Coldest summer since 1917

[Guest]

Here in Washington , this summer has been the coldest since 1917. We've only had 7 90 degree days from June 1st through August 21st (today). Hopefully mother nature doesnt compensate with a mild winter...

[USAwx1]

it's disturbing to see that some still believe in the old cliché that a cool summer always foretells a warmer than average winter. Or that a warmer than normal summer always means a cold winter.

[Guest]

i wasnt saying that, i was saying hopefully we dont get a mild winter.

[Superstorm]

1917-18 was the coldest winter on record for VA and MD, and most of the northeast. DCA snowfall 36.4" with 2-3" storms in November and April. January 1918 was second only to 77. If this is a potential analog, you just made my day. Bring it on!

[Guest]

wow i didnt know that. Hopefully it comes true lol. But look at the Farmers Almanac forecast for the Northeast, that forecast would be indicitive of a winter like that.

[donsutherland1]

Nikolai,

Washington, D.C. (DCA) has not had the coolest summer since 1917, if one considers the average temperature for the summer. It has had the coolest summer since 2000:

2000 Monthly Mean Temperatures:
June: 74.7°
July: 74.7°
August: 75.1°
Summer Mean: 74.8°

2004 Monthly Mean Temperatures:
Through August 21:
June: 73.4°
July: 78.5°
August: 75.5°
Summer Mean: 75.8°

Other recent summers that have been cooler than Summer 2004 include:
1972: 74.5°
1992: 75.1°
2000: 74.8°

Of the 65 summers that saw DCA average under 76.0°, 13 turned out very cold with a mean temperature (December-February) under 34°. However, 14 turned out very warm with a mean temperature of above 38°, including 4 with mean temperatures above 40°.

Coldest Winter: 1904-05 29.0°
Warmest Winter: 1889-90 44.3°

Therefore, one cannot assume that a cool summer will automatically translate into a cold winter. Nevertheless, one also cannot automatically assume that a pattern switch will occur.

Of the 53 such summers for which seasonal snowfall the following winter are available, 22 winters received 20" or more of snowfall while 31 winters received less than 20" of snowfall. In terms of extreme winters, 10 such winters received 30" or more of snow and 11 received less than 10" of snow. Again, as with temperatures, one cannot assume that a cool summer will lead to a snowy or relatively snowless winter.

As for cool and wet summers (Mean temperature below 76° and 15" or more of rain), such winters were typically somewhat warmer than those that followed cool and dry summers (Mean temperature below 76° and less than 10" of rain). Winters following cool and wet summers typically were somewhat less snowy and more likely to see very low snowfall (less than 10") than those following cool and dry summers.

Again, there is too much variability to really draw definitive conclusions:

Cool & Wet Summers:
Winter mean temperature: 36.7°
Average Snowfall: 18.7"
20" or more: 7/18 (39%)
Less than 20" snowfall: 11/18 (61%)
Less than 10" snowfall: 5/18 (28%)

Cool & Dry Summers:
Winter mean temperature: 35.4°
Average Snowfall: 21.0"
20" or more: 7/12 (58%)
Less than 20" snowfall: 5/12 (42%)
Less than 10" snowfall: 2/12 (17%)

[donsutherland1]

Also, FWIW, Summer 2004 would be grouped as "cool and wet" by the criteria discussed earlier given its mean temperature and the fact that it has received more than 16.50" of rainfall so far.

Of course, if it warms before the end of the month, it is not out of the question that the seasonal mean temperature reaches or even exceeds 76.0°.

[Guest]

I was reading the local weather at wjla, im not the one who originally said it was coldest since 1917.

[USAwx1]

Nikolai,

Washington, D.C. (DCA) has not had the coolest summer since 1917, if one considers the average temperature for the summer. It has had the coolest summer since 2000:

2000 Monthly Mean Temperatures:
June: 74.7°
July: 74.7°
August: 75.1°
Summer Mean: 74.8°

2004 Monthly Mean Temperatures:
Through August 21:
June: 73.4°
July: 78.5°
August: 75.5°
Summer Mean: 75.8°

Other recent summers that have been cooler than Summer 2004 include:
1972: 74.5°
1992: 75.1°
2000: 74.8°

Of the 65 summers that saw DCA average under 76.0°, 13 turned out very cold with a mean temperature (December-February) under 34°. However, 14 turned out very warm with a mean temperature of above 38°, including 4 with mean temperatures above 40°.

