November Med/Long Range Disco

[psuhoffman]

They rightly get a bad rap. We luck into them on extremely rare occasions - certainly not often enough to look forward to them. They produce far more frustration for us than they do snow.

If we were to have a stout -NAO and one showed up in the models, then maybe I'd be more interested.

You just described almost all of our snow threats though which is why much of this forum gets way less snow then we would like. When are we really truly likely to cash in on a sig 4"+ snow? With a stj driven miller a during a -nao. And how often and likely are those in any given winter or pattern. If we threw out the occasional miller b hits and numerous minor snowfalls from them our avg would fall another 5" a year or so. I'm not willing to go there.

[mattie g]

You just described almost all of our snow threats though which is why much of this forum gets way less snow then we would like. When are we really truly likely to cash in on a sig 4"+ snow? With a stj driven miller a during a -nao. And how often and likely are those in any given winter or pattern. If we threw out the occasional miller b hits and numerous minor snowfalls from them our avg would fall another 5" a year or so. I'm not willing to go there.

But I never said anything about big snows or Miller As...just that Miller Bs do nothing for me. I seriously doubt we average 5" per season from them, especially where I am. Wispy clouds and chilly. No thanks.

[psuhoffman]

But I never said anything about big snows or Miller As...just that Miller Bs do nothing for me. I seriously doubt we average 5" per season from them, especially where I am. Wispy clouds and chilly. No thanks.

I think first of all we would have to split our region into zones because the north and east portions of this forum tend to do a lot better then areas south and west of DCA with miller b's.  So for anyone living in Manassas or Fredericksburg for instance, your statement would probably be correct.  For much of Maryland, however, miller bs can be a significant portion of our snowfall.  Just last winter we got a couple 2-3" snowfalls from miller b storms that hit new england really hard.  I can remember several moderate snowfalls in past years without even digging through records.  There was the really big one in Feb 2010 for DC north.  We had a 3-4" snowfall Dec 2005 from a storm with a primary up into Michigan before a secondary developed.  A lot of sleet mixed in with that one.  I remember a 3-6" snowfall area wide in Jan 2005 from one.  In late January 2004 there was a 3 day storm where most of our area got 4-8".  The first low went up near St Louis then eventually a coastal formed off NJ.  We got 4-5" from the initial low overrunning then another 1-3" from the coastal redevelopment.  Dec 2003 most of our area got 3-8" from a storm where the primary went up into Ohio then a secondary formed off the VA capes. The christmas 2002 storm that got much of our area with 2-4" was a miller b, I remember the initial low going up west then a secondary forming along the coast.  Back further I remember a clipper that redeveloped in feb 1996 and gave our area 6-10".  Those are all just off the top of my head and there are a LOT of examples of less significant 1-2" snowfalls in our area from the southern edge of miller b's that hit north of us.  Many of those did hit to our north far worse so I guess if you want to be in the bullzeye they are frustrating but they do produce snowfall here, and given our climo I dont think we can afford to throw away anything.  I will say there are different types of miller b's.  Some on here when we talk of miller bs only seem to think of northern stream clipper initiated miller b's that bomb off new england.  Those are really bad for our area and are less likely to give us any snowfall, although we do sometimes get into them a bit, feb 76 and jan 2005 we got decent snows from that type of system.  But southern stream or hybrid systems where a primary goes up into the ohio valley then a secondary redevelops are miller b's as well and some of those have been very good storms in our area, and many consider PDII Feb 2003 to be a miller b storm since its primary low went up west of the apps then redeveloped.  I agree and would much prefer a miller a in our area I am just saying people are way to quick to just dismiss miller b storms out of hand because we get screwed compared to new england with them often times.  Unfortunately we get screwed with almost every snow threat around here so throwing out all miller bs seems silly to me.

[PrinceFrederickWx]

Some bad memories for many here from failed miller b events. I actually did decently here in the Dec 2010 Boxing Day storm (about 5") but even that was well less than forecast. The eastern and NE areas in this subforum tend to do better overall in these events I suppose, but I can recall plenty of misses and under performers.

