NYC/PHL Dec 26-27 Boxing Day Blizzard Part 8

[earthlight]

Agree, but what is troubling about the GEFS ensemble mean?

I don't see anything troubling at all. Just noting that I myself have been burned several times weighing them into my forecasts to heavily on the fringes of precipitation.

[SnowGoose69]

I don't see anything troubling at all. Just noting that I myself have been burned several times weighing them into my forecasts to heavily on the fringes of precipitation.

See 2/6/10

[earthlight]

If the Suny MM5 is right NYC and the immediate suburbs (both on Long Island and in Northeast New Jersey) are going to come in with the locally high totals for the event. It's showing a very clear developing deformation band with intense frontogenic forcing and very heavy snow. The band moves northwest, stalls, and then pivots back eastward over the same areas. Extremely concerning setup for the potential of ridiculously high snowfall totals in comparison to other areas.

[LocoAko]

After learning more about momentum transfer in BUFKIT, it is hard for me to see how blizzard conditions won't be verified in a wide range of areas (going by the NAM). From the NJ shore to NYC and LI, almost all stations have transfered winds around 35 to near 40kts starting tomorrow night and lasting through the night. I guess it will be dependent on when the strongest bands come through to meet the visibility requirement, but I think this has a much better chance for widespread verification than past events. We'll see if I'm being overly optimistic soon, I suppose.

And just peaking at the 00Z GFS, it is even crazier with the winds. Coastal NJ mixes down 55kts around 00Z tomorrow.

EDIT: Even JFK and ISP and EWR mix down 55kt winds on the GFS. Not to mention the 18-20" snow totals.... All seem to be around 00Z tomorrow as the peak of the mixing.

[Deano]

Lower Bucks County PA - A few flurries pasted through, partial overcast.

[SmokeEater]

Oh boy.

MODEL DIAGNOSTIC DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD

1130 PM EST SAT DEC 25 2010

VALID DEC 26/0000 UTC THRU DEC 29/1200 UTC

...

THE NAM AND GFS ARE 3-4 HPA TOO WEAK WITH THIS SYSTEMS

SURFACE LOW...BOTH MISSING OUT ON A LARGE ENOUGH 1008 HPA ISOBAR

THAT SHOULD HAVE BEEN CAUGHT BY THE GUIDANCE...WHICH COULD

INDICATE THEIR SURFACE LOW CENTRAL PRESSURE SOLUTIONS WILL BE

SLIGHTLY TOO WEAK OVER THE NEXT DAY OR TWO.

[earthlight]

After learning more about momentum transfer in BUFKIT, it is hard for me to see how blizzard conditions won't be verified in a wide range of areas (going by the NAM). From the NJ shore to NYC and LI, almost all stations have transfered winds around 35 to near 40kts starting tomorrow night and lasting through the night. I guess it will be dependent on when the strongest bands come through to meet the visibility requirement, but I think this has a much better chance for widespread verification than past events. We'll see if I'm being overly optimistic soon, I suppose.

And just peaking at the 00Z GFS, it is even crazier with the winds. Coastal NJ mixes down 55kts around 00Z tomorrow.

Strongly agree. This is the best example of a potential widespread blizzard event I have seen in several years. The MM5 is also very bullish with it's 10m winds. Anybody that sits underneath these heavy snow rates in the frontogenic forcing as depicted below would be suspect to whiteout and/or blizzard conditions. It has been a while since I have seen a signal like this.

[SnowGoose69]

Ladies and Gentlemen....it is snowing on a boat 15 miles south of Amityville in the Atlantic!

[nzucker]

Here's the map:

[AbsoluteVorticity]

Any one seen the 04z RUC, WOW. Looks way west, watch the 7H and 85H animations, can you say BOMBOGENESIS!

[ptb127]

Agree, but what is troubling about the GEFS ensemble mean?

Not on the fringe, just more QPF. (.25-.50 on the op but .75 to 1.00" on the ensem) also the SREF give a good 1.00" widespread too.

[NorthNJwx]

This is Farmingdale NJ in se Monmouth County on 00z gfs. Winds tail off on these soundings as you head inland but holy moly, still incredibly bullish on these wind gusts in coastal counties and long island...JFK 00z bufkit hasn't loaded in yet, but was showing 59kt at the surface 11PM tmrw nightt on 18z

00Z NAM continues wind thread, particularly out of over Long Island. Over "inland" locations (checked KEWR) there is a bit of a stronger signature for an inversion aloft but still 50kts underneath it. At KISP, 70kts is present at 875hPa at 9PM tomorrow. The layer beneath that is seemingly well-mixed (920hPa to surface) and there is moderate snow falling at the time. Fun times ahead.

