The March 6 Storm- The (last) Great White Hope

[Deck Pic]

wow...guidance moved north with more of a coastal component..6z GFS has 500mb low exactly where we want it with almost a perfect track....based on what I am hearing about the euro ens, 0z op euro is probably an outlier....still lots of changes probably....

[MN Transplant]

I am a wee bit confused. Looking at the 84 hour panel for 2m temps, which has the freezing line all the way up near the US/Canadian border, and the sounding for NW DC for the same time having the surface temp at or about 35, doesn't make sense. Could I be misreading one or the other? I know I'm a weenie but that is a big difference to me.

Those are consistent.  We are into March now, so even with cold temperatures aloft, the surface is only going to be so chilly.  We are past the time where we are tapping great Arctic airmasses.  So, we need to count on the great weenie idea of "creating our own cold."  That is a silly way of stating that surface temperatures and the lower levels can be cooled by:  1) lack of sun, 2) evaporational cooling, and 3) precipitation drag.  So, it may very easily be the case that we are 34 and snowing on Wednesday, and State College is 38 and sunny (just throwing an example out, I have no idea what central PA's temps will be).

 

Also, for those fretting about the surface temps, yes, that is a concern.  Our ratios for this storm will be cruddy.  However, just because the model says that it is going to be 36 during a period of heavy precipitation, doesn't mean that it actually will be.  Turns out, they are not perfect.  And if we can get heavy precipitation forming as snow and falling into a column that is only warm near the surface, we will be ok. 

[Deck Pic]

Those are consistent.  We are into March now, so even with cold temperatures aloft, the surface is only going to be so chilly.  We are past the time where we are tapping great Arctic airmasses.  So, we need to count on the great weenie idea of "creating our own cold."  That is a silly way of stating that surface temperatures and the lower levels can be cooled by:  1) lack of sun, 2) evaporational cooling, and 3) precipitation drag.  So, it may very easily be the case that we are 34 and snowing on Wednesday, and State College is 38 and sunny (just throwing an example out, I have no idea what central PA's temps will be).

 

Also, for those fretting about the surface temps, yes, that is a concern.  Our ratios for this storm will be cruddy.  However, just because the model says that it is going to be 36 during a period of heavy precipitation, doesn't mean that it actually will be.  Turns out, they are not perfect.  And if we can get heavy precipitation forming as snow and falling into a column that is only warm near the surface, we will be ok. 

 

good post, but you are probably wasting your time...2 hours from now the thread will be 50 pages longer and the same things that have been addressed and discussed will be brought up by more and more people, many of whom have 11 posts or are from Paramus NJ

[MN Transplant]

wow...guidance moved north with more of a coastal component..6z GFS has 500mb low exactly where we want it with almost a perfect track....based on what I am hearing about the euro ens, 0z op euro is probably an outlier....still lots of changes probably....

 

Allan's site doesn't have 84, but this is pretty good.  North of the op.

[Deck Pic]

Allan's site doesn't have 84, but this is pretty good.  North of the op.

00zecmwfens500mbHGHTNA096.gif

 

nice...way north of the OP

[Bob Chill]

Soundings from 6z look good enough.

 

@ 0z wed when precip is knocking on dca's door it's warm at the surface (38-39) but wetbulb is just above freezing. There will be some quick cooling at precip saturates. It's still a snow sounding imo as precip gets going. 

 

 

 

@ 12z when the deform band is kicking pretty good. This is a sweet sounding for dca. Best profile so far. Yea, it's the 6z gfs but it's looks great.

 

[Deck Pic]

Soundings from 6z look good enough.

 

@ 0z wed when precip is knocking on dca's door it's warm at the surface (38-39) but wetbulb is just above freezing. There will be some quick cooling at precip saturates. It's still a snow sounding imo as precip gets going. 

 

dca0zwed.JPG

 

 

@ 12z when the deform band is kicking pretty good. This is a sweet sounding for dca. Best profile so far. Yea, it's the 6z gfs but it's looks great.

