ERIN (40 KTS)

[BarryStantonGBP]

@jconsor lad posted this

https://hurricanehacker.substack.com/p/tropical-storm-erin-forms-in-eastern

[Kevin Reilly]

6 minutes ago, BarryStantonGBP said:

@jconsor lad posted this

https://hurricanehacker.substack.com/p/tropical-storm-erin-forms-in-eastern

Models should be interesting today.  Out ahead of Erin you can clearly see the push from NE to SW coming off the Sarhan Dust Fields of Africa.  This flow is trying to reassert itself as Erin moves generlly west.  I would think that this fairly robust NE to SW motion of drier air will do two things keep Erin in check possibly even a period of weakening and force Erin more south or even southwest for  a time as she heads generally westbound.  I think this is what to watch now and until nearing the Leeward Islands over the next two days. The models may need to adjust to this possibility over time. 

[40/70 Benchmark]

57 minutes ago, Kevin Reilly said:

Models should be interesting today.  Out ahead of Erin you can clearly see the push from NE to SW coming off the Sarhan Dust Fields of Africa.  This flow is trying to reassert itself as Erin moves generlly west.  I would think that this fairly robust NE to SW motion of drier air will do two things keep Erin in check possibly even a period of weakening and force Erin more south or even southwest for  a time as she heads generally westbound.  I think this is what to watch now and until nearing the Leeward Islands over the next two days. The models may need to adjust to this possibility over time. 

Paradoxically, a weakening trend in the near term is probably the most omninous sign possible for the US, as it would cause the system to remain lower in latitude while being steered by the lower level flow. Obviously this increases the risk of the system missing the westerlies should it reorganize down the road.

[BarryStantonGBP]

I literally implied Irma in my last post because of the SW dip. What the bloody hell happened lad 

[BarryStantonGBP]

[GaWx]

9 hours ago, GaWx said:

 The good news in the short-term for the US is that Erin climbed slightly from 17.4N to 17.6N since the previous advisory or at 275 degrees vs a prog to stay at 17.4N/270 degrees. Maybe this is a sign that the latitude will be mainly maintained instead of losing much. We’ll see.

 Edit: But the NHC is still progging the low point of 17.1N on Wednesday morning. That will be one key benchmark to compare the actual track to.

- Followup to above: Per the 5AM advisory, Erin dropped back down slightly to 17.4N with a 265 degree heading. The new track has a low point of 17.0N tomorrow instead of 17.1N. The 17.0N will be a key latitudinal benchmark to compare to tomorrow.

- The 6Z Icon at 120 is slightly W of that ominous looking for Conus 0Z run at 126.

-The 6Z GFS is similar to the 0Z GFS and again goes just NW of Bermuda with a hard hit there.

-The 6Z Euro 144 is barely SE of the 0Z Euro 150.

[MANDA]

17 minutes ago, GaWx said:

- Followup to above: Per the 5AM advisory, Erin dropped back down slightly to 17.4N with a 265 degree heading. The new track has a low point of 17.0N tomorrow instead of 17.1N. The 17.0N will be a key latitudinal benchmark to compare to tomorrow.

- The 6Z Icon at 120 is slightly W of that ominous looking for Conus 0Z run at 126.

-The 6Z GFS is similar to the 0Z GFS and again goes just NW of Bermuda with a hard hit there.

-The 6Z Euro 144 is barely SE of the 0Z Euro 150.

Appreciate your model summaries for those of us on the run.  Nice to get a quick summary when I am in the road with minimal time to check the latest guidance.  Thanks!

[WxWatcher007]

55 minutes ago, 40/70 Benchmark said:

Paradoxically, a weakening trend in the near term is probably the most omninous sign possible for the US, as it would cause the system to remain lower in latitude while being steered by the lower level flow. Obviously this increases the risk of the system missing the westerlies should it reorganize down the road.

And once the system becomes convectively active again (as it did last night in the southern part of the system) we’ll have to see if that tugs the LLC in one direction or another temporarily.

[WxWatcher007]

You don't need to look far to see why Erin is struggling convectively this morning. 

First, it's still in a marginally favorable SST environment

Second and more important, it is plowing into an area of drier, more stable atmospheric conditions--something that was anticipated days ago. 

 

The microwave image I posted last night was illustrative of its organization, which still exists this morning. 

 

Note the well defined center and its symmetrical nature. Note also the more stable conditions to its northwest. This should keep Erin in check for a bit, but given the internal organization, if that doesn't fade once this finds a more favorable environment it should still be primed to ramp up. 

 

As for track, I still think it's highly unlikely to directly impact the US coast, but Atlantic Canada should be monitoring more closely.