tombo82685

6 minutes ago, JakkelWx said:

Does anyone have the latest QBO data? I'm not so sure where to look. Any websites? @C.A.P.E. So far the QBO has been one of the factors has or is going to work in our favor moving forward. Now that it's December and the QBO is in a favorable spot and has granted CAPE's wishes so far, hopefully it stays between -5 and +5 throughout the winter.

 

https://acd-ext.gsfc.nasa.gov/Data_services/met/qbo/qbo.html

29 minutes ago, 40/70 Benchmark said:

You are right, there is no immediate response with respect to the coupling of the stratosphere and troposphere, which takes a good 3 weeks to a month for propagation and such. However as referenced in my blog, there is a tendency for a successful SSW to excite the MJO response, which I was tentatively progged at extended leads to be in phase 7 or 8 come mid December. Last season, the MJO was entering a la nina like phase at the time of the SSW, which accentuated deconstructive interference of an el Nino that had already been struggling to couple with the atmosphere. This also created an environment even more hostile to blocking during the subsequent recovery of the PV.

Anyway, I will not be suprised to see it fail because I only expected minor attacks on the PV early this season, from which it will be able to recover. However some guidance suggested that a SSW would indeed take place a week or two back.

Don't mean to bombard, but you are correct. There is actually a paper out that shows evidence that when you get a rather robust phase 3 mjo that propagates around, like we had last year that it does lead to a SSW if the conditions are favorable. With how weak the PV got in late nov I wonder if we had a more robust mjo signal through phase 3  would it of initiated anything. Though, we really didn't get a strong wave 2 hit on the pv after the wave 1 displacement which is needed usually. 

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2012GL053144

3 minutes ago, WxUSAF said:

@tombo82685 says 18z euro is wetter with same thermals as 12z. Not sure if that’s just for Philly or us too.

Yea it’s a bit wetter for you. I haven’t kept track of when you guys changeover. I’ve been using the 546thickness as the start looking aloft signal. So 12z run had .25 a little west of dc at 15z Wednesday. This run brings .25 into DC now with 546 thickness exactly the same 

You can't go off 850s with this setup, the warming is above 850 in the 700-800mb zone. Best bet is to go off 546 thickness. Once that passes you best to look for a warm nose poking in in that zone. 

1 hour ago, NorthArlington101 said:

 

I think this is counting sleet as snow, in fact it most likely is. Look at the meteogram off the ukmet for DC.  It has one tiny window where the 850s are below zero while the rest is above zero. Yet the map above is showing 8-10 there. To me the more logical thing to use that map for is just how much qpf falls as frozen or freezing. 

They are colder with a flatter H5 look. Still doesn't support an all snow event but could raise the bar for more thump on the front end and also help you guys out with the overunning event beforehand. Also, the colder 850 with stronger CAD could lead to an icier look too. 

3 minutes ago, DCTeacherman said:

Yeah their algorithm is highly suspect, but for comparison purposes I think maybe it's still useful.  Does weatherbell have the 6z/18z Euro?

No, but I know USweathermodels does. Some people have that so thats what I was asking. 

Just now, osfan24 said:

I thought the vista snow maps were usually much more conservative than the weatherbell ones?

Other way around...Here is what I mean. 0z eps from weatherbell to vista

8 minutes ago, DCTeacherman said:

EPS 6z snow map improved again for our area.  Noticing the nothern part of our subforum down to about Baltimore is now in the 4-6 range.  Also noticing better coverage in western NC.

 

 

I'd be careful with those vista snow maps, they are pretty suspect. The weatherbell ones at 0z are much less than what those ones have at 0z. Does anyone have USweathermodels 6z eps snow map to compare?

1 hour ago, showmethesnow said:

For those wondering how we get this...

 

 

from this. 

 

 

 

The precip we are seeing through our area is being driven from the lower levels with very little upper level support.

Below we have the 850's. Notice we have a trough at 850's running through the region with energy running through it.

 

 

This trough is reflected somewhat at 700 mbs.

 

 

Now what we are seeing at 850s is we are getting very good lift with the frontal passage. This taken alone would probably imply a quick squally deluge of rain with little to no flip over to snow as the moisture feed shuts off rapidly as the cold moves in. 

