January Pattern and Storm Discussion

[Wow]

Euro looks good...in the lr

It pushes the new years storm way SW out into the Pacific. A well known Euro bias. Should it drop south into the Baja of California then move eastward into S TX by 240 hrs, then we'd have a big, big threat on our hands as an Aleutian Low settles in, pumps our western ridge, and a vortex forming over SE Canada.

[DopplerWx]

It pushes the new years storm way SW out into the Pacific. A well known Euro bias. Should it drop south into the Baja of California then move eastward into S TX by 240 hrs, then we'd have a big, big threat on our hands as an Aleutian Low settles in, pumps our western ridge, and a vortex forming over SE Canada.

It looked like the euro was trying to send a low up the coast on 12/30? i may be seeing it wrong though.

[griteater]

It pushes the new years storm way SW out into the Pacific. A well known Euro bias. Should it drop south into the Baja of California then move eastward into S TX by 240 hrs, then we'd have a big, big threat on our hands as an Aleutian Low settles in, pumps our western ridge, and a vortex forming over SE Canada.

This matches up well with the various ensembles, with the first week in January having an increased threat for wintry weather...tho Mr. Bob says the Euro Ens not quite there across the south with the cold air. We'll have to see how the 12z looks later.

[griteater]

PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS

NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD

300 PM EST FRI DECEMBER 21 2012

8-14 DAY OUTLOOK FOR DEC 29, 2012 - JAN 04, 2013

AN INTERESTING PATTERN IS UNFOLDING HEADING INTO THE NEW YEAR. ANALOGS BASED ON TODAY'S OFFICIAL 500-HPA MANUAL BLEND REVEAL SOME HEAVY-HITTING WINTER PERIODS. WHILE THERE IS STILL A GREAT DEAL OF UNCERTAINTY, ESPECIALLY GIVEN RECENT MODEL PERFORMANCE, A PERSISTENTLY NEGATIVE ANNULAR MODE AND SOME POTENTIALLY IMPORTANT STRATOSPHERIC CHANGES TILT THE NEEDLE TOWARD A CONTINUED ACTIVE WINTER PERIOD.

THE GFS, ECMWF, AND CANADIAN ENSEMBLE MEANS ARE IN GOOD AGREEMENT ON THE LONGWAVE PATTERN, WHICH IS SIMILAR TO THE 6-10 DAY PERIOD. ONE NOTICEABLE DIFFERENCE FROM THAT PERIOD IS THE DECREASED NEGATIVE ANOMALIES NEAR THE SOUTHWEST COAST AS THE NEGATIVE ANOMALIES GENERALLY INCREASE IN MAGNITUDE TOWARD THE EAST, CULMINATING OFF THE EAST COAST. THE ECMWF AND GFS ENSEMBLE MEMBERS CONTINUE TO EXHIBIT RELATIVELY LOW SPREAD IN AGREEING UPON BELOW-NORMAL 500-HPA HEIGHTS ACROSS THE CONUS, WITH SLIGHTLY LARGER SPREAD ON THE WEST COAST. HIGH-LATITUDE, POSITIVE HEIGHT ANOMALIES OVER NORTH AMERICA ARE LIKELY TO BE A DOMINATING FEATURE ALONG WITH NEGATIVE ANOMALIES NEAR THE ALEUTIANS, BOTH TELECONNECTING TO LOWER-THAN-NORMAL HEIGHTS OVER MOST OF THE CONUS. THOSE TWO HEIGHT CENTERS DO NOT TELECONNECT WELL WITH EACH OTHER, HOWEVER, AGAIN SUGGESTING A TRANSIENT PATTERN.

ABOVE-MEDIAN PRECIPITATION PROBABILITIES REMAIN HIGH OVER MOST OF THE CONUS, WITH VERY LITTLE CHANGE FROM YESTERDAY'S FORECAST DUE TO AN ACTIVE STORM TRACK. SOME TENDENCY TOWARD BELOW-MEDIAN PRECIPITATION REMAINS FORECAST FOR THE NORTHWEST AS THE STORM TRACK SLIPS SOUTH. AS THE PATTERN SLOWLY EVOLVES TOWARD HIGHER HEIGHTS OVER NORTHWESTERN NORTH AMERICA, THE GREATEST PROBABILITIES FOR BELOW-NORMAL TEMPERATURES SHIFTS EAST. ON THE THE OFFICIAL 500-HPA BLEND, NOTE THE CUTOFF RIDGE NEAR THE POLE WHICH ENABLES AN EQUATORWARD TRANSPORT OF COLD AIR INTO CENTRAL CANADA, A MORE FAVORABLE STAGING AREA FOR IMPACTING THE CONUS. BELOW-NORMAL TEMPERATURES ARE ALSO FAVORED FROM THE ROCKIES TO THE CENTRAL CONUS AND ALONG THE WEST COAST WHERE UPPER-LEVEL HEIGHTS ARE EXPECTED TO REMAIN BELOW NORMAL. LARGE ENSEMBLE SPREAD IN THE GEOPOTENTIAL HEIGHT FORECAST REDUCES CONFIDENCE ALONG THE WEST COAST, ESPECIALLY LATE IN THE PERIOD. AS MENTIONED EARLIER, GREATER TENDENCY FOR RIDGING NEAR THE WEST COAST AS THE WEEK PROGRESSES MAKE THE TEMPERATURE OUTLOOK IN THE PACIFIC NORTHWEST DIFFICULT.

