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January Medium/Long Range Discussion Part 2

WinterWxLuvr

By WinterWxLuvr,
in Mid Atlantic

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BTRWx

BTRWx

Posted
Posted
2 minutes ago, RDM said:

I'm talking a long long time ago as in the 80's.  While JB's main gig was Accuweather for decades, recall him being an occasional guest contributor on TWC back in the 80's (TWC started in 82).  My comments co-mingled the evolution of JB and TWC as the two evolved somewhat in parallel as cyber weather forecasting exploded in the 80's.  Mixing in TWC with JB and Accuweather was probably confusing.  It probably would have been better to forego reference to TWC and just use JB/Accuweather.  That's where JB made his name.  Regret any confusion...

Not at all. Very cool and thank you for sharing that!

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RDM

RDM

Posted
Posted
2 minutes ago, BTRWx said:

Not at all. Very cool and thank you for sharing that!

Your welcome BTRWx - I remember when CNN started in 80 - everyone was like...  "Huh?  News 24 hours?  What's up with that?"  Then it took off. Then TWC started in 82 and that seemed like a natural add to the media mix.  But back then TWC was far more focused on the science of weather.  They had some really sharp Pro Mets who knew their stuff.  They may have not been the most exciting commentators in history, but you could learn a lot about the "why's" of weather.

When TWC changed its formatting years ago, they pushed many of the Pro Mets out in favor of, shall we say - more "presentable" people to put in front of the camera.  As a result, TWC almost overnight became not much more than a tabloid by comparison.  Was a real letdown from what it used to be and still is for those that remember the difference. 

MODS - sorry for the diatribe here, back on topic... 

Let's hope the breakdown showing up for later in Jan is just a blip, just like the HRR was last night showing 4-5 inches IVO the beltway.  But the projected AN temps look depressing...

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psuhoffman

psuhoffman

Posted
Posted

So we have the high working for us. But this shows how much trouble the overall pattern is going to give us. Yes we get a 24 hour period of snow and ice first but the ridging causes a weak gulf wave to bully its way due north through a 1050 high. Literally due north. 

how does this...,

IMG_0159.PNG

 

become this

IMG_0160.PNG

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PDIII

PDIII

Posted
Posted
2 minutes ago, psuhoffman said:

So we have the high working for us. But this shows how much trouble the overall pattern is going to give us. Yes we get a 24 hour period of snow and ice first but the ridging causes a weak gulf wave to bully its way due north through a 1050 high. Literally due north. 

how does this...,

IMG_0159.PNG

 

become this

IMG_0160.PNG

I think the high pressure just slides.but at this range I will take my chances with a 1050 high over Quebec 

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midatlanticweather

midatlanticweather

Posted
Posted
15 minutes ago, psuhoffman said:

So we have the high working for us. But this shows how much trouble the overall pattern is going to give us. Yes we get a 24 hour period of snow and ice first but the ridging causes a weak gulf wave to bully its way due north through a 1050 high. Literally due north. 

how does this...,

IMG_0159.PNG

 

become this

IMG_0160.PNG

You live in the mid Atlantic and this happens! Lol 

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WinterWxLuvr

WinterWxLuvr

Posted
  • Author
Posted
18 minutes ago, psuhoffman said:

So we have the high working for us. But this shows how much trouble the overall pattern is going to give us. Yes we get a 24 hour period of snow and ice first but the ridging causes a weak gulf wave to bully its way due north through a 1050 high. Literally due north. 

how does this...,

IMG_0159.PNG

 

become this

IMG_0160.PNG

My quick thought is, it doesn't.

I think three options are available.  1) the high slides east sooner and the system slides to our west like the euro, 2) the high is either weaker or further west and the system can come north but much warmer, 3) the system tries to come north, can't , and then slowly slides east and gives us a hell of a wintry mess.

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BTRWx

BTRWx

Posted
Posted
28 minutes ago, psuhoffman said:

So we have the high working for us. But this shows how much trouble the overall pattern is going to give us. Yes we get a 24 hour period of snow and ice first but the ridging causes a weak gulf wave to bully its way due north through a 1050 high. Literally due north. 

how does this...,

IMG_0159.PNG

 

become this

IMG_0160.PNG

I'm not even interested in trying. It looks that bad.

