Medium Range Discussion Spring 2012

[Thundersnow12]

any of you long range guys have any thoughts on mid may severe wise?

[GaWx]

4. The PDO Index goes back to 1900

Hey Don,

Just FYI, there is at least one version of the PDO that goes back to 1854:

ftp://ftp.ncdc.noaa.gov/pub/data/ersst-v2/pdo.1854.latest.ts

The one back to 1900 that I look at is here:

http://jisao.washington.edu/pdo/PDO.latest

[donsutherland1]

Hey Don,

Just FYI, there is at least one version of the PDO that goes back to 1854:

ftp://ftp.ncdc.noaa.....1854.latest.ts

The one back to 1900 that I look at is here:

http://jisao.washing.../pdo/PDO.latest

GaWx,

When I try to click on the link, rather than getting a table, I keep getting a message that the Windows Media Player doesn't recognize the file. I'll try the link at home, just in case I'm having firewall issues.

[donsutherland1]

Two days ago, the 12z run of the GFS showed a low temperature of 37° at May 1 9z in New York City. Readings below 40° in NYC have become rare. The last such reading was May 1, 1978 when the temperature fell to 38°. Today's run forecast a low temperature of 43° at 6z on May 1. No other model has been showing the kind of notable cold the earlier run of the GFS had indicated for the start of May.

[donsutherland1]

Verification:

My thoughts for the April 16-22, 2012 timeframe (#86) were as follows:

...The chart below shows the composite temperature anomalies for ENSO Region 3.4 anomalies of -0.4°C to +0.1°C, a PNA of -1.25 to +0.25, and an AO of -0.50 to +1.25 for North America.

On account of the large spread for the AO, there are 81 dates that show up in the teleconnection analogs. There is quite a variation among them, but a tendency that favors milder weather in parts of the East (except for New England/eastern Canada) and cooler readings in parts of the West.

The April 14-20 timeframe on the NAEFS shows warm anomalies across much of North America except for the Great Lakes region and parts of the West. In those areas, the NAEFS shows near normal readings.

Conclusion:

Using the NAEFS to help corroborate the teleconnection analogs, I pretty much agree with the teleconnection analogs except for the following modest changes:

1. Near normal readings are likely in the Great Lakes area (there was a signal for wetter than normal conditions in that area)

2. Warmer than normal in southern Alaska but colder than normal in northern Alaska

This was not a great forecast. The cold was more expansive than anticipated across Canada. The East was warm, as was the West. There was a narrow area of cool anomalies running from eastern Texas into the Southern Plains. The warmth in the West resulted from less of a trough than I had anticipated in with my underlying assumptions.

[Isotherm]

For perspective, the GFS shows a low temperature of 37° at May 1 9z in New York City. Readings below 40° in NYC have become rare. The last such reading was May 1, 1978 when the temperature fell to 38°. The 1960s saw 5 days on which the temperature fell below 40° in May. The 1970s also saw 5 such days. The coldest day since then has been 40° on May 9, 1992. More than likely, subsequent runs of the model will be milder and the actual outcome will also be milder (perhaps with a low temperature in the low 40s?). Nevertheless, areas outside the big cities, will likely experience a late-season frost.

Point and click has NYC down to 37F tonight. I think that might be a bit too cool, but should be interesting to see how low they go. Certainly a decent freeze for suburbia of NJ and CT tonight.

[donsutherland1]

Point and click has NYC down to 37F tonight. I think that might be a bit too cool, but should be interesting to see how low they go. Certainly a decent freeze for suburbia of NJ and CT tonight.

Tonight, I believe NYC can get into the 30s. My guess would be 38°, which is not far from the 37° figure you cite. The MET MOS is actually showing 35°. At 7 pm, the temperature was 46°. It will be interesting to see how low it gets.

[donsutherland1]

This morning saw the temperature fall to 38° in New York City. The last time NYC saw a temperature of 38° or below this late or later in the season was May 1, 1978, when the temperature fell to 38°. That was also the last May reading below 40° in New York City.

Some of the distant suburbs had readings below freezing. Poughkeepsie had a low temperature of 29°. Danbury had a minimum temperature of 26°.

