Medium Range Discussion Summer 2012

[easternsnowman]

Since 2005 with the exception of 2009 every summer has been above normal I believe. Some have been slightly above and some well above, another above normal summer is now the norm.

[am19psu]

Glad to see easternsnowmanbot is still active after my vacation.

[wxmx]

Glad to see easternsnowmanbot is still active after my vacation.

He is now the norm. Deal with it.

[N. OF PIKE]

refreshing that BOS/ORH/PVD all ended their streak of + departure months this June.

[donsutherland1]

WUWT did a very good post yesterday entitled The highest temperature reading

does not necessarily mean a record hot day. Puts a better perspective on the

hot spell and the global warming hype in general.

To determine which record was more impressive, one can standardize the figures. The 104° reading was 2.928 standard deviations above the June 16-30 mean temperature (1981-2010 base period). I don't have data for Washington, DC that goes back to the 1901-1930 base period, so I can't definitively comment on the 101° figure from June 11, 1911.

I can note that the 101° reading was 2.558 standard deviations above the June 1-15 mean temperature (1951-1980 base period) and 2.384 standard deviations above the June 1-15 mean temperature (1981-2010 base period). If one extrapolated back to the 1901-1930 base period, the 101° reading would be about 2.848 standard deviations above the mean for that period. In short, one can reasonably guess that the 104° reading was comparable to or slightly more impressive than the 101° record set in 1911.

[donsutherland1]

agree with the hype comment. You'd think that this was the greatest hot spell of them. Not really. Let's remember that TWC needs to sell sizzle for ratings, and they are simply doing just that. They jump from weather crisis to weather crisis like a whirling dervish.

Several cities had readings > 3 sigma above their mean temperature for this time of year. It was an extreme event. However, the "Summer in March" heat was probably the greatest outbreak of anomalous heat in recorded weather history for North America. Multiple cities had high temperatures in excess of 4 and even 5 sigma above normal. To put things into perspective, a high temperature of 5 sigma above the mean would be about 120° in Washington, D.C. at this time of year.

[easternsnowman]

He is now the norm. Deal with it.

We must learn to accept the new norm.....lol!

[donsutherland1]

FWIW, it appears likely that the exceptional heat through the end of June boosted June 2012 to or above the 30th warmest June on record. Here's a comparison of June 2012 vs. June 1971 (currently 30th warmest June). Areas of positive temperature departures denote areas where June 2012 was warmer than June 1971. Negative temperature departures indicate areas where June 2012 was cooler than June 1971.

[donsutherland1]

Verfication:

My June 2012 forecast (Message #6) was as follows:

Although past transitions to possible El Niño conditions have witnessed a chilly summer, it appears that the current transition will witness at least the first month of summer turning out warmer than normal across much of North America.

Key Assumptions:

• Neutral ENSO conditions are likely to prevail through much or all of June

• The AO will likely be near neutral (with variability in negative and positive ranges)

• The PNA will likely be predominantly positive (but generally < +1)

The top analog was 1969. Both 1953 and 2009 were close behind.

The charts on which my June idea is based are:

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

Right: Observed Decadal Temperature Change for June

Some of the greatest warm anomalies in the East occurred during the 6/20-30 timeframe, especially in 1953 and 1969. The leading analogs do not clarify the ENSO situation going foward, but they maintain the theme that odds lean toward the develop of an El Niño. 1953 saw neutral ENSO conditions. 1969 and 2009 witnessed the onset of El Niño conditions.

Based on the combination of the composite teleconnection analogs, observed notable warmth in the Arctic region, and the observed decadal temperature changes, my thoughts for June are as follows:

Much of North America will likely be warmer than normal. A portion of northern Canada could be near to somewhat above normal. Part of the West Coast, probably somewhere in California to perhaps the Pacific Northwest could be cooler than normal.