Both are pure insanity. There is some climatological precedence for very strong N winds to occur just west of bombing lows like this in our area, but I don't think it has happened in a long time (a bomb in November 1953, mentioned in Great Storms of the Jersey Shore, is one example that comes to mind quickly). If this verifies or comes close, these winds will be way beyond anything seen in such other major snow events as '78 (at least west of central LI), '83, '96, '05, '06, the storms of this past Feb, etc. Big wind profiles are more associated with big W/NW CAA events or S/SE LLJ events in this area, along with nor'easters with a E or NE direction...so seeing it with a N wind is somewhat uncharted territory in my view.

I think LI/coastal NJ/NYC can verify wind warning criteria (sustained 40+ or gust 58+). Inland it looks like advisory criteria (gust 46+), which is rare for a snow event. I think the strongest winds will coincide with the heavy snow more along the coast, while inland the stronger winds may be after the heaviest stuff or even after it all tapers off on Monday, when the CAA/pressure rises/greater westerly component direction kick in.

[earthlight]

Yeah...the RUC isn't the most reliable at this range but it has the very strong band moving in starting 22z Sunday. It seems to be on the further west envelope of guidance..and we could be seeing some evidence for this given the NCEP details about tonight's model runs. I suggest we all carefully watch the surface low pressure tonight through the morning..that should give us an idea where this banding will set up in relation to modeling.

[Tiburon]

96 was a weak la nina indeed. It was just further west basically...further west when everything closed off at 500mb that is and this allowed the overunning to flood northward and occur as the surface low crawled north. I wouldnt say that there is anything really missing to get those totals in SOME areas, but just not widspread like 96 was (because of that overunning leading to more precip/longer duration).

What's causing the precip over SNJ right now, if not overrunning? Is this still that little northern stream blob that moved through?

[earthlight]

.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...

NO CHANGES TO THE BLIZZARD OR WINTER STORM WARNING OR THE SNOW

AMOUNTS BASED ON THE 18Z MODEL RUNS. AMOUNTS STILL EXPECTED AT

AROUND A FOOT...GIVE OR TAKE A FEW INCHES (PLUS BLOWING AND

DRIFTING WILL MAKE FOR GREAT DIFFICULTY IN MEASURING).

SOME OF THE 18Z DATA IS RATHER CONCERNING. GFS IS SUGGESTING 60+

KT AT 500 FT AND UP TO 90 KT AT 2000` (KLGA BUFKIT AT 03Z). WE COULD

VERY WELL SEE WIND GUSTS OVER 50 KT RESULTING IN SOME SIGNIFICANT

POWER OUTAGES.

MEDIA...PLEASE RELAY THE WIND IMPACTS WITH THIS STORM - RESIDENTS

SHOULD SECURE THE HOLIDAY DECORATIONS AND OTHER LOOSE

OBJECTS....ETC. THIS IS NOT JUST ANOTHER SNOW STORM.

[Bluescat1]

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/ruc/hr4/index_hlc_l_loop.shtml

Helicity A property of a moving fluid which represents the potential for helical flow (i.e. flow which follows the pattern of a corkscrew) to evolve. Helicity is proportional to the strength of the flow, the amount of vertical wind shear, and the amount of turning in the flow (i.e. vorticity). Atmospheric helicity is computed from the vertical wind profile in the lower part of the atmosphere (usually from the surface up to 3 km), and is measured relative to storm motion. Higher values of helicity (generally, around 150 m²/s² or more) favor the development of mid-level rotation (i.e. mesocyclones). Extreme values can exceed 600 m²/s².

[tmagan]

LAMP guidance has been indicating temps. in the upper 30's over KISP and KFOK late today, but as you get towards 24 hours, it becomes less reliable.

[SnowGoose69]

http://www.nco.ncep....lc_l_loop.shtml

Helicity A property of a moving fluid which represents the potential for helical flow (i.e. flow which follows the pattern of a corkscrew) to evolve. Helicity is proportional to the strength of the flow, the amount of vertical wind shear, and the amount of turning in the flow (i.e. vorticity). Atmospheric helicity is computed from the vertical wind profile in the lower part of the atmosphere (usually from the surface up to 3 km), and is measured relative to storm motion. Higher values of helicity (generally, around 150 m²/s² or more) favor the development of mid-level rotation (i.e. mesocyclones). Extreme values can exceed 600 m²/s².

I know a meteorologist who named his daughter Helicity

[JTA66]

Oh boy.

MODEL DIAGNOSTIC DISCUSSION NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD 1130 PM EST SAT DEC 25 2010

VALID DEC 26/0000 UTC THRU DEC 29/1200 UTC

...

THE NAM AND GFS ARE 3-4 HPA TOO WEAK WITH THIS SYSTEMS

SURFACE LOW...BOTH MISSING OUT ON A LARGE ENOUGH 1008 HPA ISOBAR

THAT SHOULD HAVE BEEN CAUGHT BY THE GUIDANCE...WHICH COULD

INDICATE THEIR SURFACE LOW CENTRAL PRESSURE SOLUTIONS WILL BE

SLIGHTLY TOO WEAK OVER THE NEXT DAY OR TWO.

