December Medium/Long Range Discussion

[frd]

19 minutes ago, CAPE said:

Cutter at 240. Ji in 3..2..1..

Beyond the physics of the GFS to handle that mega block. I would not trust the Euro either just yet.  Although I would think the EPS mean snowfall should be above climo, we shall see later . 

[psuhoffman]

4 minutes ago, CAPE said:

Good post. I pointed this out with the last storm. The lack of a block and the resulting transient 50-50 low was one fundamental problem, esp for eastern areas. The confluence was on the move and displaced too far NE. 

I agree to an extent but like every setup it’s a matter of degrees.  Problem is in DEC with warm SST even for Dec you need almost a perfect setup. You are right it wasn’t the PERFECT setup for a DC BIG snow and I never had DC pegged as the epicenter of that storm. I think 3-6 was my original thought from 72 hours.  But at that time guidance had a better mid level pass/close and wasn’t picking up on that crazy mid level warm layer. The actual track was ok for a messy but significant snow. We get caught in the HECS look but most of DC snows aren’t HECS. That look was fine for a 3-6” to ice event in DC had other details gone better.  A better mid level track or earlier phase and DC provably gets a few more inches before that warm layer blasts in...and maybe more on the back as a less westward intrusion takes less time to recover. So if the point is that look was not ideal for a HECS I totally agree. But it was a look that has lead to plenty of good solid snows in and around DC just not HECS level. 

2 minutes ago, losetoa6 said:

Gfs snow on Xmas eve  then flurries on Xmas day.  Gotta love it . And really only a few hours above normal Thursday temp wise .Wednesday leading in has cad keeping us cool 

If we can somehow avoid the spike to 50 dews on Thursday we could hold our pack. It’s like 8” of solid you can stand on it concrete with like 1.5 qpf content here.  It won’t melt easy if we can avoid a complete torch somehow. 

[Prestige Worldwide]

This is pretty exciting 

[psuhoffman]

5 days ago the GFS had a cutter with rain to Canada today. Instead there is a weak wave squashed to our southeast. Just pointing that out. Might be relevant. 

[40westwx]

2 minutes ago, psuhoffman said:

5 days ago the GFS had a cutter with rain to Canada today. Instead there is a weak wave squashed to our southeast. Just pointing that out. Might be relevant. 

Are you saying that maybe the cutter on the 10 day gfs might not work out?

[psuhoffman]

One last point regarding super long range. For 3 weeks now guidance suddenly shifts to a central pac Nina ridge look after week 3. But the generally weak AO continues.  But that pac look continues to get kicked in time as the WPO vortex persists. I think the guidance may be keying on the enso SST and missing the north pac pattern suppressing the Nina ridge. I think that north pac pattern may be a result of the very odd (for a Nina) warm waters to the north of the enso regions. We’ve seen this game before where guidance wants to shift the look to a classic enso response week 3+ but it never happens. The last two years were a classic example of this when the weak ninos were offset by other factors. It’s possible we are seeing the same but in out favor this time. Either way even if the pac goes to hell if we keep a -NAM state we could still get periods of opportunity unlike last year. 

[psuhoffman]

10 minutes ago, Prestige Worldwide said:

This is pretty exciting 

Holy....I’ve never seen the PV that obliterated. 

[BornAgain13]

DT just tweeted again "WOOF" for December 30th.

[osfan24]

1 minute ago, BornAgain13 said:

DT just tweeted again "WOOF" for December 30th.

If he keeps changing the dates enough times, he will get it right one time!

[CAPE]

5 minutes ago, psuhoffman said:

I agree to an extent but like every setup it’s a matter of degrees.  Problem is in DEC with warm SST even for Dec you need almost a perfect setup. You are right it wasn’t the PERFECT setup for a DC BIG snow and I never had DC pegged as the epicenter of that storm. I think 3-6 was my original thought from 72 hours.  But at that time guidance had a better mid level pass/close and wasn’t picking up on that crazy mid level warm layer. The actual track was ok for a messy but significant snow. We get caught in the HECS look but most of DC snows aren’t HECS. That look was fine for a 3-6” to ice event in DC had other details gone better.  A better mid level track or earlier phase and DC provably gets a few more inches before that warm layer blasts in...and maybe more on the back as a less westward intrusion takes less time to recover. So if the point is that look was not ideal for a HECS I totally agree. But it was a look that has lead to plenty of good solid snows in and around DC just not HECS level. 

