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Our region's extreme run


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  • 2 weeks later...

June 28-July 8, 2012 vs. July 15-20, 2013 Heat Waves

 

June 28-July 8, 2012

Avg Max: 99.5

Avg Min: 76.4

Avg Dly: 88.0

 

July 15-20, 2013

Avg Max: 95.5

Avg Min: 79.3

Avg Dly: 87.4

 

So, last year's heat wave lasted five days longer and featured record-breaking average maximum and average daily temperatures for an 11-day period.  This year's heat wave's claim to fame was the highest six-day average minimum temperature,* with the last five days each reaching at least 80 -- breaking the record of four consecutive 80+ minimums set July 21-24, 2011.  Also, there was one other significant difference:  Last year's heat wave featured the derecho on the second day, causing many folks to be without power for one of the hottest stretches in DC history.  This year, happily, power outages were minimal. 

 

* I just discovered that July 19-24, 2011 averaged almost 2 degrees higher, at 81.2.  However, only four of those days featured an 80+ minimum. 

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nice article...I'd like to see CWG cover some aspects of the heat of the last 4 years without referencing AGW (not referring to the above article)....I don't know the answer, but it would be interesting to discuss the pattern driven and indice driven aspects of the big heat....MSP's top 8 max mins are all dust bowl.....9 of Denver's top 10 are dust bowl or 1880's....all of DC's are fairly recent...and of course the frequency too.....So if it isn't JUST UHI, why aren't places like MSP and DEN shattering their max min records?

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nice article...I'd like to see CWG cover some aspects of the heat of the last 4 years without referencing AGW (not referring to the above article)....I don't know the answer, but it would be interesting to discuss the pattern driven and indice driven aspects of the big heat....MSP's top 8 max mins are all dust bowl.....9 of Denver's top 10 are dust bowl or 1880's....all of DC's are fairly recent...and of course the frequency too.....So if it isn't JUST UHI, why aren't places like MSP and DEN shattering their max min records?

MSP's records at the time were right downtown. It could be argued that the UHI was more acute in the 1930s than at the airport location now. Of course, since the dust bowl was partly anthropogenic, you wade into other territory...

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Tying anything to global warming is tough to steer from because it doesn't involve a lot of research and it guarantees comments.

 

I need to look at the frequency of 79+, 78+ type lows.. close but not 80+.  80+ is kind of arbitrary other than the fact that we all focus on the starts of 10s naturally.

 

AT DC at least the lows have been impacted considerably more than the highs though I suppose it's arguable that we are seeing more frequency of the higher level highs if not the highest temps.  My in depth knowledge of other stations is limited--there are some interesting comparisons between DC and Balt when the Balt station was downtown though.

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MSP's records at the time were right downtown. It could be argued that the UHI was more acute in the 1930s than at the airport location now. Of course, since the dust bowl was partly anthropogenic, you wade into other territory...

 

yes...there are too many factors to properly isolate and parse out cause and effect.  

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Tying anything to global warming is tough to steer from because it doesn't involve a lot of research and it guarantees comments.

 

I need to look at the frequency of 79+, 78+ type lows.. close but not 80+.  80+ is kind of arbitrary other than the fact that we all focus on the starts of 10s naturally.

 

AT DC at least the lows have been impacted considerably more than the highs though I suppose it's arguable that we are seeing more frequency of the higher level highs if not the highest temps.  My in depth knowledge of other stations is limited--there are some interesting comparisons between DC and Balt when the Balt station was downtown though.

 

Good points.  Though of course one cannot link singular events to a climatological phenomenon (stating the obvious here, I know!), it is hard to ignore global warming.

 

As for this July, last I checked DCA was ~3 degrees above normal for the month, through yesterday (Jul. 22).  And much of that from my quick look and calculation was due to the overnight lows, not so much the daily highs, as you stated.  I think the lows are ~4 degrees above so far (vs. ~+1 or so for the highs) compared to the July mean for the entire month.  Not the best to compare to the overall July climo since we've got just over a week left this month, but you get the idea.  Interesting.  It was quite oppressive the past week or so, that's for sure, even if it wasn't excessively hot in terms of absolute temperatures.  I'm sure the amount of precipitation we've received since June played a role there.  If the latest forecasts for the next week are correct, I'd expect that DCA departure to decrease somewhat, maybe to ~+2 degrees or even less(?).  After the past 3 Julys...or, heck, the past 3 summers!...this year has seemed relatively moderate.  Though, yes, that's somewhat subjective.

