1370 replies to this topic

[WxUSAF]

Srain...as someone who lived in TX from late 06-late 09, I'm glad it's finally raining again! We certainly got into that drought like pattern for the last year I was there and I know it just got worse after I left.

[donsutherland1]

thunderbolt, on 19 February 2012 - 09:08 PM, said:

Don, i agree with buckeye, you have been spot on this year just like past years...keep up the great work. Next year has to be better (considering there has only been 4" compared to 20" being the norm in langhorne, pa.

ps if i had to pay for a forecast it would be yours!

chris

Thanks for the very generous compliment, Chris.

[donsutherland1]

GaWx, on 20 February 2012 - 12:17 AM, said:

Well, Savannh didn't even have to wait for 2/22-24 to get to 78. It got there today. Additionally, Savannah has already had an 82, a 79, and three other 78's this met. winter!

It's been an incredible winter, GaWx. Unfortunately, it's been incredible for warmth, not cold and snow.

[donsutherland1]

With respect to the upcoming 2/22-24 warmth, select forecasts from the 2/20/2012 12z MOS Guidance for the highest temperature during the period include:

Allentown: 62°
Atlantic City: 65°
Baltimore: 69°
Boston: 55°
Charleston, SC: 73°
Charleston, WV: 72°
Charlotte: 73°
Columbia: 77°
Columbus: 66°
Harrisburg: 62°
Hartford: 57°
Lexington, KY: 68°
New York City: 63°
Newark: 63°
Norfolk: 74°
Philadelphia: 65°
Pittsburgh: 63°
Portland, ME: 48°
Providence: 60°
Raleigh: 76°
Richmond: 74°
Roanoke: 71°
Salisbury: 70°
Savannah: 76°
Washington, DC:
...DCA: 69°
...IAD: 68°
Wilmington, DE: 63°

Father out, the 2/20 12z GFS has trimmed the magnitude of cold it had been forecasting for the end of February/start of March. Previously, the GFS had shown some extreme cold for that period in some previous runs, despite the likely AO+ for that timeframe.

[donsutherland1]

Many thanks for the kind words, Steve. The above normal rainfall in parts of the Southern Plains and Texas has been welcome. Hopefully, wetter conditions will persist to continue to ease the drought.

[donsutherland1]

Although winter remains dormant in the eastern U.S., there appears to be a growing possibility that the return of cold weather in the Pacific Northwest could also coincide with an opportunity for at least some snowfall. The February 24-27 timeframe is perhaps a good candidate for such a snowfall. Both the 2/20 12z and 18z runs of the GFS point to the possibility of accumulating snow in the Seattle area during that timeframe.

Such a snowfall would be consistent with experience following Seattle's big snowstorms (6" or greater snowfalls). Additional snow fell following 8 of the 9 (89%) previous 6" or greater January storms. Additional snow fell in all four previous January La Niña cases. Sometimes, as was the case following the first two storms in January 1950 and first two storms in January 1969, the additional snowfall was significant.

Finally, the opening week of March looks to be unseasonably cold in the Pacific Northwest.

[donsutherland1]

March 2012 Thoughts:

- The La Niña, which peaked at the beginning of February with Region 3.4 anomalies of -1.2°C, will likely weaken steadily during March. It is possible that the ENSO Region 3.4 anomalies could approach or rise above -0.5°C toward the end of March. The increasing frequency of days on which the SOI has been negative indicates a weakening La Niña.

The SOI has been negative the following percentage of days:

December: 3.2%
January: 25.8%
February: 50.0% (through 2/20)

Both the CFSv2 and ECMWF forecast a weakening La Niña during March.

Therefore, the core assumption is that the La Niña will weaken during March and neutral ENSO conditions could develop toward the end of March or perhaps during early April.

- The PDO is likely to remain solidly negative during February. A negative PDO correlates well with a negative PNA. As this winter has seen the PNA average higher than what might have been expected during the strongly negative PDO that has predominated, the March assumption is that the PNA will remain locked in a fairly narrow range close to neutral (-0.5 to +0.5). The overall average could be somewhat negative.

- The stretch of 22 consecutive days on which the AO was negative ended on February 11. Consistent with a number of La Niña cases that featured powerful AO+ regimes in December, particularly 1974-75 and 2006-07, the March AO is likely to be positive for the most part.