 

I don't wanna hijack the thread, but I am saying that if there been a block leading in, and with better confluence/ more of a suppressive mechanism, the evolution would probably have been different enough that the surface low/850 low tracks would have been further SE, and the temp profile colder, thus a better outcome for places further south and east. Nothing to do with HECS, just in general, underscoring the importance of a -NAO/ 50-50 combo, making the timing less critical. Ofc there are other aspects(upstream) that had it played out a little differently, could have also led to a better outcome.

[North Balti Zen]

In fairness, he is pointing and has been pointing to a range at the end of the month for being favorable for a potential storm. 

[clskinsfan]

1 hour ago, losetoa6 said:

Pretty cool that the block forced redevelopment off NC from Chicago this run . Lots of potential coming up.

Agreed. The GFS is not handling the upcoming block very well. A little stronger HP up top and that is a KY to SC jumper and we get smashed.

[jaydreb]

I’m not mad at the GEFS for the xmas storm.  Some nice looks there.  

[psuhoffman]

8 minutes ago, 40westwx said:

Are you saying that maybe the cutter on the 10 day gfs might not work out?

Imo global operationals have become really amazing at giving a generally accurate (so long as you don’t expect dead on balls accurate details) look at synoptic setups once inside about 150 hours or so. Longer leads in some incredibly stable blocking patterns and less in volition ones but in general once inside 150 you get a decent idea what the general look will be. That’s an amazing thing considering day 6 used to be a complete crapshoot not long ago.  But past 150 they go haywire fast. Chaos and exponential errors start to take over. So imo what’s more important then looking at the op output past 150 is to look at the general H5 pattern at about day 5/6 then extrapolate where that SHOULD go based on history. That is where the “woofs” are coming from. The look day 5/6 has a LOT of potential regardless of how any one op run handles the details after. 

[clskinsfan]

8 minutes ago, osfan24 said:

If he keeps changing the dates enough times, he will get it right one time!

I mean he is just pointing out that the setup is perfect for a big storm. Trying to nail down the day it happens from 10 days out is laughable. 

[Chris78]

2 minutes ago, clskinsfan said:

I mean he is just pointing out that the setup is perfect for a big storm. Trying to nail down the day it happens from 10 days out is laughable. 

He was woofing for the 14 - 18th time period back at the end of November/ Beginning of December. He nailed that. 

Everyone in this subforum would of liked the final results to be further south but their was a major winter Storm in the East during the time frame he was woofing.

[osfan24]

11 minutes ago, clskinsfan said:

I mean he is just pointing out that the setup is perfect for a big storm. Trying to nail down the day it happens from 10 days out is laughable. 

That's fine, but he was woofing for the swing and a miss in early December, and saying it's the best look since 1996 is ridiculous. No credible met would say that.

[psuhoffman]

11 minutes ago, CAPE said:

I don't wanna hijack the thread, but I am saying that if there been a block leading in, and with better confluence/ more of a suppressive mechanism, the evolution would probably have been different enough that the surface low/850 low tracks would have been further SE, and the temp profile colder, thus a better outcome for places further south and east. Nothing to do with HECS, just in general, underscoring the importance of a -NAO/ 50-50 combo, making the timing less critical. Ofc there are other aspects(upstream) that had it played out a little differently, could have also led to a better outcome.

I think we might be differing based on perspective of location.  I was analyzing based on 95 but that’s different from the eastern shore in coastal synoptic events. We did have a -NAO and a 50:50. The NAO wasn’t perfectly centered but how often is it?  The high was still located near Montreal as the storm turned the corner in SC. To me that’s not a problem.  The surface track ended up fine. That crazy up the bay track didn’t verify. It tracked east of VA beach then NNE to just off cape may. Of course that’s inside of where you want it but honestly you need a completely different look then west of the bay.  You either need a progressive wave look or in the case of an amplified coastal setup a damn near PERFECT setup to score. With a coastal track a 3-6” to mix event in DC is mostly rain for you.  But 95 has had warning events with the track that verified before. A slightly colder airmass and they would have this time. Or a slightly better mid level phased system.  I can’t stress enough how anomalous that disconnect between the surface and mid levels was. It is NOT common to get 30-40” along the PA NY border from a surface system that tracks outside VA beach and Cape May. Their perfect track would be tucked up the Chesapeake Bay!  There is a reason those areas don’t typically get 20”+ snowstorms. They are usually too far inland to benefit much from coastals. Or had that exact setup been in Jan/Feb with cooler SST even with the disconnect I doubt we see as fast a warm surge. With that mid level track we were never getting a HECS but could have had a warning level mix event into 95. But like I said...for the eastern shore not so much.  It’s super difficult there. So much has to go exactly perfect that I get where you’re coming from. 

