2/1 - 2/4 Storm potential

[Bluescat1]

Dr Uccellini was quoted last week in an article saying the models do not handle the northern stream as well as the southern as there are less sampling of the atmosphere.

http://voices.washingtonpost.com/capitalweathergang/2011/01/at_weather_expo_top_snowstorm.html

[tombo82685]

euro is out to hr 12 fwiw...updates as we get closer.

[earthlight]

[Maximum lawman]

Wow almost every one of those ensemble members is an awesome hit. No real Nw solutions,

Yeah, that's a lot of consistency this far out - 8, arguably 9- show the same solution.

[ace0927]

144HR clown maps...

[Maximum lawman]

And that's at the height of the precip. Fun.

[TheTrials]

Normally I would say enjoy the snow to ice to rain with more wet than white but this winter, can't say that. Deep cold dry air in place with deep cold dry air throughout canada argues for a snowier solution. That plus the redevelopment,well, winter 2010-11 ftw.

[TheTrials]

GGEM 120. Does not go further than this on this map.

[TheTrials]

GGEM has WAA precip before this too around 108 hours before the main show.

[earthlight]

Normally I would say enjoy the snow to ice to rain with more wet than white but this winter, can't say that. Deep cold dry air in place with deep cold dry air throughout canada argues for a snowier solution. That plus the redevelopment,well, winter 2010-11 ftw.

That's not a snowstorm setup in this area despite the dry air and the low level cold. The mid levels almost always warm faster than modeled in that situation with the H85 low to our northwest. You can say we might hang on to low level cold longer, that's fair, especially given the snow pack. But the mid level temps from anywhere between 850 and 925mb would likely be warm enough for sleet to work in faster than forecast with that depiction aloft.

[earthlight]

And that's at the height of the precip. Fun.

Yeah, likely a snow to sleet to dryslot event on the GFS verbatim as the mid level centers move overhead.

[TheTrials]

Yeah, likely a snow to sleet to dryslot event on the GFS verbatim as the mid level centers move overhead.

What is your sounding station?

[earthlight]

What is your sounding station?

Somewhere between EWR and MMU usually works.

[TheTrials]

That's not a snowstorm setup in this area despite the dry air and the low level cold. The mid levels almost always warm faster than modeled in that situation with the H85 low to our northwest. You can say we might hang on to low level cold longer, that's fair, especially given the snow pack. But the mid level temps from anywhere between 850 and 925mb would likely be warm enough for sleet to work in faster than forecast with that depiction aloft.

Depends on how quick the primary dies. OP GFS seems to be on the nw side of its ensembles for the primary. Im not counting anything out right now.

[ag3]

Somewhere between EWR and MMU usually works.

Warmest point on GFS is at hour 132 and by then there is practically no precip left.

All levels before that are plenty cold for snow.

This is the GFS verbatim.

[earthlight]

Here's a twisterdata sounding showing exactly what I'm referring to. The ~850mb warm push almost always turns things over to sleet before expected. Just a general trend to keep in mind over the next few days.

[chrisNJ]

I guess this could be another VDAY 2007?

[earthlight]

Warmest point on GFS is at hour 132 and by then there is practically no precip left.

All levels before that are plenty cold for snow.

This is the GFS verbatim.

Right, which is not what I'm arguing, but what I'm saying is that the track of the mid level centers is not favorable and often the mid level WAA is underforecast.

[TheTrials]

Somewhere between EWR and MMU usually works.

Looks a lot like the KNYC sounding. You would stay all snow by the skin of your teeth. I agree with you about the mid level warth, but do you remember the event in December 2008? Very similar setup with the -EPO. I think NYC and around your area pulled out 7 inches.

[tombo82685]

Warmest point on GFS is at hour 132 and by then there is practically no precip left.

All levels before that are plenty cold for snow.

This is the GFS verbatim.

yes, but with that 850 low how its progged, the mid levels would warm a lot quicker. If the gfs was to keep this exact track on tuesday i garuntee you would see the 850s surge north faster. As of now it means nothing cause its still 5 days away.

[earthlight]

Looks a lot like the KNYC sounding. You would stay all snow by the skin of your teeth. I agree with you about the mid level warth, but do you remember the event in December 2008? Very similar setup with the -EPO. I think NYC and around your area pulled out 7 inches.