 

 

But when you add what we are seeing at 700s. Notice we are seeing very good lift behind the 850s. What this setup is doing is allowing the warmer moisture air being lifted by the frontal passage to be transported back over top the cold as it sees even more lift at 700s to the west.

 

 

Typically we fail big time when it comes to waiting for a flip over as the cold moves in. But as depicted now on the GFS this is a workable solution. One thing I would like to see though is a little less separation between the the best lift at 850's and 700's but beggars can't be choosers. This setup could be somewhat dynamic as well with a quick 1-2, 2-4 inches falling within an hour or two and a clap of thunder could not be ruled out. 

 

Now for those looking for a little more then what the GFS is delivering now, maybe keep an eye on the 850s at 1 1/2 to 2 days earlier. Right now the GFS shows the trough moving out of the Rockies with NS energy/closed low to its north. At this point the NS energy is a little ahead of the trough and dumps little to no energy into it. But slow that feature down somewhat and a little more dig as to where it can dump some energy into that feature and you have the possibility of something spinning up on the tail end of the front as it moves through our region. At this point though the GFS is very luke warm to that idea.

 

 

 

One last comment. Though the models aren't really throwing up anything of consequence at this point I wouldn't dismiss the possibility. Especially with the initial drop of the p[v and when it withdraws. It is a very fluid setup with a good deal of energy running through all the levels of the atmosphere with extreme temperature contrasts present. Just a change here or there could make a world of difference and changes should be expected. 

 

Nice post. That wave on the front is actually energy from the s/w that delivers a snow storm to the lakes. You can track it. This was from 18z gfs yesterday. 

Gfs shows how you can possibly get something middle of next week, albeit not a blockbuster. So we have our northern stream s/w diving down through canada

Then that same s/w splits into 2.

One piece of energy takes the northern route and delivers a snow storm to the lakes. While the other piece of energy dives down into the south. 

that southern piece of energy then gets stretched out along the arctic front. As of now, the energy isn't that consolidated so it's not a big qpf producer but it's something to watch down the road. If we get a stronger piece of energy along that front then it could develop an area of low pressure along the front to bring a few inches of powder.

1 hour ago, poolz1 said:

Almost feel like ducking behind something by posting this...But, I liked what I saw on the EPS LR.  If we are looking forward and not allowing the failure of past epic looks so far to cloud our opinion, the eps looks primed to jump right into it's weekly progression.

 

Agreed, had the same thought when I saw the eps. Was starting to get a pain in my stomach when I saw the lower hgts shoot to AK but then as it progressed, at least on this run it looks like it's dumping it into the Aleutian trough which should pop a respectable pna ridge out west. You can already see the hgts starting to respond to it in the 14.5-16 day progression.  At least for this run of the eps it was encouraging, and is more of a canonical nino look for February, but the LR has been bouncing a lot.  

6 minutes ago, ORH_wxman said:

WTF is that? It goes from like SW VA to the benchmark...even a bit east of the BM

Do you think that could just be a follow up wave along the front if it's strung out?

Here is the comparison from 0z to 6z euro. As someone mentioned slower, but there also seems to me atleast there is a bit more press down in hgts from the tpv lob swinging through

I know we all want what the ukmet shows, and that is a non phase with the tpv lobe that swings around. Here are the last 3 runs of the euro, including the 18z run. Can see each run of the euro continues to delay the northern stream interaction and almost tries to make it just a separate southern stream wave by itself.  Can also see in response to the pac nw low the ridge in the west is losing amplitude and rolling over pushing east.  Just thought I  would share

6 minutes ago, OSUmetstud said:

It has profiles (like bufkit) of temp and rh. But i dont think its actually at full model vertical resolution. So warm layers can get missed. 

This is what it has, I always thought it was a sounding. But I guess not. 

11 minutes ago, OSUmetstud said:

Windy.com has soundings but its just a plot of the course resolution upper level temps that exist elsewhere on the internet (925, 850, 700, 500) i think real soundings would be super pricey. 

weatherbell I believe has a skew-t kind of sounding

3 minutes ago, WxUSAF said:

As with most storms, this will probably inch north over the next 2-3 days.  That puts us in a good spot for a potential boom scenario if the coastal does play out.  The confluence can also serve to create a good band somewhere in the WAA snows as HM has been discussing on twitter recently.  But that can create a narrow gradient, particularly on the north side of that band from a healthy 2-3" to nothing.  Weaker gradient on the south side, but still noticeable.  Creates a scenario where our Jackpotville friends along the M/D line score big from the WAA snows while DC-Balt get ~1" spread out over a long duration and then we wait for the coastal to take over.  

