Medium Range Discussion Winter 2011-12

[GaWx]

Jb says severe cold coming late feb. sorry don

**Fwiw** Well, the 6Z GFS breaks the four in a row GFS string of cold 11-15's with it being only moderately chilly at best. Will JB be forced to back down eventually or will the cold runs return? The drama builds.

P.S. Never bet against Don. He's been absolutely awesome this winter!

[Ji]

**Fwiw** Well, the 6Z GFS breaks the four in a row GFS string of cold 11-15's with it being only moderately chilly at best. Will JB be forced to back down eventually or will the cold runs return? The drama builds.

P.S. Never bet against Don. He's been absolutely awesome this winter!

00z euro was cold too by d10

[uncle W]

I've been expecting colder weather for February for some time now but going against Don scares me...He's one of our best forecasters on the board...I still think we eventually get some late cold this winter and snow but I'm not as bullish about it...

[GaWx]

**Fwiw** Well, the 6Z GFS breaks the four in a row GFS string of cold 11-15's with it being only moderately chilly at best. Will JB be forced to back down eventually or will the cold runs return? The drama builds.

P.S. Never bet against Don. He's been absolutely awesome this winter!

Per 12Z GFS suite: advantage Don over JB...no surprise. Both the 6Z and 12Z GFS suites look warmer during the 11-15 than the prior four runs.

[donsutherland1]

Yesterday, I noted that historic climatology associated with La Niña winters argues against a KU-type snowstorm this coming weekend. Since 1950, when daily recordkeeping concerning the AO commenced, there has been only one KU snowstorm during La Niña conditions with an AO > 0: the January 24-26, 2000 storm. A more localized snow event cannot be ruled out, but such an outcome is not assured.

The wild oscillation among the 2/15 0z, 2/15 6z, and 2/15 12z GFS solutions suggests that there is a lot of uncertainty associated with the possible event. Taken literally, none of the three runs showed a KU snowstorm. Solutions shown were for a localized snow event (favoring interior sections of the northern Mid-Atlantic and perhaps much of southern New England vs. a more suppressed outcome). Such "near misses" are par for the course for La Niña-lack of blocking situations. Given the high uncertainty, it would not surprise me if more wildly divergent model solutions are printed out in succeeding runs before a model consensus finally emerges. Moreover, I would not be surprised if the upcoming 12z run of the ECMWF is markedly different from the GFS. IMO, one should not assume any of the current solutions will lock in, nor should one discount any of the solutions. There's too much certainty to reach hard conclusions right now.

[am19psu]

The wild oscillation among the 2/15 0z, 2/15 6z, and 2/15 12z GFS solutions suggests that there is a lot of uncertainty associated with the possible event. Taken literally, none of the three runs showed a KU snowstorm. Solutions shown were for a localized snow event (favoring interior sections of the northern Mid-Atlantic and perhaps much of southern New England vs. a more suppressed outcome). Such "near misses" are par for the course for La Niña-lack of blocking situations. Given the high uncertainty, it would not surprise me if more wildly divergent model solutions are printed out in succeeding runs before a model consensus finally emerges. Moreover, I would not be surprised if the upcoming 12z run of the ECMWF is markedly different from the GFS. IMO, one should not assume any of the current solutions will lock in, nor should one discount any of the solutions. There's too much certainty to reach hard conclusions right now.

As I mentioned in the Philly subforum earlier, the envelope of solutions from the Euro ensemble at T+90 had the 552dam line between Aberdeen and Dallas. At T+114, the envelope included Thunder Bay and Savannah. I have zero confidence in any solution at this time, given the apparent sensitivity to initial conditions.

[donsutherland1]

As I mentioned in the Philly subforum earlier, the envelope of solutions from the Euro ensemble at T+90 had the 552dam line between Aberdeen and Dallas. At T+114, the envelope included Thunder Bay and Savannah. I have zero confidence in any solution at this time, given the apparent sensitivity to initial conditions.