 

dca12zwed.JPG

 

most of us realize that any solution is going to come with its share of adverse factors, not the least of which is the BL/Sun angle....We dont HAVE to get some massive storm that flushes everyone with feet of snow...that doesnt HAVE to happen....no solution HAS to happen....the storm will do whatever the storm does and it will be imperfect

[MN Transplant]

A difference that will be interesting to track is the timing of precipitation onset.  The GFS (and NAM) start us off early in the overnight period, while the Euro holds back until the morning.

[mdhokie]

wow...guidance moved north with more of a coastal component..6z GFS has 500mb low exactly where we want it with almost a perfect track....based on what I am hearing about the euro ens, 0z op euro is probably an outlier....still lots of changes probably....

 

I thought thats what I saw on the 6z, more of a "classic" coastal look once it stalls. It then runs up the coast, but too far away to give anyone north of us snow. Position of H5 features still look great for our area. Not sure why all the doom and gloom posts around here are about.

[SLPressure]

Those are consistent.  We are into March now, so even with cold temperatures aloft, the surface is only going to be so chilly.  We are past the time where we are tapping great Arctic airmasses.  So, we need to count on the great weenie idea of "creating our own cold."  That is a silly way of stating that surface temperatures and the lower levels can be cooled by:  1) lack of sun, 2) evaporational cooling, and 3) precipitation drag.  So, it may very easily be the case that we are 34 and snowing on Wednesday, and State College is 38 and sunny (just throwing an example out, I have no idea what central PA's temps will be).

 

Also, for those fretting about the surface temps, yes, that is a concern.  Our ratios for this storm will be cruddy.  However, just because the model says that it is going to be 36 during a period of heavy precipitation, doesn't mean that it actually will be.  Turns out, they are not perfect.  And if we can get heavy precipitation forming as snow and falling into a column that is only warm near the surface, we will be ok. 

Thank you!

[Bob Chill]

most of us realize that any solution is going to come with its share of adverse factors, not the least of which is the BL/Sun angle....We dont HAVE to get some massive storm that flushes everyone with feet of snow...that doesnt HAVE to happen....no solution HAS to happen....the storm will do whatever the storm does and it will be imperfect

 

Totally. It's going to be messy. I'm sure there are those out there envisioning a feb 10 cold smoke whiteout but most (i think) have a handle on reality. Now that we've been teased with 3 shades of purple it kinda raises the bar of expectations. And 3 shades of purple could be right but so could one shade of blue. It's looking like a high prob that this is going to be a big precip make either overhead or within a 2 hour drive. 

 

I'm becoming confident that dca is going to break the streak but plenty can go wrong. I'm going to enjoy each model suite for what it is in the meantime. 

[Deck Pic]

A difference that will be interesting to track is the timing of precipitation onset.  The GFS (and NAM) start us off early in the overnight period, while the Euro holds back until the morning.

 

the euro is out to lunch right now.....the 6z GFS/GEFS/0zEuroens, just punched it in the face

[stormtracker]

Ok, had to step away, but I'm cutting and moderating now...which I hate to do.  Let's steer the thread back to some high quality and competent model disco and interpretation.  

[winterymix]

the euro is out to lunch right now.....the 6z GFS/GEFS/0zEuroens, just punched it in the face

The LWX AFD is eloquent.  They look for rain at onset with flip to snow as column cools and

then on Wednesday, when the low level east jet sets up, rain mixes back in.  They look for

a return to all snow at the tail end as CAA sets up.   They are doing the GFS shuffle and agree

the EURO is off its rocker.  After all, the EURO never breaks stride, the low keeps moving SE as

if, when off the coast, it imbeds itself into the SE ridge.

[WinterWxLuvr]

Soundings from 6z look good enough.

