Jan 23/24 2016 obs/nowcast - the fight for the North

[codfishsnowman]

Well the modeling leading up to this helped a lot with the sentiment of the SNE portion of the storm.

It's amazing how much that makes a difference in an opinion about a storm.

Had the models continued the huge hits they were showing at Day 6 (2-3" QPF in SNE), and then it regressed to where it did in the final 48 hours, everyone would be devastated right now. However the rug was pulled out from you guys with enough lead time to make peace with it, and changed the tune to "just give me 1-3 inches". Then when it comes back slightly to a better event it seems like a positive bust almost.

Just the timing of changes in modeling makes a huge difference in the "overall feel" of an event.

good post and its true for me, sure i was heartbroken but not pissed off like last January...last January was just horrific and reminded me of that sick feeling i got from boxing day, dec 09 and march 01 back in central ct

[codfishsnowman]

Rarely (almost never) post but thought I would throw my 2 cents into the NAM discussion!  As Ryan indicated and showed & also harped correctly about all week was the best forecast for most areas was a blend of the GEFS / Euro numbers.  That was the starting point for most of my predictions and while it will usually serve you well, the need to not focus on actual qpf numbers and do some tweaking (up or down) is essential based on other non GFS and/or Euro products.  I had 2 conversations with a well-known NWS forecaster now at MT Holly Thu & Fri... He has always stressed to look at the NAM frotgen and forcing products as a means of refining some of your forecast zones.  He was adamant about boosting numbers into the excessive range across much of the NYC/LI areas and increasing the I-95 corridor and points just north to a bit south of the I-84 corridor into RI and then hitting Cape Cod area even harder than most modeled qpf.  The NAM modeled forcing and banding products were a red flag that numbers had to be picked up into the historic category for the greater NYC area and boosted east northward across southern CT into RI/Cape and that some banding would eventually get into parts of nrn CT and eastern Mass based on the phenomenal 850/700 inflow modeled just south of SNE.  The NAM qpf numbers were not to be believed and were not used, but the forcing / banding products were a red flag to pick numbers up big time across NYC area, as well as parts of CT/RI and Cape Cod area.  That is what the issue is really all about.  Forget the actual qpf numbers; use the ensemble means as a great starting point and tweak accordingly by analyzing other products such as the NAM forcing/banding products and other available info.  To say the NAM qpf #'s verified is pretty much flat out wrong, but it was a useful model and was a great indicator of where to boost numbers in the area that was already known to likely get into the good precip shield.

who are you and why dont you post in here more often!! best post of the winter so far!

[powderfreak]

I think we all agree about the factors that were red flags. You just need to know how to use the NAM. It's easy to see when to toss it, but you can use it to your advantage when you already have mass agreement on a storm. The NAM can actually help you identify and target areas for S+. But by no means should this storm now cause people to dry hump it. Let's see what happens with multiple s/w's involved with cyclogenesis.

If people really think the NAM was right, there should be a lot more really disappointed people out there. That model had runs of 2" QPF to the Pike and like 1" to NH/VT.

[powderfreak]

I never felt the rug pulled out feeling. It had that feeling of a MA storm all along, even without the bumps north at times.

Yeah sorry wasn't implying you personally. You, Ryan and Will especially were very level headed the whole time from Day 6 onward. Guess that's why you're the pros.

There were definitely some that had that feeling at day 4 when it went way south.

[CT Rain]

Yeah sorry wasn't implying you personally. You, Ryan and Will especially were very level headed the whole time from Day 6 onward. Guess that's why you're the pros.

There were definitely some that had that feeling at day 4 when it went way south.

 

The SNE weather weenies on twitter went on a full-on bashing spree on Twitter. Apparently, posting the RGEM showing a whiff (not a forecast just an image) was enough to send some into a tailspin. It was really odd and sort of sad to see. 

 

Interesting storm for sure - I had 5.5" here - better than I expected. 0.50" liquid too. 

[codfishsnowman]

i was so glad bdl was light...we totally have a shot at futility

[Ginx snewx]

[MJO812]

One thing for sure .. The Euro blew

And gfs and gefs. Jma wasnt bad.

[Ginx snewx]

Great post! Please do it more often :-)

Ryan also picked a spot just north of the sharp cutoff as his verification spot. Makes sense since it is a population center and close to his hood, but it does skew it a bit.

Correct me if I'm wrong but it also seemed to have a clue synoptically that it would tuck closer to the coast before kicking east.

all true. There was also a reason I posted the banding site stuff.

[Ginx snewx]

Dont care what the NAM showed for qpf. The banding signal was loud and clear. Inside 24 the 4K NAM performed spectacular. Don't understand why some will not acknowledge that. 2 day out posts in here were almost entirely on the total whiff side. What changed the tune were these meso runs. The Euro ENS did not come around until 48 out. To me the GEFS performed better mid range.

