Idalia to heavily affect large portion of SE

[GaWx]

 Idalia is forecasted to heavily affect a large portion of the SE. In some areas even away from the FL Big Bend that are near the track, it will very likely end up as the most impactful wx event in many years.

 Moderators, please pin this. Thanks

[NJsnow89]

What impacts are we looking in central

NC? 

[GaWx]

 The more reliable models are pretty tightly centered on Taylor County, FL, landfall centered on ~9AM EDT. Then tracks go mainly just inland from Savannah, which is about the worst possible track regarding winds. Also, high tide there, which is an astronomical high tide due to perigee and full moon, is at 8:30PM, which is near the time of the center being closest.

[Shack]

Just now got upgraded to Tropical Storm Warning here in Macon(Bibb County)

Thinking my friends to the south around Valdosta are going to get an (unfondly) memorable event. 

[Ser Pounce]

High tide over here (Charleston) is around 8:30 and they're talking about 3-5' of storm surge. That's on top of the tropical storm warning / hurricane watch, so it looks like the usual flooding is going to happen around the lower parts of downtown. Unless the track really shifts overhead and we pick up a lot more rain it looks like the biggest problem in the metro will be power outages.

 

In the immediate area Dominion trimmed everything a good 6' or more back from power lines (looks like a hungry dinosaur came through). People complained about it to no end but they'll be glad it happened later tonight.

[eyewall]

I think for Raleigh we may be too far NW to see much out of this. I am just hoping one solid outerband makes it up for drone shots.

[PackGrad05]

16 minutes ago, eyewall said:

I think for Raleigh we may be too far NW to see much out of this. I am just hoping one solid outer band makes it up for drone shots.

High res NAM and HRRR are still showing a steady rain from this afternoon all the way to mid-morning.  I definitely think the big story will be ponding/localized flooding.  Morning commute could be messy.  Scattered power outages as always.
Big gradient possible across Wake (as always). 

[GaWx]

 Compared to the 5AM NHC forecast, it has weakened quite a bit more quickly than forecasted then. The 5AM had Idalia still with winds of 100 mph as of 2PM. But as of 1PM, winds were already down to 80.

 The 11AM had adjusted for this quicker weakening because it was already down to 90 then. This updated forecast had it weakening from 90 at 11AM to 75 at 8PM. But with it already down to 80 at 1PM, it appears that it is weakening even more quickly than the 11AM NHC forecast.

[gtg947h]

2 hours ago, GaWx said:

 Compared to the 5AM NHC forecast, it has weakened quite a bit more quickly than forecasted then. The 5AM had Idalia still with winds of 100 mph as of 2PM. But as of 1PM, winds were already down to 80.

 The 11AM had adjusted for this quicker weakening because it was already down to 90 then. This updated forecast had it weakening from 90 at 11AM to 75 at 8PM. But with it already down to 80 at 1PM, it appears that it is weakening even more quickly than the 11AM NHC forecast.

Let's hope that trend continues....

[Shack]

Thankfully, the terribleness for my area has subsided. 

Our NWS-Tropical Storm-Warned, county endured nearly an INCH, (1)  of precipitation, along with a howling sustained wind of hmmmm, (checks again).......11mph with catastrophic gusts to........wait for it,.........23mph.

[Stormpc]

I will get my frontal boundary enhanced two to four inches of rain with 55 mph gusty winds as forecasted and will appreciate the rain. Dry as hell here. Little concerned with the frontal boundary hanging over the area with the incoming storm. Someone in eastern North Carolina may get 8-10 inches of rain. Probably around the Albemarle and south. Either way I need the rain.

[GaWx]

I lost power an hour ago. My highest gusts have been ~45 mph. So, not bad vs what we were facing IF that were to end up being the worst. I was worried about gusts in the 60s, which would bring a lot more trees down.