[SnowGoose69]

3 minutes ago, psuhoffman said:

I think we might be differing based on perspective of location.  I was analyzing based on 95 but that’s different from the eastern shore in coastal synoptic events. We did have a -NAO and a 50:50. The NAO wasn’t perfectly centered but how often is it?  The high was still located near Montreal as the storm turned the corner in SC. To me that’s not a problem.  The surface track ended up fine. That crazy up the bay track didn’t verify. It tracked east of VA beach then NNE to just off cape may. Of course that’s inside of where you want it but honestly you need a completely different look then west of the bay.  You either need a progressive wave look or in the case of an amplified coastal setup a damn near PERFECT setup to score. With a coastal track a 3-6” to mix event in DC is mostly rain for you.  But 95 has had warning events with the track that verified before. A slightly colder airmass and they would have this time. Or a slightly better mid level phased system.  I can’t stress enough how anomalous that disconnect between the surface and mid levels was. It is NOT common to get 30-40” along the PA NY border from a surface system that tracks outside VA beach and Cape May. Their perfect track would be tucked up the Chesapeake Bay!  There is a reason those areas don’t typically get 20”+ snowstorms. They are usually too far inland to benefit much from coastals. Or had that exact setup been in Jan/Feb with cooler SST even with the disconnect I doubt we see as fast a warm surge. With that mid level track we were never getting a HECS but could have had a warning level mix event into 95. But like I said...for the eastern shore not so much.  It’s super difficult there. So much has to go exactly perfect that I get where you’re coming from. 

As far as I know this was only the second storm on record where BGM and ALB recorded 20 plus inches and NYC also had 10 or more.  3/3/93 was the only other case

[psuhoffman]

1 minute ago, SnowGoose69 said:

As far as I know this was only the second storm on record where BGM and ALB recorded 20 plus inches and NYC also had 10 or more.  3/3/93 was the only other case

Not surprisingly Imo. That disconnect between the mid levels and the surface while limiting big totals on the southern area also created a HUGE expense of significant snow. The initial WAA fgen snowfall band set up for a time where you would expect with that surface track. But the mid levels ended up driving the forcing WAY further NW then typical. 

[CAPE]

13 minutes ago, psuhoffman said:

I think we might be differing based on perspective of location.  I was analyzing based on 95 but that’s different from the eastern shore in coastal synoptic events. We did have a -NAO and a 50:50. The NAO wasn’t perfectly centered but how often is it?  The high was still located near Montreal as the storm turned the corner in SC. To me that’s not a problem.  The surface track ended up fine. That crazy up the bay track didn’t verify. It tracked east of VA beach then NNE to just off cape may. Of course that’s inside of where you want it but honestly you need a completely different look then west of the bay.  You either need a progressive wave look or in the case of an amplified coastal setup a damn near PERFECT setup to score. With a coastal track a 3-6” to mix event in DC is mostly rain for you.  But 95 has had warning events with the track that verified before. A slightly colder airmass and they would have this time. Or a slightly better mid level phased system.  I can’t stress enough how anomalous that disconnect between the surface and mid levels was. It is NOT common to get 30-40” along the PA NY border from a surface system that tracks outside VA beach and Cape May. Their perfect track would be tucked up the Chesapeake Bay!  There is a reason those areas don’t typically get 20”+ snowstorms. They are usually too far inland to benefit much from coastals. Or had that exact setup been in Jan/Feb with cooler SST even with the disconnect I doubt we see as fast a warm surge. With that mid level track we were never getting a HECS but could have had a warning level mix event into 95. But like I said...for the eastern shore not so much.  It’s super difficult there. So much has to go exactly perfect that I get where you’re coming from. 

Yes there was a -NAO numerically. It wasn't a block though. Seeing red at h5 up over GL does not equal a block. 50-50 lows don't go racing into the NA unimpeded if there is a block. A block, as you said, will slow down/trap a 50/50 underneath. We did not have that for this past storm, and I was just using it as an example. I was AGREEING with the key point of your initial post. Remember? 