[Sugarloaf1989]

3" OTG here in my part of Enfield.

[CT Valley Snowman]

Excellent posts in here today. The Mesoscale details the NAM provided were a big help with this storm. With all the deep convection firing in the gulf,you could see a more amped and tucked solution. Just comparing modeled QPF fields and radar etc., vs. actual obs, radar, satelitte, you could see it was running fast and north and the globals were playing catch up at the end.

[Ginx snewx]

Fantastic LR GEFS EPS look for this very very long lead. We said to watch out for the 23 rd way back on Jan 14 th when both ENS had an extremely big signal for intense East Coast CycloG. The long,mid, short consensus overall was impressive. Reminded me of 93 model performance wise

[October_1979]

Yeah we had a report of 12" in East Hampton. I normally wait for the cocorahs/coop obs. The problem with a lot of reports we get is that they're measured on a deck with snow blowing off the roof. 

I actually measured 7.5" on my deck but only 5.5" on the snow board away from the house.

[/qzuote]

I am a new poster, but I have learned the ins and outs of measuring snow over the last several years. I measured 13.75 (maximum snow depth) last night at the best spot I have available ( a non blacktop walk a fair distance from the house). FWIW 12 hours later I still have 14 + 0n the deck and 15 out on the lawn. I am actually much closer to the center of Moodus than the center of E. Hampton

[JC-CT]

Excellent posts in here today. The Mesoscale details the NAM provided were a big help with this storm. With all the deep convection firing in the gulf,you could see a more amped and tucked solution. Just comparing modeled QPF fields and radar etc., vs. actual obs, radar, satelitte, you could see it was running fast and north and the globals were playing catch up at the end.

Well, some of the globals. The ones people usually pay less attention to did better than the most looked at ones. The ukie was the first major to show a decent northern edge and hold onto it. The arpege is going to be a useful tool to add to the ensemble mix I think. And I always look at the JMA anyway and sometimes even the navgem to see what they show, even if I give them little weight on their own. So there were other hints other than just the NAM and srefs that the GFS/Euro were not robust enough on the northern edge.

Food for thought.

[Ginx snewx]

Yeah we had a report of 12" in East Hampton. I normally wait for the cocorahs/coop obs. The problem with a lot of reports we get is that they're measured on a deck with snow blowing off the roof.

I actually measured 7.5" on my deck but only 5.5" on the snow board away from the house.

[/qzuote]

I am a new poster, but I have learned the ins and outs of measuring snow over the last several years. I measured 13.75 (maximum snow depth) last night at the best spot I have available ( a non blacktop walk a fair distance from the house). FWIW 12 hours later I still have 14 + 0n the deck and 15 out on the lawn. I am actually much closer to the center of Moodus than the center of E. Hampton

nice, crushed.

[metagraphica]

I saw a report that IJD had 15.5

But PnS says 9.5

 

 

It was on a TWC map on Twitter lol

A poster here had 13.25 on Colchester/ East Hampton line

 

 

PNS 9.0 in Hebrew

 

 

My brother in law had 13" in Colchester.

 

Wow to all of these reports.  Only 6.3" here on line between Salem and East Lyme.  We did have period of really weak snow growth from 2:30 - 3:30 and then that snow hole/dry air for hours last night.  Oh well, it was an easy clean up this morning.

[HullMA]

Really happy for the NWS crew in NYC. They did an amazing job. What a horrible storm to forecast.

After last years blizzard this was their chance to redeem themselves to the public and they really did.

[CoastalWx]

Yeah that blizzard watch worked out. I thought at first it may have been jumping the gun but it worked out.

[Ginx snewx]

Really happy for the NWS crew in NYC. They did an amazing job. What a horrible storm to forecast.

After last years blizzard this was their chance to redeem themselves to the public and they really did.

all the NWS crews did fantastic with all the elements, its not just snow either.

[Ginx snewx]

Yeah that blizzard watch worked out. I thought at first it may have been jumping the gun but it worked out.

your boy Dans live shot on TWC in Boston last night was classic, right in the middle of a ripping swirling band.

[CoastalWx]

your boy Dans live shot on TWC in Boston last night was classic, right in the middle of a ripping swirling band.

 

He told me about it. Right in the middle of the S+.

[ORH_wxman]

If people really think the NAM was right, there should be a lot more really disappointed people out there. That model had runs of 2" QPF to the Pike and like 1" to NH/VT.

 

NAM was partially right...it scored the coup of showing the much further north solution, but verbatim it was too far north which is why it's forecasts in places like Hartford and Boston weren't really any better than the Euro....but for places like NYC, down over to Morristown and Trenton into E PA it was much better than the Euro.

 

There was a point there about 72h out where a lot of guidance was struggling to get good snow past Philly.

