Medium Range Discussion Winter 2011-12

[donsutherland1]

Verification:

In Message #806, I stated:

For the first time this winter, my medium-term forecast shows cold anomalies in the eastern U.S., southern Ontario, and southern Quebec. There is risk that a warmer outcome could still unfold and much will depend on the Arctic Oscillation. Currently, there is a huge spread among the ensemble members for the AO...

I'm pretty much in agreement with the chart based on the teleconnections (1st one). The only adjustment would be that Maine and possibly eastern Canada could be near normal to slightly above normal based on a combination of the blocking and decadal observed warming in that area for February.

More than likely, this cold period won't lock in.

This was one of my weaker medium range forecasts. Although much of Maine was somewhat above normal and the rest was near normal, the area of cold anomalies was more widespread than I had anticipated.

Finally, the days following the February 8-15, 2012 period saw generally mild conditions. As has been the case all winter, the cold did not lock in.

[donsutherland1]

Some quick morning thoughts:

1. The MJO continues to race ahead. It has now moved into Phase 2. The progression is so rapid that the colder outcomes that would be implied by Phase 1 and now Phase 2 are not likely to be widespread.

2. With the AO approaching +1, the weekend storm will be suppressed. A portion of Virginia could still pick up 3"-6" snow, but Washington, DC will probably see an inch or two and perhaps less. The Northeast and northern Mid-Atlantic won't be impacted.

3. Analog support for a cold March in a portion of the West and warm one in much of the East continues to increase. The strongest analogs I'm coming across at present are 1976 and 2011. 1975 is still in the mix, but 1956 is not. The analog trends would be consistent with where the MJO is heading.

[cbmclean]

Verification:

In Message #806, I stated:

For the first time this winter, my medium-term forecast shows cold anomalies in the eastern U.S., southern Ontario, and southern Quebec. There is risk that a warmer outcome could still unfold and much will depend on the Arctic Oscillation. Currently, there is a huge spread among the ensemble members for the AO...

I'm pretty much in agreement with the chart based on the teleconnections (1st one). The only adjustment would be that Maine and possibly eastern Canada could be near normal to slightly above normal based on a combination of the blocking and decadal observed warming in that area for February.

More than likely, this cold period won't lock in.

This was one of my weaker medium range forecasts. Although much of Maine was somewhat above normal and the rest was near normal, the area of cold anomalies was more widespread than I had anticipated.

Finally, the days following the February 8-15, 2012 period saw generally mild conditions. As has been the case all winter, the cold did not lock in.

Don (If I may call you that),

First of all, I applaud you for this type of forecast evaluation summary, which to me is a sign mark of a true scientific mindset. I know that this might be a complex question which requires a complex answer, but I am interested in understanding the causal mechanism(s) which lead to the observed temperature anomaly pattern.

We have your forecast, and we have the actual result, and you talked about where you got it right, where you were somewhat off etc. What I am interested in learnign about is the "why". Why did it turn out the way it did? I am most interested in the significant warm anomaly in Norther North America. There is a broad strip of very large positive anomalies in basically all of mainland Nunavut, west across much of the Northwest Terr., through the Yukon into Alaska. The Canadian Archipelago is not AS warm, but still there isn't a spec of white or blueish colors to be seen. What sortof anomalous atmoshperic dynamics lead to this? And whats with the random bubble of cold anomalies in norther Quebec/Ungava?

[buckeye]

Some quick morning thoughts:

1. The MJO continues to race ahead. It has now moved into Phase 2. The progression is so rapid that the colder outcomes that would be implied by Phase 1 and now Phase 2 are not likely to be widespread.

2. With the AO approaching +1, the weekend storm will be suppressed. A portion of Virginia could still pick up 3"-6" snow, but Washington, DC will probably see an inch or two and perhaps less. The Northeast and northern Mid-Atlantic won't be impacted.

3. Analog support for a cold March in a portion of the West and warm one in much of the East continues to increase. The strongest analogs I'm coming across at present are 1976 and 2011. 1975 is still in the mix, but 1956 is not. The analog trends would be consistent with where the MJO is heading.

continued good news! A warm March would be welcome!