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psuhoffman

psuhoffman

Posted
Posted
14 minutes ago, mitchnick said:

I'll tell you how that comes due north...

http://www.tropicaltidbits.com/analysis/models/?model=gfs&region=us&pkg=z500a&runtime=2017010718&fh=186&xpos=0&ypos=0

Winner!

others are right that it probably won't go down that way. And if it did I'd take it anyways as it looks like several inches of snow and sleet. But the overall ridge in the east allows it to just bully the high. Just the fact it shows a wave choosing to force its way through a 1050 high rather then slide under it shows how hostile the overlying pattern is. 

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Ender

Ender

Posted
Posted
29 minutes ago, hosj III said:

18z GFS has a wintry mess next Sunday. Looks like .8" or so QPF as a mix of sleet, zr, and snow.

The Analog years to the GFS' own anomaly centers basically show...not a single snow event in the 10-day window centered on the forecast date (next Sunday). Not for any of the 10 Analog years centered on the 15th. If you look at the analog years to D+11 (centered on 1/18) you find a single snowfall event on what would be the 16th (2.1" on analog date 1/13/91). So...20 OP GFS analog dates and a 5% chance of snow. Okay, so how about we expand to include all the analog years that the OP GFS has been tossing around for the last four days (16 cycles of GFS analogs). That gives us....28 different weeks...and...two analog dates that would lead to snow in the 10-day window centered on 1/15/17 (4.1" on 1/11/91 gets included along with the other 1991 date). 

Maybe we should look at the Ensemble analog years? After all this is 10-days out. That nets us one more "snowfall match"...analog date 1/19/99 and .3" on what would likely be 1/14/17 this year. So...next weekend is a really long shot; at least if the GFS' own analogs are to be trusted. 

Do I have anything positive to contribute? Ever? Yes... 

74% of the GEM + GEFS + GFS analog years that have been spit out over the last four days point to a cold February. Cold as in if you average all the analog Februaries you get a monthly temp for IAD at 34. If you discard the five "warm" analogs you're 4.6F below IAD's longterm average for February, and if you only focus on the "warm analogs", you end up about 1.2F above normal. Better yet, the top seven analog weeks you get one really crappy snowfall year (Feb 1973, .03") and the rest are pretty good with an average snowfall of 9.2" and none with less than 5.6". 

All that said, the most frequently picked analog weeks since December 26th, which was the first set of analogs that were screaming about this little arctic outbreak and a SE VA snowfall, has pointed toward a back-half of January that basically sucks with the month as a whole ending up in the +3.5F range and total snowfall at less than 3" with multiple analog years having between 0" and 2" for the month as a whole. Those analogs pointed toward an EPO that would quickly go back into strong positive territory and a NAO that wouldn't be able to sustain a negative state or a strong east based -NAO. 

 

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psuhoffman

psuhoffman

Posted
Posted
14 minutes ago, Ender said:

The Analog years to the GFS' own anomaly centers basically show...not a single snow event in the 10-day window centered on the forecast date (next Sunday). Not for any of the 10 Analog years centered on the 15th. If you look at the analog years to D+11 (centered on 1/18) you find a single snowfall event on what would be the 16th (2.1" on analog date 1/13/91). So...20 OP GFS analog dates and a 5% chance of snow. Okay, so how about we expand to include all the analog years that the OP GFS has been tossing around for the last four days (16 cycles of GFS analogs). That gives us....28 different weeks...and...two analog dates that would lead to snow in the 10-day window centered on 1/15/17 (4.1" on 1/11/91 gets included along with the other 1991 date). 

Maybe we should look at the Ensemble analog years? After all this is 10-days out. That nets us one more "snowfall match"...analog date 1/19/99 and .3" on what would likely be 1/14/17 this year. So...next weekend is a really long shot; at least if the GFS' own analogs are to be trusted. 

Do I have anything positive to contribute? Ever? Yes... 

74% of the GEM + GEFS + GFS analog years that have been spit out over the last four days point to a cold February. Cold as in if you average all the analog Februaries you get a monthly temp for IAD at 34. If you discard the five "warm" analogs you're 4.6F below IAD's longterm average for February, and if you only focus on the "warm analogs", you end up about 1.2F above normal. Better yet, the top seven analog weeks you get one really crappy snowfall year (Feb 1973, .03") and the rest are pretty good with an average snowfall of 9.2" and none with less than 5.6". 

