February Medium/Long Range Discussion Thread

[eurojosh]

4 minutes ago, 87storms said:

I heard it's gonna snow next Winter.

You're so optimistic!

[Bob Chill]

3 hours ago, Wonderdog said:

What are the things I need to look at for me to come up with the same conclusion that you have to identify signal for a storm?

Start with the very basic ens mean plots. Op models are a bad place to make decisions on longer lead stuff (beyond 5-7 days). They'll jump every run and present all kinds of different  solutions. When the rare case happens like with the blizzard where they don't jump then they definitely carry a good bit of weight. But that hasn't been the case a single time this year so relying on them is bad practice. 

Here's a good exercise. The follow up storm beyond this weekend is a big warm rainer. It's nearly a lock now. Using the MSLP panels from the GEFS/EPS from last night show a very strong signal for a rain storm with low pressure passing to the north. High pressure off the coast and low pressure to the NW = very strong SW midlevel and surface flow. Terrible for winter wx:

 

 

 

 

Mean mid level temps for the same period:

 

 

 

What happens after gets really muddy really quick. First thing to do is think back in history to how often we get storms right on the heels of a strong NW low passage/cold front with a western atlantic ridge. Can you think of many? I can't either. It's worked out before (2014 & 15 we're very kind) but not nearly often enough to invest a whole lot of energy at 7+ day leads.  The timing has to be perfect.  Anything forming along the trailing boundary is going to be a fast mover and we would need everything to come together just right. It's complicated and we don't do complicated well.  

Take a look at this panel. This is right about when the front is clearing after the rain storm. See the red ball off the coast of canada in the wetern atlantic? Think of that as a storm vacuum. Anything running the boundary is going to race to that spot. See the sharp sw-ne gradient on the height contours? Think of those lines as lanes in a highway. The steering mechanism in the upper levels. What we want to see is a big blue ball where the red ball is and a much more w-e gradient with the lines instead of sw-ne. The w-e gradient is called confluence. This blocks storms and provides a feed of cold air from the north. Not the case right now:

 

Ensembles do show the *possibility* of something running the boundary after the cold sweeps in. But it all has to break right. A storm may not form at all. Or it will form harmlessly off the coast and rain/snow on the fishes. Being in the bullseye can work out but if it does happen it will be beating strong odds against it happening vs taking advantage of a favorable setup. 

 

Here's the ens MSLP plots from the GEFS/EPS. You can see the signal for a coastal running the boundary:

 

 

 

 

 

What are the problems with these mean plots? The big one is high pressure placement. It's directly to the west of the storm. What we want to see is high pressure over the top. If that was the case right now it would be a much better storm signal at range. 

 

Unless you want to pay for detailed EPS panels, the best free tools are the basic EPS mean panels on trop tidbits but another fantastic GEFS tool is also available on TT. Never overlook the 24 hour mean precip panels and the individual member low pressure location plots. Gives you an idea how the clusters look and also chances for precip. 

The 0z GEFS actually looks pretty good with both panels for the trailing wave. 

 

Here's the mean precip panel. It's awful wet for the lead time to be honest. .5" QPF @ 216 hours is pretty strong:

 

 

Here's the MSLP member locations. Pretty muddy to be honest but there are some really big hits on the 0z GEFS and also the EPS run so hope is alive:

 

 

 

 

Is there a signal for a follow up storm? Yes, there definitely is. Is it a strong signal? No, definitely not. The setup is tenuous, the lead is long, and going off past history we don't do well with this kind of stuff. 

Now is time to monitor trends. The idea is out there. The possibility is there. If consensus within the ensemble suites keeps improving then it will get more interesting. For right now we just have a modest chance at an unusual way to get a good storm to work out. That's it. 

 

[WinterWxLuvr]

3 minutes ago, 87storms said:

I heard it's gonna snow next Winter.

This adds a lot.

