December moving forward...pattern disco

[SnowGoose69]

The question really is why is the GFS so more amped with the SE ridge than the Euro. Typically in these patterns, probably 9 out of 10 times its the GFS that has the suppressed ridge.

[H2Otown_WX]

It had that '93-'94 look with the cold spread out and pressing down over the east for a time. It's the op run, so you know the drill. Anything goes beyond 180hrs.

It starts to get that Will Smith flat top Pac. ridge you were talking about a few days ago post 300 hrs but that's clown land so hopefully we won't have to worry about that.

[ORH_wxman]

The question really is why is the GFS so more amped with the SE ridge than the Euro. Typically in these patterns, probably 9 out of 10 times its the GFS that has the suppressed ridge.

The ensembles have been less than the Euro ensembles...I think any one OP run can fluctuate obviously.

[CoastalWx]

I did like the parade of high pressures moving north of us in Quebec. That is good for us in gradient patterns. We'll be walking a fine line, but as long as we don't see a big phasing system come out of the SW...we might cash in on one of these things.

I'm hoping that second push of cold after the 8th features just that....a big ridge starting out on the east slopes of the Canadian Rockies and moving east or branching out east. It's defintely a tight rope.

[weathafella]

It had that '93-'94 look with the cold spread out and pressing down over the east for a time. It's the op run, so you know the drill. Anything goes beyond 180hrs.

How was the 1993-94 winter?

[CoastalWx]

How was the 1993-94 winter?

Awful.

[Weather Girl 22]

That is fairly typical in a gradient pattern...because you normally do not have a typical lapse rate in the mid-levels. 850mb can be like -3C and 750mb can be the same temp or even warmer in a gradient SW flow pattern....in a typical airmass, 750mb would be noticeably colder than 850mb...but because it isn't in that type of pattern, it raises the 1000-500mb thicknesses.

Okay, I understand that now that you explained it. I was noticing how 850 was as or slighty colder than 500 MB. Thanks for that explanation. And I see that "event" on the GFS at 11 days now as well. : )

[40/70 Benchmark]

Yeah it looks almost classic. Big trough in the west with a s/w ejecting out from the southwest and moving northeast.

Wouldn't wanna be too far s of the pike.

[ORH_wxman]

I'm hoping that second push of cold after the 8th features just that....a big ridge starting out on the east slopes of the Canadian Rockies and moving east or branching out east. It's defintely a tight rope.

I think what we like to see is the shortwaves get almost crunched in the confluence to the east of the western trough as they move east....look at 12/13/07 as an example...SE ridge but also good heights pressing down from Canada so we get a weak to moderate high north of us and the s/w gets deamplified as it goes east which is good because it becomes a OH Valley runner off NJ coast instead of a lakes cutter.

http://www.meteo.psu.edu/~gadomski/NARR/2007/us1212.php

http://www.meteo.psu.edu/~gadomski/NARR/2007/us1213.php

12/19/08 was very similar as well

http://www.meteo.psu.edu/~gadomski/NARR/2008/us1219.php

Big trough trying to dig into the NW and that s/w got compressed in the confluence and slid underneath us.

[ORH_wxman]

Okay, I understand that now that you explained it. I was noticing how 850 was as or slighty colder than 500 MB. Thanks for that explanation. And I see that "event" on the GFS at 11 days now as well. : )

There is no chance that happens...you must be looking at thickness. 500mb temps will always be colder than 850mb unless you have something beyond ridiculous...not sure its really possible. 850mb can def be colder than 700mb though in very strong SWFEs.

[CoastalWx]

I think what we like to see is the shortwaves get almost crunched in the confluence to the east of the western trough as they move east....look at 12/13/07 as an example...SE ridge but also good heights pressing down from Canada so we get a weak to moderate high north of us and the s/w gets deamplified as it goes east which is good because it becomes a OH Valley runner off NJ coast instead of a lakes cutter.

http://www.meteo.psu...2007/us1212.php

http://www.meteo.psu...2007/us1213.php

12/19/08 was very similar as well

http://www.meteo.psu...2008/us1219.php

Big trough trying to dig into the NW and that s/w got compressed in the confluence and slid underneath us.

I was looking at 12/19/08 when we were talking about that storm a couple of hours ago. That is a textbook high pressure for this area. Absolutely classic.

[CoastalWx]

Felger pants tent high pressure.

[ORH_wxman]

I was looking at 12/19/08 when we were talking about that storm a couple of hours ago. That is a textbook high pressure for this area. Absolutely classic.