All that said, the most frequently picked analog weeks since December 26th, which was the first set of analogs that were screaming about this little arctic outbreak and a SE VA snowfall, has pointed toward a back-half of January that basically sucks with the month as a whole ending up in the +3.5F range and total snowfall at less than 3" with multiple analog years having between 0" and 2" for the month as a whole. Those analogs pointed toward an EPO that would quickly go back into strong positive territory and a NAO that wouldn't be able to sustain a negative state or a strong east based -NAO. 

 

Thanks for taking the time to put all that together. I wonder about the analogs for the day 8 threat. It has to be pretty rare to get a 1050ish high coming across just to our north with the kind of h5 pattern all the guidance shows. That could argue to be skeptical of it. But with so much guidance showing it the other possibility is just how rare a phenomenon it would be. I agree it's a longer shot then the almost 50/50 look the ensembles paint but I also wonder if the analogs would sniff it out of we truly got an anomaly like the one being shown. Either way we have to hope we break out of this by feb and get a better look. 

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Bob Chill

Bob Chill

Posted
Posted
17 minutes ago, psuhoffman said:

Want to feel good go look at e13. Low slowly slides under us and snows for 4 days straight. 

The setup would definitely support a long duration event somewhere. Not necessarily snow or whatever but a big precip maker in general. It's such an uncommon way to get a big winter event but the possibility exists for someone somewhere. Lol

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Ender

Ender

Posted
Posted
15 minutes ago, psuhoffman said:

Thanks for taking the time to put all that together. I wonder about the analogs for the day 8 threat. It has to be pretty rare to get a 1050ish high coming across just to our north with the kind of h5 pattern all the guidance shows. That could argue to be skeptical of it. But with so much guidance showing it the other possibility is just how rare a phenomenon it would be. I agree it's a longer shot then the almost 50/50 look the ensembles paint but I also wonder if the analogs would sniff it out of we truly got an anomaly like the one being shown. Either way we have to hope we break out of this by feb and get a better look. 

The 1050 high is impressive, but I think the EC vs GFS evolution probably has more to do with the faster and deeper evolution of negative anomalies over Alaska Friday into Saturday along with the speed at which the EC basically evacuates the negative H5 negative anomaly over eastern Canada (Just NE of Jame's Bay on the GFS as opposed to in the Davis straight on the EC). Heights are tanking faster in AK than they are on the GFS and the rest of the H5 flow is responding quicker over eastern Canada in response. 

That and...that amazing closed H5 feature the EC has in southern NV at FH-144 as opposed to the GFS's (literally) half as strong vort, that's wide open, and proceeds to get semi-torn apart as it progresses eastward into the rising (but not as quickly as on the EC) heights east of the Rockies. The EC's aggressive height falls over Alaska explain a great deal of what it then does with the heights across Canada and CONUS. That H5 feature over NV on the EC, assuming its real, would probably do exactly what the EC is showing. 

Of course that's two very important assumptions: that heights really do drop that fast and over such a board area in AK and that the H5 mega feature in the SW is truly that impressive. 

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psuhoffman

psuhoffman

Posted
Posted
1 hour ago, Bob Chill said:

The setup would definitely support a long duration event somewhere. Not necessarily snow or whatever but a big precip maker in general. It's such an uncommon way to get a big winter event but the possibility exists for someone somewhere. Lol

It's intriguing from a rare event stand point. I'm extremely skeptical but as run after run continues to show a similar scenario I've begun to give more thought to what may happen. 

It seems as the pattern breaks down a peice of the PV lobe rotates around through Canada combined with ridging going up under it and  developing AK height falls. The build up of cold in western Canada has to go somewhere and some of it ejects out into the northern conus as a high comes across into the developing ridging. It's a small window, and it looks funky on h5, but if it did play out that way the surface argues it's a real threat. Yea there is an h5 disconnect but that happens sometimes. On the other hand it's complicated and weird and those are not usually ways we describe winning scenarios here. 