[donsutherland1]

May 8-15, 2012 Thoughts:

Out in the Pacific, another burst of westerlies is underway. As a result, the SOI has plunged below -20. At the same time, the 90-day moving average of the SOI has now gone negative. All of that is an indication that the 2011-12 La Niña event has ended. What remains less clear is whether the summer and beyond will witness neutral ENSO or El Niño conditions. More than likely, any El Niño would be on the weak side, if it were to develop. Interesting enough, 1979 and 2001 are showing up among some of the teleconnection analogs.

More immediately, the AO is forecast to fall below -1 down the road. However, with wavelengths continuing to shorten, the response is not necessarily the same as that in the winter.Nevertheless, it appears that second week of May likely will not feature the kind of heat that occurred in March and also for a time in April.

The teleconnection composite anomalies below is based on:

ENSO Region 3.4 anomalies of -0.5°C to +0.1°C, a PNA of 0.00 to +0.75, and an AO of -2.00 to -1.00 for North America (1950-2011).

The latest NAEFS for the May 6-12 timeframe has much of the Northeast, Ohio Valley, and Great Lakes region normal, with cool anomalies focused on the Great Lakes region.

At this time, taking into consideration the ensemble guidance, NAEFS, decadal trends, and teleconnection composite anomalies, I believe the East Coast will likely see readings near or somewhat above normal. An area covering the Central Plains, Northern Plains, Great Lakes area will likely see below normal to near normal readings. The Western third of the U.S. should see above normal readings, with the Desert Southwest and Rockies perhaps seeing the warmest anomalies. Much of Canada should be near normal. However, Central Canada could have below normal readings. Northern Canada could see above to much above normal readings develop.

[uncle W]

May 8-15, 2012 Thoughts:

Out in the Pacific, another burst of westerlies is underway. As a result, the SOI has plunged below -20. At the same time, the 90-day moving average of the SOI has now gone negative. All of that is an indication that the 2011-12 La Niña event has ended. What remains less clear is whether the summer and beyond will witness neutral ENSO or El Niño conditions. More than likely, any El Niño would be on the weak side, if it were to develop. Interesting enough, 1979 and 2001 are showing up among some of the teleconnection analogs.

More immediately, the AO is forecast to fall below -1 down the road. However, with wavelengths continuing to shorten, the response is not necessarily the same as that in the winter.Nevertheless, it appears that second week of May likely will not feature the kind of heat that occurred in March and also for a time in April.

The teleconnection composite anomalies below is based on:

ENSO Region 3.4 anomalies of -0.5°C to +0.1°C, a PNA of 0.00 to +0.75, and an AO of -2.00 to -1.00 for North America (1950-2011).

The latest NAEFS for the May 6-12 timeframe has much of the Northeast, Ohio Valley, and Great Lakes region normal, with cool anomalies focused on the Great Lakes region.

At this time, taking into consideration the ensemble guidance, NAEFS, decadal trends, and teleconnection composite anomalies, I believe the East Coast will likely see readings near or somewhat above normal. An area covering the Central Plains, Northern Plains, Great Lakes area will likely see below normal to near normal readings. The Western third of the U.S. should see above normal readings, with the Desert Southwest and Rockies perhaps seeing the warmest anomalies. Much of Canada should be near normal. However, Central Canada could have below normal readings. Northern Canada could see above to much above normal readings develop.

1979 and 2001 bring up the mushroom and barley soup in thr throat...1979 and 2001 had record cold in July...I hope a weak El nino develops...

[Met1985]

May 8-15, 2012 Thoughts:

Out in the Pacific, another burst of westerlies is underway. As a result, the SOI has plunged below -20. At the same time, the 90-day moving average of the SOI has now gone negative. All of that is an indication that the 2011-12 La Niña event has ended. What remains less clear is whether the summer and beyond will witness neutral ENSO or El Niño conditions. More than likely, any El Niño would be on the weak side, if it were to develop. Interesting enough, 1979 and 2001 are showing up among some of the teleconnection analogs.

More immediately, the AO is forecast to fall below -1 down the road. However, with wavelengths continuing to shorten, the response is not necessarily the same as that in the winter.Nevertheless, it appears that second week of May likely will not feature the kind of heat that occurred in March and also for a time in April.