The June 2012 anomalies were:

The widespread warmth in June is a strong indication that Summer 2012 will turn out warmer than normal across much of North America. Often, during summers when El Niño events take hold, June's anomalies do a fairly good job in pointing to the overall summer outcome (especially with respect to possible areas where readings would be cooler than normal). Of course, there are exceptions, but given the continued warmth in the Arctic, any turn to cooler than normal conditions (possible in late August based on the timing of a number of similar El Niño transitions, but not assured), won't wipe out the warm anomalies that will accumulate prior to then.

Below are some charts comparing the June and summer outcomes for 1976, 2002, and 2009:

Much of the 2002 scenario is what I expected in my summer thoughts. However, I had expected the Great Lakes region to average near normal. The June outcome provides a strong signal that the summer anomalies in that area will also be warmer than normal (and perhaps much warmer than normal).

[donsutherland1]

While large portions of North America continue to suffer through extreme and even historic heat, a partial analysis based on the emerging El Niño (the ENSO Region 3.4 anomaly has now reached +0.6°C) suggests that blocking will be key to both Fall 2012 and Winter 2012-13 outcomes. El Niño events that followed either neutral or La Niña ENSO winters and had warm summers in North America were 1953, 1957, 1986, 1991, and 2002. ENSO-Teleconnection analogs have persistently been highlighting 1953, 1991, and 2002 for the summer. The 2009 analog had faded and Summer 2012 is on course to be notably warmer than the 2009 case.

The following are the summer anomalies for the above noted cases:

Below are composite temperature anomalies for the fall and winter outcomes depending on the presence/absence of blockiness:

This partial analysis does not take into consideration the ongoing observed warming that remains underway. Both fall and winter outcomes have become warmer across the northern U.S. and all of Canada between the 1971-2000 and 1981-2010 base periods. The lone exception is a portion of the Southeast that has grown slightly cooler for the winter months.

The partial analysis also does not take into consideration the abnormal Arctic warmth. June 2012 had Arctic anomalies that were warmer than all of the above cases. June 1953 offered perhaps the closest match. Were the excessive warmth to persist in the Arctic, the actual fall/winter outcomes would probably be somewhat warmer than denoted by the maps and the expanse of warm anomalies would likely be larger/cool anomalies would likely be smaller. Those are details left for later.

For now, the important point is that neither the fall nor winter outcome is a proverbial slamdunk on either the warm or cold side. A lot will depend on whether blocking develops and then predominates.

[ORH_wxman]

FWIW, it appears likely that the exceptional heat through the end of June boosted June 2012 to or above the 30th warmest June on record. Here's a comparison of June 2012 vs. June 1971 (currently 30th warmest June). Areas of positive temperature departures denote areas where June 2012 was warmer than June 1971. Negative temperature departures indicate areas where June 2012 was cooler than June 1971.

It looks like that is January, Don.

I get this for the June comparison:

I still think that looks warmer than June 1971.

[donsutherland1]

It looks like that is January, Don.

Thanks Will. I had forgotten to change the month to June when running the anomalies.

[Harry]

WUWT did a very good post yesterday entitled The highest temperature reading

does not necessarily mean a record hot day. Puts a better perspective on the

hot spell and the global warming hype in general.

Out this way many records are falling and IF this forecast NWS plays out the all time record for here and a number of others will be broken. For here that record is 104!

Mind you this is Michigan and yesterday it was up to 102 here and a new record high as well.

7-DAY FORECAST

• This Afternoon A 30 percent chance of showers and thunderstorms, mainly after 5pm. Mostly sunny and hot, with a high near 104. Northwest wind 8 to 10 mph, with gusts as high as 18 mph.
  
• Tonight A 10 percent chance of showers and thunderstorms before 7pm. Mostly clear, with a low around 77. Northwest wind 5 to 9 mph becoming calm in the evening.
  
• Friday Sunny and hot, with a high near 107. Calm wind becoming east southeast around 5 mph in the afternoon.
  