The GFS ensemble members show a strongly positive AO entering March. My assumption is an AO that will generally range somewhere between +0.50 to +1.50.

- The MJO is currently in Phase 2. The ensemble guidance brings the MJO to Phase 3 and possibly Phase 4 during the first week of March with some hints of a slowing of its rate of progression and reduction of its amplitude. If so, the MJO could wind up primarily in Phases 4-7 during March.

The composite maps for February based on the above assumptions are as follows:

1. Top Left: North America temperature anomalies
2. Top Right: Europe temperature anomalies
3. Bottom Left: CFSv2 Forecast for March (February 20 run)
4. Bottom Right: Observed decadal temperature trend



FWIW, the top analog for March was 2011.

An adjustment based on the observed decadal change in temperatures for March would be a somewhat warmer outcome than what is shown for the Central Plains States.

All said, I believe March will likely wind up warmer than normal across much of the eastern United States and eastern Canada, but colder than normal across much of Canada, excluding southern Ontario and southern Quebec. The Pacific Northwest (Oregon, Washington, British Columbia) and Alaska will likely see a return of colder than normal conditions.

[CoastalWx]

Don, agree with March in the East. Feel good about that call.

[donsutherland1]

Thanks Scott.

[usedtobe]

Don,

I very much like your call but am inclined to be warmer than the composite across the northern Plains just based on persistence and the presence of a positive AO which most times like it warm there. You've been stellar all year.

[donsutherland1]

usedtobe, on 21 February 2012 - 08:26 AM, said:

Don,

I very much like your call but am inclined to be warmer than the composite across the northern Plains just based on persistence and the presence of a positive AO which most times like it warm there. You've been stellar all year.

Thanks Wes. I agree about the risk of more widespread warmth e.g., in the Northern Plains. It will be interesting to see how March plays out.

[donsutherland1]

With respect to the ongoing La Niña, the ENSO Region 3.4 anomalies warmed to -0.6°C for the week centered around 2/15 vs. -1.0°C for the prior week. The warming is likely a response to several recent bouts of the SOI's being < 0. Overall, the La Niña should, in general, continue to fade and the recent warming suggests that neutral ENSO conditions could arrive at some point in March. The recent development should not make a material difference in the posted idea concerning March (Message #1197).

[Ji]

donsutherland1, on 21 February 2012 - 08:23 PM, said:

With respect to the ongoing La Niña, the ENSO Region 3.4 anomalies warmed to -0.6°C for the week centered around 2/15 vs. -1.0°C for the prior week. The warming is likely a response to several recent bouts of the SOI's being < 0. Overall, the La Niña should, in general, continue to fade and the recent warming suggests that neutral ENSO conditions could arrive at some point in March. The recent development should not make a material difference in the posted idea concerning March (Message #1197).

any idea of Enso for next season?

[donsutherland1]

Ji, on 21 February 2012 - 09:52 PM, said:

any idea of Enso for next season?

Not yet. Most of the guidance I've seen shows either neutral or weak El Niño conditions going into the winter. However, the model skill level from this far out is very poor. For example, the CFSv2's error approaches 1.0°C.

[goobagooba]

donsutherland1, on 21 February 2012 - 10:11 PM, said:

Not yet. Most of the guidance I've seen shows either neutral or weak El Niño conditions going into the winter. However, the model skill level from this far out is very poor. For example, the CFSv2's error approaches 1.0°C.

OT, but haven't noticed a new ENSO thread. I saw the CPC/IRI probabilistic forecast of ENSO conditions up til November. Seemed to be calling for about even chances for any of Nino, Nina or Neutral.

http://iri.columbia....fo/figure1.html

Of the five previous episodes of multi-year Ninas, four of them ended with a Nino the following winter. The one that didn't was 2001-2002, which ended as slightly negative-neutral. With the models trending positive, a Nino might be the best bet. Course, that may be wishful thinking on my part.

[donsutherland1]

goobagooba, on 21 February 2012 - 11:05 PM, said:

With the models trending positive, a Nino might be the best bet. Course, that may be wishful thinking on my part.

I hope that will be the case. My guess is that by late spring/early summer, there will be a reasonable model consensus.

