December and January Pattern Discussion

[John1122]

The 00z Euro also threw out some eye-candy and the GFS is close too, but as with every precip maker, it's a world full of ????

[jaxjagman]

The 00z Euro also threw out some eye-candy and the GFS is close too, but as with every precip maker, it's a world full of ????

It disturbs me the Euro looked warmer on the 0Z.But what you said is true,the GFS does sniff cold out

[weathertree4u]

WeatherTree, I assume this is what OHX is referencing. The trough shifts east and the pattern change will be the NW flow, clipper after clipper shots coming to an end. This is 8 days out.

 

 

But 5 days later, this is the 500mb map.

 

 

Then we see this in place.

 

Which leads to the following.

 

While the GFS hasn't been doing well with individual storms, it's been pretty good sniffing out these cold patterns and it looks downright frigid towards late January as you see above. Similar to the first of the month Arctic outbreak. Once again, this is the GFS and past 300, but it showed -0 temps in the 300+ range that verified earlier this month. 

 

Lets just hope that at some point, there's some moisture to meet this air mass. Right now, it's pretty scarce.

 

That helps thanks for passing that along, that makes sense; I too have been following the GFS along with othe modeling and what is depicted the last of the month for the TN Valley, is, in fact, concerning. While I love cold and snow, the area is accustomed to short duration events, not events that last for 7 - 10 days. The Nashville area is projected to remain well below freezing for an extended period of time; I cant recall the last time the Cumberland River froze over in Nashville, I know it did in 1940 not sure since then but that type of cold a freeze up is possible along with other major navigable rivers in the region, Ohio, TN, etc.

[Coach B]

  I cant recall the last time the Cumberland River froze over in Nashville, I know it did in 1940 not sure since then but that type of cold a freeze up is possible along with other major navigable rivers in the region, Ohio, TN, etc.

 

I don't think it completely froze over, but January 1977 was actually slightly colder in Nashville than 1940.  Increased barge traffic might be the difference.  While long duration cold spells are certainly not common in the mid-south historical records indicate they can and do happen.  In fact, I would consider the first part of January 2010 as one.  While we remember it as wasted because we did not get a big winter event the first 12 days of January 2010 were mostly below freezing. Had 10 straight days with lows at 15 or lower.

[Stovepipe]

Lawdy mercy at that 12z GFS... I'm loving the consistency. Hopefully the Euro becomes consistent as we'll.

 

 

How's that for a Tennessee Valley Special?

[Stovepipe]

Don Sutherland's latest thoughts:

 

 

Morning thoughts on the longer-range...

 

If one takes a look at the overnight 1/16 0z and 6z operational GFS runs, one finds both are very cold in the days 7-15 timeframe. Both also feature a strong EPO-. Both also contain a number of analog dates near moderate or larger snowstorms for some parts of the eastern half of North America.

 

 

But if one looks more closely, there is actually a rather dramatic change between the 0z and 6z runs. The latter shows the development of meaningful Atlantic blocking to coincide with the strong EPO-. Indeed, if one goes to the 11-day objective analogs from each of these runs, one finds the following:

 

0z Run:

Average AO: +0.125

AO > 0: 60% of analogs

AO of -1 or below: 30% of analogs

AO of +1 or above: 20% of analogs

 

6z Run:

Average AO: -1.128

AO < 0: 80% of analogs

AO of -1 or below: 70% of analogs

AO of +1 or above 10% of analogs

 

If one checks out the GFS ensemble forecast for the AO, one also finds that the many members are now favoring a negative AO in the extended range:

 

 

If this forecast verifies and dual Atlantic and Pacific blocking develop, that would increase prospects for a cold February in the eastern third to half of the CONUS, along with southern Ontario and Quebec. The latter cold anomalies would depend on the magnitude of blocking. If the blocking becomes too strong, then the cold anomalies could be driven southward.