Wasn't Boxing Day a Miller A? I thought it was.

[Fozz]

Great to have data on this, thanks for sharing. I'm not sure why, but the idea that 4" isn't significant around here touches a nerve. Based on the data you posted, it might be a DC specific thing, with the odds of a 4"+ event yearly being much higher at the other two locations.

What constitutes a significant event to you?

Living here, I think (at least in DC) 4" is the line for significant, 8" is major (I know warning criteria is lower) and 12+ is the holy grail.

That may be skewed though, as I think I've only seen one or two true 8" events and nothing over 12" in the two years I've been here.

 

It definitely depends on your climo where to draw the line on what is significant. I agree with 4" being significant for the immediate metros.

[Scarlet Pimpernel]

Taken through time...these equations tend to have exponential error growth.

 

wxeq.png

 

 

 Ens means are good...but varying initial conds is still a crude and over avg'd way to account for inherent model error and lack of data. Also...outliers can be randomly good or bad.    

 

Aaaaah...flashbacks from Holton (and others)!!  Maybe that image should be in the Panic Room, as those equations are sure to cause despair!

 

Seriously though, you make a very good point that I think some people forget.  Especially in regard to looking at the longer range and seeing wild swings in the deterministic GFS, for instance, and wondering "where did our storm go?"  Using the ensemble mean in the medium-longer range is perhaps one of the best tools...in combination with the spread of solutions.  But as you say or imply, we don't necessarily vary the initial conditions as well as we should, though that science has improved over the years.  My understanding is that we still tend to make things underdispersive compared to reality.  That, and it's really tricky if there are a couple of solution clusters; the mean just takes the middle of that, but with disparate solutions it's not necessarily the best one to use.

[Heisy]

Pretty powerful Nor'Easter on the GFS for Dec 1-3rd, but by the time it comes the HP moves into a bad spot, so obviously all rain. 

[Ian]

Pretty powerful Nor'Easter on the GFS for Dec 1-3rd, but by the time it comes the HP moves into a bad spot, so obviously all rain.

#strongninoing

[Ian]

I split all the posts discussing significant snow off:

 

http://www.americanwx.com/bb/index.php/topic/47289-what-is-a-significant-winter-weather-event-to-you/

[Heisy]

The Dec 1st storm on the EURO is pretty close. Cold air source is fairly weak though, so most likely a N & W frozen storm. 

[RedSky]

The Dec 1st storm on the EURO is pretty close. Cold air source is fairly weak though, so most likely a N & W frozen storm. 

No problem it will make it's own cold air, an oldie but still a goody

[H2O]

I think this will be a thread the needle deal.

[BristowWx]

I mean at this point I think this is thread the needle even for 40N...Interior NE would do well.  Tough time seeing this work out for us unless be had a better HP

[midatlanticweather]

The Dec 1st storm on the EURO is pretty close. Cold air source is fairly weak though, so most likely a N & W frozen storm.

Weather bell weenie maps are nice to see. Cold rain the likely outcome! Still a ways off but cool to see nonetheless!

[Bob Chill]

I think this will be a thread the needle deal.

 

Heh, early Dec climo with marginal conditions verbatim on the euro op run. I don't get too fired up when there is no leeway with track, timing, and temps 8 days out. Surface temps are above freezing everywhere on the op run. 

 

Euro Ensembles are all over the place with good setups being in the far minority. GEFS has virtually no good looks. Not really much to get excited about. 

[mappy]

not sure i can remember a time where a lakes cutter than transfers to the coast has ever worked out for us? 

[stormtracker]

not sure i can remember a time where a lakes cutter than transfers to the coast has ever worked out for us? 

That's bad for us in Mid February, much less early December.  

[WinterWxLuvr]

not sure i can remember a time where a lakes cutter than transfers to the coast has ever worked out for us? 

Depends when it cuts and where you are in our region.