Yeah it was quite strong in the 1030s...we don't even need it that strong, but it certainly made our bed for the inverted trough snow the next day...without those -10to -12C 850 temps, we likely don't get those perfect dendrites...say if it was -6C instead.

We have hints of similar setup occurring, but maybe not quite as cold...but we can't be sure until we get there. One thing that does happen when the EPO goes negative, is that the models often under estimate the cold air. We've been positive EPO recently which has them over estimating it...but we might see that flip as we head into that pattern. That is one hope to hang our hats on.

[SnowGoose69]

Yeah it was quite strong in the 1030s...we don't even need it that strong, but it certainly made our bed for the inverted trough snow the next day...without those -10to -12C 850 temps, we likely don't get those perfect dendrites...say if it was -6C instead.

We have hints of similar setup occurring, but maybe not quite as cold...but we can't be sure until we get there. One thing that does happen when the EPO goes negative, is that the models often under estimate the cold air. We've been positive recent;y which has them over estimating it...but we might see that flip as we head into that pattern. That is one hope to hang our hats on.

One this strong might be better....

http://www.meteo.psu...1994/us0126.php

[40/70 Benchmark]

Sonoran trigger release cancel

[CoastalWx]

Yeah it was quite strong in the 1030s...we don't even need it that strong, but it certainly made our bed for the inverted trough snow the next day...without those -10to -12C 850 temps, we likely don't get those perfect dendrites...say if it was -6C instead.

We have hints of similar setup occurring, but maybe not quite as cold...but we can't be sure until we get there. One thing that does happen when the EPO goes negative, is that the models often under estimate the cold air. We've been positive EPO recently which has them over estimating it...but we might see that flip as we head into that pattern. That is one hope to hang our hats on.

You can see evidence of that even in the ensembles. It's not as verbatim like the op has, but you can see hints of how it would probably show op similar to what the op has.

I hope the GEFS are more correct in not shaving off the top of that ridge in AK and replacing it with lowering heights, because they look pretty decent.

[ORH_wxman]

One this strong might be better....

http://www.meteo.psu...1994/us0126.php

Lol, like 1050mb...PDII high pressure wasn't that much weaker either.

I doubt we see anything like that...that was a crazy winter where every high seemed to be better than 1040mb.

[Weather Girl 22]

There is no chance that happens...you must be looking at thickness. 500mb temps will always be colder than 850mb unless you have something beyond ridiculous...not sure its really possible. 850mb can def be colder than 700mb though in very strong SWFEs.

OH,,,,,, It says "Thickness" . I clicked the 500 MB VORT off the GFS OP run off the NCEP site ( I wanted to see the pattern and energy maxes at 500 MB) and the 540 isoheight line was a tad to the north of the 850 0C line. I'm still learning. However, I want to start posting now after about 9 months of watching and reading posts. You seem really sharp with this stuff!

[ORH_wxman]

You can see evidence of that even in the ensembles. It's not as verbatim like the op has, but you can see hints of how it would probably show op similar to what the op has.

I hope the GEFS are more correct in not shaving off the top of that ridge in AK and replacing it with lowering heights, because they look pretty decent.

One coop the GEFS did score was showing the -EPO..even if transient. The Euro ensembles never showed it until well after the GEFS did, which is a rare coop scored by the GEFS on the Euro ensembles. GEFS looks like they were too aggressive with it, but still impressive they were "more" correct.

Hopefully they are right in lingering its effects longer than the Euro ensembles.

[weatherwiz]

December is overrated. It's like rooting for severe wx in May...sure May begins severe wx season but severe wx doesn't happen here too often in May...December is to May what May is to May.

[ORH_wxman]

December is overrated. It's like rooting for severe wx in May...sure May begins severe wx season but severe wx doesn't happen here too often in May...December is to May what May is to May.

No its not....December is way more wintry than severe season is "severe" in May....we've been spoiled recently, but Dec is still a winter month here.

[H2Otown_WX]

Is this December showing any characteristics of December 2000? I'm guessing not at all since I think that was a cold December throughout but didn't we have to wait til 12/30/2000 for a snow event (which I know was a toaster bath for some). Just curious since I know that was analog being thrown around at one point.

[ORH_wxman]

Is this December showing any characteristics of December 2000? I'm guessing not at all since I think that was a cold December throughout but didn't we have to wait til 12/30/2000 for a snow event (which I know was a toaster bath for some). Just curious since I know that was analog being thrown around at one point.