 

Such dual blocking would also allow for potentially more opportunities for larger snowfalls. The Great Lakes region, northern Mid-Atlantic (e.g., Philadelphia) and southern New England areas remain on track for above normal seasonal snowfall, as the December outcomes were consistent with such seasons. The pattern ahead looks promising, particularly for the 1/25-2/15 period. If blocking develops, things could also become more favorable further south in the Mid-Atlantic region, including the Baltimore and Washington, DC areas.

 

The takeaway is that the theme of a growing probability of a cold outcome in parts of the eastern CONUS has been sustained in the overnight guidance. In fact, even as it is still outside its skillful range, the CFSv2 has recently shifted from featuring widespread February warmth to an increasingly colder idea for the eastern third to half of North America.

[jmundie]

12z GFS hour 228-264 deserves a "mother of god" meme

[Vol Man]

Stove, what timeframe is that gfs snapshot? Is that all snow? I have limited views when on mobile...thx.

[jaxjagman]

Lawdy mercy at that 12z GFS... I'm loving the consistency. Hopefully the Euro becomes consistent as we'll.

 

 

How's that for a Tennessee Valley Special?

Impressive run indeed,my text from BNA is showing Nashville don't get above 0 on the 28th,low is -7.GFS keeps getting colder

[Stovepipe]

Stove, what timeframe is that gfs snapshot? Is that all snow? I have limited views when on mobile...thx.

 

That would be around hour 240, snow accumulation, a week from Sunday.  Probably a long shot but the GFS has been exploring similar possibilities in that time frame for the past 4 days or so.  The 0z Euro seemed to be catching on to the idea of something around hour 240 as well. 

[jaxjagman]

From yesterdays HPC 8-14 outlook,cant wait until todays

 

 

8-14 DAY OUTLOOK FOR JAN 23 - 29 2014

THE WEEK-2 OUTLOOK REMAINS LARGELY UNCHANGED FROM YESTERDAY, WITH GROWING
PROBABILITIES FOR BELOW-NORMAL TEMPERATURES ACROSS MUCH OF THE CENTRAL AND
EASTERN CONUS. THE OFFICIAL 500-HPA HEIGHT MANUAL BLEND DEPICTS AN EXPECTED
SUBTLE RETROGRESSION WHEN COMPARED WITH BOTH THE 6-10 DAY OUTLOOK AND
YESTERDAY'S WEEK-2 OUTLOOK. THE GFS AND ECMWF SYSTEMS DIVERGE IN SOME NUANCED
DETAILS OF THE OUTLOOK, HOWEVER, WITH THE GFS FAVORING COLDER TEMPERATURES
ACROSS THE NORTHERN PLAINS THAN THE ECMWF. THIS IS INTRIGUING SINCE BOTH
ENSEMBLE MEANS ARE NEARLY IDENTICAL. TELECONNECTIONS UPON THE HIGH AMPLITUDE
POSITIVE HEIGHT ANOMALY FORECAST OVER THE ALASKAN PANHANDLE FAVORS THE GFS
SOLUTION, AND SO TODAY'S MANUAL SURFACE OUTLOOK REFLECTS MORE OF THE GFS
SOLUTION ACROSS THE NORTHERN PLAINS AND NORTHERN ROCKIES. ADDITIONALLY, THERE
HAS BEEN REASONABLY GOOD RUN-TO-RUN CONSISTENCY AMONG RECENT DETERMINISTIC RUNS
OF THE GFS, ALL OF WHICH SUGGEST A COLDER SOLUTION ACROSS THE CENTRAL CONUS,
NORTHERN PLAINS, AND NORTHERN ROCKIES. THE LOWER AMPLITUDE CANADIAN ENSEMBLE,
HOWEVER, FAVORS THE ECMWF SOLUTION.