The teleconnection composite anomalies below is based on:

ENSO Region 3.4 anomalies of -0.5°C to +0.1°C, a PNA of 0.00 to +0.75, and an AO of -2.00 to -1.00 for North America (1950-2011).

The latest NAEFS for the May 6-12 timeframe has much of the Northeast, Ohio Valley, and Great Lakes region normal, with cool anomalies focused on the Great Lakes region.

At this time, taking into consideration the ensemble guidance, NAEFS, decadal trends, and teleconnection composite anomalies, I believe the East Coast will likely see readings near or somewhat above normal. An area covering the Central Plains, Northern Plains, Great Lakes area will likely see below normal to near normal readings. The Western third of the U.S. should see above normal readings, with the Desert Southwest and Rockies perhaps seeing the warmest anomalies. Much of Canada should be near normal. However, Central Canada could have below normal readings. Northern Canada could see above to much above normal readings develop.

Great stuff Don. I have been watching the teleconnections for the past few days and like you said the AO looks to be taking a dive of somewhat and also noticing that the NAO also looked to go negative for a short period but who nows how far negaitve.Looks like we could actually have some near normal temps for a few days. Also i wanted to get your input and really anybody who wants to respond about this March being the coolest March since 1999 even with all the record there were in the US. Just amazing that were were so hot and the rest of the world was so cool it seems. Thanks.

[donsutherland1]

Also i wanted to get your input and really anybody who wants to respond about this March being the coolest March since 1999 even with all the record there were in the US. Just amazing that were were so hot and the rest of the world was so cool it seems. Thanks.

I suspect that March 2012 was the least warm March since 1999 on account of the La Niña, PDO-, and also teleconnections. I used the term "least warm," because both the NCDC and GISS datasets showed positive anomalies. The pattern was unusually amplified, leading to an area of extreme warmth in parts of North America and notable cold in parts of Eurasia (similar to what one witnessed in parts of January and February when North America was so warm and parts of Europe were so cold).

In fact, considering ENSO, PDO, and the teleconnections, one could perhaps argue that March should have been even colder globally than it was. Below is a chart showing global anomalies in the 1950-2011 timeframe with similar ENSO, PDO, and Teleconnections (I accidentally omitted PDO in the description) vs. March 2012:

The discussion as to whether March 2012 should have been even colder globally is beyond the scope of this thread. What is more certain is that the ENSO, PDO, and Teleconnection framework implied the kind of outcome that resulted.

[donsutherland1]

1979 and 2001 bring up the mushroom and barley soup in thr throat...1979 and 2001 had record cold in July...I hope a weak El nino develops...

I strongly agree. I'd be more worried if they were showing up in September or October. Hopefully, by later this summer, it will be clear that a weak El Niño is ongoing or developing.

[Met1985]

Thanks Don for the info. All ready neat about how everything should align one way but goes another way.

[Isotherm]

1979 and 2001 bring up the mushroom and barley soup in thr throat...1979 and 2001 had record cold in July...I hope a weak El nino develops...

This would be a real kick in the teeth after the winter we had - get our record cold in July of course...

[uncle W]

This would be a real kick in the teeth after the winter we had - get our record cold in July of course...

I believe it was on July 5th 1979 NYC had a max/min of 69/53...That was the only time a July max was below 70 with Sunshine all day...

[KEITH L.I]

I believe it was on July 5th 1979 NYC had a max/min of 69/53...That was the only time a July max was below 70 with Sunshine all day...

I think a weak nino is developing..that puts 1963,1968,1976,2002,and 2009 in play

[JBG]

I think a weak nino is developing..that puts 1963,1968,1976,2002,and 2009 in play

Certainly no consistency in the ensuing summers from those pattern years. 1963 and 1968 were normal summers with some real hot spells. 2002 was hot and 1976 and 2009 were gelid.