No, that month had blocking in the NAO region at one point when it got cold...no sign of that. It might have been a decent analog before winter started before we knew the blocking situation, but its turning out to be not very similar at all.

We did have a couple minor snow events leading up to Xmas that year. We had a few inches on the ground for a white Christmas.

[weatherwiz]

No its not....December is way more wintry than severe season is "severe" in May....we've been spoiled recently, but Dec is still a winter month here.

Perhaps but I don't think it's a big deal if this December does suck. I still envision January/February being much more kind. Anyways, despite the modeled warmth for the east you still can't discount the potential for a wintry storm system..might be a much higher potential for northern New England but you never know.

[ORH_wxman]

Perhaps but I don't think it's a big deal if this December does suck. I still envision January/February being much more kind. Anyways, despite the modeled warmth for the east you still can't discount the potential for a wintry storm system..might be a much higher potential for northern New England but you never know.

I equate November snow more to May for severe wx...we get a decent event every now and then but it is not the norm just like we get a decent May severe wx event every now and then but we don't expect it as the norm.

December snow is a norm for most of SNE...even bad Decembers generally have at least one advisory or better event. A bad December is not good...esp in a La Nina as stats have shown.

I think we'll end up doing ok, but we might be walking a tight rope and may have to make the best of our chances in an overall warm pattern like we did in 1956...or even 2008 which was a warm month too.

[weatherwiz]

Hopefully though the raging +AO can relax. Unfortunately though ensemble spread continues to show a +AO through the first half of December, although there is a quite a bit of spread with regards to strength. The same thing goes with the NAO...TONS of spread continued here with regards to strength and phase. We do see a -EPO develop but all that does is allow the cold air to work into the northern Plains and upper mid-west and that's about it. Would be an active wx pattern too but with the sE ridge flexing strong we could be forced with cutters.

[H2Otown_WX]

No, that month had blocking in the NAO region at one point when it got cold...no sign of that. It might have been a decent analog before winter started before we knew the blocking situation, but its turning out to be not very similar at all.

We did have a couple minor snow events leading up to Xmas that year. We had a few inches on the ground for a white Christmas.

Thanks Will. That's discouraging to some extent I guess...I know this is way out there (maybe even technically OT) but what are your thoughts on blocking asserting itself later in the winter (2nd half of Feb. on?) and giving us a chance at a solid March? Would the Nina weakening help our cause?

[OSUmetstud]

While it's the long range disco from NWS BUF...I think it's excellent at highlighting the potential. Hitchcock graduated a three years before me at SUNY Oswego...excellent forecaster and discussion writer.