ABOVE-NORMAL HEIGHTS OVER ALASKA POINT TOWARD A BETTER CHANCE OF CONTINENTAL AIR IMPACTING THE CONUS. WITH THE AO BEING PERSISTENTLY NEGATIVE, WE MIGHT NOW BEGIN SEEING THE CANONICAL IMPACTS MORE SO THAN EARLY IN THE WINTER, ESPECIALLY IN THE EAST AS THE PNA HEADS NEUTRAL OR SLIGHTLY POSITIVE.

[Wow]

This matches up well with the various ensembles, with the first week in January having an increased threat for wintry weather...tho Mr. Bob says the Euro Ens not quite there across the south with the cold air. We'll have to see how the 12z looks later.

Averaged PV position needs to drop further south but given this is 10+ days, not really worried about it. The -EPO signal will help displace it south.

[GaWx]

Despite assuming that that epic run from 12Z Thu showing a classic major 1/1-2 SE snowstorm wouldn't repeat itself (that's why I enjoyed the dream), I was hoping that subsequent runs wouldn't all take the Miller A away and also wouldn't all be so much warmer. Initial indications are that the 18Z Goofy will be colder (as of 192 hours). Let's see how this evolves.

Edit: doesn't look promising so far.....

No Miller A and quite a bit too warm with that too far north track. Next!

It looks like a wet system. However, the trends have been away from wintry fwiw. So, no reason to be excited about its potential right now. If I see a trend back to a Miller A/colder, only then would i get excited. Until then, this looks like a good rain producer for most nonmountain locations for lovers of winter rainstorms. At least Tony should be happy.

[NC_hailstorm]

Good lord the 18z strat run was the biggest yet.

GFS has a huge strat ridge over Alaska, this one even more stronger than the one over the area now with the core there with strong warming in NW Canada,western US.Meanwhile in la la land the PV in Siberia goes back to the pole,N.Canada and splits all the way up to the 5 hPa level!

This sends a split PV straight into SE Canada,Hudson Bay.With a very strong block out west and a very cold PV moving close that could be some severe cold.Also some warming going into southern Greenland.

Just another solution but the GFS has been splitting some sort of PV in la la land into SE Canada,this was obviously the strongest yet.

[Cold Rain]

Good lord the 18z strat run was the biggest yet.

GFS has a huge strat ridge over Alaska, this one even more stronger than the one over the area now with the core there with strong warming in NW Canada,western US in la la land.Meanwhile in la la land the PV in Siberia goes back to the pole,N.Canada and splits all the way up to the 5 hPa level!

This sends a split PV straight into SE Canada,Hudson Bay.With a very strong block out west and a very cold PV moving close that could be some severe cold.Also some warming going into southern Greenland.

Just another solution but the GFS has been splitting some sort of PV in la la land into SE Canada,this was obviously the strongest yet.

So, is this good? It sounds good, but I'm not sure.

[NC_hailstorm]

So, is this good? It sounds good, but I'm not sure.

That's a cold look if the PV can stay in SE Canada.

[Cold Rain]

That's a cold look if the PV can stay in SE Canada.

Ok, thanks. That's what I thought you were saying. But I wasn't sure if you were talking about the regular PV or the Stratospheric PV being in SE Canada.

[GaWx]

I know it is still far out in time. So, there's still plenty of time for the trends to change back to colder. Also, I am quite encouraged by the general colder and wet outlook for January as it appears right now. At some point in Jan., I would expect at least a close call to an actual winter storm for much of the inland SE. However, just to illustrate how much warmer the 18Z GFS run is vs. the 12Z of yest. for 1/1-1/5, that 12Z run had KATL going below 32 1/1 AM with snow, KATL getting heavy snow (some insane amount like 9" from 0.87" liquid equiv.) thus putting down a thick snowcover, KATL going down to 12 1/3 AM, and KATL not rising above 32 for 96 hours til 1/5. In a stark comparison, today's 18Z gives a heavy (2.74"!!), mild rain (50's) with southerly winds and the coldest it gets 1/1-5 is only down to 26 F (after the storm)!

[NC_hailstorm]

Ok, thanks. That's what I thought you were saying. But I wasn't sure if you were talking about the regular PV or the Stratospheric PV being in SE Canada.

The stratospheric vortex has a strong relationship with the tropospheric vortex below.The stronger the stratospheric vortex,the stronger the tropospheric vortex becomes.

I haven't looked at the 18z run but there should be a strong PV somewhere over southeast/south central Canada considering it split at 5hPa.

[Cold Rain]

The stratospheric vortex has a strong relationship with the tropospheric vortex below.The stronger the stratospheric vortex,the stronger the tropospheric vortex becomes.