 

If it cuts to the eastern Ohio valley, then we do well on the front end of those sometimes (Dec 2012 I think is one example).

 

If it cuts through Nashville and Louisville, and westward, yeah, we don't get much of anything from those.

[H2O]

Heh, early Dec climo with marginal conditions verbatim on the euro op run. I don't get too fired up when there is no leeway with track, timing, and temps 8 days out. Surface temps are above freezing everywhere on the op run. 

 

Euro Ensembles are all over the place with good setups being in the far minority. GEFS has virtually no good looks. Not really much to get excited about. 

 

I didn't like one thing about the overnight model runs TBH.  Pac is wonky looking frame to frame and no blocking.

[Bob Chill]

I didn't like one thing about the overnight model runs TBH.  Pac is wonky looking frame to frame and no blocking.

 

Guidance is generally moving towards a pretty standard Dec nino look. Ridging in central Canada with an active southern stream undercutting everything. It may be wet in our area but it's pretty hard to envision how we can get cold enough during the first half of the month. We really need solid cold air delivery to stand a chance. Like you said, no blocking means any cold will be in and out faster than a (fill in the blank. lol).

 

Marginal or modified are 2 words that = not much chance this far south. Maybe late Dec through the heart of winter climo. Not much to worry about either way. Things are moving along pretty much as expected. 

[packbacker]

Guidance is generally moving towards a pretty standard Dec nino look. Ridging in central Canada with an active southern stream undercutting everything. It may be wet in our area but it's pretty hard to envision how we can get cold enough during the first half of the month. We really need solid cold air delivery to stand a chance. Like you said, no blocking means any cold will be in and out faster than a (fill in the blank. lol).

 

Marginal or modified are 2 words that = not much chance this far south. Maybe late Dec through the heart of winter climo. Not much to worry about either way. Things are moving along pretty much as expected. 

 

Going to be relatively boring Dec, unless you like seasonal temps and rain but we all kind of knew that.  Hopefully by mid/end December we see a weakened PV, if it isn't it may be a long wait till Feb.

[WinterWxLuvr]

Guidance is generally moving towards a pretty standard Dec nino look. Ridging in central Canada with an active southern stream undercutting everything. It may be wet in our area but it's pretty hard to envision how we can get cold enough during the first half of the month. We really need solid cold air delivery to stand a chance. Like you said, no blocking means any cold will be in and out faster than a (fill in the blank. lol).

 

Marginal or modified are 2 words that = not much chance this far south. Maybe late Dec through the heart of winter climo. Not much to worry about either way. Things are moving along pretty much as expected. 

One thing that is interesting to me is the difference between what is forecast for Sunday today vs. what was forecast about 4-5 days ago.  Completely different.  And it had good ensemble support (gfs).  Not that it was a snow event, but what's coming now isn't even the same neighborhood.

 

As always, I think forecasts 10+ days in advance should be viewed with skepticism, even ens. means.

[mappy]

Going to be relatively boring Dec, unless you like seasonal temps and rain but we all kind of knew that.  Hopefully by mid/end December we see a weakened PV, if it isn't it may be a long wait till Feb.

 

Im not sure such definitive statements can be said this time around. The models are changing constantly long term..... unless you have a crystal ball that works, in which case, i will talk some lotto numbers if you got them. 

[Scarlet Pimpernel]

I didn't like one thing about the overnight model runs TBH.  Pac is wonky looking frame to frame and no blocking.

 

Pretty much...that was my feeling as well.  Other than a couple of below normal days perhaps in the early part of December, there's nothing very inspiring to look at.

 

 

Guidance is generally moving towards a pretty standard Dec nino look. Ridging in central Canada with an active southern stream undercutting everything. It may be wet in our area but it's pretty hard to envision how we can get cold enough during the first half of the month. We really need solid cold air delivery to stand a chance. Like you said, no blocking means any cold will be in and out faster than a (fill in the blank. lol).

 

Marginal or modified are 2 words that = not much chance this far south. Maybe late Dec through the heart of winter climo. Not much to worry about either way. Things are moving along pretty much as expected. 