[donsutherland1]

Some prior runs have teased warm-weary Easterners about significant cold (a few runs were truly extreme, with one featuring single-digit lows as far south as Washington, DC) and snowfall opportunities during the first week in March. However, the composite anomalies I came up with showed that the cold would likely be focused in the West (Pac NW) and a large portion of Canada. The day 11 objective analogs rolled forward 2 days (to be centered on March 4) also focus the cold away from the eastern CONUS.



With the GFS ensembles showing the AO (currently +1.145 and rising) reaching between +2 and +3, along with a somewhat negative PNA, one probably should be wary of cold model runs in the East. Instead, the cold will likely be dumped into the West (possibly the Plains, too).

Moreover, in a somewhat cruel irony, the 1985 analog is finally popping up for the first week in March. Unfortunately, it's not the one most here would welcome. Based on the forecast AO and PNA, the March 8-10, 1985 period is showing up. That timeframe featured conditions reasonably similar to the temperature anomalies shown above.

In sum, new data since I posted my March 1-7, 2012 thoughts (#1183 in this thread) have increased my confidence in that idea. Cold shots in the East will likely continue to follow the winter pattern: quick-hitting and not too severe. The Pacific Northwest will likely feature more sustained cold.

[am19psu]

I'm definitely concerned about busting the period post March 7. There is quite a large difference between the Roundy MJO guidance (which shows the MJO zipping through the phase space, getting into P7 by March 11 and P1 by the 18th) and the Euro Weekly Ensemble (which shows the MJO in P5 and P6 at those same periods, respectively). The Roundy guidance would bring cold back to the East much more quickly than the Euro, which shows very warm temps through its Week 3 and Week 4 periods.

[Ginx]

donsutherland1, on 21 February 2012 - 11:24 PM, said:

Some prior runs have teased warm-weary Easterners about significant cold (a few runs were truly extreme, with one featuring single-digit lows as far south as Washington, DC) and snowfall opportunities during the first week in March. However, the composite anomalies I came up with showed that the cold would likely be focused in the West (Pac NW) and a large portion of Canada. The day 11 objective analogs rolled forward 2 days (to be centered on March 4) also focus the cold away from the eastern CONUS.

http://img.photobucket.com/albums/v327/donsutherland1/March1to72012b.jpg

With the GFS ensembles showing the AO (currently +1.145 and rising) reaching between +2 and +3, along with a somewhat negative PNA, one probably should be wary of cold model runs in the East. Instead, the cold will likely be dumped into the West (possibly the Plains, too).

Moreover, in a somewhat cruel irony, the 1985 analog is finally popping up for the first week in March. Unfortunately, it's not the one most here would welcome. Based on the forecast AO and PNA, the March 8-10, 1985 period is showing up. That timeframe featured conditions reasonably similar to the temperature anomalies shown above.

In sum, new data since I posted my March 1-7, 2012 thoughts (#1183 in this thread) have increased my confidence in that idea. Cold shots in the East will likely continue to follow the winter pattern: quick-hitting and not too severe. The Pacific Northwest will likely feature more sustained cold.

See a lot of 56s here, now that would be unreal!

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[donsutherland1]

Ginx, on 22 February 2012 - 08:45 AM, said:

See a lot of 56s here, now that would be unreal!

Ginx,

Unfortunately, the composite temperature anomalies for the 1956 dates shown are very warm in the East. The composite is not very different from the composite anomalies I posted in Message #1183 in this thread.

[donsutherland1]

am19psu, on 22 February 2012 - 07:54 AM, said:

I'm definitely concerned about busting the period post March 7. There is quite a large difference between the Roundy MJO guidance (which shows the MJO zipping through the phase space, getting into P7 by March 11 and P1 by the 18th) and the Euro Weekly Ensemble (which shows the MJO in P5 and P6 at those same periods, respectively). The Roundy guidance would bring cold back to the East much more quickly than the Euro, which shows very warm temps through its Week 3 and Week 4 periods.

I agree. The difference is quite striking. However, it appears that the MJO is now progressing more slowly through Phase 1, so I lean against the Roundy guidance at this time. I favor a rate of progression somewhere between the faster Canadian and slower ECMWF ensembles.

