Medium Range Discussion Winter 2011-12

[Lee]

The Euro day 10 ensemble mean has the look of 1/17/50.

Hey Chris, good work/research as usual.

They do look similar. However, I wouldn't expect the same overall outcome to unfold, particularly in the South, even if that depiction verified to a tee.

Where were all the upper Lows that fall and winter as compared to this one?

Also, what phase was the QBO then?

I will say, if that by chance did verify; several days in a row of 70's for highs around here. I would bet the house that won't happen.

[bluewave]

Hey Chris, good work/research as usual.

They do look similar. However, I wouldn't expect the same overall outcome to unfold, particularly in the South, even if that depiction verified to a tee.

Where were all the upper Lows that fall and winter as compared to this one?

Also, what phase was the QBO then?

I will say, if that by chance did verify; several days in a row of 70's for highs around here. I would bet the house that won't happen.

I was just looking at that single date and comparing it to what the Euro ensemble mean was showing.

I am not looking to extrapolate much past that date right now. The buckling of the Pacific jet and amplification

has been challenging for the models especially some of the OP runs like the GFS has been showing.We'll have

to see what actually verifies to know the shape of things to come after.

[BethesdaWX]

Is the question is climo vs no climo? I'm researching the MJO obsessively and am aware that the MJO weakly in zones 4 through 6 earlier resulted from the ENSO mode itself and not a typical periodic forcing shift, but what is the basis for forecasting a return to those regions? Maybe I'm missing something but with the SOI dropping and GLAM increasing, doesn't that argue for a weakening of the background Nina forcing? Can the forcing base resettle without a passage into zone 8 through 3? I can't recall ever observing a spike in momentum correlating to an MJO pulse from zones 4 and 5 to zone 6 followed by a crash back to zone 5 to stay, but rather a return passing before rounding back.

With the AO flipping as the ridge heads into Alaska, and a vortex spinning in eastern Canada dispositioned I'd think the NAO would remain positive while troughing initially enters the west while the East torches until the 25th or so before a flip to cold, is my guess.

[mempho]

Is the question is climo vs no climo?

The question is which climo. At this point one can argue torch and another could argue 1985...but we all know that a midwinter flip to a -AO/NAO in a this enso environment means the other extreme.

X

[donsutherland1]

Today saw the first week of January close out with much above normal warmth in the East. Some maximum temperatures included:

Allentown: 61°

Atlanta: 69°

Baltimore: 66°

Boston: 60°

Charleston: 74°

Charlotte: 71°

Hartford: 61°

New York City: 62°

Newark: 64° (broke the record of 63° set in 2008)

Philadelphia: 63°

Providence: 61°

Raleigh: 72°

Richmond: 69°

Salisbury: 67°

Savannah: 73°

Washington, DC:

DCA: 68°

IAD: 64°

Wilmington, DE: 64°

Although the upcoming week will not see such exceptional warmth, readings could reach or exceed 50° into southern New England on at least a day and parts of the Mid-Atlantic (especially lower Mid-Atlantic) might make a run at 60° on 1-3 days. All said, the second week of January again looks to be warmer than normal in the winter-starved East.

Finally, the MJO is in Phase 6. Today's blowtorch is consistent with that phase. For those who are interested, composite anomalies for the MJO phases are below.

[Geos]

Interesting discussion going on today. Looks like the MJO is doing a small loop in phase 6 - weak though. Looks it will slowly work into phase 7.

[weathafella]

Interesting discussion going on today. Looks like the MJO is doing a small loop in phase 6 - weak though. Looks it will slowly work into phase 7.

Interesting I was going to post something similar. GEFS MJO prog is favorable in that it leans left in the cod but the euro ensemble is solidly in the circle. Iow....todays prog are not exciting but mt awful. I am gaining confident that the colder wx coming after the coming week but it is doubtful to me that it persists beyond mid february and even that is a possible stretch. 1999-00 to me is the perfect analog in terms of sensible wx.

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml#for

[Geos]

Interesting I was going to post something similar. GEFS MJO prog is favorable in that it leans left in the cod but the euro ensemble is solidly in the circle. Iow....todays prog are not exciting but mt awful. I am gaining confident that the colder wx coming after the coming week but it is doubtful to me that it persists beyond mid february and even that is a possible stretch. 1999-00 to me is the perfect analog in terms of sensible wx.

http://www.cpc.ncep....ar_wh.shtml#for

Looks like it's going to back up then head back into 6, then to 7. Hopefully it will get out of the circle and stay out! lol. I think the coldest part of the winter will be after the storm next week till mid-February compared to normal. I think trends will bounce back to near normal with stormier conditions - and no where as warm as it has been. It can't get much more tranquil than this.