THE PRECIPITATION OUTLOOK ALONG THE EAST COAST REMAINS UNCERTAIN. DESPITE
DRIER-THAN-MEDIAN SIGNALS FROM THE ENSEMBLE SYSTEMS, NEAR-MEDIAN PRECIPITATION
IS FAVORED BASED ON THE TELECONNECTIONS AND ANALOGS. ESSENTIALLY, THIS SOLUTION
HEDGES TOWARD THE IDEA THAT THE FORECAST WAVELENGTHS ARE PROBABLY TOO LONG
BASED ON THE FORECAST AMPLITUDE OF THE RIDGE UPSTREAM JUST OFF THE WEST COAST.
THE TELECONNECTIONS AND ANALOGS ARE MORE REALISTIC IN THIS REGARD AND HAVE
ADDED SUPPORT FROM VARIOUS RUNS OF THE DETERMINISTIC GFS.

THE LATEST DYNAMICAL MODELS ARE COMING INTO BETTER AGREEMENT ON THE DEVELOPMENT
OF AN INTENSE CONVECTIVE ANOMALY MOVING EASTWARD TOWARD THE DATE LINE IN THE
EQUATORIAL PACIFIC. THIS COULD FAVOR ENHANCED ODDS OF COLD AIR OUTBREAKS TOWARD
THE END OF THE WEEK-2 PERIOD AND BEYOND, CENTERED OVER THE CENTRAL CONUS.

THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 15 PERCENT OF TODAY'S
OPERATIONAL 0Z GFS CENTERED ON DAY 11...5 PERCENT OF TODAY'S OPERATIONAL 6Z GFS
CENTERED ON DAY 11...15 PERCENT OF TODAY'S 0Z GFS ENSEMBLE MEAN CENTERED ON DAY
11...20 PERCENT OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 11...AND 45
PERCENT OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11.

FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: ABOVE AVERAGE, 4 OUT OF 5, DUE
TO GOOD AGREEMENT AMONG MODELS AND FORECAST TOOLS, OFFSET SLIGHTLY BY
UNCERTAINTY IN THE TEMPERATURE OUTLOOK ACROSS THE CENTRAL AND NORTHERN CONUS,
AS WELL AS THE PRECIPITATION OUTLOOK ALONG THE EAST COAST. 

[tnweathernut]

I always did like Canadians.....

Sent from my iPhone using Tapatalk

[Stovepipe]

[jaxjagman]

 

The Euro is also in with the ridge built up N.It's not  gonna hit and run this time.

[Stovepipe]

To give you an idea of how extreme the GFS solution was, on Tuesday January 28th at TYS the high would be -4, the low would be -11, and there would be 7+ inches of snow on the ground.

[ben4vols]

To give you an idea of how extreme the GFS solution was, on Tuesday January 28th at TYS the high would be -4, the low would be -11, and there would be 7+ inches of snow on the ground.

 

In the words of Ari Gold, is that something you might be interested in?  I don't think I have seen a pattern like this since I have been closely following weather.  Quite amazing. 

[BNAwx]

To give you an idea of how extreme the GFS solution was, on Tuesday January 28th at TYS the high would be -4, the low would be -11, and there would be 7+ inches of snow on the ground.

 

Yeah, it was pretty epic all around.  With all the model agreement, it's got me thinking that Mother Nature is gettin' ready to keep it real!

[dwagner88]

What a ridiculous run. Through 384, 1.9 inches of precip at KCHA, and the vast majority of it is snow. Lowest temp is -8 (within 2 degrees of the all time record) which occurs with at least 5 inches of snow on the ground. Another big snow storm at the end of the run. One of the best runs I've ever seen. Now let's watch it reduce it all to dry clippers over the next week, LOL. 

[John1122]

Maybe we'll get lucky for once. I'm thinking probably a 5-10 percent chance right now. Jan 15th-Feb 15 is the coldest and snowiest portion of winter in the Tennessee Valley. So climatologically speaking, this is the prime time of year. We've been fairly wet, and we've been very cold. Hopefully this is the time they actually meet.

[John1122]

6-10 day outlook, 8-14 looks very similar. 

 

[tnweathernut]

Right now pattern recognition is the most important thing.  There is an UNBELIEVABLE amount of agreement on where this pattern is heading, especially considering we are talking day 7+. 