[usedtobe]

donsutherland1, on 22 February 2012 - 12:35 PM, said:

I agree. The difference is quite striking. However, it appears that the MJO is now progressing more slowly through Phase 1, so I lean against the Roundy guidance at this time. I favor a rate of progression somewhere between the faster Canadian and slower ECMWF ensembles.

Don,

I'm with you about going with a compromise between the Canadian and Ecmwf plus even when we went through phases 8-2 last time it just wasn't that cold.

[Ginx]

donsutherland1, on 22 February 2012 - 12:33 PM, said:

Ginx,

Unfortunately, the composite temperature anomalies for the 1956 dates shown are very warm in the East. The composite is not very different from the composite anomalies I posted in Message #1183 in this thread.

It was the roll forward that interests me Don.

[Ottawa Blizzard]

donsutherland1, on 21 February 2012 - 11:24 PM, said:

Some prior runs have teased warm-weary Easterners about significant cold (a few runs were truly extreme, with one featuring single-digit lows as far south as Washington, DC) and snowfall opportunities during the first week in March. However, the composite anomalies I came up with showed that the cold would likely be focused in the West (Pac NW) and a large portion of Canada. The day 11 objective analogs rolled forward 2 days (to be centered on March 4) also focus the cold away from the eastern CONUS.



With the GFS ensembles showing the AO (currently +1.145 and rising) reaching between +2 and +3, along with a somewhat negative PNA, one probably should be wary of cold model runs in the East. Instead, the cold will likely be dumped into the West (possibly the Plains, too).

Moreover, in a somewhat cruel irony, the 1985 analog is finally popping up for the first week in March. Unfortunately, it's not the one most here would welcome. Based on the forecast AO and PNA, the March 8-10, 1985 period is showing up. That timeframe featured conditions reasonably similar to the temperature anomalies shown above.

In sum, new data since I posted my March 1-7, 2012 thoughts (#1183 in this thread) have increased my confidence in that idea. Cold shots in the East will likely continue to follow the winter pattern: quick-hitting and not too severe. The Pacific Northwest will likely feature more sustained cold.

Don, March 4, 1985 had a pretty big snowstorm (about 10") in both Toronto and Ottawa, while March 1956 wasn't too bad for snowfall in both of those cities.

[Snowstorms]

Ottawa Blizzard, on 22 February 2012 - 04:28 PM, said:

Don, March 4, 1985 had a pretty big snowstorm (about 10") in both Toronto and Ottawa, while March 1956 wasn't too bad for snowfall in both of those cities.

We were lucky to be on the cold side of the gradient. With strong temperature gradients as depicted by Don's maps, there's quite the gradient which is a good recipe for not only stronger storms but more severe wx as climo favors severe wx starting to develop across the south.

This pattern is a typical Nina pattern which is FAR better than what we've been seeing which is very unusual for a Nina regime, esp a second year Nina.

[donsutherland1]

Ottawa Blizzard, on 22 February 2012 - 04:28 PM, said:

Don, March 4, 1985 had a pretty big snowstorm (about 10") in both Toronto and Ottawa, while March 1956 wasn't too bad for snowfall in both of those cities.

The February 24-25 period offers Toronto an opportunity to pick up accumulating snow. Right now, my initial thinking is something in the 7.5 cm-15.0 cm (3"-6") range appears reasonably likely. There may be some additional opportunities afterward.

Along the East Coast, I'm less optimistic despite the 2/22 12z ECMWF's 192-hour solution and, to a lesser extent, the 12z ECMWF Ensembles solution. First, only one KU snowstorm occurred during La Niña conditions and a positive AO (January 2000 event). The blockbuster March 1956 La Niña snowstorm had an AO-/PNA+ combination. Typically, with AO+/PNA- combinations (what is forecast for the 192-hour timeframe) and ENSO Region 3.4 anomalies < 0, snowstorms have a more moderate impact (March 2009 is an example) or focus on New England (April Fool's Day Storm of 1997 and mid-March 2007 storm). In short, if there is a winter weather event around 192 hours, my guess is that it would far more likely be a relatively localized event/near miss/changeover case than a KU-type one.