@ 0z wed when precip is knocking on dca's door it's warm at the surface (38-39) but wetbulb is just above freezing. There will be some quick cooling at precip saturates. It's still a snow sounding imo as precip gets going.

dca0zwed.JPG

@ 12z when the deform band is kicking pretty good. This is a sweet sounding for dca. Best profile so far. Yea, it's the 6z gfs but it's looks great.

dca12zwed.JPG

Bob, or others, quick question. I'm trying to take opportunities to learn how to read those things. Is the first sounding a virga situation for DC with the upper levels being saturated and the lower not? Also, if it is circa, would the red line fairly quickly move toward the green (toward each other I suppose)?

[WinterWxLuvr]

OK, I always preface with " I don't know how useful" but anyone with precip concerns is probably going to love the latest srefs. Over 1" precip with 850's under the whole time ( and crashing). Gotta love it, if you don't, then I don't know what to say.

[winterymix]

A difference that will be interesting to track is the timing of precipitation onset.  The GFS (and NAM) start us off early in the overnight period, while the Euro holds back until the morning.

At 300 mb, a huge jet running 150 kts is aligned off the US East Coast.  My hunch is that the jet speeds

onset because it creates divergence aloft.

[Bob Chill]

Bob, or others, quick question. I'm trying to take opportunities to learn how to read those things. Is the first sounding a virga situation for DC with the upper levels being saturated and the lower not? Also, if it is circa, would the red line fairly quickly move toward the green (toward each other I suppose)?

 

 

I don't know enough to define exactly when it's virga or not but in this case, dews and temp are pretty close at the surface and saturated air is pretty close overhead so this wouldn't be a virga sounding. The non saturated air is very shallow. Maybe mn, ian, or wxusaf could go into better detail at determining when a sounding shows dry enough overhead to have a period of virga. 

 

The blue line is the wet bulb so the temp and dew lines would basically meet at the wet bulb line. 

[vinylfreak89]

so the differences between the 00Z and 06Z GFS are due to mainly strength difference of the ULL and phasing interaction. We only have a 2 contour closed low as opposed to a 3 contour on the 6Z GFS.... thus QPF cuts down. Barring any shifts in the 12Z suite, I think we have finally resolved the situation in the N Atl. While I do agree with HM that phasing makes things messier, I disagree that it is irrelevant to the injection of cold air. The thermals in the 6z have cooled down, and I do think that is partially in part to more interaction between the northern stream and the bowling ball. On the flip side, I also think thats why the bowling ball has trended weaker. Because there is more interaction between the two vorts, some of the energy has to be split. With 3 days until go time this can go either way. But one sure way to screw it up is to partially phase but not complete the job.

[Huffwx]

the euro is out to lunch right now.....the 6z GFS/GEFS/0zEuroens, just punched it in the face

 

 

I wish we could see the 6 hours on the EC ENS--

 

SLP is 75 miles east of the OP.

[PDIII]

the euro is out to lunch right now.....the 6z GFS/GEFS/0zEuroens, just punched it in the f  

 

What do you mean by out to lunch?  Obviously it is different than the others.. but I want to get your take on why you think it is an outlier?

[nflwxman]

I think it's silly to consider the euro an outlier- it's been most consistent on the general bullseye from run to run. In addition the 0z GFS actually matched the 0z euro in SLP placement (until

the 6z bounced around). The GEFS is beginning to lose its usefulness, the NAM and SREFs have little usefulness to begin with. The UKMet was fairly far south matching up with the euro. The GGEM has been strangly consistent with a inland SLP. I just don't see how one can throw out the 0z euro given the above summary.

[Huffwx]

I think it's silly to consider the euro an outlier- it's been most consistent on the general bullseye from run to run. In addition the 0z GFS actually matched the 0z euro in SLP placement (until

the 6z bounced around). The GEFS is beginning to lose its usefulness, the NAM and SREFs have little usefulness to begin with. The UKMet was fairly far south matching up with the euro. The GGEM has been strangly consistent with a inland SLP. I just don't see how one can throw out the 0z euro given the above summary.

