Major Hurricane Grace

[Yeoman]

11 hours ago, WxWatcher007 said:

Absolutely. Love me some HWRF, but when it’s not in its wheelhouse it can be hot garbage. 

Wheelhouse being an hour before landfall?

[WxWatcher007]

9 minutes ago, Yeoman said:

Wheelhouse being an hour before landfall?

It's not THAT bad

We think it's worse than it actually is because weenies here toss it around like it's a global. That's like trying to sub a kicker in at middle linebacker. Won't work. If you have a system that has a closed and relatively stable LLC, it's the best intensity guidance in the toolbox.

 

[ldub23]

GFS  back to showing  it a  hurricane. Wind and flooding for  many on here.

 

[DownS.EasternVa]

Grace is getting her act together fast this morning, HWRF keep a more northerly component to Grace. The globals more of a west motion, wouldn't a stronger system pull more northward? 

[Kevin Reilly]

1 minute ago, DownS.EasternVa said:

Grace is getting her act together fast this morning, HWRF keep a more northerly component to Grace. The globals more of a west motion, wouldn't a stronger system pull more northward? 

Yes a weaker system would slide west 

[Windspeed]

Little suspicious that strong MCS/CDO feature is outrunning the broader low level circulation versus aligning over it. Easterly mid level steering flow appears to still be stronger than low level steering flow. We'll have a much clearer picture when recon gets out there of course.

[WxWatcher007]

8 minutes ago, Windspeed said:

Little suspicious that strong MCS/CDO feature is outrunning the broader low level circulation versus aligning over it. Easterly mid level steering flow appears to still be stronger than low level steering flow. We'll have a much clearer picture when recon gets out there of course.

Good point. Probably still a bit tilted, so it'll be helpful to see what kind of organization there actually is when recon gets there. Early morning microwave images showed strong convection, but not much in the way or banding or the kind of organization you'd see with a TC putting up an inner core.

The last few hours have looked good from the satellite view however, and I'm starting to think the models that showed a weaker system into the Greater Antilles are going to be way off. Note how both the GFS and Euro show some organization right before PR. As this slows down and aligns it could ramp up a good bit given where it is right now and the favorable environment ahead.  

 

[SnowenOutThere]

3 minutes ago, WxWatcher007 said:

Good point. Probably still a bit tilted, so it'll be helpful to see what kind of organization there actually is when recon gets there. Early morning microwave images showed strong convection, but not much in the way or banding or the kind of organization you'd see with a TC putting up an inner core.

The last few hours have looked good from the satellite view however, and I'm starting to think the models that showed a weaker system into the Greater Antilles are going to be way off. Note how both the GFS and Euro show some organization right before PR. As this slows down and aligns it could ramp up a good bit given where it is right now and the favorable environment ahead.  

 

When will recon get into Grace? Do we have an hour also for future reference where can I find when recon is scheduled?

[WxWatcher007]

3 minutes ago, SnowenOutThere said:

When will recon get into Grace? Do we have an hour also for future reference where can I find when recon is scheduled?

It should be early afternoon from what I saw online. Here's the link to find recon plans, but sometimes it's easiest to just follow on Twitter (I follow the official recon page and @TheAstroNick) in case there are flight changes. I believe today's flight will have both low level recon and high level environmental sampling that'll go into the models.  

https://www.nhc.noaa.gov/recon.php

[WxWatcher007]

Tropical Storm Grace Discussion Number   5
NWS National Hurricane Center Miami FL       AL072021
1100 AM AST Sat Aug 14 2021

Grace is sending mixed signals on its intensity this morning.  The 
storm has been producing persistent convective bursting since 
overnight, which would suggest that some strengthening has occurred. 
The latest subjective data-T numbers are 2.5 (35 kt) from TAFB and 
SAB, while objective satellite estimates are higher, roughly between 
45-50 kt.  Then, an ASCAT pass from 1302 UTC showed winds between 
35-40 kt.  Given these data, the initial intensity is set at 40 kt.  
A NOAA Hurricane Hunter aircraft is scheduled to investigate Grace 
this afternoon to provide a better estimate of the storm's 
intensity.

Grace is speeding along toward the west (280 degrees) at 19 kt.  
Mid-level ridging, entrenched over the western Atlantic, is 
expected to weaken slightly during the next couple of days.  This 
evolution should cause Grace to slow down to 10-15 kt by Sunday 
night and Monday and take on a west-northwestward heading.  That 
general trajectory should continue through the end of the forecast 
period.  The track guidance is tightly clustered during the first 
48-60 hours or so, showing Grace moving near or across the Leeward 
Islands, Puerto Rico, and the Dominican Republic.  On days 3-5, 
there is a little more spread, with a few models keeping the system 
on a southern track across Cuba while others show tracks across the 
Bahamas.  The NHC track forecast splits this difference and 
continues to show a track running between Cuba and the Bahamas, 
very close to the HCCA consensus solution.

