ATL: ISAIAS - Models

[otowntiger]

12z HWRF simulated IR looks to bring some nasty weather to the SEFL Coast on up towards the Space Coast

https://www.tropicaltidbits.com/analysi ... 80112&fh=9

Look what the HWRF does on the simulated IR between hours 6 and 12. Does anyone believe that?

I do not. It is just about impossible for it do that in its current position and especially its current state.

[Slughitter3]

Good afternoon all, newbie here, how accurate is the RAP analysis/model for tropical events? The current RAP has the storm making landfall in Broward County, just looking for a better understanding. Thanks in advance!

[Steve]

Good afternoon all, newbie here, how accurate is the RAP analysis/model for tropical events? The current RAP has the storm making landfall in Broward County, just looking for a better understanding. Thanks in advance!

The Rapid products have been doing great all early season. Again, it's to be expected considering they are the closest thing we have to real time, and also because they don't run that far out. For anyone doubting Isaias at the moment and over the next 2-3 hours, you might want to think again after that. As it was indicating earlier today, the first burst of the 18 hour period from that run shows up about 6pm Eastern. Again, as everyone has been saying on the Discussion thread, it's only July. And conditions aren't that ripe. So it's probably going to weaken and then strengthen again before morning. Here's the progression through the next 4 hours:

All EDT
5pm


7pm


8pm

[Slughitter3]

Good afternoon all, newbie here, how accurate is the RAP analysis/model for tropical events? The current RAP has the storm making landfall in Broward County, just looking for a better understanding. Thanks in advance!

The Rapid products have been doing great all early season. Again, it's to be expected considering they are the closest thing we have to real time, and also because they don't run that far out. For anyone doubting Isaias at the moment and over the next 2-3 hours, you might want to think again after that. As it was indicating earlier today, the first burst of the 18 hour period from that run shows up about 6pm Eastern. Again, as everyone has been saying on the Discussion thread, it's only July. And conditions aren't that ripe. So it's probably going to weaken and then strengthen again before morning. Here's the progression through the next 4 hours:

All EDT
5pm
https://i.imgur.com/MHwHfH6.png

7pm
https://i.imgur.com/IbPUP2I.png

8pm
https://i.imgur.com/bPmG5eE.png

Steve, thank you for the information, that's great to hear! Something to watch for sure.

[Steve]

Yeah, no problem. I love watching HRRR satellite depictions and seeing how they work out. Looks like it backs off from about 9-12am y'all's time. Then the second burst commences around midnight.

Here we are at Midnight as the convection is starting to re-fire


2am


4am - backing off a little


Certainly looks like there should be some weather to experience tonight if HRRR is right.

[Steve]

Here is 8am Sunday, so you can see a 3rd burst which though mostly offshore, should bring some weather from the barrier islands to the coast to slightly inland.

[Slughitter3]

Here is 8am Sunday, so you can see a 3rd burst which though mostly offshore, should bring some weather from the barrier islands to the coast to slightly inland.

https://i.imgur.com/qoqAHHM.png

It's amazing to see how many "pulses" it's expected to go through.

[Steve]

NAM 3km 18z explodes convection onshore in Florida. This is a bit different from the HRRR. However, they do share basically the same bursting/increasing of convection periods. If this is right, don't think there won't be power outages tonight and tomorrow. For whatever reason, NAM explodes the heaviest convection toward the west side of the system. But because it does dumb things sometimes, it doesn't show much of any rainfall.

Model run
https://www.tropicaltidbits.com/analysi ... 0118&fh=18

Rainfall - day and a half
https://www.tropicaltidbits.com/analysi ... 0118&fh=33

[SFLcane]

 https://twitter.com/pppapin/status/1289658146223345665

[Steve]

Here is 8am Sunday, so you can see a 3rd burst which though mostly offshore, should bring some weather from the barrier islands to the coast to slightly inland.

https://i.imgur.com/qoqAHHM.png

It's amazing to see how many "pulses" it's expected to go through.

Yeah. I think it's a combination of trying to get organized while fighting shear. With majors, you generally only see diurnal periods and eyewall replacement cycles warming the high cloudtops. But when a storm is trying to strengthen, they will tend to kick it up as they can and hopefully get that proverbial snowball rolling downhill. I don't think it happens with Isaias as it's not expected to strengthen coming up in the SW Atlantic. So it's probably going to continue to pulse up and down along the way. I wouldn't be surprised if it's fairly symmetrical though.

[toad strangler]

NAM 3km 18z explodes convection onshore in Florida. This is a bit different from the HRRR. However, they do share basically the same bursting/increasing of convection periods. If this is right, don't think there won't be power outages tonight and tomorrow.

Dr Rick mentioned that there will be power outages not too long ago regardless of the current state of the former cyclone. Also included here is a brand new tweet from the Dr.

 https://twitter.com/DrRickKnabb/status/1289639147687358464



 https://twitter.com/DrRickKnabb/status/1289660108658614272

[TheStormExpert]

In my opinion models did poorly overall with Isaias. Yes some models did predict a weaker more western solution even a few days ago like the NAVGEM, which very rarely gets credit. We even saw the models way under-forecast Hanna’s landfall last week. Hopefully this is a fluke and the models will do better especially if a far more serious threat approaches.

[Jr0d]

The NHC has to downgrade but I think they will leave the hurricane warnings up because of the potential of Isaiac to restrengthen quickly over night. The HWRF, NAM, and even the Euro suggests the storm will deepen as it appoaches the Florida coastline.

Right now Isaias is no where close to hurricane strength, but the potential to become a hurricane again is still there and hurricane warning are still necessary.

[dkommers]

The 18z NAM appears SW of the 12z and seems to slow it down. It also takes a westward jog for about 6 hours around Bimini and landfalls south PBC.

[Steve]

18z ICON stays offshore along with the majority of the rain. It goes on to hit Eastern NC
https://www.tropicaltidbits.com/analysi ... 0118&fh=33

[Steve]

20Z HRRR
7pm (hour and a half away)


8pm peak


4am next peak

[Evil Jeremy]

Wow. I just went back to the farthest possible HRRR run on Tropical Tidbits, which is from 7 hours ago. I would say it did an excellent job foreseeing the current convective burst:

https://www.tropicaltidbits.com/analysi ... 80114&fh=0

[Steve]

GFS looks to briefly cross the shore. We'll see what it does after
https://www.tropicaltidbits.com/analysi ... 0118&fh=12

[toad strangler]

GFS looks to briefly cross the shore. We'll see what it does after
https://www.tropicaltidbits.com/analysi ... 0118&fh=12

If ANY convection can wrap around the COC and that 18z GFS track verifies, I'll have a turbulent Sunday

[Blown Away]

GFS looks to briefly cross the shore. We'll see what it does after
https://www.tropicaltidbits.com/analysi ... 0118&fh=12

Yeah, 18z GFS slightly W through 30 hours with landfall near Pt St Lucie and I noticed it’s showing a much moister environment around Isaias through 30 hours...