Febuary 9-11 threat

[SnoSki14]

Again the pattern is very unfavorable for us to get a big storm, but things always seem to work out somehow in the end. The 12z and 18z gfs runs are like night and day after 3 days, but the threat is on the table whether it be a flooding rainstorm which I'm strongly favoring or snow.

[earthlight]

[Juliancolton]

Usually a sub-970mb surface low with plentiful QPF would be fun to look at it, but the GFS depictions are so unrealistic looking it's not even good for eye candy.

[A-L-E-X]

John, it sounds like you'll be laughing all the way to the snowbank if this verifies

[A-L-E-X]

Again the pattern is very unfavorable for us to get a big storm, but things always seem to work out somehow in the end. The 12z and 18z gfs runs are like night and day after 3 days, but the threat is on the table whether it be a flooding rainstorm which I'm strongly favoring or snow.

I agree, the trends dont look good right now; Im still favoring a return back to strong blocking for the last week of Feb and most of March, like what Don S. talked about. If we get a few rainstorms in between so what lol.

[Kaner587]

Again the pattern is very unfavorable for us to get a big storm, but things always seem to work out somehow in the end. The 12z and 18z gfs runs are like night and day after 3 days, but the threat is on the table whether it be a flooding rainstorm which I'm strongly favoring or snow.

pattern is definitely unfavorable, but based on seasonal trends, while this may not ending up being a snowstorm, esp for the coast I really doubt we get a flooding rainstorm. Snow to rain to snow or something like that sure. I just don't see where you're pulling a flooding rainstorm from, esp since we've been in an unfavorable pattern for a couple wks throughout our 6 wk run of amazing winter weather, and the most we've seen is ice to rain. The signal is definitely for an inland snowstorm with the ridge axis so far west, but "strongly favoring" a flooding rainstorm? I think that is about as likely as a major snowstorm. This will likely fall in between the 2

[A-L-E-X]

pattern is definitely unfavorable, but based on seasonal trends, while this may not ending up being a snowstorm, esp for the coast I really doubt we get a flooding rainstorm. Snow to rain to snow or something like that sure. I just don't see where you're pulling a flooding rainstorm from, esp since we've been in an unfavorable pattern for a couple wks throughout our 6 wk run of amazing winter weather, and the most we've seen is ice to rain. The signal is definitely for an inland snowstorm with the ridge axis so far west, but "strongly favoring" a flooding rainstorm? I think that is about as likely as a major snowstorm. This will likely fall in between the 2

While this winter started out very reminiscent of 2009-10 (for us, not DC) it has morphed into a 1993-94 type winter, in terms of storm frequency and that nagging 0C line that seems determined to bisect our region.

[Sundog]

As far as I'm concerned drawing any conclusions based on a 160 hour upper air depiction is foolish, regardless if the final surface representation is favorable or not.

[Kaner587]

While this winter started out very reminiscent of 2009-10 (for us, not DC) it has morphed into a 1993-94 type winter, in terms of storm frequency and that nagging 0C line that seems determined to bisect our region.

exactly why I believe this doesn't turn out to be a flooding rainstorm lol...odds are we get frozen overrunning with a change to rain at the coast back to snow at the end. Obviously there are about a million ways this could turn out along with the possibility of this heading ots with no phasing. I think there is only so much room for this to cut west, at least in the way the models are advertising it now, because of the confluence over the mid-west and NE as the s/w digs southeastward into the plains. So while a more wet scenario is definitely favored there is room for us to "thread the needle" as we've done about 5 times this winter so far.

[TheTrials]

As far as I'm concerned drawing any conclusions based on a 160 hour upper air depiction is foolish, regardless if the final surface representation is favorable or not.

No way dude. The rain snow line is set in stone, 168 hour soundings always verify.

[eduggs]

Everything about this storm signal is huge:

Huge temperature gradient across the continental US, huge amplitude trof and ridge, huge wind maxes, and huge moisture influx. Definitely could be a massive storm.

But that doesn't mean we get big snows. Any surface system will be very quick unless the mid-level southern stream s/w is stronger and more negatively tilted and ideally cutoff, beginning in the SE. Could easily cut inland but there's so much antecedent cold and a reinforcing shot. The preceeding system also looks interesting, and could impact the development of the follow up storm. I also like the lead overrunning snow threat.