[NJwinter23]

I know many have brought up 1951 as an analog as well. The 500 mb pattern in the beginning of May looks similar to whats going on right now..It turned cool in the east with a -NAO/central canada high pressure anomaly thru the first half of May 1951 similar to what the gefs have been showing as well. The second half of May 1951 turned warm to start though which I'm not sure will happen this year. Any temp/precip thoughts on the 2nd half of May? really tough without any ENSO/MJO signal and given the time of year.

[reber500]

Any Idea when the next Significant Severe Weather/ Tornado Outbreak might happen? I'm thinking Late/ Mid May... The GFS shows a REALLY Strong 200 and 500mb winds over KS/OK/TX/MO around May 7-11.... BUT it's not showing ANY Instability whatsoever up there.. interesting..

[donsutherland1]

Verification:

My April 2012 forecast (Message #1) was as follows:

Top Left: Composite temperature anomalies based on ENSO/Teleconnection Analogs.

Top Right: 1976 Reference Case

Bottom Left: Observed Decadal Temperature Change for April

Bottom Right: CFSv2 Forecast for April (from March 20)

Based on the combination of the composite teleconnection analogs, the 1976 reference case, and the observed decadal temperature changes, my thoughts for April are as follows:

The eastern half to two-thirds of the U.S. and most of eastern Canada will likely be warmer than normal. Eastern Quebec and Labrador could see cooler readings. The warmest anomalies might be present in an area that includes the Great Lakes, Northeastern U.S. southern Ontario, and southern Quebec. The Western quarter of the U.S. and Canada will likely be cooler than normal. The northern half of Alaska could be warmer than normal with the observed decadal trends and CFSv2 being given greatest weight for that area, while the rest of the state is normal to cooler than normal.

The April 2012 anomalies were as follows:

[CoastalWx]

It looks like for the next 15 days anyways, it will be tough to get prolonged warmth past a DCA-DTW line. While models don't agree completely on specifics, they try to feature some sort of ridging out west or even in NW Canada if you believe the GEFS..and a hint of ridging near the Davis Straits. It all combines to generate a mean trough that is anywhere from the OV to northeast. We'll have warm temps from time to time especially if the axis is west enough, but it doesn't scream warm to hot imo. Also could be wet in the east with ring of fire stuff in the MW and OV?

[donsutherland1]

Verification:

My April 23-30, 2012 thoughts (Message #127) were as follows:

The charts below are as follows:

Left: ENSO Region 3.4 anomalies of -0.6°C to 0.0°C, a PNA of -0.25 to +0.50, and an AO of -0.75 to +0.25 for North America.

Right: NAEFS (April 21-27, 2012 timeframe)

Given the upstream conditions in the Arctic, I favor a compromise between the warmer NAEFS and colder teleconnection analogs.

My thoughts are as follows:

1. Areas of cool anomalies interspersed with near normal readings in the Great Lakes, Ohio Valley, northern Mid-Atlantic, and New England regions and somewhat cooler than normal to near normal across Quebec and Ontario.

2. Cooler than normal along the U.S. West Coast into perhaps southern British Columbia.

3. Generally warmer than normal elsewhere in the U.S., but near normal to perhaps somewhat below normal across the rest of Canada. The Rockes and Central Plains could be very warm for a time.

The anomalies were:

[donsutherland1]

It looks like for the next 15 days anyways, it will be tough to get prolonged warmth past a DCA-DTW line. While models don't agree completely on specifics, they try to feature some sort of ridging out west or even in NW Canada if you believe the GEFS..and a hint of ridging near the Davis Straits. It all combines to generate a mean trough that is anywhere from the OV to northeast. We'll have warm temps from time to time especially if the axis is west enough, but it doesn't scream warm to hot imo. Also could be wet in the east with ring of fire stuff in the MW and OV?

I agree. Interestingly enough, among my top analogs for May (1965, 2001, 2002, and 2009), 3/4 of those cases saw the greatest warmth relative to normal occur after May 20. It will be interesting to see how things evolve this year.

[CoastalWx]

I agree. Interestingly enough, among my top analogs for May (1965, 2001, 2002, and 2009), 3/4 of those cases saw the greatest warmth relative to normal occur after May 20. It will be interesting to see how things evolve this year.

It does seem like the east will warm after the 20th. How much I'm not sure, but I think the warmth will build east some more.