A pattern rearrangement will likely yield something different past mid- Feb. I think a lower AO will effect the spring in the East with cooler then normal conditions. I think a more active storm track will set up soon as well, and last into spring ~ especially from the GL's westward.

[BethesdaWX]

I don't put much faith in the MJO forecasts in the longer ranges, they seem to change wildly.

[donsutherland1]

Recent runs of the GFS have been cold to very cold in the East for the January 16-23 timeframe. The AO is forecast to go negative by most ensemble members, but the PNA is also forecast to go negative by most. Hence, I remain concerned that the GFS may be rushing things and/or overly aggressive with the cold in the East. Given the lack of cold and snow to date, I hope that the GFS will verify. Time will tell.

[Weathergun]

Huge differences in the AO forecast between the GFS and ECMWF guidance, as of 0z last night:

Also the ECWMF ensembles has the MJO heading faster into phases 4/5 again, than the GEFS:

[okie333]

GEFS is decent... straddling "Phase 0" (as I like to call the COD)... but still on the right side of things... I expect it to emerge back into 6 (maybe even 7) and then go through 7 at at least 1.5 amplitude at one point or another... 8-through-3 might be pretty fast though, especially if it gets pumped up... should deal the final blow to the PV with USA impacts by Valentine's Day IMO. Could also be the beginning of the end for La Niña if it's strong enough to start a Kelvin wave.

[DaculaWeather]

The models are VERY confused right now, I don't expect it to get better until the pattern becomes more focused.

[wxmx]

So far it looks like Canada will be the big winner of the -WPO ridge. Nothing on the radar so far for the CONUS < 40N, other than the N Plains and NW Pac

[usedtobe]

So far it looks like Canada will be the big winner of the -WPO ridge. Nothing on the radar so far for the CONUS < 40N, other than the N Plains and NW Pac

The 6-10 forecasts from the gfs and euro are miles apart as the gfs has a negative noa (east based) and shows a cold look for the east while the euro has the fire hose starting fromt he pacific which usually ends up warmer than normal across much of the conus. The bad think is either looks possible though I'd sort of bet against the negative NAO just based on persistence. The strong positive anomaly hear the aluetians usually correlates with a firehose solution with the west coast and California getting wet so I'd lean a little more towards the euro idea but with little confidence.

[wxmx]

The 6-10 forecasts from the gfs and euro are miles apart as the gfs has a negative noa (east based) and shows a cold look for the east while the euro has the fire hose starting fromt he pacific which usually ends up warmer than normal across much of the conus. The bad think is either looks possible though I'd sort of bet against the negative NAO just based on persistence. The strong positive anomaly hear the aluetians usually correlates with a firehose solution with the west coast and California getting wet so I'd lean a little more towards the euro idea but with little confidence.

I see little evidence of an east based NAO in the GFS ensembles...what could help is the central Siberian ridge gaining latitude and pushing the PV towards Canada...but in that case we would see a big temp gradient from the Mid Atlantic to the NE, IMO

[usedtobe]

I see little evidence of an east based NAO in the GFS ensembles...what could help is the central Siberian ridge gaining latitude and pushing the PV towards Canada...but in that case we would see a big temp gradient from the Mid Atlantic to the NE, IMO

Thinking back at the telleconnections, I think keying on the positive near the aluetians does keep the northern tier chilly but not the south or Mid atlantic. With no negative nao and a -pna ridge, it's usually hard to stay real cold even with all the amplitude in this area.

[varicweather]

Quite a difference in the 8-10 day 500 mb mean maps between the ECMWF and GFS:

http://www.meteo.psu.edu/~gadomski/ECMWF_12z/hgtcomp.html

[wxmx]

GFS ensembles are more Euro like...with a more zonal flow across the CONUS

[BethesdaWX]

GFS ensembles are more Euro like...with a more zonal flow across the CONUS

Looks like the negative at 500mb is split there? GEFS aligning with the Euro fits in with the idea that sustained cold won't arrive in the east until the NAO goes negative after the AO tanks which could be in about 20 days?

