potential for a few (million) mangled flakes part 2

[TheTrials]

Much less snow then 18z.

shocking. We all know 18z was overdone. A few slushy inches north and west, just wet snow for the city and immediate burbs. Special no matter what this time of year.

[jm1220]

People have to stop relying on the clown maps, and instead look at soundings. The NAM's also notorious for these run to run wobbles anyway. Watch 6z be a flat wave.

The Euro by far is the model to go with-every model has gone to a version of it based on a few degrees/miles etc.

[NaoPos]

you can see the difference between the 18z NAM and 0z NAM when you look at 21z sat on both models repsecitve time frames.

18z has a stornger sw, and a sharper trough.. 0z nam a little broader and weaker witht he h5 vort/trough.

[NEXtreme]

http://twitter.com/#!/BigJoeBastardi/status/129735969267138560/photo/1/large

[earthlight]

unless the 2m temps are ridiculously warm there is no reason to expect nothing on the coast. this run is probably better for the coast than 18z

[simpsonsbuff]

The soundings back this up... Temperatures (especially the surface) are a degree or two cooler vs. 18z.

unless the 2m temps are ridiculously warm there is no reason to expect nothing on the coast. this run is probably better for the coast than 18z

[TheTrials]

KNYC under that deform band. Surface is .4C

[SnowGoose69]

The 18Z NAM always has a wet bias prior to storms, and it gets worse as the event nears, much like the 06Z NAM usually has a warm bias and the 18Z GFS tends to have a suppressed tendency.

[snywx]

unless the 2m temps are ridiculously warm there is no reason to expect nothing on the coast. this run is probably better for the coast than 18z

Takes a decent amount of qpf away from inland locations.. What is it with these tight precip gradients the last 3 yrs??

[CAT5ANDREW]

unless the 2m temps are ridiculously warm there is no reason to expect nothing on the coast. this run is probably better for the coast than 18z

The Watchung Hills are going to do nicely in this storm.

[SBUWX23]

The 18Z NAM always has a wet bias prior to storms, and it gets worse as the event nears, much like the 06Z NAM usually has a warm bias and the 18Z GFS tends to have a suppressed tendency.

Are we able to say this with the new nam model they are running now?

[tmagan]

Takes a decent amount of qpf away from inland locations.. What is it with these tight precip gradients the last 3 yrs??

Did you see the gradient in the Blizzard of 1996?

[ag3]

That Raleigh snow map looks weird.

Coast is definitely colder then 18z and the deform band is right overhead.

[TheTrials]

Its 48 hours away, its gonna wobble. NAM seems a little too far east given the blend of the euro, gfs, and ukmet. Still a nice October surprise..

[CAT5ANDREW]

Actually the earliest snowfall I can remember in Upsate NY was on OCT 4 1987.I think there was light snow as far south as White Plains.

[phil882]

While I know you guys are getting all excited, lets see if we can learn something from earlier this week in why the models kept this coastal feature so offshore.

Rina is actually one wildcard factor that caused the models to "lose" the system earlier this week. The GFS was a strong outliner for the last several days taking Rina further north than the rest of the guidance. This was a bad thing for the coastal low because the latent heat release due to deep convection near Rina would have helped to increase the mid to upper level heights when the southern stream shortwave would have moved overhead, which would have weakened its overall intensity, leading to a delayed and weaker phase of the two pieces of energy.

Now that it seems the models are converging on a solution that shows Rina staying in the Caribbean or dissipating, the major coastal up the east coast has returned. Its worth noting that the ECWMF never forecasted Rina to move into the Gulf of Mexico, and thus it is primarily why it was the most steadfast in the mid range in keeping to Coastal Low solution. Rina once again shows how the tropics can have major impacts on modeling error. The GFS was obviously too strong and too far right with Rina in the mid range forecasts from 3-5 days out, and now we are seeing the consequences of less tropical influence!

[earthlight]

The Watchung Hills are going to do nicely in this storm.

don't jinx me

[snywx]

Did you see the gradient in the Blizzard of 1996?

in 96' I received over 2' in Monroe NY

http://www1.ncdc.noaa.gov/pub/data/cmb/images/snow/nesis/19960106-19960108-11.78.jpg

[TheTrials]

While I know you guys are getting all excited, lets see if we can learn something from earlier this week in why the models kept this coastal feature so offshore.