If big huge if, we do get that look, with a mega high over the lakes under the developing eastern ridge and lower heights to the northeast of it, the key is the strength of energy ejecting from the west. The runs that bring a strong closed system out cut. Op euro and ggem for example. Runs that eject a weaker system tend to slide east under the high. Seasonal trend may argue progressive here. Wishful thinking. 

Below is a look at the para, gfs, and euro. The overall pattern is similar. Details will decide our fate. The other is pd2. Hopefully no one takes that out of context. But it's off the top of my head a situation where the h5 alone wouldn't argue for a snowstorm. But find a way to get 1045+ highs in good spots and a lot can go right without needing a perfect pattern. I'm skeptical but mildly interested. 

IMG_0161.GIF

IMG_0162.PNG

IMG_0163.PNG

 

IMG_0164.PNG

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psuhoffman

psuhoffman

Posted
Posted
1 hour ago, Ender said:

The 1050 high is impressive, but I think the EC vs GFS evolution probably has more to do with the faster and deeper evolution of negative anomalies over Alaska Friday into Saturday along with the speed at which the EC basically evacuates the negative H5 negative anomaly over eastern Canada (Just NE of Jame's Bay on the GFS as opposed to in the Davis straight on the EC). Heights are tanking faster in AK than they are on the GFS and the rest of the H5 flow is responding quicker over eastern Canada in response. 

That and...that amazing closed H5 feature the EC has in southern NV at FH-144 as opposed to the GFS's (literally) half as strong vort, that's wide open, and proceeds to get semi-torn apart as it progresses eastward into the rising (but not as quickly as on the EC) heights east of the Rockies. The EC's aggressive height falls over Alaska explain a great deal of what it then does with the heights across Canada and CONUS. That H5 feature over NV on the EC, assuming its real, would probably do exactly what the EC is showing. 

Of course that's two very important assumptions: that heights really do drop that fast and over such a board area in AK and that the H5 mega feature in the SW is truly that impressive. 

Excellent analysis it's great to have your input lately. Thank you. 

Of all the contradictions you point out between the euro and gfs the biggest one that might determine our fate wrt snow is the strength of whatever ejects out of the west and comes east. The euro breaking down the AK ridge faster doesn't help no doubt but even given that progression it still manages to eject an anomalous strong high across the northern conus with some of what's left of the extreme cold from western Canada before it gets routed out. Even with the op euro look we even manage some ice issues for a time and even some snow up my way the last two runs. But the killer is that closed h5 low that comes across. Given the ridging in the east and no blocking if the system cuts off in the middle of the country it's going to cut, high or no high. Get a weaker system or series of waves to eject and we could "possibly" get the gfs idea. 

I also don't think this is purely gfs v euro. At that range op runs will bounce around a lot, especially in something as convoluted as this setup. It was only a few cycles ago the euro spit out the crazy para gfs idea of a big snow and the gfs was showing the cutter. Since then we have seen the ggem show it a couple times, the euro control had it last night, and a couple gfs runs and now the para. Plus there is a cluster of about 18 EPS members that get decent snow into the D.C. Area and about 7 big hits that look like the gfs. Conversely there are several euro like members within the gefs. I think they both have the same general idea but are showing the reasonable spread of solutions within the variables that neither is yet able to resolve.  

I think given our climo, the anomaly of this setup, and just law of averages, the reasonable take is a snow event is unlikely with this. But it's all we really have to look at, it's interesting from a crazy meteorology perspective, and it's persistence showing up as a threat on guidance for a while now in that window has me at least keeping an eye on it. 

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psuhoffman

psuhoffman

Posted
Posted
22 minutes ago, mitchnick said:

I guess I'm confused by the interest notwithstanding the High pressure. 

http://www.tropicaltidbits.com/analysis/models/?model=ecmwf-ens&region=us&pkg=T850_mslp&runtime=2017010712&fh=168&xpos=0&ypos=0

Mean temps are misleading at that range. Several euro members disagree on timing and or have a cutter pumping warmth up ahead. Of course if those solutions are right none of this matters. But the roughly 40% of the EPS that had a more southern solution we see at least some snow. The mean is washing the two camps out to a half way in between look. I agree it's a greatly flawed setup but not as dire as that temp profile makes it seem. 

It might be 3rd and 15 after a sack but as flawed as this setup may be I'm not punting threats until it's 4th down.

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