• Friday Night Mostly clear, with a low around 80. Northwest wind 5 to 9 mph becoming calm in the evening.
  

That is for here!

Chances are good many of us never see this sort of thing again in our lifetime!

[JBG]

Since 2005 with the exception of 2009 every summer has been above normal I believe. Some have been slightly above and some well above, another above normal summer is now the norm.

I don't think that 2006, 2007 or 2008 was "above normal". 2007 was for September and October, if I recall correctly. 2008 was for June. 2006 may have been for July.

[Ed Lizard]

High in Phoenix yesterday was 91ºF. I know this is a medium range thread, but it isn't all time record heat everywhere right now. Speaking of warm anomalies- check out Central Russia.

[donsutherland1]

July 16-23, 2012 Thoughts:

Even as the heat is likely to ease back after this coming weekend, the respite may prove short-lived. The evolving pattern could lead to a new outbreak of heat during the third week of the month.

Recent guidance has forecast a new trough to push into the Pacific Northwest with a diving PNA after mid-month. Such a development would be consistent with what appears to be a trend for more frequent strong negative PNA values (-1.00 or below). The number of days with the PNA reaching -1 or below was as follows for the April-June timeframe:

April: 2 days

May: 3 days

June: 6 days

The charts below are as follows:

Top Left: The composite temperature anomalies for ENSO Region 3.4 anomalies of +0.20°C to +1.00°C, a PNA of -0.50 to 0.50, and an AO of +0.50 to +1.50 for North America.

Top Right: NAEFS for the July 13-19, 2012 timeframe

Bottom Left: 7/5/2012 GFS Ensemble 11-15-Day anomalies (7/16-20/2012) from RaleighWx's page

Bottom Right: July Decadal Temperature Trend

It should also be noted that the Arctic region remains warmer than normal. This could also limit the magnitude, expanse, and duration of any chilly air masses.

Taking into consideration the upstream conditions, teleconnection analogs, ensemble guidance, and decadal trends, I expect the following for the July 16-23 timeframe:

- Warmer than normal across most or all of Canada, possibly much warmer than normal across central Canada

- Near to perhaps somewhat cooler than normal across Texas and the Western Gulf states

- Cooler than normal in the Pacific Northwest

- Warmer than normal across the rest of the U.S. The warmest anomalies will likely cover the Central Plains to the lower Great Lakes region and perhaps into the Middle Atlantic states.

Finally, given some of the monthly analogs, there remains the potential for some excessive heat beyond the July 16-23, 2012 timeframe.

[Srain]

A rather interesting pattern is developing in the medium range across the Gulf Coastal Regions and on W into Texas. A rather unseasonable frontal boundary sags S across Central Texas and on E while the monsoonal trough lift N into the EPAC, Western Caribbean, and Western Gulf. PW's appear to increase from Coastal Texas on E to the 2.2+ range with embedded upper level disturbance rotation W underneath the retreating heat ridge and an inverted trough becomes established over Texas. A Polar front will sag S and stall being the focal point for copious rainfall potential for Central/SE Texas, Louisiana, Mississippi, Alabama, Tennessee, Georgia into North/South Carolina and Southern Virginia. Another area to watch may be the tail end of that stalled/washing out frontal boundary. It’s not uncommon to see potential for a quick spin up tropical disturbance with this type of setup. Next week could provide some very heavy rains in areas that have been in a multi year drought situation.

[HeatMiser]

July 16-23, 2012 Thoughts:

Even as the heat is likely to ease back after this coming weekend, the respite may prove short-lived. The evolving pattern could lead to a new outbreak of heat during the third week of the month.

