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WxWatcher007

Hurricane Sally

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6Z and 12Z SHIPS is still modest on RI probabilities, but it does strengthen Sally to a cat 1 hurricane by landfall.

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Next 12 hours we will know if RI is going to happen or not.  If it does not get structurally organized by then I don't see it being any more than cat 1 at best once over shelf waters.  That said the convection NW of the CoC is a good first step in this.

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Most Guidance has a CAT1 at landfall.  Best guess is probably 980-990mb Cat1.   It will organize some but proximity to land and windshear should keep it from blowing up.

rGnrEGs.png

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People should not under estimate the flooding threat here even if it doesn't only end up as a cat 1.  This much rain especially somewhere like New Orleans could be catastrophic. Look at Houston with Harvey and that is all above sea level with huge drainage canal projects in place designed to drain the city quickly.  Granted Sally won't dump quite as much as Harvey, but 20-25+ inches is still a crazy amount of rain.

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Just looking at upper level cloud motion, it appears high cirrus are beginning to bend anticyclonically W to NW of the LLC as well. Shear is likely abating enough now that this new convective trend will continue from here on out. A core should be able to develop over night with relative ease with such a vigorous LLC in place and the decreasing NW mid-to-upper flow getting out of the way.

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9 minutes ago, bugalou said:

People should not under estimate the flooding threat here even if it doesn't only end up as a cat 1.  This much rain especially somewhere like New Orleans could be catastrophic. Look at Houston with Harvey and that is all above sea level with huge drainage canal projects in place designed to drain the city quickly.  Granted Sally won't dump quite as much as Harvey, but 20-25+ inches is still a crazy amount of rain.

Given the approach angle we also should not even dismiss surge. The angle it is approaching at could be very problematic for NO even asa cat 1 or cat 2.

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8 minutes ago, Amped said:

Euro has 15-20" of rain grazing the coast.

SDFnRmg.png

All kinds of trouble on that map. We debate over intensity, but that's not going to change the fact that flooding/surge look to be the biggest hazards. That's a long swath of big rains into the SE. 

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8 minutes ago, KPITSnow said:

Given the approach angle we also should not even dismiss surge. The angle it is approaching at could be very problematic for NO even asa cat 1 or cat 2.

Agreed fully. This is a situation that surge will be more indicative of a category or two higher than what sally achieves due to slow speed, nature of the coastline and angle of approach 

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Latest WPC QPF for days 1-3 has the NOLA area at 10-20 inches of rain. That will be the story of this storm if the forecast holds.

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Looking at the mid-level shear, upper level shear, as well as shear tendency charts...Sally should now be in a light-shear environment. 

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Outflow has improved, but still some E/SE tilt to the vortex with height. Would either like to see a dominant curved band (to wrap around the center) or a convective burst over/near the center in the next several hours. It has neither at the moment.

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1 hour ago, ldub23 said:

I  personally  think with it  so disorganized rainfall totals  can be  cut  in half. Also see the Euro has a  massive ridge with Sally likely getting  left behind  off the  SE  coast. Good  possibility  it  gets a 2nd  chance. With that ridge it wouldnt  take  much for  TD20 to start  heading west.

slp8.png

That bold part is one of the most dumba** statements I think I have ever seen on here. 

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6 minutes ago, csnavywx said:

Outflow has improved, but still some E/SE tilt to the vortex with height. Would either like to see a dominant curved band (to wrap around the center) or a convective burst over/near the center in the next several hours. It has neither at the moment.

It’s curious bc a few hrs ago it seemed to be doing just that. At the same time the LLC is becoming increasingly obscured on satellite —so I’m wondering if this is one of those times the LLC redevelops under the MLC, where the deepest convection is collocated...I’m noticing increasing symmetry ~100 miles to the southeast .... thinking it’s a possibility everything is beginning to consolidate around that point...

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I think part of the issue is that the wind field is rather broad and flat, with no well defined max near the center or anywhere else for that matter (and fairly weak at <35kt flight level for most of it), so it's not helping focus latent heat flux near where it could do the most good. The lack of a dominant band makes sense with that last recon pass. Going to have to wait for a more substantial/concentrated burst to get anything going. Otherwise, strengthening will continue to be an inefficient process.

That might happen tonight as we approach Dmax, the shear lessens and the wind field gradually gets broadly above TS force (enough to trigger better LH flux).

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33 minutes ago, jbenedet said:

It’s curious bc a few hrs ago it seemed to be doing just that. At the same time the LLC is becoming increasingly obscured on satellite —so I’m wondering if this is one of those times the LLC redevelops under the MLC, where the deepest convection is collocated...I’m noticing increasing symmetry ~100 miles to the southeast .... thinking it’s a possibility everything is beginning to consolidate around that point...

We'll get another pass here soon and may get an answer to that question.

 

Ehhh, on second look, it looks like they might be done.

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1 hour ago, ldub23 said:

I  personally  think with it  so disorganized rainfall totals  can be  cut  in half.

Here in Gulfport, FL, it has been raining steady since about 6:00 am. Nice breeze, with gusts between 20 and 30, but light rain and right now my yard only has about 2/3 of an inch of rain recorded since this morning.

Great for the yard and landscaping, little disappointing as far as spending a Sunday at home being in a Tropical Storm. But no complaints, only issue was our Basil plant in a plastic pot tipping over. It was easy to set back up right.

It felt more like an early Spring rainy day in West Virginia than a Tropical Storm in Florida in September.

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1 minute ago, the ghost of leroy said:

Remember when hurricane hunters used to complete their missions and transmit data without issues? Good times. 

It’s been so weird to see. It’s like every mission is having data issues. It makes no sense. 

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