[Srain]

Once again, as we saw in December, these closed cold core upper lows are a forecasting challenge at best. This morning we see Winter Storm Watches hoisted for New Mexico with Special Weather Statements for winter weather from El Paso, Midland/Odessa, to Amarillo. San Angelo has joined in the question of whether they will see wintery mischief across their area and even Dallas/Ft Worth is mentioning the possibility of a wintry mix to their W as the upper low treks E. Further S, rains and storms look likely beginning late Sunday into Tuesday morning. The SPC is mentioning even a possible tornado or two for S Texas as a Coastal Low develops. It does appear that heavy rains and storms are likely for Central/SE TX Sunday night into Monday night/early Tuesday morning. There still remain some uncertainty on the exact track of the U/L and precip could linger into Tuesday as the closed cold core upper low passes. The focal point for heavy rains will be along a stalled frontal boundary draped across Central/SE TX and wide spread 1-2 inch amounts, with isolated 4+ inch amounts possible where any training of heavy showers/storms develop.

For verification purposes...

[CoastalWx]

We are going to end up with a big gradient across the CONUS come week 2, especially around and just after day 10. That big block gets the ball rolling after d7. It will in essence sort of fall or press the cold to the south.

It complete this around day 10

The op runs have hinted at the magnitude of this gradient. The euro op at some point has +12C 850 temps in Kansas with -24C temps at 850 touching the border of the US.To the south of the jet, you'll have strong west winds downsloping off the Rockies and blow torching the srn Plains possibly. It's going to be a big case of the haves vs have nots.

Eventually the ensembles back everything nw. Notice how they do try and pop a ridge in the sw, but that's a strong PAC flow right there and would allow heights to rise in the east, especially if that block moves to the nw into Siberia and heights lower closer to AK.

So my guess is that without a -NAO..this isn't going to be very favorable for the MA..and possibly up to SNE, after 2 weeks or so. However, with higher heights near the Pole, there will still be some cold and cross polar flow coming into Canada so the nrn tier may still be ok. Any little change in the block strength or how quickly it retrogrades will have a big outcome..especially those that are playing with fire.

Now the op runs have tried to pop transient PNA ridges and those may be the best shot for the MA to cash in...or perhaps some overrunning from a Plains low, but I think the MA is needing a -NAO here. The block in AK may not allow a prolonged intrusion of cold into those areas. Week 4 of the euro weeklies did hint at a -NAO, but it's week 4 so the natural caveats apply.

[Geos]

I think the Great Lakes and Northern Plains will have the best chance of seeing more wintry systems as we transition to a lower NAO and a -AO. Looks like the bulk of central Canada will have arctic air in place, that will press into the northern tier. Impressive gradient above^

[donsutherland1]

Verification:

From 12/21/2011 (#287):

Below is, among other things, a composite chart showing analogs based on an AO in the +1 to +3 rangem PNA in the -0.50 to +0.50 range, and ENSO R3.4 anomalies in the -1.50 to -0.75 range for the 1/1-10 timeframe (1950-2011).

From 12/25/2011 (#303):

Below is a chart that reflects a PNA in the +0.5 to +1.5 range (now likely for the first week in January). All other factors remain the same.

As a result, my initial thinking is likely to be wrong. The first 1-3 days could still start somewhat mild, but a push of cold is likely to assure that overall anomalies in the eastern third to half of the CONUS will likely wind up cooler than normal. The recent expansion of a pool of cold anomalies in the Arctic (past week) suggests that the cold air mass might be sufficient to result in temperatures falling into the low 20s or even teens from Washington, DC northward at some point during the push of cold air.

Afterward, once the PNA declines, the cold could moderate and milder readings could again return. It's a little soon to speculate on that timing, but it could occur during the second week in January unless the PNA stays elevated, the AO becomes negative, and/or the EPO becomes negative.

The revision was incorrect. Warmth was very widespread. Below is the map showing the 1/1-7/2012 anomalies:

[Hoosier]

00z Euro has some very chilly air moving into the northern tier toward mid to late week (next week).

[am19psu]

00z Euro has some very chilly air moving into the northern tier toward mid to late week (next week).

Yep, that seems quite likely. The question is how much and how often can pieces break off into the CONUS.

[CoastalWx]

Ensembles really continue the retrogression and height rises in the east after d12. EC especially.

[am19psu]

Ensembles really continue the retrogression and height rises in the east after d12. EC especially.

Yep. Even the trends in the "cold" period are getting warmer. Only days below normal verbatim at PHL/BWI/DCA are Jan 14-15 and maybe the 19th.

[CoastalWx]

Yep. Even the trends in the "cold" period are getting warmer. Only days below normal verbatim at PHL/BWI/DCA are Jan 14-15 and maybe the 19th.

Yeah looks ugly, even for up here. Oh well.

[wxmx]

Doesn't look that good for cold in the mid range, but it would only take some height rises in W Canada to bring most of the CONUS into the icebox with all that cold air bottling up in Canada.