[uncle W]

donsutherland1, on 22 February 2012 - 08:30 PM, said:

The February 24-25 period offers Toronto an opportunity to pick up accumulating snow. Right now, my initial thinking is something in the 7.5 cm-15.0 cm (3"-6") range appears reasonably likely. There may be some additional opportunities afterward.

Along the East Coast, I'm less optimistic despite the 2/22 12z ECMWF's 192-hour solution and, to a lesser extent, the 12z ECMWF Ensembles solution. First, only one KU snowstorm occurred during La Niña conditions and a positive AO (January 2000 event). The blockbuster March 1956 La Niña snowstorm had an AO-/PNA+ combination. Typically, with AO+/PNA- combinations (what is forecast for the 192-hour timeframe) and ENSO Region 3.4 anomalies < 0, snowstorms have a more moderate impact (March 2009 is an example) or focus on New England (April Fool's Day Storm of 1997 and mid-March 2007 storm). In short, if there is a winter weather event around 192 hours, my guess is that it would far more likely be a relatively localized event/near miss/changeover case than a KU-type one.

first off Don, great work...I agree about no KU events unless we get a similar storm to the October 29th event...if we see any snowfalls they might be like March snowfalls from 1955, 1965, 1968, 1976, 1989, 1999...3-5" range...two to three day cold period if we are lucky...without cold air it can't snow...This winter will end up with the least amount of days with a minimum of 32 or lower in NYC...The record will be crushed if March is warm...

[donsutherland1]

uncle W, on 22 February 2012 - 08:55 PM, said:

first off Don, great work...I agree about no KU events unless we get a similar storm to the October 29th event...if we see any snowfalls they might be like March snowfalls from 1955, 1965, 1968, 1976, 1989, 1999...3-5" range...two to three day cold period if we are lucky...without cold air it can't snow...This winter will end up with the least amount of days with a minimum of 32 or lower in NYC...The record will be crushed if March is warm...

Thanks Uncle W. I agree about the fewest days with minimum readings of 32°F or below in NYC. Already, some of what I'm looking at hints that the general milder than normal readings likely in the first week in February will persist beyond the first week of the month.

[donsutherland1]

Some evening thoughts:

1. The idea of a 7.5 cm-15 cm (3"-6") snowfall for Toronto still appears reasonable for the February 24-25 timeframe. There is some potential for somewhat more snowfall. Should such a snowfall materialize, it would be Toronto's biggest snowfall of the winter. Additional opportunities for snowfall appear possible afterward.

2. The idea that Toronto would likely not see any -20°C (-4°F) days in February (Message #808 in this thread) appears increasingly probable. To date, the month's lowest reading is -13.9°C (7.0°F) on February 11.

3. The month is likely to end on a colder than normal note in the Pacific Northwest as the PNA (currently +0.341) heads negative in coming days. The generally colder than normal weather should persist through at least the first week in March. At least one strong shot of cold with the potential to send the temperature into the 20s in Seattle appears possible over the next 2 weeks. There may also be some opportunities for snowfall.

4. The NAEFS is showing above normal temperatures across the eastern third of the U.S. for the March 1-7 timeframe. With the NAEFS, objective analogs, and composite pattern based on expected teleconnections all showing warmth in that part of North America, any cold shots will likely be short-lived and rather moderate. Severe cold outbreaks that have shown up in the extended range on some runs of the GFS (not the 2/23 0z run) appear unlikely given the increasingly strong AO+ (currently +2.275 and rising) that is now getting established. Similarly, guidance hinting at KU-type East Coast snowstorms is likely to be incorrect. No such storm has occurred with an AO of +2.4 or above.

[ORH_wxman]

donsutherland1, on 23 February 2012 - 12:12 AM, said:

Similarly, guidance hinting at KU-type East Coast snowstorms is likely to be incorrect. No such storm has occurred with an AO of +2.4 or above.

I agree Don...the more Nina-like pattern developing doesn't support a big KU type storm in the east...esp with a +AO....they mostly look like SWFEs like 2/24 and now 2/29-3/1 is trending that way which makes sense in this pattern...someone to the north of the Nina gradient will probably get some decent snow, but that gradient looks to develop over NY State and New England rather than the large cities...though BOS could conceivably pull out a few minor to moderate events if things break right.

[donsutherland1]

I agree, Will, about SWFEs being much more likely than a KU-type storm.

