinced, it looks to me like the llc and mlc have become misaligned. The mlc looks be going south of due west while the llc is going north of due west. If this is the case, it means less time over land but possibly a lower intensity at exit

[HurricaneEnzo]

Grace is still looking really good and looks to splash down in another 1-2 hours. As far as land goes the Northern part of the Yucatan isn't too inhospitable. I think as soon as Grace splashes down it hits the ground running.