[cbmclean]

Verification:

My April 23-30, 2012 thoughts (Message #127) were as follows:

The charts below are as follows:

Left: ENSO Region 3.4 anomalies of -0.6°C to 0.0°C, a PNA of -0.25 to +0.50, and an AO of -0.75 to +0.25 for North America.

Right: NAEFS (April 21-27, 2012 timeframe)

Given the upstream conditions in the Arctic, I favor a compromise between the warmer NAEFS and colder teleconnection analogs.

My thoughts are as follows:

1. Areas of cool anomalies interspersed with near normal readings in the Great Lakes, Ohio Valley, northern Mid-Atlantic, and New England regions and somewhat cooler than normal to near normal across Quebec and Ontario.

2. Cooler than normal along the U.S. West Coast into perhaps southern British Columbia.

3. Generally warmer than normal elsewhere in the U.S., but near normal to perhaps somewhat below normal across the rest of Canada. The Rockes and Central Plains could be very warm for a time.

The anomalies were:

Wow, look at that; actual impressive cold anomalies in the arctic archipelago over a week period. Seem like kind of a rare event lately. Should we hold throw a party?

[nzucker]

I think a weak nino is developing..that puts 1963,1968,1976,2002,and 2009 in play

Only 63-64, 68-69, and 76-77 were weak Niño winters however...02-03 was moderate and 09-10 was strong.

[donsutherland1]

May 16-23, 2012 Thoughts:

Another week without excessive early-season heat appears to be on tap in eastern North America.

The teleconnection composite anomalies below is based on:

ENSO Region 3.4 anomalies of -0.3°C to +0.4°C, a PNA of 0.00 to +1.00, and an AO of -0.50 to +0.50 for North America (1950-2011).

The latest NAEFS are reasonably similar, except that they show mainly near normal readings in the areas shown above as cool, and warmth generally elsewhere.

At this time, I suspect that the eastern third of the United States will wind up generally cooler than normal with some areas having near normal readings. The western two-thirds of the U.S. will likely be warmer than normal and the Southwest could be much warmer than normal, though an area running from California into the Pacific Northwest could see somewhat below normal to near normal readings. Most of Canada will probably wind up warmer than normal.

[The_Global_Warmer]

Wow, look at that; actual impressive cold anomalies in the arctic archipelago over a week period. Seem like kind of a rare event lately. Should we hold throw a party?

yeah a party would properly celebrate there quick return and go.

[donsutherland1]

Some morning thoughts....

1. May has started warm in much of the U.S. and Canada. Central Canada, a portion of western Canada, the Pacific Northwest, and New England are exceptions. There, cool weather has prevailed.

2. The SOI has been positive for 7 consecutive days, the 30-day moving average has gone positive, and the 90-day moving average remains slightly negative. With some exceptions, usually for stronger El Niño events, the transition to an El Niño can be discontinuous, with bursts of westerly winds that weaken the easterly trade winds followed by reversals. It's still too soon to be confident that an El Niño will develop during or after the summer, though the modeling favors an El Niño over Neutral ENSO conditions. Later MEI data could provide insight.

3. The ensembles show persistent heat in the Southwestern portion of the U.S. Over time, that area of heat is forecast to slowly expand. Some past analogs for May had the warmest anomalies relative to normal (not necessarily excessive heat) occurring after May 20, sometimes close to the end of the month.

4. Even a delayed El Niño would not necessarily mean an active hurricane season. The Tropical North Atlantic (TNA) Index, which measures the average SSTA in the region bounded by 5.5°N to 23.5°N and 15°W to 57.5°W, remains cool. The last year in which the TNA had cool spring anomalies was 2009. 2009 also saw the development of an El Niño. There were 9 named storms, 3 hurricanes, and 2 major hurricanes. There were an additional 2 tropical depressions. The 2009 Accumulated Cyclone Energy (ACE) figure for the Atlantic Basin was 53. The first tropical system was TD 1, which formed on May 28, 2009. The last was Hurricane Ida, which formed on November 4. Hence, at least at this point in time, it appears that a foundation for a less active than normal tropical season may be emerging. There may also be some risk of an early tropical system.