[Ottawa Blizzard]

Wow, if the 18z GFS even came close to verifying, mother nature would be forgiven for this crap winter

[donsutherland1]

Wow, if the 18z GFS even came close to verifying, mother nature would be forgiven for this crap winter

I agree, but believe the GFS solution is highly unlikely when it comes to the magnitude of the cold. For example, what it is showing is near historic in parts of the Mid-Atlantic region. The GFS shows a minimum temperature as low as -13.3°C (8°F) for Washington, DC. The coldest reading since 1950 was 14°. The all-time monthly low is 4° (March 4, 1873). I believe March 1872 was the only other case with single digit readings in Washington. I don't expect cold anywhere close to that magnitude in Washington. Where a fairly strong shot of cold might be more likely would be the northern tier, including Ontario, Quebec, Maine, New Brunswick, Nova Scotia, PEI, and Newfoundland, unless there is more blocking than I expect.

[donsutherland1]

Don (If I may call you that),

First of all, I applaud you for this type of forecast evaluation summary, which to me is a sign mark of a true scientific mindset. I know that this might be a complex question which requires a complex answer, but I am interested in understanding the causal mechanism(s) which lead to the observed temperature anomaly pattern.

We have your forecast, and we have the actual result, and you talked about where you got it right, where you were somewhat off etc. What I am interested in learnign about is the "why". Why did it turn out the way it did? I am most interested in the significant warm anomaly in Norther North America. There is a broad strip of very large positive anomalies in basically all of mainland Nunavut, west across much of the Northwest Terr., through the Yukon into Alaska. The Canadian Archipelago is not AS warm, but still there isn't a spec of white or blueish colors to be seen. What sortof anomalous atmoshperic dynamics lead to this? And whats with the random bubble of cold anomalies in norther Quebec/Ungava?

Thanks for the kind words.

Two quick thoughts:

1. I believe the cold anomalies in part of North America were more extensive than I had anticipated largely because the PNA was more strongly positive than I had thought. My assumption was a +0.25 to +1.25 PNA. The actual outcome was +0.87 to +1.63.

2. Northern North America likely reflects the dual blocking that was in place leading up to and during a portion of the period (February 8-15): AO and PNA. Snowcover in Quebec helped slow the moderation of the cold air, enhancing the prospect of cold anomalies.

[N. OF PIKE]

Here is CPC's outlook for Feb 24-28...it matches up fairly well with the analog composite I posted a couple days ago in here

A bit more bullish on the precip to our SW...but same general idea with the cold spilling over the top and with several shortwaves in the mix, there will probably be a few chances to get something wintry out of this...obviously its not January 2011 with an awesome block and great MJO support when it fizzled...but it should give some chances. Certainly it would be a change in the dry pattern we've had.

[cbmclean]

Thanks for the kind words.

Two quick thoughts:

1. I believe the cold anomalies in part of North America were more extensive than I had anticipated largely because the PNA was more strongly positive than I had thought. My assumption was a +0.25 to +1.25 PNA. The actual outcome was +0.87 to +1.63.

2. Northern North America likely reflects the dual blocking that was in place leading up to and during a portion of the period (February 8-15): AO and PNA. Snowcover in Quebec helped slow the moderation of the cold air, enhancing the prospect of cold anomalies.

Is there a seperate branch or subspeciality of meteorology dealing with temperature by itself? I am extremly interested in learning about the mechanisms which determine the air temperature athe the earth's surface.

[donsutherland1]

Is there a seperate branch or subspeciality of meteorology dealing with temperature by itself? I am extremly interested in learning about the mechanisms which determine the air temperature athe the earth's surface.

Thermodynamics is probably the closest field to what you are looking for.

[donsutherland1]

March 1-7, 2012 Thoughts:

With winter weather still a possibility in March, I'll post my thoughts concerning March in this thread. Meteorological winter ends on February 29 this year.

Given the forecast teleconnections, progression of the MJO, and continuing La Niña conditions, I suspect that there will be two big meteorological stories during the opening week in March:

1. Much of Canada turns cold.

2. Colder than normal temperatures hold on across a large part of Eastern Europe into Russia.

The below chart shows:

Top Left: The composite temperature anomalies for ENSO Region 3.4 anomalies of -1.35°C to -0.60°C, a PNA of -1.25 to -0.50, and an AO of +1 to +2 for North America.

