Gravity Wave

5 minutes ago, Will - Rutgers said:

nobody else got hail?  it hailed pretty decently in Piscataway, pea-sized and maybe a bit bigger.

Some pea-sized hail on the east side of Manhattan.

27 minutes ago, SRRTA22 said:

Our best events always seem to happen on marginal svr days  

All the best severe events growing up in PA happened on slight risk days, Mod risks almost invariably disappointed. The only exception was the high risk on May 31, 1998.

2 hours ago, Brian5671 said:

yeah I would never pay good $$ to go away Memorial day in the northeast, still spring really (and subject to cloudy 60 degree weather or worse)

Memorial Day usually manages to have good weather, even in years with bad springs (like most recent years).

I'm fine with the cool weather but the lack of any thunderstorm activity is annoying given that May into early June is generally our best shot at severe weather around here. I'd gladly take a transient hot day if it came with an interesting severe  outbreak.

1 hour ago, bluewave said:

Model forecasts indicating a very impressive cold frontal passage on Wednesday. Temperatures quickly rise into the low 70s ahead of the front. The forecast soundings indicate near record surface to 500 mb lapse rates. So severe convection looks possible. This is followed by a quick temperature drop to near freezing just N and W of NYC Thursday morning. Lapse rates remain steep to above 700mb so 50+ mph gusts will be possible behind the cold front. 

 

 

Lapse rates are usually the missing ingredient for big severe outbreaks in this region, I remember the October 2018 PA tornado outbreak where they played a key role. If it hadn't been for the low instability (it was October after all) it would have been a memorable event.

https://en.wikipedia.org/wiki/Tornadoes_of_2018#October_2

No sleet on the UES, just a few pings of graupel 15 minutes ago.

Is the 700 mb low forming as quickly as it was expected to? The mesoanalysis site doesn't seem to show an organized low at that level yet.

Getting heavier, that band over Queens should be here soon.

HRRR has been flipping and flopping and its thermals are trash. I've honestly never been impressed with it, it'll sniff out a nut every once in a while but its performance is generally underwhelming.

Moderate snow on UES Manhattan, hoping those bands to the south drift north soon.

1 minute ago, PeteThe Greek said:

Yes, seen several waves pushing through headed north on those panels. As much as we strive to get these snow totals, its actually refreshing to know we can never even try to predict where these CCB bands will setup. I love the randomness of it all. Leaves something to the imagination instead of constantly insisting to have an answer for everything. I would say prime rapid accumulation hours on monday would be from 11am to 6pm. Would that sound correct to you? 

 

Yes, although I might push the start of that range up to 8:00 given the HRRR depiction. You'll at least want to be checking the radar by then so you can see when the heavy banding will be arriving.

Just now, Pete Lymberopoulos said:

Thank you. I figured it was off. Even precipitation to its west was all over the place. Not even correct unreal time. When can we expect a true model representation of where these CCB bands will set up shop? Curious as CCB's are hard to pinpoint. Thanks again. 

At this point I don't think we're looking at 1 band that's just going to sit over an area, there's going to be a series of heavy bands rotating in and moving north. The largest looks like it'll come through in midafternoon. 

3 minutes ago, Pete Lymberopoulos said:

HRRR depicting sleet/mix into the system just after noon. What are your thoughts on this? The threat of ANY mixing would've been for monday late evening or night, NOT noon monday! That should be CCB own age time. Is it the HRRR just warming mid-levels too soon? The low does seem to track too close to the coast, but not sure it is accurate. Don't see that on the other models. 

 

Ignore the Ptype depiction on the HRRR. I checked some soundings and it's all snow through the end of the run (5:00 PM) for everyone Nassau and west.

4Z HRRR has 2" of liquid equivalent in the city by 5:00 PM tomorrow.

Just now, SI Mailman said:

5 inches of snow otg at midnight.  I think I'm gonna end up with 2 feet at this rate.

HRRR didn't have anyone in the City reaching the 3" mark until about 2:30 this morning. No question this is overperforming so far.

1 minute ago, Jt17 said:

I'd venture to guess there's a bit of a delay in their estimates, right?

Last update was 11:51, which was 5 minutes before I went outside. 

2" on the UES with moderate snow and really nice flake size. Looks like the radar is filling in in CNJ, should provide a great base for the CCB to do its damage tomorrow.

Another thing to note: KNYC has reported a total liquid equivalent of .11" since the snow started, and I assume that they have the same accumulations I do (the castle is about a mile to my NW). This would indicate excellent ratios, which isn't a surprise given it's only 22 degrees here at the moment.

I grew up in Allentown and know the pain of barely missing out on huge snowstorms; we got fringed a ton when I lived there (Jan 2005, Feb 2006, Dec 2009, Feb 5-6 and Snowicane, 2010). Glad to see the NAM improving for everyone out there, good luck!

Just now, HVSnowLover said:

By hour 18? I think hrrr only goes out 18 hours 

Yes, but I'm not putting much stock in hour 18 of the HRRR. 

Latest HRRR has the city (minus SI) reaching an inch of snow around 11:00 PM. Looks as though we should beat that.

Finally steady snow on the UES.

Light snow on the UES.

15" for NYC on the new GEFS, and that with three 6" whiffs mixed in.

1 hour ago, SnowGoose69 said:

See my post about 1983...similar type setup with that east inflow and Allentown saw 5 inches an hour and 15 in 4 hours I think 

Growing up in Allentown the old timers would always talk about that storm before 96 and 93, even though 96 ended up dropping a few more inches. 

NAM is east of the other models with the low, good news for NYC and LI.