Very well said. And no surprise, the Euro differed from the GFS.

[GaWx]

Per 12Z GFS suite: advantage Don over JB...no surprise. Both the 6Z and 12Z GFS suites look warmer during the 11-15 than the prior four runs.

With the 0Z 2/16 GFS run, there have now been four runs in a row without remarkable cold in the E 1/2 of the US during the 11-15. This follows the four prior quite cold runs which I strongly suspect were a sig. factor leading to JB's prediction of intense late Feb cold. Will he back down soon? Master Sutherland continues to shine this winter.

[donsutherland1]

Currently, the Arctic Oscillation has climbed to +0.967 and ENSO Region 3.4 anomalies were last reported at -1.0°C. The combination of an ongoing La Niña and a positive Arctic Oscillation is a bad one for KU snowstorms. The upcoming storm this weekend will likely be typical of such a pattern. Despite all their differences over recent cycles and poor run-to-run continuity for the most part, the one consistent theme on the modeling is that there very likely won't be a KU snowstorm. Instead, a more localized snow event is possible, but not assured.

The 2/16 6z run of the GFS illustrates one solution for that kind of localized snow event outcome. If one uses Bufkit's soundings, one finds a rain-ending-as-some-accumulating-snow outcome in Richmond; a moderate snowfall in the greater Washington, DC area, and then lighter amounts from Philadelphia north and eastward. Right now, the exact details remain to be worked out, but the one thing that seems reasonably certain is that the kind of blockbuster East Coast snowstorm that occurred during Winters 2009-10 and 2010-11 is highly unlikely.

Farther ahead, through the remainder of the month, it still appears that cold shots will be short-lived and not very impressive. It also appears unlikely that colder than normal conditions will lock into the areas that have been warm overall for the winter.

[wxmx]

12z Euro gives a "warm" welcome back to Josh .

[Srain]

WSR is getting a nice work out in the Atlantic and Pacific...

NOUS42 KNHC 161700

WEATHER RECONNAISSANCE FLIGHTS

CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.

1200 PM EST THU 16 FEBRUARY 2012

SUBJECT: WINTER STORM PLAN OF THE DAY (WSPOD)

VALID 17/1100Z TO 18/1100Z FEBRUARY 2012

WSPOD NUMBER.....11-079

I. ATLANTIC REQUIREMENTS

1. FLIGHT ONE - TEAL 76 -

A. A-66/ DROP 9 (28.2N 93.9W)/ 18/1200Z

B. AFXXX 02WSA TRACK66

C. 18/0730Z

D. 10 DROPS ON TRACK AS PUBLISHED

E. AS HIGH AS POSSIBLE/ 18/1400Z.

2. OUTLOOK FOR SUCCEEDING DAY: PSBL TRACK 62, FOR BOTH

19/0000Z AND 19/1200Z, CP- (31.3N 75.9W), FLOWN (CW).

II. PACIFIC REQUIREMENTS

1. FLIGHT ONE - NOAA49 -

A. P-54/ DROP 10 (45.0N 166.0W) 18/0000Z

B. NOAA9 21WSC TRACK54

C. 17/1930Z

D. 17 DROPS ON TRACK AS PUBLISHED

E. 41,000 TO 45,000 FT/ 18/0600Z

2. SUCCEEDING DAY OUTLOOK: PSBL ANOTHER TRACK P-54

FOR 19/0000Z/ 45.0N 166.0W.

[Ottawa Blizzard]

the 12z GFS looks quite cold

[Chinook]

Currently, the Arctic Oscillation has climbed to +0.967 and ENSO Region 3.4 anomalies were last reported at -1.0°C. The combination of an ongoing La Niña and a positive Arctic Oscillation is a bad one for KU snowstorms.

I did a quick search on the AO/ENSO correlations. I have been fascinated with the major teleconnections for years. This winter has certainly turned out to be different than predicted by several people. I thought for sure the cold temps would make a strong showing in the North, but I was wrong.

