IDA remnants-Moderate to isolated Major Impact (esp NJ-LI), general storm total 2-8" rainfall Wednesday-Thursday September 1-2 2021

[Neblizzard]

3 minutes ago, jm1220 said:

Looks like overall a trend back north here. RGEM shifted quite a bit. GFS has the heaviest rain along I-84. 

The overnight part of the storm still slams the metro area 

[NJwx85]

 

5 minutes ago, jm1220 said:

Looks like overall a trend back north here. RGEM shifted quite a bit. GFS has the heaviest rain along I-84. 

Doesn't reflect that in the totals.

[TriPol]

3-6 inches looks like a good call.

[SnowGoose69]

1 minute ago, TriPol said:

3-6 inches looks like a good call.

Given we are seeing the speed of the system increase we may see QPF totals drop slightly over the next 24-36 hours

[LibertyBell]

14 minutes ago, Neblizzard said:

The overnight part of the storm still slams the metro area 

when we're all sleeping lol

[Snowlover11]

8 minutes ago, LibertyBell said:

when we're all sleeping lol

or working

[EasternLI]

12z Ukie

[NJwx85]

Yikes

 

[jm1220]

44 minutes ago, bluewave said:

HREF has a widespread 3-6” with localized 10”+ where the best banding sets up.

Geez. I-78 would become the I-78 Rapids on that map. 

[RU848789]

1 hour ago, SnowGoose69 said:

Given we are seeing the speed of the system increase we may see QPF totals drop slightly over the next 24-36 hours

All of the 12Z global/regional models have measurable precip over by 2 pm Thursday, with some over by 8 am to 11 am (except the Euro which isn't in yet).  For selfish reasons (our RU football tailgate starts around 2 pm and the game is at 6:30 pm), I'm hoping that verifies.  I won't love wet grass and maybe some mud, but it's way better than falling rain.  Looks like the afternoon and evening could end up being very nice in Piscataway.  Any comments on rainfall end time?  Thanks!!

[jm1220]

12z Euro back to pretty far north. For NYC, LI and south of I-78 it's 1-2" pretty much. Big amounts over 5" are in NE PA, parts of N NJ and I-84 corridor. The trough amplifying and stronger ridge as usual seem to be bumping it north. Keep the trend going!! 

[LongBeachSurfFreak]

2 hours ago, jm1220 said:

Looks like overall a trend back north here. RGEM shifted quite a bit. GFS has the heaviest rain along I-84. 

There’s going to be a stratiform rain shield with lots of yellows and oranges on the radar on the north side that will produce an even 4-6”. It’s the south side where there will be banding with much heavier rates and isolated 10”+ amounts that will be the danger zone. As always it will be impossible to predict exactly where the bands set up.

[jm1220]

8 minutes ago, LongBeachSurfFreak said:

There’s going to be a stratiform rain shield with lots of yellows and oranges on the radar on the north side that will produce an even 4-6”. It’s the south side where there will be banding with much heavier rates and isolated 10”+ amounts that will be the danger zone. As always it will be impossible to predict exactly where the bands set up.

It’ll be north of where the warm front sets up. There’ll be heavy rain in spots south of it along with possible severe but north of the warm front is where that heavy steady rain will be. 12z models all trended that front north. It’s also probably helpful for severe that the worst of the storm here will be at night. 

[jets]

Focus on where front is not where models have heaviest precip

[forkyfork]

i've seen the models put too much convection north of the warm front many times

[doncat]

Updated nws

 

 

 

[Rtd208]

 

[White Gorilla]

26 minutes ago, doncat said:

Updated nws

 

 

 

I am imagining the red means 2-3 feet of snow in a huge winter storm about to strike.  

[TriPol]

27 minutes ago, doncat said:

Updated nws

 

 

 

I love all the reds and oranges. Feels like fall is coming soon!

[Maureen]

9 minutes ago, Rtd208 said:

 

It doesn’t take much for us to flood here in Carteret in the best of circumstances, so…. 
 

 

[Maureen]

1 minute ago, White Gorilla said:

I am imagining the red means 2-3 feet of snow in a huge winter storm about to strike.  

If only!

[wdrag]

5-10 year rainfall recurrence interval per NWS updated 24 hr forecast issued this afternoon. 

Thread stands as written... we've mentioned 10" max which the 12z/30 SPC HREF and 18z/30 HRRR now seem to have, but overall I think 2-8" works well. Bulk in a Wednesday morning period (note the widespread 1-1.5" amounts today near I76 OHIO-W PA, which arrives by ~4AM), then Wed night-Thu morning torrents.

G 35 kt.  Not hammering wind harder at this time tho some of the modeling has 45 kt gusts which would be a big problem for parts of the saturated area-uproots-power. TOR potential dependent on northward incursion of the warm front. 

As much as we root for big events, it gets quite uncomfortable when embedded in 3 hours of torrents 1-2"/hr, wondering whether first time leaks/basement flooding occurs, how much submersible pump water rerouting should we do.  

We all should be well prepared to minimize impact. I plan to monitor NWS shorter fuse warnings/statements and handle detours Wed night-Thursday as flooding requires.

Advice: do not cross  flooded roads near streams at night.  Too much risk of not seeing the dangers or respecting the powerful current of water which can be a killer. 

May post something late evening or overnight or otherwise back in the morning.

Will begin an IDA OBS thread near 10PM tonight or 4AM Wednesday. 

[SnowGoose69]

18Z NAM wonky evolution trying to sort of double barrel the low but overall idea of heaviest rain placement is same

[Rtd208]

Obviously location dependent but if you don't get the heaviest rain the tradeoff will be dealing with severe weather (including tornadoes) in the warm sector. I think regardless just about everyone in the sub forum will see at least 2" of rainfall.

[dmillz25]

Had 9” of rain just last weekend to get another 5” plus of rain just 10 days later is pretty absurd 

[sferic]

Are areawide reservoirs all at 100% capacity?

[nycwinter]

lee goldberg future cast showed just less then 3 inches in the city even he said those numbers are low..

[nycwinter]

30 minutes ago, sferic said:

Are areawide reservoirs all at 100% capacity?

ny reservoir levels are at 95% normally this time of year should be 82% nyc normally  uses a billion gallons of water every day..

[Brian5671]

1 minute ago, nycwinter said:

lee goldberg future cast showed just less then 3 inches in the city even he said those numbers are low..

yeah never doubt a tropical origin system

[SnoSki14]

1 hour ago, Rtd208 said:

Obviously location dependent but if you don't get the heaviest rain the tradeoff will be dealing with severe weather (including tornadoes) in the warm sector. I think regardless just about everyone in the sub forum will see at least 2" of rainfall.

That's where I'm leaning. Less rain more severe potential.