December Medium/Long Range Discussion

[North Balti Zen]

March 17 four inch event dead ahead.

[aldie 22]

Odds Los Angeles gets a snow event before our next one?

[CAPE]

1 minute ago, leesburg 04 said:

Odds Los Angeles gets a snow event before our next one?

No idea, but I would root for that. Just to see the freak show. They can't drive in drizzle.

[Bob Chill]

14 minutes ago, C.A.P.E. said:

No idea, but I would root for that. Just to see the freak show. They can't drive in drizzle.

How about rooting for the weeklies control run? 46 days worth of tracking ahead for this... you really can't make this one up. I want to know who lives in the little dot sw of Baltimore. Lol. 

[WxUSAF]

8 minutes ago, Bob Chill said:

 I want to know who lives in the little dot sw of Baltimore. Lol. 

Hi

 

 

Good news is that 18z FV3 has our white Xmas storm. 35F rain verbatim but 15 days to adjust.

 

 

 

[CAPE]

8 minutes ago, Bob Chill said:

How about rooting for the weeklies control run? 46 days worth of tracking ahead for this... you really can't make this one up. I want to know who lives in the little dot sw of Baltimore. Lol. 

 

Looks like Ellicott City. At least they wont have to worry about excessive snow melt followed by heavy rain.

[psuhoffman]

Nino climo says Jan 15 on is money. I'm disappointed things seem to be pushing back to when I kind of had expected and been prepared for but it doesn't necessarily make me think we're in trouble. How much snow did we have prior to mid January in 1966, 1978, 1987, 2015... some years had some early snow.  A lot got good post Jan 10. Even 2010 only had the one big storm really otherwise didn't get good until later.  I'll stay optimistic until we see signs the pattern isn't getting good come January. 

[Maestrobjwa]

12 minutes ago, psuhoffman said:

Nino climo says Jan 15 on is money. I'm disappointed things seem to be pushing back to when I kind of had expected and been prepared for but it doesn't necessarily make me think we're in trouble. How much snow did we have prior to mid January in 1966, 1978, 1987, 2015... some years had some early snow.  A lot got good post Jan 10. Even 2010 only had the one big storm really otherwise didn't get good until later.  I'll stay optimistic until we see signs the pattern isn't getting good come January. 

That's weird, isn't it? Like no matter what kind of winter it is, we don't usually snow between Jan 1st and Jan 15th! One of the strange quirks of our region, lol

[showmethesnow]

Hmmm.... Higher heights are showing up to our south, lower to our north. I do believe that is the signature of an over running event if I am not mistaken. And what's the date stamp? Just saying.

[Maestrobjwa]

1 minute ago, showmethesnow said:

Hmmm.... Higher heights are showing up to our south, lower to our north. I do believe that is the signature of an over running event if I am not mistaken. And what's the date stamp? Just saying.

Could you clarify for me what exactly "overrunning" means? (never have been clear on that)

[AfewUniversesBelowNormal]

Too much worshiping El Nino climatology. 

[AfewUniversesBelowNormal]

I'd expect a SE ridge February.. just because this is the trend 2013-on. WAR..lol

[Interstate]

34 minutes ago, Maestrobjwa said:

Could you clarify for me what exactly "overrunning" means? (never have been clear on that)

A condition that exists when a relatively warm, less dense air mass moves up and over a cooler, denser air mass on the surface. The result is usually low clouds, fog and steady, light precipitation.  Basically means that we have cold weather at the surface with warm air moving in aloft... as long as we can keep the atmosphere cold enough... it will produce snow.

[Maestrobjwa]

7 minutes ago, Interstate said:

A condition that exists when a relatively warm, less dense air mass moves up and over a cooler, denser air mass on the surface. The result is usually low clouds, fog and steady, light precipitation.  Basically means that we have cold weather at the surface with warm air moving in aloft... as long as we can keep the atmosphere cold enough... it will produce snow.

I see....so could you call our white Christmas in 2002 an overrunning event?

[87storms]

55 minutes ago, Interstate said:

A condition that exists when a relatively warm, less dense air mass moves up and over a cooler, denser air mass on the surface. The result is usually low clouds, fog and steady, light precipitation.  Basically means that we have cold weather at the surface with warm air moving in aloft... as long as we can keep the atmosphere cold enough... it will produce snow.

i remember talking to a met professor at umd (when i was considering going there for grad school) and we were talking about winter weather.  i was saying how most of our storms are from nor'easters and he was saying from overrunning.  i'm sure there's some overlapping, but he was generally right.

[psuhoffman]

50 minutes ago, Maestrobjwa said:

I see....so could you call our white Christmas in 2002 an overrunning event?

No it was a miller b that developed just in time to clip us with the ccb. 

[PDIII]

2 hours ago, Bob Chill said:

How about rooting for the weeklies control run? 46 days worth of tracking ahead for this... you really can't make this one up. I want to know who lives in the little dot sw of Baltimore. Lol. 

I do

[SnowGolfBro]

1 hour ago, PDIII said:

I do

That’s the perfect setup. Based on the last storm i assume those big totals will be suppressed right over our backyards. 

[WVclimo]

Big difference between the 00Z runs of the GFS and FV3 for this weekend's event.  GFS has the 5h low over DC at 126 and over NYC at 138.  FV3' has it exiting the coast at Myrtle Beach during the same time frame.

[AfewUniversesBelowNormal]

00z Euro has maybe some light snow after 48hr

[Herb@MAWS]

11 hours ago, Bob Chill said:

How about rooting for the weeklies control run? 46 days worth of tracking ahead for this... you really can't make this one up. I want to know who lives in the little dot sw of Baltimore. Lol. 