Recent guidance has forecast a new trough to push into the Pacific Northwest with a diving PNA after mid-month. Such a development would be consistent with what appears to be a trend for more frequent strong negative PNA values (-1.00 or below). The number of days with the PNA reaching -1 or below was as follows for the April-June timeframe:

April: 2 days

May: 3 days

June: 6 days

The charts below are as follows:

Top Left: The composite temperature anomalies for ENSO Region 3.4 anomalies of +0.20°C to +1.00°C, a PNA of -0.50 to 0.50, and an AO of +0.50 to +1.50 for North America.

Top Right: NAEFS for the July 13-19, 2012 timeframe

Bottom Left: 7/5/2012 GFS Ensemble 11-15-Day anomalies (7/16-20/2012) from RaleighWx's page

Bottom Right: July Decadal Temperature Trend

It should also be noted that the Arctic region remains warmer than normal. This could also limit the magnitude, expanse, and duration of any chilly air masses.

Taking into consideration the upstream conditions, teleconnection analogs, ensemble guidance, and decadal trends, I expect the following for the July 16-23 timeframe:

- Warmer than normal across most or all of Canada, possibly much warmer than normal across central Canada

- Near to perhaps somewhat cooler than normal across Texas and the Western Gulf states

- Cooler than normal in the Pacific Northwest

- Warmer than normal across the rest of the U.S. The warmest anomalies will likely cover the Central Plains to the lower Great Lakes region and perhaps into the Middle Atlantic states.

Finally, given some of the monthly analogs, there remains the potential for some excessive heat beyond the July 16-23, 2012 timeframe.

good write-up as usual Don. Do you feel the severe drought conditions showing up in the Central Plains and most of the interior US will limit the spread of heat onto the eastern coast?

[donsutherland1]

good write-up as usual Don. Do you feel the severe drought conditions showing up in the Central Plains and most of the interior US will limit the spread of heat onto the eastern coast?

The worst of the heat will likely remain confined in the region where the drought is developing. Periodically, some of the hot air will likely spread eastward, but the greatest warmth relative to normal and the longest duration heat will be centered farther west. Should precipitation along the East Coast be near normal or even a little above normal, that will increase odds of the scenario I just described.

[JamieOber]

I think the development of a wet pattern for the SE/mid-Atlantic is the top story once we get a break from the heat. That is fantastic news.

[icebreaker5221]

A rather interesting pattern is developing in the medium range across the Gulf Coastal Regions and on W into Texas. A rather unseasonable frontal boundary sags S across Central Texas and on E while the monsoonal trough lift N into the EPAC, Western Caribbean, and Western Gulf. PW's appear to increase from Coastal Texas on E to the 2.2+ range with embedded upper level disturbance rotation W underneath the retreating heat ridge and an inverted trough becomes established over Texas. A Polar front will sag S and stall being the focal point for copious rainfall potential for Central/SE Texas, Louisiana, Mississippi, Alabama, Tennessee, Georgia into North/South Carolina and Southern Virginia. Another area to watch may be the tail end of that stalled/washing out frontal boundary. It’s not uncommon to see potential for a quick spin up tropical disturbance with this type of setup. Next week could provide some very heavy rains in areas that have been in a multi year drought situation.

You can see the fairly significant pattern change for the west quite nicely in the HPC forecast. The dry downslope flow regime over the front range of the Rockies has flipped to a very moist upslope flow regime. With that ample moisture you mentioned over TX as a source region, there should be plenty of much needed rains from northwest TX through NM, CO and WY.

[icebreaker5221]

I agree, Don and Iso. Add to that the fact that this upcoming transient heat in the east should only be a break in the -NAO reloading. Both long-range GFS/ECMWF + ensembles are redeveloping Greenland blocking in what appears to be a very stable configuration over the N Atlantic, which should keep the NAO more negatvie than positive into the start of July.

I like the idea of a trough-ridge-trough pattern to end Jun / start off Jul. Cool on both coasts (and maybe cool Great Lakes) and warm over the Rockies and central plains.