 

If we can realize the pattern currently depicted, there WILL be snow and or ice issues from multiple storms.  A block like that, if it forms as projected, will not easily be beaten down.  Time will tell, but this is as BULLISH as I have ever been for a significant period of winter weather for a good chunk of the southeast.

[Stovepipe]

18z holds serve with cold and stormy pattern for the time period everyone is watching.  Not as extreme as 12z, no surprise there, but gotta love the consistency. 

[Stovepipe]

12z Euro Control:

 

[jaxjagman]

12z Euro Control:

 

Just compared that to the 0z.Most of the valley was -6 for those same dates,what a difference one run makes,now lets be consistent

[Stovepipe]

For those that may not check the SE forum, Batman just posted this:

 

 

If you are interested in a good read on the potential upcoming pattern, check out Kirk Mellish's Blog on wsbradio.com. Mellish does not update his blog as often as I wish he would. In fact he sometimes goes weeks without an update. However he usually weighs in when something substantial is about to happen. If you read the blog, he appears to think something very substantial (possibly even historic) may happen in the SE over the next few weeks. Mellish is not big on hype. He is usually more likely to play something down rather than play it up. His discussion and summary of what the models and teleconnections are showing has me very encouraged

 

It is indeed an interesting read and a good summary of the potential pattern.

 

http://www.wsbradio.com/weblogs/kirk-mellishs-weather-commentary/2014/jan/16/signs-another-siberian-expresspolar-vortex-shift/

[tnweathernut]

Morning thoughts.

 

After the lack of activity from last night, in both southeast forums, and negativity from some of the posts, I was a little concerned.  After checking the global ensembles, they ALL (GFS, EURO, GGEM) build the ridging in the west, and through Alaska so strongly that it connects over the top of the pole (between hours 144-168), trapping the polar vortex  in southeast Canada and forcing much colder than normal air into much of central and eastern North America for an extended duration.  The GFS and GGEM ensembles give the appearance that the PV goes "poof" underneath the monster ridging at some point in the longer range (beyond hour 300).  I don't buy that it would fairly quickly scour out that quickly. 

This STILL has the look of a long duration cold snap, the only question is can we develop some split flow at some point, or do we have to rely on energy diving in so far west to create a weak gulf system with overrunning potential (like what the GGEM does around hour 180).  Time will tell, but I think the idea of some southern energy getting involved at some point (maybe more than once) is more likely than ONLY northern stream energy.

 

People pay WAY too much attention to the OP runs IMO, and the ensembles still look very good. 

 

It continues to look very "clipperish" through day 7, with only a 1 day warmup centered around MLK day.  The energy coming in from the northwest so far has sucked, but clippers have overperformed for the TN valley, and at some point, they will again.  We have a few "clipper" opportunities coming at us in the coming week, let's see if we can get lucky. 

 

Have a great day everyone.

[Stovepipe]

I like what I see on the 0z Euro for the upcoming week.  More of the same clipper wise BUT the one that dives down on Thursday looks to be the best yet for the TN valley.  It lays down 2-4 inches across the eastern half of the state with 1-2 in the north west.  Some stout cold shots too.  Then, for next weekend, it's still showing a similar storm to what the GFS has been honking for awhile.  A wet system coming up from the south with temps good enough for a good portion of the state to get in on the snow action.  Details don't matter a week away but that was not a bad run at all.

[tnweathernut]

I like what I see on the 0z Euro for the upcoming week.  More of the same clipper wise BUT the one that dives down on Thursday looks to be the best yet for the TN valley.  It lays down 2-4 inches across the eastern half of the state with 1-2 in the north west.  Some stout cold shots too.  Then, for next weekend, it's still showing a similar storm to what the GFS has been honking for awhile.  A wet system coming up from the south with temps good enough for a good portion of the state to get in on the snow action.  Details don't matter a week away but that was not a bad run at all.

Agree.

[jaxjagman]

 

 

[tnweathernut]

Loop the euro ensembles if you have access.  You can see the repetitive pushes of cold air as the PV gets trapped.  The ridging over the top looks to be in place around hour 120, so that piece of the puzzle seems to be getting closer.