[SnoSki14]

I do like the fact that we get a lot of cold prior to the storm. This will once again be all about timing, but basically we have 3 events on the table for the next 7 days. The first one could give us a couple of inches (rain to snow type of deal). The 2nd is really interesting at hours 90-108, I wonder if we could get that to dig further south, maybe we could a coastal that gives us a few more inches, then of course there's this threat. I'm hoping it does not phase and just keeps moving right along because that way we could at least pick up some frozen precipitation.

This threat does not need to phase because it's already pumped with plenty of moisture. It reminds me of those storms that develop along an arctic front or cold front because that's essentially what the gfs shows. I think the best case would be some snow in the overrunning, than a change to sleet/rain for a bit, and back to heavy snow giving us 6"+. Fun week ahead though.

[NJwinter23]

Everything about this storm signal is huge:

Huge temperature gradient across the continental US, huge amplitude trof and ridge, huge wind maxes, and huge moisture influx. Definitely could be a massive storm.

But that doesn't mean we get big snows. Any surface system will be very quick unless the mid-level southern stream s/w is stronger and more negatively tilted and ideally cutoff, beginning in the SE. Could easily cut inland but there's so much antecedent cold and a reinforcing shot. The preceeding system also looks interesting, and could impact the development of the follow up storm. I also like the lead overrunning snow threat.

Agreed. HUGE storm signal. The temperature contrast is unbelievable and thats why I'm already confident about this storm taking shape 160+hrs out..Where it tracks and what we get is a whole different battle and one that only the true weenie's will take the time to dwell over.

That trough is serious, look how the depicted storm dominates the whole nearby scene/continent

[A-L-E-X]

Agreed. HUGE storm signal. The temperature contrast is unbelievable and thats why I'm already confident about this storm taking shape 160+hrs out..Where it tracks and what we get is a whole different battle and one that only the true weenie's will take the time to dwell over.

That trough is serious, look how the depicted storm dominates the whole nearby scene/continent

One thing is true-- and that is, if this storm turns out to be mostly rain our snowpack will be gone. Im very ambivalent about any storm threat right now before we go back to a December 2010 kind of pattern, which looks to set up in latter Feb and most of March. I would love to get a winter storm before then, but I think this is a situation where being on the south shore of LI (maybe even NYC) might make it more wet than white.

[IsentropicLift]

We need some blocking and that threat at day 5 may be just what the doctor ordered in terms of a 50/50 low setting up. Noticed one thing about this run, it was less organized with the first system, and that seemed to have quite the downstream effect. Track actally looks very similar to the Euro op.

[tombo82685]

of the 11 18z gfs ens members shown on ewall...5 are warm solutions...4 are hits...2 ots

[IsentropicLift]

of the 11 18z gfs ens members shown on ewall...5 are warm solutions...4 are hits...2 ots

Thanks Tombo, sort of sounds like right where we want to be. I bet the mean itself was a fairly nice hit considering the spread.

[IsentropicLift]

Getting quite ahead of myself but.....Saturday could be the appetizer, Tuesday/Wed could be surf and turf, and the following weekend could be the bannana split......

What an epic winter, 3 legitimate threats to follow all at once.

[NorthShoreWx]

I followed this storm north on the 18z GFS and immediately called my eye doctor to make an appointment. These crummy glasses made it look like a 936 low in the Gulf of St Lawrence at 180. Definitely time to get the prescription checked

[Analog96]

hr 156 850's and surface over the city low over sc

Hr 159 rain for the city...nw areas getting crushed....

hr 162 low of eastern delmarva...snow rain line is pretty much 95.....dc getting crushed...nyc it prob back to frozen

162-170 we are pretty much crushed by heavy snow.....low track over eastern LI

There is no plain rain on the GFS. 2m temps never get above 30.

[Analog96]

Thanks Tombo, sort of sounds like right where we want to be. I bet the mean itself was a fairly nice hit considering the spread.

I'd personally like a few more OTS solutions myself.

[LakeEffectKing]

I followed this storm north on the 18z GFS and immediately called my eye doctor to make an appointment. These crummy glasses made it look like a 936 low in the Gulf of St Lawrence at 180. Definitely time to get the prescription checked

And if you click on the next panel at 192, you'll see that indeed you do have crummy glasses.....it's 932.....

[hudsonvalley21]

And if you click on the next panel at 192, you'll see that indeed you do have crummy glasses.....it's 932.....