Deep-layer shear is forecast to be 10 kt or less for the next 36 
hours or so while Grace is approaching the islands of the Greater 
Antilles.  The thermodynamic environment also appears conducive for 
strengthening, but the system's continued fast motion is likely to 
be an inhibiting factor on the rate of intensification.  The NHC 
intensity forecast remains on the conservative side, bringing 
Grace's intensity up to 50 kt by the time the storm reaches the 
Virgin Islands and Puerto Rico, but it should be noted that this 
forecast is on the lower side of the guidance.  Only one model, the 
HWRF, brings Grace to hurricane strength, but it does this by 
having the storm move farther north and avoid land interaction 
altogether.  The intensity forecast is highly uncertain on days 3-5 
since it depends on exactly how much Grace moves over the Greater 
Antilles, and there is some model signal that increasing 
northeasterly upper-level winds over the Bahamas and Florida could 
become a negative factor.

Key Messages:

1.  Tropical storm conditions are expected in portions of the
Leeward Islands tonight and early Sunday, and the Virgin Islands 
and Puerto Rico on Sunday.  Tropical storm conditions are possible 
over eastern parts of the Dominican Republic by early Monday.

2.  Heavy rainfall could lead to flash and urban flooding over the 
Leeward and Virgin Islands.  Across Puerto Rico and the Dominican 
Republic, heavy rainfall may lead to flash, urban and small stream 
flooding, along with the potential for mudslides.

3.  There is a risk of wind and rainfall impacts across the rest of 
the Dominican Republic, Haiti, the Turks and Caicos Islands, the 
Bahamas, and Florida next week, and interests in those areas should 
monitor the progress of Grace and updates to the forecast. 

FORECAST POSITIONS AND MAX WINDS

INIT  14/1500Z 16.2N  57.9W   40 KT  45 MPH
 12H  15/0000Z 16.8N  60.6W   45 KT  50 MPH
 24H  15/1200Z 17.5N  63.8W   50 KT  60 MPH
 36H  16/0000Z 18.1N  66.4W   50 KT  60 MPH...OVER PUERTO RICO
 48H  16/1200Z 18.6N  68.6W   50 KT  60 MPH...OVER DOMINICAN REP.
 60H  17/0000Z 19.4N  70.7W   45 KT  50 MPH...OVER DOMINICAN REP.
 72H  17/1200Z 20.5N  72.8W   45 KT  50 MPH...OVER WATER
 96H  18/1200Z 22.8N  77.3W   45 KT  50 MPH
120H  19/1200Z 25.4N  81.2W   45 KT  50 MPH

$$
Forecaster Berg

[WxWatcher007]

Recon is en route to Grace.

[cptcatz]

28 minutes ago, SnowenOutThere said:

When will recon get into Grace? Do we have an hour also for future reference where can I find when recon is scheduled?

You can follow it here. They left from Aruba, probably have a couple hours until they get to the storm.

https://www.tropicaltidbits.com/recon/

[ldub23]

JB says grace will be crushed  by Fred.

[NorthHillsWx]

I think it’s a prerequisite these days that every single storm in the Atlantic at some point has it’s center modeled to be over Tampa bay, but it never actually happens 

[NorthHillsWx]

Convectively at the moment, Grace looks well on its way to becoming a hurricane. Fast motion is the only roadblock at the moment. Might have a window in next 36 hours. 

[WxWatcher007]

GFS basically threads the needle again and brings a strong system into the Gulf. 

[MJO812]

2 minutes ago, WxWatcher007 said:

GFS basically threads the needle again and brings a strong system into the Gulf. 

 

[WxWatcher007]

Seems a little far west to me, but I guess we’ll see. Without a trough or weakness induced in the ridge it’d just keep chugging WNW.

[Chinook]

Current radar shows that TS Grace is composed of a series of thunderstorms, that are not spiraling around a center of circulation. Currently thunderstorms are over Dominica and Martinique, with a bigger blob to the east of Dominica.

link for radar loops

https://www.barbadosweather.org/BMS_Radar_Composite_Resp.php#

[MJO812]

16 minutes ago, WxWatcher007 said:

Seems a little far west to me, but I guess we’ll see. Without a trough or weakness induced in the ridge it’d just keep chugging WNW.

Cmc coming in hot also

[WxWatcher007]

4 minutes ago, MJO812 said:

Cmc coming in hot also

You can see how initializing stronger before the Greater Antilles impacts downstream. What a ridge too. Still a longer range set of solutions so the usual model caveats apply.

[LoboLeader1]

On 8/13/2021 at 12:20 PM, thunderbolt said:

My humble opinion is once the eastern Pacific calms down then the Atlantic will ramp up but until then Crickets

Too much rising air out in the Pacific right now.

[MJO812]

Cmc

[cptcatz]

Recon is in. Will be very interesting to see what they find. 

[Windspeed]

Radar has some suspicious banding that may be trying to consolidate a core. That feature is only barely coming unto view. This may still only be a mid level displaced circulation from the low level center however. So yes, reiterating recon's importance. But there is no doubt Grace looks improved over yesterday.

See red X..

[Windspeed]

[Windspeed]

I think recon missed the center. Actually they flew on a heading through where hypothetically the broader center should have been located. Perhaps there is a low level vorticity maximum further west.

[hawkeye_wx]

The 12z HWRF and HMON both take Grace across the heart of Hispaniola, where it meets the same fate as Fred.

[NorthHillsWx]

4 minutes ago, hawkeye_wx said:

The 12z HWRF and HMON both take Grace across the heart of Hispaniola, where it meets the same fate as Fred.

Always a possibility at these low latitudes

[cptcatz]

Looks like the LLC might be right under the intense convection. I have a feeling we're gonna see some surprisingly big wind numbers when they find the center.