Top Right: The composite temperature anomalies for Europe using the same ENSO-Teleconnections listed above.

Bottom Left: March temperature anomalies for La Niña conditions when the MJO was in Phase 3 or Phase 4.

Bottom Right: The observed decadal temperature change for March.

It should be noted that the ECMWF ensembles slow down the progression of the MJO somewhat more than the Canadian ensembles do. Nevertheless, it remains a reasonable prospect that the MJO could move from Phase 3 to Phase 4 during the first week in March. MJO composites were not shown for Europe, because the influence of the MJO is less in Europe than it is over North America.

I believe both composite charts offer a good idea of what to expect during the first week in March. The corrections I would make based on the observed decadal change would be to expand the warm anomalies across the northern portion of the British Isles into perhaps western Norway. Also, the cold would probably not be as severe as shown on the composite in Eastern Europe.

[buckeye]

March 1-7, 2012 Thoughts:

With winter weather still a possibility in March, I'll post my thoughts concerning March in this thread. Meteorological winter ends on February 29 this year.

Kudos once again for never buying into the model-induced MA snowstorm. You really are making LC, DT and JB look like clowns playing catch-up.

Streak continues on the DonS. express!

[donsutherland1]

Thanks for the kind words, Buckeye.

[donsutherland1]

For several model cycles, there has been a growing signal for a period of excessive warmth in the Ohio Valley and East Coast for the February 22-24, 2012 timeframe. Temperatures of 70° or above could be recorded in Virginia and southward and possibly as far north as Washington, DC. A few isolated 80° readings cannot be ruled out. At least one reading 60° or above could be registered from Washington, DC northward to New York City and perhaps portions of southern New England (Connecticut and maybe Rhode Island). Top readings in the middle 50s and above are possible in the Ohio Valley.

Some forecasts from the 2/19/2012 12z MOS Guidance include:

Allentown: 56°

Atlantic City: 61°

Baltimore: 62°

Boston: 53°

Charleston, SC: 77°

Charleston, WV: 65°

Charlotte: 71°

Columbia: 78°

Columbus: 59°

Harrisburg: 56°

Hartford: 53°

Lexington, KY: 64°

New York City: 61°

Newark: 62°

Norfolk: 71°

Philadelphia: 60°

Pittsburgh: 56°

Portland, ME: 49°

Providence: 58°

Raleigh: 73°

Richmond: 72°

Roanoke: 69°

Salisbury: 73°

Savannah: 78°

Washington, DC:

...DCA: 65°

...IAD: 66°

Wilmington, DE: 59°

Given the abnormal warmth this month and this winter in many parts of the East, bees have been observed gathering nectar from early-blooming flowers. Below is a photo from the New York Botanical Garden taken February 18, 2012:

[thunderbolt]

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

[GaWx]

For several model cycles, there has been a growing signal for a period of excessive warmth in the Ohio Valley and East Coast for the February 22-24, 2012 timeframe. Temperatures of 70° or above could be recorded in Virginia and southward and possibly as far north as Washington, DC. A few isolated 80° readings cannot be ruled out. At least one reading 60° or above could be registered from Washington, DC northward to New York City and perhaps portions of southern New England (Connecticut and maybe Rhode Island). Top readings in the middle 50s and above are possible in the Ohio Valley.

Some forecasts from the 2/19/2012 12z MOS Guidance include:

Savannah: 78°

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!

[Feb]

http://www.meteo.psu.edu/~gadomski/ECMWF0.5_0z/ecmwfloop.html

I would think if the 0z Euro comes close to verifying at day 10, March will see the lamb die of heat exhaustion along the east coast this year.

[Srain]

While many have languished with the lack of winter snowfall and cold, we in the drought parched S Plains have been very fortunate that some forecasts of ‘hot and dry' did not materialize and great inroads have been made into our ongoing 3 year drought situation. This has certainly been a winter of the haves and the have not. I will also add that Don as well as HM, Adam and others have been stellar this year in contrast of some forecasts suggesting otherwise in a very complicated and at times very un La Nina type pattern.

[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]

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]

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]

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).