Temperature anomalies December 1st-February 13th

AO/ENSO composite research article:

http://www.cpc.ncep.noaa.gov/research_papers/ncep_cpc_atlas/8/toc.html

AO/ENSO phase influences on the USA surface temperature.

http://www.cpc.ncep.noaa.gov/research_papers/ncep_cpc_atlas/8/figures/temp/DJF.temp.test.gif

You can see that the +AO and La Nina combine to give a similar type of anomaly pattern that we saw this year.

Last year at this time, the USA had a similar temperature anomaly pattern to the ENSO-Neutral with Negative AO, as shown on the link. That's sort of weird because last year was a stronger La Nina than this year, but the AO made a big difference.

[donsutherland1]

the 12z GFS looks quite cold

If the AO+/PNA- pattern develops as shown by some of the guidance, it would be more likely that any cold would be dumped into the West or the Plains with only glancing shots farther east. The 12z GFS was probably overdone on the cold for the end of February and perhaps start of March.

[uncle W]

If the AO+/PNA- pattern develops as shown by some of the guidance, it would be more likely that any cold would be dumped into the West or the Plains with only glancing shots farther east. The 12z GFS was probably overdone on the cold for the end of February and perhaps start of March.

if the AO stays positive I think it's over for this year...I'm hoping this positive rise is temperary...

[donsutherland1]

if the AO stays positive I think it's over for this year...I'm hoping this positive rise is temperary...

I agree. Unfortunately, most of the guidance is pointing to an AO+ to end February and begin March.

[donsutherland1]

Consistent with La Niña-AO+ conditions, the upcoming storm is very likely to produce only a localized snow event. Although a substantial snowfall of 10" or more is not likely except perhaps in a few widely scattered areas, a moderate 3"-6" snowfall appears likely for a portion of the Mid-Atlantic region. As of the 6z guidance, a possible area that could see such a snowfall would probably be bounded by Richmond-Charlottesville-Washington, DC (IAD and DCA). Richmond would get rain and sleet before the changeover to snow and might wind up somewhere below 3". However, the GFS thumps Richmond with more than 4" of snow following the changeover, while the NAM calls for an extended period of sleet before the changeover. How quickly the changeover occurs will determine whether Richmond also picks up a moderate snowfall. Charlottesville and Washington, DC (DCA and IAD) are shown to be cold enough for a mostly or all snow event (wet snow). One should keep in mind that the air mass ahead of the storm will be quite mild, so initial boundary layer problems could be present even in areas shown as all snow by the NAM and GFS might see some rain or mixed precipitation early on.

Further, despite the cold ending to the month shown on the 2/16 12z GFS, the subsequent guidance has shifted to a less cold outlook. Such an outcome would be consistent with the expected teleconnections during a La Niña. Some East Coast cities could wind up with among their 5 or 10 warmest winters on record. Courtesy of information from Famartin (Ray), Central Park has had the third warmest December 1-February 16 period on record.

Meanwhile, the MJO is rapidly approaching Phase 2. Barring a slowdown in the progression, the MJO could push across Phase 3 and perhaps into Phase 4 sometime during the first week in March. Both the Canadian and European ensembles show the potential for such a scenario. Should such an outcome unfold, the stage could again be set for another month of mild conditions across perhaps across a large part of the eastern third to half of North America, as the MJO again works its way through the "warmer" phases. Odds of such an outcome have been increasing. FWIW, the CFSv2 forecasts widespread mild conditions for March, including the first two weeks of the month.