 

 

We all have a bias of wanting to favor the model that's best for our region. however, in CHO you're going to get clocked either way.

 

We don't have the details of the EC ENS-- its more east and a shade weaker. I'm not sure what that mean totally. Without the model support of the GFS, I'm not a fan of this event yet for my area. 

[PDIII]

The LWX AFD is eloquent.  They look for rain at onset with flip to snow as column cools and

then on Wednesday, when the low level east jet sets up, rain mixes back in.  They look for

a return to all snow at the tail end as CAA sets up.   They are doing the GFS shuffle and agree

the EURO is off its rocker.  After all, the EURO never breaks stride, the low keeps moving SE as

if, when off the coast, it imbeds itself into the SE ridge.

Bob's sounding analysis above suggests a rain quickly to snow and then "stay snow" event... I believe other sounding analysis above also supports snow... do you think LWX is being conservative.. or perhaps they are basing their forecast off of old data?  

[nflwxman]

We all have a bias of wanting to favor the model that's best for our region. however, in CHO you're going to get clocked either way.

We don't have the details of the EC ENS-- its more east and a shade weaker. I'm not sure what that mean totally. Without the model support of the GFS, I'm not a fan of this event yet for my area.

I'm more talking about the consistency of the model with this storm- the euro hasn't really shaken the idea of a west VA bullseye for many many runs- the GFS flipped twice on SLP placement in the last 2 runs.

[Bob Chill]

Bob's sounding analysis above suggests a rain quickly to snow and then "stay snow" event... I believe other sounding analysis above also supports snow... do you think LWX is being conservative.. or perhaps they are basing their forecast off of old data?  

 

It's just one sounding though from the 6z gfs. There is plenty of support for more rain than the 6z is showing. If 12z comes with with better thermals then there is slightly more confidence but it's so borderline that rain won't be off the table at any time. It's become clear that heavy rates will be snow. Even with a very marginal sounding. Heavy rates are far from locked. LWX is totally doing to right thing. 

 

As I've stated many times the last couple years, I typically focus on what's good and point it out. 

[mitchnick]

12z NAM is holding on to the Canadian maritime vort longer than 6z, at  least through 48 hrs, which is causing it to slow down the midwest vort a bit

[Huffwx]

I'm more talking about the consistency of the model with this storm- the euro hasn't really shaken the idea of a west VA bullseye for many many runs- the GFS flipped twice on SLP placement in the last 2 runs.

 

 

Agree-- in stats, of you can throw out the high and low extremes and get a good average. That's a decent strategy most of the time.

 

I'm running a comparison to the 0z EC vs 12z NAm-- like a crack addict. 

 

It did hold that vort a little longer east of NE, and the MW vort is maybe 100 miles NE of the EC at the same point. NW MO vs NE Iowa. 

 

However, this is a wasted effort on the EC. (Unless it shows big snows)

[Bob Chill]

12z NAM is holding on to the Canadian maritime vort longer than 6z, at  least through 48 hrs, which is causing it to slow down the midwest vort a bit

 

Before anybody starts the "nam is north" with slp stuff... the nam has consistently been north of the globals past its useful range. It's doing it again and it's nothing to overanalyze and freak out on. 

[winterymix]

Bob's sounding analysis above suggests a rain quickly to snow and then "stay snow" event... I believe other sounding analysis above also supports snow... do you think LWX is being conservative.. or perhaps they are basing their forecast off of old data?  

Based upon the LWX AFD they have the insight that best snow accumulations will occur at night, (diurnal effect), at elevation and with best rates/precipitation velocities/banding and

during the day Wednesday, the strong loow level east wind may overcome the positive-for-snow factors, it will be a tag of war equilibrium.

 

A second look at the GFS suggests a good bit of sleet mixing in during the morning west of the C. Bay (Wednesday).