I would think this is good news, yes?

[ace0927]

Radar seems to be filling in over LI and NYC. Anything falling there?

not on south Shore

[goombatommy]

I would think this is good news, yes?

It is indeed good news.

[tmagan]

.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...

NO CHANGES TO THE BLIZZARD OR WINTER STORM WARNING OR THE SNOW

AMOUNTS BASED ON THE 18Z MODEL RUNS. AMOUNTS STILL EXPECTED AT

AROUND A FOOT...GIVE OR TAKE A FEW INCHES (PLUS BLOWING AND

DRIFTING WILL MAKE FOR GREAT DIFFICULTY IN MEASURING).

SOME OF THE 18Z DATA IS RATHER CONCERNING. GFS IS SUGGESTING 60+

KT AT 500 FT AND UP TO 90 KT AT 2000` (KLGA BUFKIT AT 03Z). WE COULD

VERY WELL SEE WIND GUSTS OVER 50 KT RESULTING IN SOME SIGNIFICANT

POWER OUTAGES.

MEDIA...PLEASE RELAY THE WIND IMPACTS WITH THIS STORM - RESIDENTS

SHOULD SECURE THE HOLIDAY DECORATIONS AND OTHER LOOSE

OBJECTS....ETC. THIS IS NOT JUST ANOTHER SNOW STORM.

Considering this is a Sunday with NFL games on, you will be lucky to see anyone on TV today relaying info. about this storm.

[NorthNJwx]

After learning more about momentum transfer in BUFKIT, it is hard for me to see how blizzard conditions won't be verified in a wide range of areas (going by the NAM). From the NJ shore to NYC and LI, almost all stations have transfered winds around 35 to near 40kts starting tomorrow night and lasting through the night. I guess it will be dependent on when the strongest bands come through to meet the visibility requirement, but I think this has a much better chance for widespread verification than past events. We'll see if I'm being overly optimistic soon, I suppose.

And just peaking at the 00Z GFS, it is even crazier with the winds. Coastal NJ mixes down 55kts around 00Z tomorrow.

EDIT: Even JFK and ISP and EWR mix down 55kt winds on the GFS. Not to mention the 18-20" snow totals.... All seem to be around 00Z tomorrow as the peak of the mixing.

Didn't see this until after I made my last post, but wow....that's crazy. I agree totally; widespread verification of the blizzard warnings looks more likely than in any recent events. It's tough to do here in Bergen, but Hudson/NYC/LI/Coastal CT can do it much more easily.

[Voyager]

Considering this is a Sunday with NFL games on, you will be lucky to see anyone on TV today relaying info. about this storm.

Not difficult to run a scroll from time to time.

[Bluescat1]

Considering this is a Sunday with NFL games on, you will be lucky to see anyone on TV today relaying info. about this storm.

I actually got a Robo call at 11:45pm this evening on the reverse 911 system saying the mayor is going to declare a snow emergency at 9am.

[SmokeEater]

I would think this is good news, yes?

Yes sir.

[famartin]

96 was a weak la nina indeed. It was just further west basically...further west when everything closed off at 500mb that is and this allowed the overunning to flood northward and occur as the surface low crawled north. I wouldnt say that there is anything really missing to get those totals in SOME areas, but just not widspread like 96 was (because of that overunning leading to more precip/longer duration).

Don't forget that 96 also had a pretty brutal high pressure. Lows were in the single digits the morning before it started.

[Stormlover74]

Whats interesting is Upton is usually more conservative and takes longer to issue WSW's compared to Mt Holly. But they seem to issue blizzard warnings much earlier. Seems unlikely that Union county where I am gets higher winds than Monmouth/Ocean, or perhaps the snow is wetter near the shore so the visibility isn't as low?

Didn't see this until after I made my last post, but wow....that's crazy. I agree totally; widespread verification of the blizzard warnings looks more likely than in any recent events. It's tough to do here in Bergen, but Hudson/NYC/LI/Coastal CT can do it much more easily.

[gkrangers]

12:15am Dec 26 2010

Looks kinda like a storm turning the corner.

[Boreal]

Yeah...the RUC isn't the most reliable at this range but it has the very strong band moving in starting 22z Sunday. It seems to be on the further west envelope of guidance..and we could be seeing some evidence for this given the NCEP details about tonight's model runs. I suggest we all carefully watch the surface low pressure tonight through the morning..that should give us an idea where this banding will set up in relation to modeling.

Model reliability as compared to others aside, what I've noticed with the RUC tonight is that it has been consistently bending the developing SLP slightly west of north during the latter frames of each of the last few runs, as it moves from Hateras toward our region.