Yup, those WAA snows can certainly have an over performing snow band. Thats where your best shot of good ratios would be too as you would get better lift in the DGZ combined with cold air a loft.

1 minute ago, WxUSAF said:

Yeah, true enough.  I'd rather go back to where the Euro had a widespread 3-5" for us, almost entirely from the WAA snows.  Less complicated.  More boom/bust potential when you throw in the coastal as @psuhoffman has said.  WAA snow extent also seems like it might have a modestly narrow N-S extent.  Still some wrinkles to iron out.  I like 2-4" for NOVA/DC/MD as well for now all things considered.  

Yup, you're basically trading in one for the other possibly. The models this morning seem to be timing the strongest push of confluence with overunning snows thus drier look there at least from m/d line north. They then move that tpv streamer out a bit faster allowing hgts to recover for possible coastal impacts. I would still like to see better bundling of energy at base of the trough on the euro. I don't like how it's so strung out. Also need to increase wave spacing between the tpv streamer and coastal to allow for even better hgt rises. At least in your case it's not like we are asking for a coastal shift of 500 miles. 100 miles north would make a big differences and still within realm of possibilities at 3.5-4 days

6 minutes ago, WxUSAF said:

@tombo82685 interesting that it seems the EPS has been consistently more bullish than the Op for the last 48 hours or so (that's probably not perfectly correct, but seems to be true enough).  As I said yesterday, I'm still *barely* good with that, but we're rapidly approaching the time window where I'm worried that the Op would be handling subtle features better than the ensembles.  Hope 12z Euro matches that 6z EPS mean. 

I think you guys are good for 2-4 at the very least IMO. What you also have to consider is, the coastal impact is still 3.5-4 days away about a day later than the overunning setup. These Canadian impulses are fickle, any sort of changing of the handling of the tpv and pieces of energy rotating around in regards to speed and strength can make for a big difference downstream. 

Couple images from 0z eps to 6z eps. Hitting a bit more on coastal impacts

This is the comparison between 6z gfs and 6z euro. Euro hangs a ton of energy back which just flattens the flow combined with the stronger tpv streamer which also compresses hgts. Gfs bundles the energy better at the base of the trough, combined with weaker tpv streamer (though trended a bit stronger at 6z from 0z) allow hgts to bend back towards the coast allowing for a closer coastal pass. 

1 hour ago, WxUSAF said:

Goofy run.  Looks so much better aloft than what transpires at the surface.  Hell, surface looks great through about 60 hours.  Confluence from the northeast seems slight better if anything from 12z, no worse at the very least.  

The 18z gfs made sense to me honestly. There is a piece of energy that goes from the GOA over the ridge and then kind of phases in with the TPV. If you look at the 12z gfs to the 18z gfs this streamer is a bit stronger and causes a bit more of a southward press of the confluence negating the stronger s/w effects. You can see the hgt lines in New england are a bit further south. The question is will it be right or wrong. That piece of energy isn't in a data rich area.  The evaporation of the precip makes sense. When you have a CAD setup, what usually happen? We have a big high that funnels down cold dry air east of the apps, thus lots of virga usually due to the low dew points. So the tandem of downsloping effect combined with very dry air causes the precip shield to get eaten up IMO.  Thats why places west of the apps are wetter because they aren't experiencing the CAD effects like we are.  

here is your h5 vort look on 18z compared 12z. Notable stronger southern s/w. Also h5 mslp and hgts. Stronger low, higher hgts out ahead. Also, the area circled for people further north on the 12z run had that jet streak that dove south and compressed the hgt field. This run doesn't have that feature. The hgt field is a tad lower in new england, but without that jet streak it may allow hgts to recover in time for a push north and west more. 

31 minutes ago, WhiteoutMD said:

The late day EURO comes out when?


.

just started right now

Just now, WxUSAF said:

Thanks @tombo82685!  I knew the Euro Op was run at 6z and 18z (with limited durations), but didn't realize they ran a full ensemble as well. Nice to see the improvements on the 6z.  

yea they run the eps out to hr 144 for off hr runs