April 1st-2nd Nor'Easter Potential

[A-L-E-X]

Euro ensemble mean

The ensembles have actually been the most accurate this winter.

[MJO812]

FWIW, Meteorologist Jeff Berardelli said on Facebook that this looks like a huge storm coming for the area with possibly a lot of snow.

[Ericjcrash]

Im wondering how much of the rarity of significant early April snowfalls in NYC is due to UHI. There was a really sharp gradient in 4/1996 and 4/2003 with all areas just outside of the city picking up much more snow.

Yeah, I had a tad more than 6" in '03.

[A-L-E-X]

To be honest I just searched on google lol, so I don't know how accurate it is. But it came up on multiple sources, including this one: http://www.stormforce31.com/?p=27 and this one: http://pages.slu.edu...weather/dec.pdf

Thanks! I wonder what the highest temp recorded for accumulating snowfall is? I've personally seen it accumulate quite well in very heavy wet snow (1 - 2 inches per hour) at 36 degrees.

[eduggs]

From 41 to 63, the 1st storm barely moves, and not allowing the height field to build along the coast. Weird scenario, considering the low isn't even closed off on H5

It's the s/w interactions in the mid-levels that don't allow a height recovery, not so much the surface low position. I still think either s/w could produce a nor-easter. I'm pulling for the 2nd wave, like the GFS/Euro consensus, because it has more model support and would occur sooner. But either wave could do the trick.

[A-L-E-X]

FWIW, Meteorologist Jeff Berardelli said on Facebook that this looks like a huge storm coming for the area with possibly a lot of snow.

Where is your snowboy sig We need it back for good luck dammit!

[IsentropicLift]

18z NAM hr 81

12z GFS hr

worlds appart

[A-L-E-X]

It's the s/w interactions in the mid-levels that don't allow a height recovery, not so much the surface low position. I still think either s/w could produce a nor-easter. I'm pulling for the 2nd wave, like the GFS/Euro consensus, because it has more model support and would occur sooner. But either wave could do the trick.

The timing with the heaviest QPF occurring at night, like with the 2nd wave, is also important. I usually root for daytime events, but this kind of borderline situation needs the heaviest precip to be at night and in the early morning hours.

[bmc10]

The NAM is always the last to catch on. But once it does catch on, it is usually a fairly good model to use. Once it gets within 48 hrs it tends to improve. Right now it fails to consolidate any of the distinct shortwaves.

[jconsor]

In terms of determining what's historic, you need to consider more than just 30 years of history. In the ~55 years between 1925 and 1981, there were no 6"+ snow storms in Apr for most of LI. There was a 6"+ snowfall on the majority of LI in on Apr 3-4, 1915, and in parts of LI on Apr 1, 1924.

Here's a list I compiled of 3"+ snowfalls after Mar 25:

Bridgehampton, NY (Records 1930-present):

4/7/2003 8"

4/9-10/1996 8"

4/7/1990 3"

4/6/1982 6.5"

3/29/1974 3"

3/30-31/1970 4.5"

4/14/1950 3.1"

4/9-10/1942 3"

4/7/1938 5.1"

Patchogue, NY (Records 1937-1997):

4/1/1997 4"

4/9-10/1996 3"

4/7-8/1996 12"

4/7/1990 3"

3/28-29/1984 6"

4/6/1982 10.5"

3/28-29/1974 3"

3/29-30/1970 5.1"

3/26-27/1959 3"

4/3-4/1944 4.9"

4/8-9/1942 4.2"

3/30/1942 3.6"

4/5-6/1938 4.8"

If you had to quantify it, what would you consider historic for early April-- let's say, a once in 10 year event? In that case, 6 inches may well be historic because (using my example) on the south shore of Long Island, I've seen 3 6 inch snowfalls in the past 30 years.

[eduggs]

Im wondering how much of the rarity of significant early April snowfalls in NYC is due to UHI. There was a really sharp gradient in 4/1996 and 4/2003 with all areas just outside of the city picking up much more snow.

I don't remember 1996, but in 2003 most reports were between 3-6. There might have been a few 7 or 8" reports, but they weren't representative. I think the metro basically received similar snowfall to the surrounding areas. UHI certainly plays a role, but the City is also the furthest NW, coastal, sea-level location. That's the worst possible combination lat/lon plus terrain.