[Feb]

Consistent with La Niña-AO+ conditions, the upcoming storm is very likely to produce only a localized snow event. Although a substantial snowfall of 10" or more is not likely except perhaps in a few widely scattered areas, a moderate 3"-6" snowfall appears likely for a portion of the Mid-Atlantic region. As of the 6z guidance, a possible area that could see such a snowfall would probably be bounded by Richmond-Charlottesville-Washington, DC (IAD and DCA). Richmond would get rain and sleet before the changeover to snow and might wind up somewhere below 3". However, the GFS thumps Richmond with more than 4" of snow following the changeover, while the NAM calls for an extended period of sleet before the changeover. How quickly the changeover occurs will determine whether Richmond also picks up a moderate snowfall. Charlottesville and Washington, DC (DCA and IAD) are shown to be cold enough for a mostly or all snow event (wet snow). One should keep in mind that the air mass ahead of the storm will be quite mild, so initial boundary layer problems could be present even in areas shown as all snow by the NAM and GFS might see some rain or mixed precipitation early on.

Further, despite the cold ending to the month shown on the 2/16 12z GFS, the subsequent guidance has shifted to a less cold outlook. Such an outcome would be consistent with the expected teleconnections during a La Niña. Some East Coast cities could wind up with among their 5 or 10 warmest winters on record. Courtesy of information from Famartin (Ray), Central Park has had the third warmest December 1-February 16 period on record.

Meanwhile, the MJO is rapidly approaching Phase 2. Barring a slowdown in the progression, the MJO could push across Phase 3 and perhaps into Phase 4 sometime during the first week in March. Both the Canadian and European ensembles show the potential for such a scenario. Should such an outcome unfold, the stage could again be set for another month of mild conditions across perhaps across a large part of the eastern third to half of North America, as the MJO again works its way through the "warmer" phases. Odds of such an outcome have been increasing. FWIW, the CFSv2 forecasts widespread mild conditions for March, including the first two weeks of the month.

I think most people have thrown in the towel Don. You did a great job this winter. Hopefully next winter will be much better.

[easternsnowman]

The models have trouble forecasting a few days out, let alone 2 weeks..........lol

[Ottawa Blizzard]

I think most people have thrown in the towel Don. You did a great job this winter. Hopefully next winter will be much better.

I second this. Great job Don.

[donsutherland1]

You did a great job this winter. Hopefully next winter will be much better.

Thanks Feb.

Hopefully, next winter will be much better.

[donsutherland1]

I second this. Great job Don.

Thank you, Ottawa Blizzard. Hopefully, something can be salvaged for the Toronto area in March.

[JBG]

Thanks Feb.

Hopefully, next winter will be much better.

How do third-year La Niña winters stack up? Is our only sample 1975-6 and 1954-5 (or is it 1955-6)?

[Hoosier]

How do third-year La Niña winters stack up? Is our only sample 1975-6 and 1954-5 (or is it 1955-6)?

There's also 2000-2001

[Snowstorms]

Thank you, Ottawa Blizzard. Hopefully, something can be salvaged for the Toronto area in March.

Yes, amazing job Don. I wouldnt put much faith in anything occuring in Toronto in March. With the way this Winters been behaving, many areas will be lucky to get a flurry.

2012-13 ftw.

[JBG]

There's also 2000-2001

Wasn't that more a La Nada with a return to La Niña at the end?

[Snowstorms]

How do third-year La Niña winters stack up? Is our only sample 1975-6 and 1954-5 (or is it 1955-6)?

2000-01, 1975-76, 1944-45, 1908-09 and 1956-57.

Besides 56-57 and 1908-09 which were quite warm across the East, the other 3 years werent bad at all.

Lets see.

[Snowstorms]

Wasn't that more a La Nada with a return to La Niña at the end?

Based on the MEI it actually peaked around November, coming in at -0.755. It was neutral in the Summer much like this year.

[JBG]

Based on the MEI it actually peaked around November, coming in at -0.755. It was neutral in the Summer much like this year.

Interesting. I always thought it was neutral. As for the summer do you mean the summer of 2000 or 2001?

[donsutherland1]

How do third-year La Niña winters stack up? Is our only sample 1975-6 and 1954-5 (or is it 1955-6)?

The results are mixed. A worse outcome would probably result from a neutral ENSO winter.