Nice surface temps. from hour 120 and higher as per the 18z GFS for KALB.

http://www.meteor.ia...=gfsm&site=kalb

[Thunder Road]

fwiw the 18z DGEX has a 973 outside the BM with ~0.25" of precip.

now all we need is the nogaps and JMA...

[eamp]

12z GFS bufkit has the three hour period ending at hr 171 with 13.6" for KPHL! Of course, 26:1 ratios really help.

110210/0300Z 159 17005KT 24.1F 0:1| 0.0|| 0.0 0.000|| 0.00 0.00|| 0.00 0.00|| 0.00 0| 0| 0

110210/0600Z 162 18006KT 25.0F SNOW 12:1| 0.1|| 0.1 0.012|| 0.01 0.00|| 0.00 0.00|| 0.00 100| 0| 0

110210/0900Z 165 09005KT 25.9F SNOW 11:1| 1.0|| 1.1 0.091|| 0.10 0.00|| 0.00 0.00|| 0.00 100| 0| 0

110210/1200Z 168 04010KT 25.7F SNOW 17:1| 3.5|| 4.7 0.213|| 0.31 0.00|| 0.00 0.00|| 0.00 100| 0| 0

----------------------------------------------+----++-------------++--------------++-------------++-----------+---+---

110210/1500Z 171 36018KT 23.9F SNOW 26:1|13.6||18.3 0.516|| 0.83 0.00|| 0.00 0.00|| 0.00 100| 0| 0

110210/1800Z 174 32017KT 26.8F SNOW 21:1| 2.3||20.6 0.110|| 0.94 0.00|| 0.00 0.00|| 0.00 100| 0| 0

110210/2100Z 177 30016KT 24.4F SNOW 14:1| 0.3||20.8 0.020|| 0.96 0.00|| 0.00 0.00|| 0.00 100| 0| 0

110211/0000Z 180 28014KT 18.3F 0:1| 0.0||20.8 0.000|| 0.96 0.00|| 0.00 0.00|| 0.00 0| 0| 0

http://www.meteor.ia...l=gfs&site=kphl

Agree: the 26:1 ratios generate by this Cobb table are.......umm.... exceptionally rare.

It could be why the link you provided has this warning just before the Cobb table: "The Cobb method shouldn't be confused or affiliated with precipitation-type algorithms in BUFKIT. "

[NorthShoreWx]

And if you click on the next panel at 192, you'll see that indeed you do have crummy glasses.....it's 932.....

[earthlight]

In regards to this potential, very much is still up in the air and that's the least that can be said. Still, I think the storm threat itself is very legitimate, and one that will offer the prospects of a severe and high impact event somewhere east of the Central United States. The Polar Vortex and Pacific jet energy have been relatively well modeled. We aren't talking of specific shortwaves and vorticity lobes here, those are intricate details which will be ironed out as we approach the event. Yet, the general idea for a mean trough over the Central and eventually Eastern US is quite concerning in this time frame when one considers the state of the atmosphere.

A very large ridge off the West Coast of the United States is forecast to be in positive flux at that time, with GEFS and ECWMF ensembles bringing 576 heights to some of the farthest north latitudes along the Western Coast of the US that I have seen thus far this winter. At the same time, the Polar Vortex will be situated over Eastern or Central Canada (it's position being very important to the eventual event impact and track). In addition, the NAO is forecast to take a nose dive towards neutral and/or negative...which sounds the alarm for me right off the bat. Archumbault events are high impact events, there is no doubting that. We don't always see Archumbault events when the NAO changes phases, this is where some confusion can come up as the credibility of the Archumbault theory and research. But the main point, without getting too in depth, is for the bigger events historically to occur when the phase change is rapid and significant, which is what is being advertised by superensemble forecasting.

With the information we have, in this tremendous lead time, it's not at all surprising that most model guidance has at least presented the idea of the larger-type event. The storm threat is certainly legitimate, and everybody is in the game at this point. It's important at this stage, that we ask ourselves what to look for. What are the red flags we can see on modeling that may tell us which direction this is going to head in? This is what modeling is designed to do..not to be taken literally, but to "talk" to us...give us signals via trends/biases/etc that we can interpret.