I haven't looked at the 18z run but there should be a strong PV somewhere over southeast/south central Canada considering it split at 5hPa.

From my very limited knowledge around the Strato-stuff, it seems that a super strong strat pv is not generally what we want. SSW events tend to weaken and even split the pv, which seems to correlate to better blocking chances. A disturbed or split strat pv is better. I hope I have that right.

Edited to say thanks for bringing this aspect into the SE forum. I appreciate the updates and insight.

[griteater]

The ongoing -QBO in the lower stratosphere combined with the relatively low solar flux values which are forecast to persist over the next month ( http://www.nwra.com/spawx/27do.html ) should favor an environment that is favorable for additional stratospheric warmings. Any comment on that hailstorm or others?

[NC_hailstorm]

The ongoing -QBO in the lower stratosphere combined with the relatively low solar flux values which are forecast to persist over the next month ( http://www.nwra.com/spawx/27do.html ) should favor an environment that is favorable for additional stratospheric warmings. Any comment on that hailstorm or others?

Solar flux is running low for December,right now it's at 107.2.I wouldn't say it's flatlined yet but the sun is sputtering.

The research I've read is something around 110 into a -QBO is a solid match for blocking but there is always exceptions to the rules.

[HKY18]

Very active LR on the GFS. Storm after storm to track, @252+ there's huge storm 1/2-1/3. Big potential with that one.

[DopplerWx]

GFS has the big dog on 1/1...

[GaWx]

I know it is still far out in time. So, there's still plenty of time for the trends to change back to colder. Also, I am quite encouraged by the general colder and wet outlook for January as it appears right now. At some point in Jan., I would expect at least a close call to an actual winter storm for much of the inland SE. However, just to illustrate how much warmer the 18Z GFS run is vs. the 12Z of yest. for 1/1-1/5, that 12Z run had KATL going below 32 1/1 AM with snow, KATL getting heavy snow (some insane amount like 9" from 0.87" liquid equiv.) thus putting down a thick snowcover, KATL going down to 12 1/3 AM, and KATL not rising above 32 for 96 hours til 1/5. In a stark comparison, today's 18Z gives a heavy (2.74"!!), mild rain (50's) with southerly winds and the coldest it gets 1/1-5 is only down to 26 F (after the storm)!

The 0Z GFS is a bit more interesting for 1/1-2 in that it is bringing snow to a lot of TN and a fair bit of NC as well as N MS/far N AL/GA/SC. There also appears to be some wedging and the resultant IP/ZR in favored CAD areas. ATL/AHN appear to get IP and then ZR. I can't tell if it would change to plain rain later. If not, it would be a major ZR as modeled for ATL/AHN fwiw. Grain of salt this far out. This will keep changing. A very wet system does seem to be a decent bet as of now.

[griteater]

Most model ensembles support the idea of a good pattern (tho not great) in the 8-14 day range.

[GaWx]

The 0Z GFS is a bit more interesting for 1/1-2 in that it is bringing snow to a lot of TN and a fair bit of NC as well as N MS/far N AL/GA/SC. There also appears to be some wedging and the resultant IP/ZR in favored CAD areas. ATL/AHN appear to get IP and then ZR. I can't tell if it would change to plain rain later. If not, it would be a major ZR as modeled for ATL/AHN fwiw. Grain of salt this far out. This will keep changing. A very wet system does seem to be a decent bet as of now.

After looking at the 0Z GFS 2M temp.'s, I can now say that this, as modeled, would appear to be a devastating icestorm for much of the CAD areas possibly as far south as the ATL/AHN areas 1/1. The 2M maps actually show 32 or colder after the precip, ~1.75" worth, has already fallen as far south as ~Gainseville. For some reason,. MeteoStar is quite a bit warmer and it doesn't look right at all. With TD's near 10 F in advance of the precip. as well as east winds and wedging, temp.'s are not going to warm to 48 F at KATL from the upper 30's when the precip. starts. The details aren't important now, but they do show the potential of what could occur.

Edit: KATL gets down to 9 F on 1/3.

[WilkesboroDude]

Early January storm we will be tracking soon...

[SN_Lover]

Wow look at that arctic air. CRAZY

[DopplerWx]

euro on board with the cold shot new years

[bhamwx205]

No storm?

[DopplerWx]

No storm?

doesnt go out that far.

[griteater]

Some thoughts on the 00z GFS Ensemble...here's the storm threat in the southern stream on Jan 2 with blocking 50/50 signature. As we go out in time, the GFS Ens wants to build a more expansive -NAO signature which is needed because you see that over the next week, many of these lows that exit the NE are undercutting the west based -NAO signature, and aren't slowing down enough, and aren't setting up the large blocking 50/50 lows that are needed to funnel more cold air south and to keep the storm track suppressed enough to the south.

[burgertime]

Euro ENS last night looked pretty much identical to the 00z GFS for the storm at around 300 hours.

[burgertime]

12z GFS has a great track for the New Years time frame but slightly too warm verbatim.

[burgertime]

GFS is kind of ugly in the long range at 12z...yikes.

[bhamwx205]

Not real worried about with the extremes from run to run last night was epic and today was meh