Verification:

Overall, the 500 mb height pattern verified quite nicely. The Great Lakes and East Coast were warmer than I expected, due in part to an anomalously warm source region over Canada as well as a failure of the trough over the northeast to retrograde further west as often seen in -NAO El Nino summers.

[Sunny and Warm]

The Great Lakes and East Coast were warmer than I expected, due in part to an anomalously warm source region over Canada as well as a failure of the trough over the northeast to retrograde further west as often seen in -NAO El Nino summers.

Nice forecast verification. As for the bolded section above, is this one of those cases where it is delayed but not denied? In other words, will the eastern trough become more pronounced as we head into and thorugh August given typical el nino jet configuration? I'm thinking the late start and degree of the Nino event is why the response has been muted of sorts.

[icebreaker5221]

Nice forecast verification. As for the bolded section above, is this one of those cases where it is delayed but not denied? In other words, will the eastern trough become more pronounced as we head into and thorugh August given typical el nino jet configuration? I'm thinking the late start and degree of the Nino event is why the response has been muted of sorts.

Thanks!

I would expect a cooler pattern developing over the Great Lakes as El Nino strengthens if the NAO remains mostly negative. Hard to forecast the NAO that far out, but in terms of persistence the NAO has remained negative every day since May 26.

[Sunny and Warm]

Thanks!

I would expect a cooler pattern developing over the Great Lakes as El Nino strengthens if the NAO remains mostly negative. Hard to forecast the NAO that far out, but in terms of persistence the NAO has remained negative every day since May 26.

interesting. I had thought the el nino pattern without a given NAO state tended toward cooler trends the further NE one went. Because of the summer wavelengths, I was under the impressions that a -NAO produced a tendency toward warmer weather, or is that not true the further one goes NE toward the anomoly? Another question I would have is does a budding Nino produce a tendency toward -NAO, thus causing the cooler climatology in the NE summers during ninos?

[donsutherland1]

Some of today's record highs included:

Grand Rapids, MI: 104° (3.525 standard deviations above the July average high)

Indianapolis, IN: 105° (3.559 standard deviations above the July average high)

Paducah, KY: 107° (3.355 standard deviations above the July average high)

To put this into perspective, the readings at Grand Rapids and Indianapolis would be the equivalent of a July temperature of 110° in Washington, DC and the Paducah reading would be the equivalent of a 109° reading at DCA.

[Hoosier]

Hey Don, just to piggyback on your post, the 105 in Indianapolis was the hottest reading there since July 14, 1936 when it reached 106 (the all-time record high).

[WxMidwest]

Hey Don, just to piggyback on your post, the 105 in Indianapolis was the hottest reading there since July 14, 1936 when it reached 106 (the all-time record high).

Same for here Hoosier, this was Rockford's hottest since that date as well..

[Srain]

The overnight guidance has come into rather good agreement with a complicated and complex weather pattern developing from the Southern Rockies on E to the East Coast. The heat ridge that has brought record high temps across the Central and Eastern US will begin to break down and retreat W into the Great Basin and embedded mid/upper air disturbance rotate W under that retreating Ridge along the Gulf Coast. Lowering heights across Texas and increasing deep tropical moisture with PW's in the 2.2 to 2.4 range will become established across the Eastern half of the Lone Star State today and meander W tomorrow. A developing trough over the Great Lakes will activate a slow moving frontal boundary on Monday which will sag S into Central/SE Texas and on E before pulling up stationary. As a weak northerly flow aloft develops N of that boundary, and onshore flow at the surface develops S of that front bringing increasing Gulf and Western Caribbean tropical moisture surging inland and setting the stage for a multi day rainfall event that has some potential to linger into next weekend. The fly in the ointment is the potential for very slow moving high rainfall rate storms to develop and training potential is not out of the question.

[Ottawa Blizzard]

What did July 1921 look like across the U.S. and Canada? That month still stands as Toronto's hottest month ever. Could we perhaps make a run at beating that record this month. At the rate we're going, it wouldn't surprise me.