 

Yeah, the "no blocking" in addition to the Pacific firehose is just killing us.  A glance at the ensemble mean flow at 500 mb is putrid-looking through the medium range.  There is no real cold air anywhere and essentially wall-to-wall flow right off the Pacific.  But as you say, I don't think this is totally surprising for a strong Nino in December and many people more or less called for this.  Right now, I certainly won't be surprised if it's just as "blah" as last December in the end.  Can't say what will happen later in the month but we can hope it shows signs of interesting things going into the New Year.

 

Funny but for some reason your "cold will be in and out faster than [fill in the blank...]" comment made me think of that line in "A Christmas Story" where Ralphie (narrating as an adult) said, after a fuse went out in the house, "My old man could change a fuse faster than a jack rabbit on a date."

[H2O]

I guess I should clarify that while the pattern isn't great having an active one is better than not.  At least each cool/warm shot is transient and we don't wall to wall bake.  

[Scarlet Pimpernel]

I guess I should clarify that while the pattern isn't great having an active one is better than not.  At least each cool/warm shot is transient and we don't wall to wall bake.  

 

Yeah, I knew what you meant.  It certainly is active, to be sure.  It's definitely not wintry-looking, but doesn't exactly look like a "torch" I don't think.

[Bob Chill]

One thing that is interesting to me is the difference between what is forecast for Sunday today vs. what was forecast about 4-5 days ago.  Completely different.  And it had good ensemble support (gfs).  Not that it was a snow event, but what's coming now isn't even the same neighborhood.

 

As always, I think forecasts 10+ days in advance should be viewed with skepticism, even ens. means.

 

Ens means are really good at getting the feel for a period of time. With sensible weather, speaking in absolutes at long leads will almost never work out. But general ideas outside of 10 days does have some skill. Especially when simply deciding if it seems more likely to be dry/wet or AN/BN. Obviously this time of year through Feb I'm pretty much only looking for snow chances (or big cold). Neither of which look promising in any way except for some weird perfectly timed fluke. And digging deep into those is best left alone until inside of 4 days. 

[packbacker]

Im not sure such definitive statements can be said this time around. The models are changing constantly long term..... unless you have a crystal ball that works, in which case, i will talk some lotto numbers if you got them.

Nino climo is a great crystal ball :-). Sure a fluke could happen, especially for you guys. Let's just say that as active/wintery mid-Jan to end of Feb will make up for the mundaneness of Dec. Although that's probably to definitive too :-)

[usedtobe]

Guidance is generally moving towards a pretty standard Dec nino look. Ridging in central Canada with an active southern stream undercutting everything. It may be wet in our area but it's pretty hard to envision how we can get cold enough during the first half of the month. We really need solid cold air delivery to stand a chance. Like you said, no blocking means any cold will be in and out faster than a (fill in the blank. lol).

 

Marginal or modified are 2 words that = not much chance this far south. Maybe late Dec through the heart of winter climo. Not much to worry about either way. Things are moving along pretty much as expected. 

 

 

You're getting good.  The euro ensemble mean through 360 hours looks pretty bad, a positive EPO and AO/NAO, the 10 mb heights across the arctic region are forecast below normal which if true may make it hard to get any high latitude blocking for the 1st half of December.  Fo course in those time ranges, there is always a decent chance that the models could be wrong.

[Bob Chill]

You're getting good.  The euro ensemble mean through 360 hours looks pretty bad, a positive EPO and AO/NAO, the 10 mb heights across the arctic region are forecast below normal which if true may make it hard to get any high latitude blocking for the 1st half of December.  Fo course in those time ranges, there is always a decent chance that the models could be wrong.

 

Weeklies look pretty boring too. Basically a continuation of the d10-15 mean with only minor variations through the end of the run. No sign of blocking. EPO goes + the last week. Not a torch pattern for us or anything but eh, nothing really worth pointing out if a person likes snow. lol