Major Hurricane Isaias

[OHweather]

3 hours ago, NorthHillsWx said:

Pretty solid gusts recorded with this one. 118, 116, 114, 110 were the highest I’ve seen and most of those were from the western edge of the degrading eyewall! Pensacola through Milton to Jay seem to have had a sting jet because they were not in the actual eyewall or at best on the edge and that area all saw gusts over 110. I see the usual discord of land obs not matching operational intensity (not worth arguing with those people after every storm) but this system produced widespread gusts over 100 and several recorded gusts over major hurricane strength. Also, that sustained wind of 92 being recorded is impressive. Overall, Kind of in line with exactly what was forecast…. As for LF pressure as @GaWx shows this thing was rapidly filling in as the actual center crossed the coast. As all of the eyewall was already ashore I don’t think it matters as much here but when the actual center crossed the coast as it was well behind the main convection i doubt Winds over 100 were occurring.

We’ll see what surge looks like but the worst is going to be between Destin and Panama City. Panama City measuring 5.6 feet makes me worried there are going to be some 7-9’ areas to the west. Daylight will reveal that.

Overall this storm was exceptionally well-forecast by NHC and with a challenging forecast, pretty early on they were advertising a dangerous hurricane at landfall. If anyone doesn’t think seeing wind gusts over 100 with some major gusts over 110 also actually recorded qualifies as a “dangerous” hurricane, not much else to say here. 

For all the talk of wind measurements with landfalls, I agree the measurements we got from Isaias were impressive and suggest it probably was in fact a low-end cat 2 around the time of landfall. Given how quickly it was weakening at that point it wouldn’t surprise me if it did weaken slightly more than the operationally estimated 90kt at landfall, but the eyewall was impacting the coast when it was at that intensity. 
 

I agree with some points raised here - the maximum sustained winds are not something people should expect to see at their location on land, and properly communicating that (while still maintaining the proper level of urgency) is important. Even if you’re not seeing the max sustained winds on land, hazards such as wind damage and surge are very much proportional to those max sustained winds. You won’t see cat 5 sustained winds away from the coast in a cat 5 eyewall, but it would still be destructive and no one would be quibbling over it. Would also like to mention that when storms are sampled by recon, there is a wide array of instrumentation measuring winds at/near the surface and aloft, with well-researched and established reduction factors to equate low-level winds to the surface winds in these storms. The NHC is not just making up the max sustained winds. I do agree with the sentiment that NHC can be slow to operationally reduce the winds in storms that are weakening as landfall approaches, but understand why they’re cautious with that. 

[NEGA_Dawg]

Looks like the NW side has become the wettest side.

[NavarreDon]

Regardless of strength (I’ve seen Andrew & Michael up close). Unless you have boots on the ground you don’t realize the amount of damage even a storm of this strength can cause. My thoughts are with the many people who are dealing with issues big or small. I can tell you the Emerald Coast got smacked by this. Glass half full thoughts, are the shear and dry air saved us from what could’ve been a monster!


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[jm1220]

15 minutes ago, NavarreDon said:

Regardless of strength (I’ve seen Andrew & Michael up close). Unless you have boots on the ground you don’t realize the amount of damage even a storm of this strength can cause. My thoughts are with the many people who are dealing with issues big or small. I can tell you the Emerald Coast got smacked by this. Glass half full thoughts, are the shear and dry air saved us from what could’ve been a monster!


.

Yep I’m glad the N Gulf finally caught something of a break with this one. Laura, Michael, Ida etc were horrific and broke the pattern of rapidly weakening N Gulf storms as they come in. Of course 2 are dead and hundreds of thousands are suffering with power out and other damage so hopefully things are running again soon. 

[GaWx]

51 minutes ago, NavarreDon said:

Regardless of strength (I’ve seen Andrew & Michael up close). Unless you have boots on the ground you don’t realize the amount of damage even a storm of this strength can cause. My thoughts are with the many people who are dealing with issues big or small. I can tell you the Emerald Coast got smacked by this. Glass half full thoughts, are the shear and dry air saved us from what could’ve been a monster!


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I’m glad the expected last minute weakening verified well saving from a MH landfall, but realize getting cat 1-2 H effects is of course still a big impactful event (I know first hand).
 

 Interestingly per Dr. Knabb, that same strong shear that caused the dramatic weakening just before landfall actually caused the worst of the thunderstorms/wind gusts (solid cat 2 gusts) to be in your area in the NW eyewall (where Stephanie Abrams great coverage was). It’s almost as if the NW eyewall weakening lagged behind. She said she had never seen so much lightning in an eyewall, which typically has limited lightning due to the upper atmosphere being too warm for as much ice in the clouds vs typically much more lightning in outer bands as Dr. Knabb explained.

 I thought TWC coverage was excellent between her, Cantore showing storm surge and sudden shift to warming S winds off Gulf in E eyewall, and Dr. Knabb.