[winterymix]

donsutherland1, on 23 February 2012 - 06:40 AM, said:

I agree, Will, about SWFEs being much more likely than a KU-type storm.

G-morning, Don.

Way down here, south of the Mason-Dixon Line, we (with brown lawns) probably have a 90% to 95% likelihood of enjoying accumulating snow ten months from now, at the soonest. Before we turn all attention to Severe and then to Tropical seasons, I have a question for you:

Where would you turn for broad-brush guidance about the 2012-2013 Winter season?

If we look at Klaus Wolter's work:

http://www.esrl.noaa.gov/psd/enso/mei/

and scroll down to this chart:
Discussion and comparison of recent conditions with historic La Niña events

it suggests to me that the index will slowly trend toward the mean during the next few months. Based upon analogs of previous La ninas of the current strength, can you make an educated guess about the state of the MEI for the 2012-2013 winter? Wolter calls for a 40% continuation of La nina for next winter.

[donsutherland1]

winterymix, on 23 February 2012 - 07:41 AM, said:

I have a question for you:

Where would you turn for broad-brush guidance about the 2012-2013 Winter season?

If we look at Klaus Wolter's work:

http://www.esrl.noaa.gov/psd/enso/mei/

and scroll down to this chart:
Discussion and comparison of recent conditions with historic La Niña events

it suggests to me that the index will slowly trend toward the mean during the next few months. Based upon analogs of previous La ninas of the current strength, can you make an educated guess about the state of the MEI for the 2012-2013 winter? Wolter calls for a 40% continuation of La nina for next winter.

Winterymix,

Even a guess at the Winter 2012-13 ENSO is risky at this point. Model verification is poor from this point in time. For example, the mean error in the CFSv2 forecast is around 1.0°C for the Region 3.4 anomaly. Usually by late spring/early summer, the verification scores are better.

One might have some early insight from the trends in the SOI through May. If the April and May figures remain solidly positive, that could be an indicator that Winter 2012-13 would feature a third consecutive La Niña. If not, odds would probably favor a Neutral or El Niño winter.

For me, it's too soon to take a guess concerning Winter 2012-13's ENSO, much less the overall outcome. However, a neutral ENSO might provide the worst possible outcome for the Mid-Atlantic region.

[Isotherm]

Speaking of third year ENSO following double ninas, there were several such cases since 1950. Bolded is what happened in the third year.

1949-51: Nina
1951-52: Weak El Nino

1954-56: Nina
1956-57: Weak Nina

1970-72: Nina
1972-73: Strong El Nino

1973-75: Nina
1975-76: Strong Nina

1998-2000: Nina
2000-01: Weak Nina

2010-12: Nina
2012-13: ?

We've essentially seen the full spectrum of possibilities, from strong Nina to strong Nino for the third year following a double Nina.

US temp composite of those 3rd year events (not very useful in itself, but interesting to look at nonetheless).



All of those years except 2000-01 were warm/snow starved for most of the East (i.e., NYC recorded < 25" in those years save for 2000-01).

Obviously it's a small sample size, and ENSO state was widely different from year to year. NAO/AO values tended to be positive in the warm winters, whereas only 2000-01 featured a neg NAO of the 5 seasons mentioned. 1951-52 was easily the worst weak el nino (snow wise and cold wise) for much of the Eastern US since 1950. Generally weak ninos are good winters for the Northeast, but there are exceptions. Based on 3rd year seasons alone, the data is pessimistic concerning a much better winter next year in the East; however, as noted, the sample size is much too small to make a conclusion. If we can get a weak Nino going, that'd be the most desirable scenario for the entire Eastern seaboard. If we remain in a LA NINA or neutral ENSO, chances are the Southeast and Mid atlantic will see another bad winter.

[HM]

I agree to go a bit slower with the MJO than Roundy here. What becomes interesting is then there would be a phase 4-6 potential during mid-March. This isn't quite the blowtorch signal as it is in January, esp. if you can continue to press the forcing eastward and allow the GWO to orbit from 3-4 to 5-6. This would shorten the waves and allow for a cyclone to break along the East Coast. The more time the MJO delays its arrival to these phases, the better potential for this and possibly a late-season wet snowstorm for the Northeast.