[SnowGoose69]

5 minutes ago, psuhoffman said:

Not surprisingly Imo. That disconnect between the mid levels and the surface while limiting big totals on the southern area also created a HUGE expense of significant snow. The initial WAA fgen snowfall band set up for a time where you would expect with that surface track. But the mid levels ended up driving the forcing WAY further NW then typical. 

I remember thinking the models were going to blow it because I didn’t understand the disconnect up in NJ given how far south the whole transfer and development happened.  In the end they did end up blowing how far north the surface low would get by NJ before it kicked east.  This caused the CCB feature to impact the NYC metro more than any guidance suggested 

[psuhoffman]

My bigger worry for the post Xmas threat is a miller b screw job not cutter. I’m talking about the Dec 28 period. Anything after that is way too far out to worry about. 

[PivotPoint]

4 hours ago, frd said:

 

For once I can say that is starting to look better.  Models are still catching on to the blocking scenario and eventual outcomes at the lower latitudes. 

Also, I have not seen this blocking signature for some time, evident by the temp anomalies to our far NE via the Canadian 10 day mean. 

 

 

 

 

This is a signal for cold dry alternating with warm and wet, imo. The anomalies in western Canada is a result of troughing below AK and that split flow that Ralph mentions below. So I see this as cold periods followed by an undulating PNA, which isn’t horrible but won’t allow amplification without a steady PNA that drives to dig south.

4 hours ago, Ralph Wiggum said:

The trof is in the Aleutian chain. Thats not a horrible look with a split flow off the West coast.

Yea, it looks like (to me) that the axis of the entry point of the northern branch is at too high a latitude for us to see the streams merge where we need them to. We need that ridge to be closer and further down in the west coast, and the ak trough to migrate so it stops squeezing that west coast ridge. That will pump up heights in the middle of the country which gives us that alternating cold dry, warm wet.

[psuhoffman]

3 minutes ago, CAPE said:

Yes there was a -NAO numerically. It wasn't a block though. Seeing red at h5 up over GL does not equal a block. 50-50 lows don't go racing into the NA unimpeded if there is a block. A block, as you said, will slow down/trap a 50/50 underneath. We did not have that for this past storm, and I was just using it as an example. I was AGREEING with the key point of your initial post. Remember? 

My bad 

[CAPE]

2 minutes ago, psuhoffman said:

My bad 

lol no worries.

[psuhoffman]

5 minutes ago, PivotPoint said:

This is a signal for cold dry alternating with warm and wet, imo. The anomalies in western Canada is a result of troughing below AK and that split flow that Ralph mentions below. So I see this as cold periods followed by an undulating PNA, which isn’t horrible but won’t allow amplification without a steady PNA that drives to dig south.

Yea, it looks like (to me) that the axis of the entry point of the northern branch is at too high a latitude for us to see the streams merge where we need them to. We need that ridge to be closer and further down in the west coast, and the ak trough to migrate so it stops squeezing that west coast ridge. That will pump up heights in the middle of the country which gives us that alternating cold dry, warm wet.

It’s not our most typical look but it’s worked before

[Maestrobjwa]

4 minutes ago, psuhoffman said:

My bigger worry for the post Xmas threat is a miller b screw job not cutter. I’m talking about the Dec 28 period. Anything after that is way too far out to worry about. 

Count on it...none of of our bigger snows have come between Dec 25th and New Years...something always seems to happen (i.e. Dec. 2010.) It's just a time where the atmospheric dice don't roll right, lol

[PivotPoint]

26 minutes ago, osfan24 said:

That's fine, but he was woofing for the swing and a miss in early December, and saying it's the best look since 1996 is ridiculous. No credible met would say that.

Yea, I never understood woofing and calling out HUGE dates like a 96 storm. Those storms are just so rare and anomalous, it’s like when you put that out there you’re encouraging people to amp a “possible” storm and promote ideas that almost NEVER happen. It’s a little sensational, imo.

I like the period coming up after xmas cutter. But there’s a lot of issues I see too, for example an unstable PNA regime, East based blocking. Doesn’t seem that we have a lot of cold air around either. Each year that goes by seems harder and harder to generate the surface temps we need for a good snow storm. 

[psuhoffman]

Wrt my h5 post from 2000 above one key to getting that to work is the extension of the east based NAO ridge west into the Hudson Bay region.