[bmc10]

I don't remember 1996, but in 2003 most reports were between 3-6. There might have been a few 7 or 8" reports, but they weren't representative. I think the metro basically received similar snowfall to the surrounding areas. UHI certainly plays a role, but the City is also the furthest NW, coastal, sea-level location. That's the worst possible combination lat/lon plus terrain.

Several reports of 6-9 inches throughout central NJ.

[eduggs]

18z NAM hr 81

12z GFS hr

worlds appart

I wouldn't go to that extreme. The longwave evolution is basically the same. The primary difference lies in which shortwave the models amplify. The GFS and most other guidance keys on the 2nd of 3, whereas the NAM waits for the 3rd in line. All 3 waves have, at various times, been modeled to bring rain/snow to our area. I'm not surprised it's still not completely clear if and when this will finally occur. The wave spacing is a problem on the NAM, but there's plenty of time to work this out.

[RutgersWx92]

Several reports of 6-9 inches throughout central NJ.

North-central NJ was the hardest hit with widespread 6 inch amounts (and localized amounts of 7 or 8). I remember measuring about 6.5 inches in Bridgewater. Amounts were slightly less in the immediate NYC metro area (generally 3-5 inches).

[eduggs]

Several reports of 6-9 inches throughout central NJ.

I think that's an exaggeration. And you don't report a range like 6-9. You report a specific total.

http://www.njfreeways.com/weather/2003/07-Apr-03.html

I see a few 7s and 1 or 2 8s, but lots and lots in the 3-6 range.

[JERSEYSNOWROB]

The fact that we are even discussing the possibility of ANY accumulating snow in April around here is fascinating and a very rare treat in my opinion. Anything over 4 inches would be historic in my book.

[Sundog]

I think that's an exaggeration. And you don't report a range like 6-9. You report a specific total.

http://www.njfreeways.com/weather/2003/07-Apr-03.html

I see a few 7s and 1 or 2 8s, but lots and lots in the 3-6 range.

There were plenty of measurements in the 6-8 range in Queens and toward Long Island.

[green tube]

I think that's an exaggeration. And you don't report a range like 6-9. You report a specific total.

http://www.njfreeway.../07-Apr-03.html

I see a few 7s and 1 or 2 8s, but lots and lots in the 3-6 range.

i had 6.6" and was amazed to measure 6" in the middle of the street during the middle of the afternoon.

there was nothing "april-like" about that storm. ive always said it would have made january proud.

[bluewave]

4/5/06 was nice but it was over too soon.

[bmc10]

I think that's an exaggeration. And you don't report a range like 6-9. You report a specific total.

http://www.njfreeway.../07-Apr-03.html

I see a few 7s and 1 or 2 8s, but lots and lots in the 3-6 range.

Yea very true reports falling in the 6-9 range were localized and confined to central NJ. Regardless, the upcoming event is much different in respect to how it might unfold. This will be a moisture latent coastal nor'easter, not an overruning WAA type event. I much rather have the upcoming pattern...

[eduggs]

There were plenty of measurements in the 6-8 range in Queens and toward Long Island.

http://www.erh.noaa.gov/okx/readtext.php?file=pns/040703.txt

[A-L-E-X]

Thanks for that nice list JC..... it looks like a one in 10 April event would be a 4-6 inch snowfall if you use a 60-70 year period. Those Bridgehampton records match my own for 4/03 and 4/96. Do they have anything listed for 4/4/2006? That was an interesting, if minor storm. It was sunny and in the upper 40s in the morning, clouded up rapidly, and it turned sharply colder and we got 2 inches of snow in 2 hours in the middle of the day, and then the skies rapidly cleared and it was all melted away by sunset with the temps back in the upper 40s again. 4/2003 was also an impressive all day snowfall event-- a longer version of 4/2006.... we picked up 8 inches between sunrise and sunset on 4/7/2003 and it stayed cold for a few days after that.

Do any of those stations also mention 4/82 and 4/83? We actually had a second storm a few days after the big 4/82 blizzard that dumped a couple of inches. On 4/19-20, 1983, JFK recorded it's latest snowfall, with 1.5" and parts of Long Island had 3". Is that the latest snowfall of record you can find for those Long Island locations? Thanks!