[VivaManchVegas]

5 hours ago, Windspeed said:

It seems like we always have to beat it into people's skulls during landfalls. It's the maximum sustained winds possible as an estimate over water for a reason. It's a marine storm before it is a land storm, and advisories have to account for what is occurring in real time over the ocean surface for any poor ships/souls that might find themselves in the worst scenario. But due to frictional convergence / drag, you will almost never see those sustained winds over land unless you have a super intense eyewall with embedded multiple mesos rotating around that overcome frictional forces with insane ground level velocities. As a general rule, the highest wind reports over land are always in gusts due to this process. You might get those highest sustained winds right on the immediate beach/shoreline perpendicular to the onshore motion of the inner edge of the eyewall, but the equipment would need to be in the right place at the right time and that is exceedingly difficult placement and timing to pull off. Interestingly, and as no surprise, the instrument anemometers that have been positioned in the right place and at the right time during past landfalls that recorded sustained winds near maximum have generally failed during that event.

I also need to add that the reason most immediate advisory packages don't rapidly ramp down maximum sustained winds after landfall is twofold: 1) part of the eyewall or outer eyewall may still be over water, 2) any large estuaries even after landfall may still experience maximum winds. Once the entire circulation is inland, subsequent advisory packages tend to ramp down quickly.

I get it.  Its a fine line to walk for the State. Not sure they really want to say "We think this is going to rapidly decay as it hits the mainland".  Were there any mandatory evacuations?  I think the "disgust" with this storm is more form those wanting chaos than those wanting the best outcome possible imho. 

Edit: should have used the google machine before posting.  There were mandatory evacs. 

 

[kgottwald]

Me, I badly wanted the shear from the Pacific storm to tear it apart and keep it from getting to TD status. I wanted a whole year without a hurricane, especially without one that hit land.

[GaWx]

13 hours ago, 40/70 Benchmark said:

Strong forecast.

https://forecastmaven.com/forecasts/easternmassweather/hurricane-isaias-landfall-accurately-forecast/

 

 

Hurricane Isaias Landfall Accurately Forecast

Timing Slightly too Slow

The center of the rapidly degrading eye of Hurricane Isaias crossed the coast near Destin, FL with 105MPH maximum sustained winds at about 930PM EDT. 

 

 

This was precisely as forecast in the Final Call issued this afternoon in terms of landfall locale and intensity, but the timing was about 1.5 hours faster than 11PM EDT forecast. Although the landfall intensity needed to be adjusted upwards slightly in the Final Call issued earlier today, the Destin, FL locale was consistent since First Call on Wednesday.

 

 

 

Final Grade: A

 

Fantastic forecast, Ray, that was spot on other than being slightly too slow!

[NorthHillsWx]

Damage in the Pensacola area looks much more significant than areas further east. Definitely structural damage in line with high-end category 2 winds. 

[Chinook]

strange 850mb chart for the transition/landfall last night

[qg_omega]

17 minutes ago, NorthHillsWx said:

Damage in the Pensacola area looks much more significant than areas further east. Definitely structural damage in line with high-end category 2 winds. 

Highest winds were well NW of the center due to the strong SE shear

[NorthHillsWx]

2 likely tornadoes otg NW of Savannah per radar. TOR threat ramping up with discrete supercells now developing 

[GaWx]

14 minutes ago, NorthHillsWx said:

2 likely tornadoes otg NW of Savannah per radar. TOR threat ramping up with discrete supercells now developing 

 
 The dewpoints here are way up in the high 70s, something very rare this late into fall. That with the 86 temp gives a heat index way up at 99-100 on Oct 10th! It feels awful! The shift from E to SE winds allowed this:

CITY SKY/WX TMP DP RH WIND PRES REMARKS 
SAVANNAH ARPT PTSUNNY 87 77 72 S17G28 29.95F HX 99

HUNTER AFB MOSUNNY 86 79 79 SE17 29.92F HX 99TC 30

 Wind gusts have picked back up with the increasing sunshine and winds at 5K feet being 30 knots (cumulus clouds are hauling) from the S along with strong SW winds at H5+ are setting up a potential for severe thunderstorms in this general area later this afternoon/eve.

[NorthHillsWx]

8 minutes ago, GaWx said:

 
 The dewpoints here are way up in the high 70s, something very rare this late into fall. That with the 86 temp gives a heat index way up at 99-100 on Oct 10th! It feels awful! The shift from E to SE winds allowed this:

CITY SKY/WX TMP DP RH WIND PRES REMARKS 
SAVANNAH ARPT PTSUNNY 87 77 72 S17G28 29.95F HX 99

HUNTER AFB MOSUNNY 86 79 79 SE17 29.92F HX 99TC 30

 Wind gusts have picked back up with the increasing sunshine and winds at 5K feet being 30 knots (cumulus clouds are hauling) from the S along with strong SW winds at H5+ are setting up a potential for severe thunderstorms in this general area later this afternoon/eve.

Confirmed tornado otg now over Captolo

[olafminesaw]

2 hours ago, NorthHillsWx said:

Damage in the Pensacola area looks much more significant than areas further east. Definitely structural damage in line with high-end category 2 winds.