[WinterWxLuvr]

Just now, Bob Chill said:

Start with the very basic ens mean plots. Op models are a bad place to make decisions on longer lead stuff (beyond 5-7 days). They'll jump every run and present all kinds of different  solutions. When the rare case happens like with the blizzard where they don't jump then they definitely carry a good bit of weight. But that hasn't been the case a single time this year so relying on them is bad practice. 

Here's a good exercise. The follow up storm beyond this weekend is a big warm rainer. It's nearly a lock now. Using the MSLP panels from the GEFS/EPS from last night show a very strong signal for a rain storm with low pressure passing to the north. High pressure off the coast and low pressure to the NW = very strong SW midlevel and surface flow. Terrible for winter wx:

 

 

 

 

Mean mid level temps for the same period:

 

 

 

What happens after gets really muddy really quick. First thing to do is think back in history to how often we get storms right on the heels of a strong NW low passage/cold front with a western atlantic ridge. Can you think of many? I can't either. It's worked out before (2014 & 15 we're very kind) but not nearly often enough to invest a whole lot of energy at 7+ day leads.  The timing has to be perfect.  Anything forming along the trailing boundary is going to be a fast mover and we would need everything to come together just right. It's complicated and we don't do complicated well.  

Take a look at this panel. This is right about when the front is clearing after the rain storm. See the red ball off the coast of canada in the wetern atlantic? Think of that as a storm vacuum. Anything running the boundary is going to race to that spot. See the sharp sw-ne gradient on the height contours? Think of those lines as lanes in a highway. The steering mechanism in the upper levels. What we want to see is a big blue ball where the red ball is and a much more w-e gradient with the lines instead of sw-ne. The w-e gradient is called confluence. This blocks storms and provides a feed of cold air from the north. Not the case right now:

 

Ensembles do show the *possibility* of something running the boundary after the cold sweeps in. But it all has to break right. A storm may not form at all. Or it will form harmlessly off the coast and rain/snow on the fishes. Being in the bullseye can work out but if it does happen it will be beating strong odds against it happening vs taking advantage of a favorable setup. 

 

Here's the ens MSLP plots from the GEFS/EPS. You can see the signal for a coastal running the boundary:

 

 

 

 

 

What are the problems with these mean plots? The big one is high pressure placement. It's directly to the west of the storm. What we want to see is high pressure over the top. If that was the case right now it would be a much better storm signal at range. 

 

Unless you want to pay for detailed EPS panels, the best free tools are the basic EPS mean panels on trop tidbits but another fantastic GEFS tool is also available on TT. Never overlook the 24 hour mean precip panels and the individual member low pressure location plots. Gives you an idea how the clusters look and also chances for precip. 

The 0z GEFS actually looks pretty good with both panels for the trailing wave. 

 

Here's the mean precip panel. It's awful wet for the lead time to be honest. .5" QPF @ 216 hours is pretty strong:

 

 

Here's the MSLP member locations. Pretty muddy to be honest but there are some really big hits on the 0z GEFS and also the EPS run so hope is alive:

 

 

 

 

Is there a signal for a follow up storm? Yes, there definitely is. Is it a strong signal? No, definitely not. The setup is tenuous, the lead is long, and going off past history we don't do well with this kind of stuff. 

Now is time to monitor trends. The idea is out there. The possibility is there. If consensus within the ensemble suites keeps improving then it will get more interesting. For right now we just have a modest chance at an unusual way to get a good storm to work out. That's it. 

 

Good post Bob.

[mappy]

Bob for president. 

[JB Fins]

Excellent post Professor Chill...It should be pinned or archived somewhere for new members to read or for those lurkers like me to review from time to time.

[Bob Chill]

I just scanned through the big hits on the EPS members. They mostly all have 1 thing in common. The frontal boundary is stretched more w-e instead of a sharp(er) N-S alignment. The stretched e-w boundary allow cold HP over the top to the north. If you want to keep a very simplistic view going forward, stretched w-e = good maybe snow, sharp n-s = bad rain then dry cold. 