That's the Columbia Death Band !

[showmethesnow]

For those on the edge ready to jump after seeing some of the maps posted yesterday you can probably back off for now. At least until the next run.  

One of my concerns I brought up a couple of days ago through the Christmas time period is that we see the NS drop hog wild down into the SW where it sees a weakness. That happens then we are looking at a monster trough in the SW and subsequently massive ridging and warm air flooding the east. I am sure many of you saw the depressing pics yesterday that showed this. It would probably wreck the pattern for a week or two depending on how long it took to eject that SW feature and to recover our temps. 

Now here is yesterday's 12z EPS run that was helping to cause some of the panic. Now below you can see the weakness down in the SW where we see southern stream troughing. Above that we are seeing the troughing in the northern stream. Notice that they are aligned with each other. This setup would more then likely dump the NS directly south into the southwest. This we do not want to see.

 

Now notice what we are seeing with the overnight 00Z EPS run. We have the weakness in the southwest but now we also see the NS troughing bypassing this weakness and moving eastward. Now this setup probably argues for a partial dumping into the SW of NS energy but nowhere near to the extreme that the previous example showed us. This is a workable look for us on the east coast.

 

Now compare both of the above to what we see on the overnight GEFS. We still have the weakness in the SW but the GEFS is much more progressive with the NS where we see the trough setting up in the mid-west. What we see is there is very little dumping into the SW so the NS is free to move eastward without getting hung up. This is a good look for potential on the east coast.

 

Now to give you an idea about the differences these different looks give us on temps for our chances around the Christmas period. Below we have yesterdays 12Z EPS run. Notice the cold rotating around and down from EPO/PNA ridge is directed almost due south with very little eastward movement. With the jacked up trough in the SW we are also see the ridging popping in the east driving the warmth with it. This whole look argues for any possible system to run well to our west.

 

Now compare the above to the overnight run. Notice the difference we are seeing with temps because of the different interaction between the NS and SS. We are seeing a much more progressive movement of the cold east. Also seeing a bump up of the warmth in the east but nowhere near to the degree as the previous example as the ridging is nowhere as extreme. This is a workable pattern as we are seeing cold close enough to possibly access. 

 

Now here we have the overnight GEFS run. Notice the cold has overrun the whole of the northern CONUS with very little to be seen in the SW. This is very workable for our chances even though the temps suggest the possibility it may be somewhat suppressive in nature.

 

Now keep in mind, everything stated is on the condition that the models are somewhat right with the long range pattern. So which of the above examples is probably more right? The GEFS. First off I have felt for awhile that the NS dumping full throttle into the SW was of low probability. I know we have had the occasional GFS op run at range that has shown the NS dumping into the SW but the GEFS has been pretty steadfast on moving the NS eastward for the most part. But the op runs at range are for entertainment value at best so I will heavily defer to the GEFS. The EPS though has been back and forth with a full dump vs. a partial dump but nevertheless has steadily progressed towards the GEFS solution. This pattern pretty much follows the takeaways I have seen so far this winter. GEFS locks into a pattern flip in the long range and the EPS follows a bit later but is wishy washy in the process. Now also consider that the EPS has had a tendency over the years to overplay the NS dumps into the SW and I think all things considered the GEFS is the horse to bet on. Now the weather will do what it is going to do so I would not be surprised if in fact we see the worst case scenario play out but that said my money is probably on a compromise between the overnight runs of both the GEFS and the EPS. A compromise favoring the GEFS' current solution.

 

 

Brought this up yesterday evening trying to bring some Christmas cheer to the downtrodden and depressed masses/weenies. The last day of runs on the GEFS has been suggesting a possible over running event right around Christmas. Am using the 18Z run because it best illustrates the look one would expect. Notice we have higher heights to our south with lower heights just to our north. What this is showing is a bump up of the southern stream overriding a cold dome of air. Between those two height anomalies we have over running and precip. Depending on duration and amount of moisture these events can be some of our more prolific snow makers. And just consider, this over running setup is showing for a somewhat extended period of time (24+ hrs) and the STJ has been a moisture laden bomb so far this year. I will let you figure out the rest on your own. 

Note: Looking at the overnight GEFS, though it still shows the look of an over running event the pattern moved a touch towards the possibility of a southern low moving up the coast if some energy was available. 

 

[psuhoffman]

@showmethesnowagree the EPS is likely doing its typical error here. If you adjust for bias the gefs and EPS are both advertising a similar look. 

[anotherman]

Stepping back from the ledge....until 12z.

[jaydreb]

Thanks @showmethesnow!

[frd]

Only using this for trends but the NASA model taking away here is Davis Straights blocking for Feb and very impressive looking . 

Actually blocking a lot more visible on this updated run versus last month across all the higher lattitudes. A big flip to colder in Europe too makes sense based on the blocking signature 

Upon 500 times screen magnification I like the coldest anomolies over MBY in the lastest forecast, give or take 50 miles. 

Certainly the expanse of cold over the East has gotten a lot smaller. Not sure I buy that. 

 

 

[Scraff]

Hmmmm. Anyone biting on this? Ohhhhh Canada....our home and native land...

[frd]

Well at the least it continues, the Ens mean is a continued gradual decline, but then again it is getting closer in time.   

 

[frd]

Some nice visuals here by Ventrice 

 

 

[AfewUniversesBelowNormal]

Check it out.. coldest air in Hemisphere