NEXT WEEK WILL EVENTUALLY FEATURE A TREND TOWARDS COLDERTEMPERATURES AND OPPORTUNITIES FOR SNOW...BUT MODEL GUIDANCE HASBEEN FLIP FLOPPING SIGNIFICANTLY ON TIMING AND SYNOPTIC DETAILS OFTHIS EVOLUTION OVER THE PAST FEW DAYS...AND FORECAST CONFIDENCEREMAINS BELOW AVERAGE FOR EARLY NEXT WEEK.THE LATEST 12Z GFS AND ECMWF HAVE SLOWED THE ARRIVAL OF COLD AIR BYABOUT A DAY...WITH A FRONTAL BOUNDARY HANGING UP NEAR OR JUST EASTOF THE AREA FROM MONDAY THROUGH TUESDAY AS THE SOUTHEAST RIDGE HOLDSSTRONG. COLD AIR FINALLY ARRIVES BY WEDNESDAY ON THE GFS AND NOTUNTIL WEDNESDAY NIGHT ON THE ECMWF. MODEL RUNS YESTERDAY LOOKEDPOTENTIALLY FAVORABLE FOR LAKE EFFECT SNOW...BUT THE LATEST 12Z RUNSARE NOT AT ALL GIVEN A RADICALLY DIFFERENT SYNOPTIC EVOLUTION. ANYLAKE EFFECT POTENTIAL WILL BE AN UNKNOWN FOR SEVERAL DAYS TO COMEUNTIL MODEL GUIDANCE CONVERGES ON A STEADY SOLUTION.GIVEN THE MODEL UNCERTAINTIES...THE BEST COURSE OF ACTION IS TO ONLYTREND GENTLY FROM THE PREVIOUS FORECAST. HAVE TRENDED TEMPS UP ALITTLE FOR MONDAY THROUGH TUESDAY GIVEN THE CURRENT SLOWER EVOLUTIONSEEN IN MODEL GUIDANCE. INITIALLY TEMPS SHOULD BE WARM ENOUGH FORJUST RAIN ON MONDAY...BUT DEPENDING ON THE EXACT FRONTAL POSITIONAND TIMING OF COLD AIR IT MAY GET COLD ENOUGH FOR A MIX OR SNOW BYTUESDAY. GIVEN THE UNCERTAINTY WILL CALL IT A CHANCE OF RAIN ANDSNOW FOR MONDAY NIGHT THROUGH TUESDAY. HAVE GONE WITH ALL SNOW BYWEDNESDAY WITH A SLOW PROGRESSION TOWARDS COLDER TEMPS.LOOKING FARTHER AHEAD...THE NORTH ATLANTIC OSCILLATION /NAO/ ANDARCTIC OSCILLATION /AO/ WILL REMAIN SOLIDLY POSITIVE THROUGH NEXTWEEK. THE PACIFIC NORTH AMERICAN /PNA/ INDEX IS FORECAST TO BECOMEMORE NEGATIVE BY NEXT WEEKEND AS THE MEAN LONGWAVE TROUGH POSITIONRELOADS IN THE WESTERN UNITED STATES. THE MADDEN JULIAN OSCILLATION/MJO/ WILL ALSO CONTINUE A SLOW ORBIT THROUGH PHASE 4-5 OVER THENEXT FEW WEEKS. A LOOK AT MJO COMPOSITES FOR THE EXPECTED OUTCOME OFPHASE 4-5 ACROSS NORTH AMERICA SUGGESTS TEMPERATURES WILL AVERAGEABOVE NORMAL THROUGH THE FIRST HALF OF DECEMBER.GIVEN THE PROGRESSION OF NORTHERN HEMISPHERIC TELECONNECTIONS...ANYSHOTS OF COLD AIR OVER THE NEXT FEW WEEKS ARE LIKELY TO REMAIN BRIEFWITH ABOVE AVERAGE TEMPERATURES MOST COMMON THROUGH THE FIRST HALFOF DECEMBER. A LOGICAL PROGRESSION OF THE MJO PAST THE END OF THEGEFS ENSEMBLE FORECAST...AND ALSO THE EXPECTATION OF A BETTER CHANCEOF NEGATIVE AO BY MIDWINTER GIVEN THE DEVELOPING EASTERLYQUASI-BIENNIAL OSCILLATION /QBO/...EXPECT A PROGRESSION TOWARDS MORECONSISTENT COLD AND SNOW BY LATE DECEMBER OR THE START OF JANUARY.

[ORH_wxman]

Thanks Will. That's discouraging to some extent I guess...I know this is way out there (maybe even technically OT) but what are your thoughts on blocking asserting itself later in the winter (2nd half of Feb. on?) and giving us a chance at a solid March? Would the Nina weakening help our cause?

I'm starting to buy into the blocking for March idea or maybe even Feb....but I'm no expert in the SSW stuff. But 2001 developed incredible blocking in late February that lasted through March which gave us that good finish to that winter. But we'll see.

If nothing else, climo has to even out at some point by throwing us a bone in March. That doesn't mean this year does it, but you know the clock is ticking on a blockbuster March.

[weatherwiz]

I equate November snow more to May for severe wx...we get a decent event every now and then but it is not the norm just like we get a decent May severe wx event every now and then but we don't expect it as the norm.

December snow is a norm for most of SNE...even bad Decembers generally have at least one advisory or better event. A bad December is not good...esp in a La Nina as stats have shown.

I think we'll end up doing ok, but we might be walking a tight rope and may have to make the best of our chances in an overall warm pattern like we did in 1956...or even 2008 which was a warm month too.

That comparison makes much more sense.

Stats do show that, however, there are exceptions, such as last winter. We just have to hope that we can see a massive 180 with the NAO/AO and I think we will be fine. Even with the EPO now trending into the negative territory that should provide some help...at least making way for more SWFE type setups rather than pure cutters...this obviously benefits central and northern New England more but it's something.

I just can't see the AO staying this strongly positive through the winter although you never know. If we can get solar activity to calm down some within a few days we should begin seeing some changes within the stratosphere and then soon after start seeing the +AO break down some...it's when this occurs we could see the potential for a decent storm system. We have seen some volatile wx patterns the past few years, especially given some of the massive swings we have seen within ENSO and some of the teleconnection patterns.