[mappy]

2 minutes ago, JB Fins said:

Excellent post Professor Chill...It should be pinned or archived somewhere for new members to read or for those lurkers like me to review from time to time.

I copied it and put in our Met Class Thread. 

[Bob Chill]

3 minutes ago, mappy said:

Bob for president. 

 

2 minutes ago, JB Fins said:

Excellent post Professor Chill...It should be pinned or archived somewhere for new members to read or for those lurkers like me to review from time to time.

Ha! Appreciate it. It's really not that hard. What I posted is what I do in my mind every day. It takes MUCH longer to post about it than it does to take some mental snapshots and reach some basic conclusions. The only reason I did it today is because I'm in a really good mood. lol. 

[kurtstack]

Great piece there Bob.  You have a talent for taking the more complex concepts and simplifying them in a practical way that makes sense to everybody. 

[Paleocene]

11 minutes ago, Bob Chill said:

 

Ha! Appreciate it. It's really not that hard. What I posted is what I do in my mind every day. It takes MUCH longer to post about it than it does to take some mental snapshots and reach some basic conclusions. The only reason I did it today is because I'm in a really good mood. lol. 

Thanks, Bob. 

[BTRWx]

13 minutes ago, Bob Chill said:

 

Ha! Appreciate it. It's really not that hard. What I posted is what I do in my mind every day. It takes MUCH longer to post about it than it does to take some mental snapshots and reach some basic conclusions. The only reason I did it today is because I'm in a really good mood. lol. 

No, seriously that could be the top post of the year among any of us!

[eurojosh]

2 minutes ago, BTRWx said:

No, seriously that could be the top post of the year among any of us!

Unless Matt posts ""

[yoda]

17 minutes ago, eurojosh said:

Unless Matt posts ""

He would say that if we could get ensemble member e8 on the 00z EPS run

[Bob Chill]

52 minutes ago, Isotherm said:

Repost from NY forum, but I have been liking the trends w/ strat and other variables for mid feb onward. Nothing is guaranteed but it is more legitimate than anything I have seen so far this winter.

 

While it would be ideal to propagate upward and split through 10hpa, it isn't really necessary insofar as the induction of tropospheric blocking (primary difference would probably be a longer duration block if it splits throughout the column). Since this is a wave 2 upwelling event, positive changes at the surface are more likely to occur than waiting patiently for a typical downwelling event. This is the first time I have actually liked how the EPS look in the LR. The NAO is too far NE initially, but once it retrogrades slightly further west, the trough will be in the Northeast, regardless of the positive EPO. The PNA will improve concurrently due to tropical forcing aid. I would also target the 15th to 20th general period for something interesting. Overall, I still like what I see down the road.

 

Appreciate the insight, Iso. I check the op and ens strat plots every day but rarely post about it. Off and on runs of showing full splits look nice but being honest, I'm pretty jaded with strat stuff. Chasing the split or warming or whatever is always a bad sign because winter is usually sucking when the strat becomes a talking point. I'll hold out hope for ground truth at 500mb before getting excited. I do like the increasing AN height trend invading the AO/NAO domain space on the ensembles. Do we finally break the back on the endless "antiblock" behavior over the high latitudes? My hunch is we do but will be happen soon enough for us "southern" folks? We only have about 5 weeks left here of decent climo. March has been deep winter 2 out of the last 3 years but that is far from the norm here. I would like to see ground truth blocking evolve within 2 weeks or it could easily be too little too late for us in the MA. 

[psuhoffman]

38 minutes ago, Bob Chill said:

I just scanned through the big hits on the EPS members. They mostly all have 1 thing in common. The frontal boundary is stretched more w-e instead of a sharp(er) N-S alignment. The stretched e-w boundary allow cold HP over the top to the north. If you want to keep a very simplistic view going forward, stretched w-e = good maybe snow, sharp n-s = bad rain then dry cold. 

Makes sense also because the members with that orientation more likely achieve that by getting the initial system on a more easterly trajectory after passing us to the north, and that would get it into the 50/50 domain. 