[GaWx]

PRELIMINARY LOCAL STORM REPORT   NATIONAL WEATHER SERVICE CHARLESTON SC   253 PM EDT WED AUG 30 2023

      .TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON       .DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE.     ..REMARKS..     1222 PM TORNADO 1 NW GOOSE CREEK 32.99N 80.04W   08/30/2023 BERKELEY SC EMERGENCY MNGR     EMERGENCY MANAGEMENT REPORTED THAT A CAR WAS FLIPPED   OVER AT THE INTERSECTION OF CAMELOT DRIVE AND SOUTH   GOOSE GREEK BLVD. VIDEO WAS USED TO CONFIRM THAT THE CAR   WAS HIT BY A BRIEF, WEAK TORNADO. NO OTHER DAMAGE   REPORTED.  

[buckeyefan1]

1 hour ago, GaWx said:

PRELIMINARY LOCAL STORM REPORT   NATIONAL WEATHER SERVICE CHARLESTON SC   253 PM EDT WED AUG 30 2023

      .TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON       .DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE.     ..REMARKS..     1222 PM TORNADO 1 NW GOOSE CREEK 32.99N 80.04W   08/30/2023 BERKELEY SC EMERGENCY MNGR     EMERGENCY MANAGEMENT REPORTED THAT A CAR WAS FLIPPED   OVER AT THE INTERSECTION OF CAMELOT DRIVE AND SOUTH   GOOSE GREEK BLVD. VIDEO WAS USED TO CONFIRM THAT THE CAR   WAS HIT BY A BRIEF, WEAK TORNADO. NO OTHER DAMAGE   REPORTED.  

That video was pretty good 

[Stormsfury]

1 hour ago, GaWx said:

PRELIMINARY LOCAL STORM REPORT   NATIONAL WEATHER SERVICE CHARLESTON SC   253 PM EDT WED AUG 30 2023

      .TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON       .DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE.     ..REMARKS..     1222 PM TORNADO 1 NW GOOSE CREEK 32.99N 80.04W   08/30/2023 BERKELEY SC EMERGENCY MNGR     EMERGENCY MANAGEMENT REPORTED THAT A CAR WAS FLIPPED   OVER AT THE INTERSECTION OF CAMELOT DRIVE AND SOUTH   GOOSE GREEK BLVD. VIDEO WAS USED TO CONFIRM THAT THE CAR   WAS HIT BY A BRIEF, WEAK TORNADO. NO OTHER DAMAGE   REPORTED.  

That spin up hit a mile away from where I live.  

[GaWx]

17 hours ago, buckeyefan1 said:

That video was pretty good 

That was wild, the car lifting up! Those little tornadoes are sneaky and can pack a heck of a punch even though this was most likely "weak" on the scale. Fortunately no serious injuries despite the car damage.

[GaWx]

I was comparing Idalia with 2016's Hermine, which peaked at 80 mph/981 mb 5 hours before FL landfall near where Idalia hit. It went steady state through landfall rather than either further strengthening or weakening. From landfall, it took a near identical NE path to a little W of Savannah. Per the archives at closest approach Hermine was at 31.9N, 82.0W..55 mi WSW of Sav and 989 mb/50 mph. (It was moving NE at 18 mph.)

 To compare, Idalia was at 32.2N, 81.7W or 40 mi W of Sav with 984 mb/70 mph. (It was moving a similar NE at 21 mph.)

 So, they were at a similar distance away at their closest but Idalia was noted to have 20 mph higher winds (70 vs 50).

 What's really strange is that Hermine produced 6 mph stronger winds than Idalia!

 From Hermine wiki:

"Hermine weakened while crossing from Florida into Georgia, but still produced sustained winds of 45 mph at Savannah, with gusts to 58 mph."

https://en.m.wikipedia.org/wiki/Hurricane_Hermine#:~:text=Hermine weakened while crossing from,(93 km%2Fh).

 Idalia's highest sustained/gust at Savannah were 6 mph lower with 39 sustained/gusts to 52. I remember clearly that Hermine was significantly stronger. And keep in mind that Idalia landfalled at 125 mph vs Hermine's only 80.

 I'm thankful but also amazed at the comparison.

 Any thoughts from anyone about this comparison?