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It may be July 15-August 15, 1980, which saw 32 consecutive 70+ minimums at DCA.

I'm pretty sure that this is the all-time record.  Other notable 70+ minimum streaks at DCA are:

July 12-August 10, 1999: 30 days

August 13-September 10, 1959: 29 days

July 17-August 13, 2011: 28 days

July 5-July 31, 2010: 27 days

June 29-July 24, 2013: 26 days

 

Last year just missed being the all time champ. June 28-August 15, 2012 encompassed 49 days, and only one (July 21) had a minimum below 70.  So, there was a 23-day streak immediately followed by a 25-day streak.

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If July ended right now, BWI would be ranked 11th hottest (avg temp of 80.7 degrees). It looks like that's going to be knocked down in the next few days though.

Quite a contrast in relative positions for DCA's average maximum and overall average temperatures in July. The average July 2013 maximum was a moderate 88.3 degrees, only 47th all-time in DC weather history. However, the overall July 2013 average was 81.2 degrees, good enough for 13th on the all-time list.
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That's helpful. Another thing to note is that 2013 marks the first August to open with the first week below 90 since 2003. That year, the streak ended on August 14th.

And this year it ended on the 9th.  Still, 18 consecutive days below 90 in July-August is a far cry from the last three years.

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Very cool.  High temps season to date almost dead median with the 1930-present climate record.

I agree -- thanks for the link, Ian. I think the most interesting temperature data for DCA are these:

Year to Date 01/01/13 - 08/14/13

Max: 67.3 T-39th warmest

Min: 51.5 6th warmest

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Possible record low for BWI tonight. NWS calling for low of 53. The record low for today is 51 and tomorrow is 49. I would assume any low would be after midnight, so the 49 will probably be the one we're competing against.

 

I was one day off- we didn't get it yesterday but we got it today. Overnight low of 53 at BWI, the record was 54.

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  • 3 weeks later...

To further update, January-August 2012 checks in at an average 64.1 degrees, breaking the 1991 first eight months record by 1.6 degrees.

Quite a contrast this year, with January-August 2013 at DCA averaging 60.4, still good enough for 18th warmest on DC's all-time list, but down 3.7 degrees from last year. The 2013 meteorological summer averaged 78.3 (26th), down 2.1 degrees from last year. But the real story of the DCA summer was the sharp contrast in relative placement between the average minimum of 70.76 (5th, down only 0.58 degrees from last year) vs. the average maximum of 85.8 (54th, down 3.7 degrees from last year). To put that in perspective, the four hottest meteorological summers in DC history (2010, 81.3; 2011, 81.1; 2012, 80.4; 1980, 80.0) were also the four hottest in the exact same order with respect to both average minimum temperatures (2010, 72.4; 2011, 72.1; 2012, 71.34; 1980, 70.79) and average maximum temperatures (2010, 90.1; 2011, 90.0; 2012, 89.5; 1980, 89.3).
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  • 4 weeks later...

But the real story of the DCA summer was the sharp contrast in relative placement between the average minimum of 70.76 (5th, down only 0.58 degrees from last year) vs. the average maximum of 85.8 (54th, down 3.7 degrees from last year). 

The 2013 astronomical summer (June 21-September 23rd) did not produce as sharp a contrast, but nonetheless the average minimum of 69.7 degrees was good enough for 13th place all-time, versus the average maximum of 85.7 being only 47th warmest.  Similarly, during the composite summer (June 1-September 23rd), the average minimum of 69.3 was tied for the 9th warmest, whereas the average maximum of 85.1 was 48th.

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2013 hasn't been very extreme compared to 2009-2012. Having said that, there's a few things I'm watching for in October for BWI:

 

-If we'll break or tie at least one daily lowest maximum record in Oct. for the 5th year in a row.

 

-If some crazy record-breaking event will occur on Oct. 29 for the 3rd year in a row.

 

-If we break a record high this Wednesday, Oct. 2. The record is 89, NWS currently calling for high of 84 and TWC calling for 86. Its an extreme long shot, but a positive bust could make it happen.

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