[psuhoffman]

6 minutes ago, Bob Chill said:

 

Appreciate the insight, Iso. I check the op and ens strat plots every day but rarely post about it. Off and on runs of showing full splits look nice but being honest, I'm pretty jaded with strat stuff. Chasing the split or warming or whatever is always a bad sign because winter is usually sucking when the strat becomes a talking point. I'll hold out hope for ground truth at 500mb before getting excited. I do like the increasing AN height trend invading the AO/NAO domain space on the ensembles. Do we finally break the back on the endless "antiblock" behavior over the high latitudes? My hunch is we do but will be happen soon enough for us "southern" folks? We only have about 5 weeks left here of decent climo. March has been deep winter 2 out of the last 3 years but that is far from the norm here. I would like to see ground truth blocking evolve within 2 weeks or it could easily be too little too late for us in the MA. 

I am somewhat encouraged by the trend towards the GEFS with last nights EPS.  Both are very insistent on developing a -AO in the long range and placing a trough over the east.  The EPS is more muted with the trough but its there.  The MJO is spiking and suddenly the temperature patterns on the GEFS match up with the phases not shockingly.  That would argue its better trough look in the east day 15 is correct and EPS will continue to come around.  The last piece honestly for me to feel we have a very good chance would be to get heights lower in the 50/50 region.  That WAR is gonna kill us if it becomes a permanent fixture even if we get the blocking up top.  That kind of thing can pop up pretty quick though if we have all the other players in place. 

[Paleocene]

Well, since our short term snow prospects look awful, let's appreciate the one piece of winter we might actually get this weekend: temperatures below freezing.

 

[Thanatos_I_Am]

If you want weather porn and can see the EPS, E8 is definitely NSFW. 

[87storms]

1 hour ago, WinterWxLuvr said:

This adds a lot.

Trust the process 

[87storms]

1 hour ago, Bob Chill said:

Start with the very basic ens mean plots. Op models are a bad place to make decisions on longer lead stuff (beyond 5-7 days). They'll jump every run and present all kinds of different  solutions. When the rare case happens like with the blizzard where they don't jump then they definitely carry a good bit of weight. But that hasn't been the case a single time this year so relying on them is bad practice. 

Here's a good exercise. The follow up storm beyond this weekend is a big warm rainer. It's nearly a lock now. Using the MSLP panels from the GEFS/EPS from last night show a very strong signal for a rain storm with low pressure passing to the north. High pressure off the coast and low pressure to the NW = very strong SW midlevel and surface flow. Terrible for winter wx:

 

 

 

 

Mean mid level temps for the same period:

 

 

 

What happens after gets really muddy really quick. First thing to do is think back in history to how often we get storms right on the heels of a strong NW low passage/cold front with a western atlantic ridge. Can you think of many? I can't either. It's worked out before (2014 & 15 we're very kind) but not nearly often enough to invest a whole lot of energy at 7+ day leads.  The timing has to be perfect.  Anything forming along the trailing boundary is going to be a fast mover and we would need everything to come together just right. It's complicated and we don't do complicated well.  

Take a look at this panel. This is right about when the front is clearing after the rain storm. See the red ball off the coast of canada in the wetern atlantic? Think of that as a storm vacuum. Anything running the boundary is going to race to that spot. See the sharp sw-ne gradient on the height contours? Think of those lines as lanes in a highway. The steering mechanism in the upper levels. What we want to see is a big blue ball where the red ball is and a much more w-e gradient with the lines instead of sw-ne. The w-e gradient is called confluence. This blocks storms and provides a feed of cold air from the north. Not the case right now:

 

Ensembles do show the *possibility* of something running the boundary after the cold sweeps in. But it all has to break right. A storm may not form at all. Or it will form harmlessly off the coast and rain/snow on the fishes. Being in the bullseye can work out but if it does happen it will be beating strong odds against it happening vs taking advantage of a favorable setup. 