[Ser Pounce]

Sorry to disappoint but from the perspective of basically next to Charles Towne Landing Park in Charleston (across Ashley River from downtown), not a lot happened at all. I did get to go show my 7 year old what high tide was, what storm surge is, and what it looks like when you combine the two which he thought was cool.

 

That, plus a few downed sticks and lots of frogs out this evening were really about it. Schools are on e-learning tomorrow so I'll be using PTO to supervise that too.

[gtg947h]

6 hours ago, GaWx said:

 I'm thankful but also amazed at the comparison.

 Any thoughts from anyone about this comparison?

I'm trying to remember Hermine...  I think we got tornado warnings for that  one too, but overnight.  I can't recall how strong it seemed but I do vaguely remember it just being longer with more rain and wind.

The buildup to Idalia definitely seemed more dire--after all we expected a full Cat 1 to pass right over my house (the track kept jumping to either side of us).  At least out here it was almost a non-event--just a couple trash cans and basketball goals tipped over and some small twigs and pine needles on the ground.  Our power never even flickered. 

But yeah, very interesting observations!

[eyewall]

Raleigh only got around a half inch of rain and gusts in the 30's. It is kind of funny that Wake cancelled schools today.

[ObiWanKarlNobi]

Don't forget Durham and Chatham county schools as well.

[GaWx]

From NWS CHS:

"A MAXIMUM TIDE LEVEL OF 3.47 FT MHHW (9.23 FT MLLW) WAS OBSERVED AT THE CHARLESTON HARBOR TIDE GAGE."

 From the first image linked below, there was a maximum surge of 2.38' at CHS at 8:12 PM on August 30th that coincided exactly with high tide to produce the 9.23 ft tide (in red)/CHS battery flooding:

https://tidesandcurrents.noaa.gov/waterlevels.html?id=8665530&units=standard&bdate=20230829&edate=20230831&timezone=GMT&datum=MLLW&interval=6&action=

 This was made worse by the center being ~50 miles closer to CHS at high tide vs where models had projected it then. Thus the strongest perpendicular SE winds came in and peaked just before and at high tide instead of being much lighter then, which would have been the case had the center been 50 miles further away.

 OTOH, it being 50 miles closer to CHS at high tide meant 50 miles N of SAV meaning W (offshore) winds at Ft. Pulaski instead of very close to SAV. That result was a major factor that lead to the maximum surge at Ft. Pulaski of 2.7' occurring much earlier at 1:36 PM on August 30th, which was luckily near LOW tide when winds were nearly perpendicular to the coast (ESE winds). Soon after that, winds shifted to SSE (no longer perpendicular and thus not pushing as much water in) and eventually to WSW at the time of high tide literally pushing the high water out. The result was that at the 8:24 PM high tide, the storm surge had shrunk to nearly nothing as per this linked image, which meant at Ft. Pulaski only an 8.95 ft tide vs a 9.4 ft tide (both in red) at the high tide the evening before. So, while CHS was having their worst flooding, Ft. Pulaski and the nearby islands/lowlands around SAV were already back to normal!

https://tidesandcurrents.noaa.gov/waterlevels.html?id=8670870&bdate=20230829&edate=20230831&units=standard&timezone=GMT&interval=6

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Edit: My power was out ~10 hours (5PM 8/30-3AM 8/31). I measured under 1" of rain. Closer to the coast got less than well inland, which was well predicted by the models. The airport got ~1.5". Just 50 miles inland from SAV despite the fast storm movement (20 mph), Candler, Bulloch, and Screven counties had flooding from very heavy rainfall as the remnants of the very wet NW eyewall hit that area. Statesboro, Metter, and Newington were deluged with 7-8"! That extended into Allendale, Hampton, and Colleton counties. Some of that scraped CHS (airport well inland), which got 3".

 There were 3 confirmed EF0 tornadoes, two in the CHS metro (including the one linked to earlier ITT that caused that car to lift in the air) and one in Liberty County, GA. No injuries and minimal damage, fortunately.