Rina is actually the one wildcard factor that caused the models to "lose" the system earlier this week. The GFS was a strong outliner for the last several days taking Rina further north than the rest of the guidance. This was a bad thing for the coastal low because the latent heat release due to deep convection near Rina would have helped to increase the mid to upper level heights when the southern stream shortwave would have moved overhead, which would have weakened its overall intensity, leading to a delayed and weaker phase of the two pieces of energy.

Now that it seems the models are converging on a solution that shows Rina staying in the Caribbean or dissipating, the major coastal up the east coast has returned. Its worth noting that the ECWMF never forecasted Rina to move into the Gulf of Mexico, and thus it is primarily why it was the most steadfast in the mid range in keeping to Coastal Low solution. Rina once again shows how the tropics can have major impacts on modeling error. The GFS was obviously too strong and too far right with Rina in the mid range forecasts from 3-5 days out, and now we are seeing the consequences of less tropical influence!

what was your reasoning in favoring the GFS' handling of Rina three days ago over the Euro?

[Chris L]

Did you see the gradient in the Blizzard of 1996?

We have seen much sharper gradients than the Blizzard of 1996... 1996 did not really have much of a gradient until you hit North of Scranton. NJ-PA-SE NY were buried 20-30+.

December 25, 2002 for example.

[phil882]

Its 48 hours away, its gonna wobble. NAM seems a little too far east given the blend of the euro, gfs, and ukmet. Still a nice October surprise..

The NAM has a physical reason why its further east... the kicker shortwave to the west over Montana/North Dakota is stronger and more progressive... meaning it pushes the 500mb trough further east. Its not a major difference, but this might be a feature worth watching as the rest of the 00z model suite comes in.

[kevbo81]

WOW...thanks Phil. Great stuff.

[phil882]

what was your reasoning in favoring the GFS' handling of Rina three days ago over the Euro?

Yes... at the time, I thought the GFS had the right idea with the intensity and track of Rina... obviously that was a mistake .

All I'm saying is that the tropics are having a larger than normal impact on the evolution of the upper level features for this potential snowstorm. You don't always see this type of interaction during the winter, especially with true tropical systems. Its been a fun case to watch.

[NaoPos]

The NAM has a physical reason why its further east... the kicker shortwave to the west over Montana/North Dakota is stronger and more progressive... meaning it pushes the 500mb trough further east. Its not a major difference, but this might be a feature worth watching as the rest of the 00z model suite comes in.

I had pointed that out with Tombo in the PHL region.. Def worth keeping an eye on. WHile i dont expect anything too major to change, it can cause headaches from a forecasting standpoint.

[snywx]

We have seen much sharper gradients than the Blizzard of 1996... 1996 did not really have much of a gradient until you hit North of Scranton. NJ-PA-SE NY were buried 20-30+.

December 25, 2002 for example.

The gradients the last 3 yrs have been insane. 96' shouldnt even be in the same sentence as the last few blizzards in terms of sharp cutoffs..

[eduggs]

The gradients the last 3 yrs have been insane. 96' shouldnt even be in the same sentence as the last few blizzards in terms of sharp cutoffs..

96 had an extremely sharp gradient, but it was further north in northern Pa and ENY. Cities like BGM and ALB got almost nothing while areas 20 miles south measured in feet.

Since 2006 it seems like several major snowstorms have produced sharp gradients right through the Hudson Valley. These have been significant gradients, but I'm not sure they were worse than 96. Growing up in the HV I can remember a lot of rain/snow lines cutting through the area, but not so many of these sharp heavy snow to light snow boundaries.

[snywx]

96 had an extremely sharp gradient, but it was further north in northern Pa and ENY. Cities like BGM and ALB got almost nothing while areas 20 miles south measured in feet.

Since 2006 it seems like several major snowstorms have produced sharp gradients right through the Hudson Valley. These have been significant gradients, but I'm not sure they were worse than 96. Growing up in the HV I can remember a lot of rain/snow lines cutting through the area, but not so many of these sharp heavy snow to light snow boundaries.

I have been in the HV for the last 17 yrs and I cannot remember anything similar to what we have seen in regards to these sharp cutoffs... Its almost expected now.

[eduggs]

I have been in the HV for the last 17 yrs and I cannot remember anything similar to what we have seen in regards to these sharp cutoffs... Its almost expected now.

Yeah it's weird. I guess it reflects a high frequency of coastal storms in recent years. But the gradient is not a foregone conclusion. And elevated spots in the lower HV look primed for heavy snow on Saturday regardless of the exact slp track.

[kevbo81]

GFS running yet?

[NaoPos]

GFS running yet?

not on ncep yet..