 

Here's the ens MSLP plots from the GEFS/EPS. You can see the signal for a coastal running the boundary:

 

 

 

 

 

What are the problems with these mean plots? The big one is high pressure placement. It's directly to the west of the storm. What we want to see is high pressure over the top. If that was the case right now it would be a much better storm signal at range. 

 

Unless you want to pay for detailed EPS panels, the best free tools are the basic EPS mean panels on trop tidbits but another fantastic GEFS tool is also available on TT. Never overlook the 24 hour mean precip panels and the individual member low pressure location plots. Gives you an idea how the clusters look and also chances for precip. 

The 0z GEFS actually looks pretty good with both panels for the trailing wave. 

 

Here's the mean precip panel. It's awful wet for the lead time to be honest. .5" QPF @ 216 hours is pretty strong:

 

 

Here's the MSLP member locations. Pretty muddy to be honest but there are some really big hits on the 0z GEFS and also the EPS run so hope is alive:

 

 

 

 

Is there a signal for a follow up storm? Yes, there definitely is. Is it a strong signal? No, definitely not. The setup is tenuous, the lead is long, and going off past history we don't do well with this kind of stuff. 

Now is time to monitor trends. The idea is out there. The possibility is there. If consensus within the ensemble suites keeps improving then it will get more interesting. For right now we just have a modest chance at an unusual way to get a good storm to work out. That's it. 

 

Good stuff.  A storm that comes to mind that formed along a stalled out front was feb 94 but that ended up being a raging sleet storm and formed along the gulf.  Brought too much warm air with it upstairs.  Ny did well.

[WinterWxLuvr]

GFS says the jury not completely done deliberating about next week.

Hey, don't laugh PSU.  At least we can have something to talk about.  

[yoda]

4 minutes ago, WinterWxLuvr said:

GFS says the jury not completely done deliberating about next week.

Hey, don't laugh PSU.  At least we can have something to talk about.  

The Day 6 storm?  That ship has sailed IMO

[WinterWxLuvr]

1 minute ago, yoda said:

The Day 6 storm?  That ship has sailed IMO

Very likely Yoda.  Probably has hit an iceberg as well.

But it's a lot closer to a little front end frozen than it was on the prior run.

[kurtstack]

2 minutes ago, WinterWxLuvr said:

Very likely Yoda.  Probably has hit an iceberg as well.

But it's a lot closer to a little front end frozen than it was on the prior run.

It looked pretty similar at 0Z - Personally I wouldn't rule out a front thump at this range, as unlikely as that might be.

[Round Hill WX]

CANSIPS had another solid monthly forecast for January. 

Forecast:

Actual:

February:

February is the best look we have seen in a long time on CANSIPS. 11 of the last 12 months have been above average so it's unlikely to suddenly reverse course, however, the favorable look to the MJO near mid-month is promising. 

[Scarlet Pimpernel]

8 minutes ago, WinterWxLuvr said:

Very likely Yoda.  Probably has hit an iceberg as well.

But it's a lot closer to a little front end frozen than it was on the prior run.

But we're dressed in our best, and prepared to go down like Gentlemen!  (to go all "Titanic" here!)

Seriously, though, the possibility of some freezing/frozen followed by a change over to rain wouldn't necessarily be too surprising, at least in some places.  While that threat has sailed on for sure, I'm more interested to see how things might evolve after that.

[Scarlet Pimpernel]

1 minute ago, Round Hill WX said:

CANSIPS had another solid monthly forecast for January. 

Forecast:

Actual:

February:

February is the best look we have seen in a long time on CANSIPS. 11 of the last 12 months have been above average so it's unlikely to suddenly reverse course, however, the favorable look to the MJO near mid-month is promising. 

 

Just going by that February temperature forecast at face value, it wouldn't seem to be half bad.  Heck, we just came out of a January that was some 6 degrees above normal.

[Amped]

Oh great, maybe a couple of inches on the front end that gets whiped out by an inch of rain before dogs even get a chance to pee in it. Shouldn't even count.

[mitchnick]

Cansips 500mb map lools a little better than prior months fwiw.