[MJO812]

TWC is calling for 6-12 inches in the big cities. Wow,they are usually conservative.

http://www.weather.com/outlook/weather-news/news/articles/late-season-major-winter-storm_2011-03-29

[Sundog]

http://www.erh.noaa.gov/okx/readtext.php?file=pns/040703.txt

Looks like most people Queens east are in the 5-8 range, especially between 5.5 to 7 inches.

[eduggs]

Yea very true reports falling in the 6-9 range were localized and confined to central NJ. Regardless, the upcoming event is much different in respect to how it might unfold. This will be a moisture latent coastal nor'easter, not an overruning WAA type event. I much rather have the upcoming pattern...

Me too. Especially up in the highlands. But 2003 had a slightly better antecedent cold airmass IMO. Dynamics and precip intensity are a big wildcard, esp in Spring. But I always, always worry about surface temps this time of year. These things have a way of becoming annoying elevation events. I'll be very curious to see the dewpoint temps and dp depressions on Thursday.

[A-L-E-X]

http://www.erh.noaa....=pns/040703.txt

The highest I remember from that storm is 8 inches.... there were two areas of heavier snow... one extended from Monmouth County to Staten Island, Queens, Brooklyn and Nassau where most of the totals were in the 6-8 inch range. Based on JC's records, Bridgehampton also got 8"

April 1996 was an amazing storm for Long Island-- I'll NEVER forget the night of April 9-10, 1996; we were getting white out conditions with snowfall 1-2 inches per hour with temps of 32-34..... Nassau County got 6-10 inches, but there were parts of Suffolk County (Patchogue, Upton, Hamptons) where foot plus totals were common.

[A-L-E-X]

Looks like Noreaster measured that storm!

NASSAU COUNTY...

BALDWIN HARBOR 7.0 600 PM 04/07

LIDO BEACH 7.0 530 PM 04/07

QUEENS COUNTY...

HOWARD BEACH 7.0 540 PM 04/07

That 7 inches agrees well with what we got here and all those locations are within 5 miles of here.

Why were they measuring snow at JFK at 6:30 PM and 8PM at LGA? It was long over by then and already melting.

[A-L-E-X]

TWC is calling for 6-12 inches in the big cities. Wow,they are usually conservative.

http://www.weather.c...torm_2011-03-29

Are you serious? On TV they were saying rain/snow mix for DC, NYC and Boston!

[bmc10]

Me too. Especially up in the highlands. But 2003 had a slightly better antecedent cold airmass IMO. Dynamics and precip intensity are a big wildcard, esp in Spring. But I always, always worry about surface temps this time of year. These things have a way of becoming annoying elevation events. I'll be very curious to see the dewpoint temps and dp depressions on Thursday.

Yes but in that situation you have warming ahead of the primary LP to the west. In this situation we benefit from the intense cyclogenesis that can help pull down the colder air with a N component wind. But I agree, April snows always present some issues. I just think this is one of those rare occasions where we might see an accumulating April snowfall, even in NYC. To the N and W, and those with elevation, these storms can be huge. People throw out 97, but that is a perfect example with Sussex county seeing 15-25 inches of snow. Either way the probability of extreme weather is increasing, and anything interests me over boring tranquil weather.

[A-L-E-X]

Yes but in that situation you have warming ahead of the primary LP to the west. In this situation we benefit from the intense cyclogenesis that can help pull down the colder air with a N component wind. But I agree, April snows always present some issues. I just think this is one of those rare occasions where we might see an accumulating April snowfall, even in NYC. To the N and W, and those with elevation, these storms can be huge. People throw out 97, but that is a perfect example with Sussex county seeing 15-25 inches of snow. Either way the probability of extreme weather is increasing, and anything interests me over boring tranquil weather.

Two highly impressive things about April 2003 snowstorm-- 1) it occurred a week later than this one 2) it was an all day time snowstorm. You can also add in the fact that it looks like south shore areas jackpotted. Howard Beach/JFK was the place to be that winter-- first 26-28 inches in PD2 and then the jackpot in April lol. We had 60" of snow that winter-- about 10 inches more than NYC!