If you ask me, important things to watch include:

The Polar Vortex positioning: This feature is critically important in almost every winter storm that involves a Polar Vortex on our side of the hemisphere. Can we get snow on the East Coast if the Polar Vortex is in Central Canada? Sure...but you can sure as hell bet that areas west of the coastal plain will be more well off.

The Pacific Ridge: Almost all of our major snowstorms on the east coast have come with west coast ridges that are further east than being advertised by most models. Again, we can work with what we're given..but the ideal setup for big ridge amplification on the west coast is well east of where it's being modeled.

The northern stream/southern stream interaction: We've seen a few different model solutions the past few days and they all are owing to separate northern stream solutions. The 18z GFS today was basically a frontal wave development because the northern stream never totally phased with the southern stream, the southern stream shortwave was tugged up the east side of the mean trough along the front. The cyclone never matured until it was north of New England. The 12z GFS was a much more favorable situation for cyclogenesis off the east coast.

Again..these are all just pieces of the puzzle which we can (hopefully) put down on the table at this extended lead time. Putting them into place will take time...and patience. Hoping for lots of snow for everybody. If there's a pattern to get snow without the "uber block" we had earlier this winter, this is the one we want.

Cheers dudes.

[hudsonvalley21]

In regards to this potential, very much is still up in the air and that's the least that can be said. Still, I think the storm threat itself is very legitimate, and one that will offer the prospects of a severe and high impact event somewhere east of the Central United States. The Polar Vortex and Pacific jet energy have been relatively well modeled. We aren't talking of specific shortwaves and vorticity lobes here, those are intricate details which will be ironed out as we approach the event. Yet, the general idea for a mean trough over the Central and eventually Eastern US is quite concerning in this time frame when one considers the state of the atmosphere.

A very large ridge off the West Coast of the United States is forecast to be in positive flux at that time, with GEFS and ECWMF ensembles bringing 576 heights to some of the farthest north latitudes along the Western Coast of the US that I have seen thus far this winter. At the same time, the Polar Vortex will be situated over Eastern or Central Canada (it's position being very important to the eventual event impact and track). In addition, the NAO is forecast to take a nose dive towards neutral and/or negative...which sounds the alarm for me right off the bat. Archumbault events are high impact events, there is no doubting that. We don't always see Archumbault events when the NAO changes phases, this is where some confusion can come up as the credibility of the Archumbault theory and research. But the main point, without getting too in depth, is for the bigger events historically to occur when the phase change is rapid and significant, which is what is being advertised by superensemble forecasting.

With the information we have, in this tremendous lead time, it's not at all surprising that most model guidance has at least presented the idea of the larger-type event. The storm threat is certainly legitimate, and everybody is in the game at this point. It's important at this stage, that we ask ourselves what to look for. What are the red flags we can see on modeling that may tell us which direction this is going to head in? This is what modeling is designed to do..not to be taken literally, but to "talk" to us...give us signals via trends/biases/etc that we can interpret.

If you ask me, important things to watch include:

The Polar Vortex positioning: This feature is critically important in almost every winter storm that involves a Polar Vortex on our side of the hemisphere. Can we get snow on the East Coast if the Polar Vortex is in Central Canada? Sure...but you can sure as hell bet that areas west of the coastal plain will be more well off.

The Pacific Ridge: Almost all of our major snowstorms on the east coast have come with west coast ridges that are further east than being advertised by most models. Again, we can work with what we're given..but the ideal setup for big ridge amplification on the west coast is well east of where it's being modeled.

The northern stream/southern stream interaction: We've seen a few different model solutions the past few days and they all are owing to separate northern stream solutions. The 18z GFS today was basically a frontal wave development because the northern stream never totally phased with the southern stream, the southern stream shortwave was tugged up the east side of the mean trough along the front. The cyclone never matured until it was north of New England. The 12z GFS was a much more favorable situation for cyclogenesis off the east coast.

Again..these are all just pieces of the puzzle which we can (hopefully) put down on the table at this extended lead time. Putting them into place will take time...and patience. Hoping for lots of snow for everybody. If there's a pattern to get snow without the "uber block" we had earlier this winter, this is the one we want.

Cheers dudes.

Great post! This might be the big one for some folks this season or for a few seasons. Interesting week of seeing how this unfolds

[Quakertown needs snow]

A+ writeup earthlight!

Thanks!

I posted JB's evening big dog highlights in the Phila forum

[Pohopoco]

Thanks for taking the time,Great Post Earthlght...