I was actually looking at that event last night (I always do for analog purposes when it comes to SWFE's), and it's amazing how much higher and more amplified the height field was over the US in general during that event. We still got 6 inches of snow, which is definitely slightly encouraging.

http://www.meteo.psu.edu/~gadomski/NARR/2008/121912.png

[NaoPos]

Right, which is not what I'm arguing, but what I'm saying is that the track of the mid level centers is not favorable and often the mid level WAA is underforecast.

You make a valid point. With the 850 that close to the area, east, se , and ne of the flow would warm a bit. Looks icy to me.

however, does the physics of the storm allow it to come that far north with the Pv and related confluence? that;'s the question at play here.

[Tiburon]

Right, which is not what I'm arguing, but what I'm saying is that the track of the mid level centers is not favorable and often the mid level WAA is underforecast.

Exactly. Look at it this way--down by PHL, we had an H85 low to our south and east, an ideal position, and we still had significant WAA enough to switch us to sleet, IP, and rain a few days ago. Now this H85 low as modeled currently slides by to our west. Regardless of what the modeling says about temperature profiles, as depicted, the H85 layers and above will not stay below freezing on screaming SW winds.

[ag3]

yes, but with that 850 low how its progged, the mid levels would warm a lot quicker. If the gfs was to keep this exact track on tuesday i garuntee you would see the 850s surge north faster. As of now it means nothing cause its still 5 days away.

Depends. WAA usually is way ahead of 850 low, h5 low and main low.

In a lot of these types of situations, the snow falls way ahead of the low and is over by the time things warm and we end as light drizzle.

Forky pointed this out as well.

[TheTrials]

I was actually looking at that event last night (I always do for analog purposes when it comes to SWFE's), and it's amazing how much higher and more amplified the height field was over the US in general during that event. We still got 6 inches of snow, which is definitely slightly encouraging.

http://www.meteo.psu...2008/121912.png

The power of the -EPO.

First part of winter it was the -NAO, last week it was the +PNA, could this week be the -EPO? The holy trinity, lol.

[earthlight]

You make a valid point. With the 850 that close to the area, east, se , and ne of the flow would warm a bit. Looks icy to me.

however, does the physics of the storm allow it to come that far north with the Pv and related confluence? that;'s the question at play here.

That's where the timing comes into play. There's definitely a confluence "lobe" over Southeast Canada before the storm, and the GFS had been timing it well so that the initial shortwave would escape east without developing too far north. Over the last day or so we've seen some poor trends in allowing the confluence to lift a little bit and bring the surface low north/more amplified before it redevelops.

There's two sides to every story and there is with this threat as well. There's no blocking, there's no getting around that fact. It's just not there, or anywhere near there. But there is a large PV over East/Southeast Canada which is helping to reinforce high pressure and confluence aloft over Southeast Canada. So it's going to be about timing, and the general idea is that the combination of that confluent flow and the shortwave amplifying in the southwest US and ejecting northeast will create a swath of moderate to heavy precipitation along the gradient.

Lots of time with this one, still.

[TheTrials]

Depends. WAA usually is way ahead of 850 low, h5 low and main low.

In a lot of these types of situations, the snow falls way ahead of the low and is over by the time things warm and we end as light drizzle.

Forky pointed this out as well.

+1

[tombo82685]

through hr 78 the euro looks like the rest of the model guidance so far. It has a plus 1040 high over lake huron

[earthlight]

Exactly. Look at it this way--down by PHL, we had an H85 low to our south and east, an ideal position, and we still had significant WAA enough to switch us to sleet, IP, and rain a few days ago. Now this H85 low as modeled currently slides by to our west. Regardless of what the modeling says about temperature profiles, as depicted, the H85 layers and above will not stay below freezing on screaming SW winds.

Yeah, you've definitely got the right idea. Each setup is different, though...that one had a return flow develop as a high pressure slid off to the east...that definitely didn't help things at all and probably caused alot of the precipitation type issues you explained...as it completely ruined the antecedent airmass.

[earthlight]

Depends. WAA usually is way ahead of 850 low, h5 low and main low.

In a lot of these types of situations, the snow falls way ahead of the low and is over by the time things warm and we end as light drizzle.

Forky pointed this out as well.

Yup, another good point. The approach of the WAA precipitation is almost always underforecast by modeling. It's funny, because every single time we have SWFE...it comes in earlier, and people start going buck wild thinking we're getting more snow. In reality, it's just faster overall..so before you know it, it's sleeting and drizzling and then the sun is out.