[NeonPeon]

Comparing the modeling one week out to what happened is incredible to me.  Yes, the details were hugely important and challenging for mets, but the look of the storm a week out was pretty accurate to my untrained eye.  

 

People have mentioned that this happens with the big ones, is there any truth to that?

[ORH_wxman]

Comparing the modeling one week out to what happened is incredible to me.  Yes, the details were hugely important and challenging for mets, but the look of the storm a week out was pretty accurate to my untrained eye.  

 

People have mentioned that this happens with the big ones, is there any truth to that?

 

It does somewhat often...but not always...Jan 26-27 last year was not modeled well at all. There were some hints of it on a few long range runs but it largely disappeared by D5 and stayed that way until roughly 72h when it reappeared.

[CoastalWx]

I feel like the storms in blocking patterns are modeled with some accuracy fairly well almost a week out. Blocking regimes are stable so it's not a huge surprise I suppose. This was kind of a s/w that snuck in and closed off. No real phasing...just dumbelling along. Probably easier to model that way.

[jm1220]

NAM was partially right...it scored the coup of showing the much further north solution, but verbatim it was too far north which is why it's forecasts in places like Hartford and Boston weren't really any better than the Euro....but for places like NYC, down over to Morristown and Trenton into E PA it was much better than the Euro.

 

There was a point there about 72h out where a lot of guidance was struggling to get good snow past Philly.

Absolutely. The NYC area probably earned the best headlines from this but man, was that painful over the last couple of days before. I considered flying back for it but I remember last January (still a decent storm in NYC and ferocious just east on Long Island, but not 24"+ like what was predicted), Feb 2010, and other disappointments, and I thought that if it did make it, it would be something like what SE MA had. 

 

I mentioned this in the NYC thread-NYC just doesn't "lock in" storms days in advance like Boston or DC. NYC always seems to be on the edges. There are some examples I can think of like 12/30/00, maybe even 2/25/10 where NYC was forecast for a while to get nailed, but in general NYC is always a nailbiter because it's in such a transitional place between Miller B climo and Miller A climo. 

[dan11295]

Just was looking over the NESIS ratings/maps for other storms, and I would be shocked if it wasn't at least a mid-high 4 (possibly #3 on the list). All first order stations in the I-95 big cities from DC-NYC (excl. DCA) were 20"+ JFK was 30+, as was ABE, MDT in PA. Saw some co-ops (the only reports other that the first order climo sites that count for NESIS, IIRC) with 30+ in PA as well. Remember you cant go by prelim NWS maps for NESIS. January 2015 NESIS didn't include any of the 30"+ CT totals because of the simple fact there were weren't any co-op reports in the most affected county in CT

[CT Rain]

 

Yeah we had a report of 12" in East Hampton. I normally wait for the cocorahs/coop obs. The problem with a lot of reports we get is that they're measured on a deck with snow blowing off the roof. 

I actually measured 7.5" on my deck but only 5.5" on the snow board away from the house.
[/qzuote]

I am a new poster, but I have learned the ins and outs of measuring snow over the last several years. I measured 13.75 (maximum snow depth) last night at the best spot I have available ( a non blacktop walk a fair distance from the house). FWIW 12 hours later I still have 14 + 0n the deck and 15 out on the lawn. I am actually much closer to the center of Moodus than the center of E. Hampton

 

Sweet - yeah you guys were in some really good banding. It was definitely the place to be. Pretty epic drop off to your east and northwest... only 4.0" in Norwich! 

 

You should send in your obs to cocorahs - it's a great way to share and keep track of rain/snow data.

[wxsniss]

Yeah that blizzard watch worked out. I thought at first it may have been jumping the gun but it worked out.

 

Case in point for what Organizing Low and I were saying last night... NAM really saved the NYC crew. Alot of us were really thrown off by the Euro and skepticism of the NAM. Going entirely by Euro (remember that Friday 0z run less than 24 hours before go-time!) would have left the NYC metro + NNJ + LI + southern CT with their guard down... 27 inches later, it would have been a Juno fail the other way with dangerous impacts.

 

I think those making the "NAM was just as wrong based on its 2 feet in Vermont depiction" are too focused on literal qpf.

 

The point is the NAM was an important signal on some critical features, at least:  

(1) surface low track could tick a little more northwest,

(2) frontogenesis was being underestimated and too far south,

(3) underestimate of the late eastern SNE impacts by the easternmost of the dual lows to produce an OES-enhanced CCB.

 

Obviously, as has been discussed, we don't go rip-reading the NAM here on out, and skepticism of NAM is totally warranted in more complex setups.

 

But I think it's worth recognizing the blind spot most of us (and NWS forecasters) had in this storm, and using this as a case study for the rare situations when the NAM strays from the pack, it might be leading the pack.