Coldest Winter: 1904-05 29.0°
Warmest Winter: 1889-90 44.3°

Therefore, one cannot assume that a cool summer will automatically translate into a cold winter. Nevertheless, one also cannot automatically assume that a pattern switch will occur.

Of the 53 such summers for which seasonal snowfall the following winter are available, 22 winters received 20" or more of snowfall while 31 winters received less than 20" of snowfall. In terms of extreme winters, 10 such winters received 30" or more of snow and 11 received less than 10" of snow. Again, as with temperatures, one cannot assume that a cool summer will lead to a snowy or relatively snowless winter.

As for cool and wet summers (Mean temperature below 76° and 15" or more of rain), such winters were typically somewhat warmer than those that followed cool and dry summers (Mean temperature below 76° and less than 10" of rain). Winters following cool and wet summers typically were somewhat less snowy and more likely to see very low snowfall (less than 10") than those following cool and dry summers.

Again, there is too much variability to really draw definitive conclusions:

Cool & Wet Summers:
Winter mean temperature: 36.7°
Average Snowfall: 18.7"
20" or more: 7/18 (39%)
Less than 20" snowfall: 11/18 (61%)
Less than 10" snowfall: 5/18 (28%)

Cool & Dry Summers:
Winter mean temperature: 35.4°
Average Snowfall: 21.0"
20" or more: 7/12 (58%)
Less than 20" snowfall: 5/12 (42%)
Less than 10" snowfall: 2/12 (17%)

Great post, Don, but be careful of that correlation between Precip and snowfall. Normally a wet summer and fall along the east coast indicates a tendency for a coastal storm track the following winter. IF we continue through the fall with a persistence of wetter-than-average conditions (which i see no reason why not given the developing El Nino, which in it's own right suggests a coastal storm track) we could really be seeing a strong signal for a persistent coastal storm track. And Im not talking about a bunch of Miller Type B systems, we're talking about the real deal---that being a few Miller Type A systems. Something which was not common during the past two winters (we saw a predominance of Miller type B systems).

[USAwx1]

here is a Nice write-up from SF regarding the miller types for those who like to dig deeper into these things:

http://www.stormsfury1.com/Weather/Cyclogenesis.html

[donsutherland1]

USAwx1,

I agree with you about the possibility of a promising winter. I only wanted to point out to Nikolai that one cannot necessarily assume that the summer pattern in Washington, DC foretells the winter pattern there.

[Guest]

ok i agree with you. I only said though, that hopefully we dont get a mild winter due to the cool summer.

[donsutherland1]

Nikolai,

That's not a problem. Sometimes the media might make an error. I just wanted to point out that Summer 2004 is far from the coldest since 1917 in the DCA area.

[Guest]

ok well then weve cleared up that issue.

[Guest]

wait but hee is what they said
from the abc 7 first alert center:
Saturday has started out quite warm and muggy with a few light showers. Heavier rain has been falling in western Maryland and central and western Pennsylvania. An approaching cold front will increase the threat of thunderstorms this afternoon, with a 60% likelihood of them from mid-afternoon until 6 PM. Soem of the storms could produce high winds, hail and significant rainfall in a short period of time. The possibility of showers will persist into the evening hours. Winds from the north will start to clear skies after midnight and decidedly drier air and sunnier skies are expected for Sunday. High temperatures for both days should be in the low 80s, but Sunday will feel far more comfortable. Pleasant weather is expected to last through the early part of next week. NOTE: There has been but one 90 degree day in August and a mere 7 in the summer to date ( June through August). Not since 1917 has a summer been so cool.

[donsutherland1]

Nikolai,

Several quick points:

1) The TV station is incorrect. There have been 8 90° days at DCA (3 in June; 4 in July; 1 in August).

2) The July-August total of 5 this summer is above the July-August total of 2000 (4).

3) If August 2004 manages one more 90° day--and that is possible later this week--then Summer 2004 will have 9 90° and that will match the number that occurred in Summer 2004.

Thus, the TV station is premature in making an announcement that, first misses the actual number of 90° days, and second, might not hold true by month's end--could this prove to be the Station's proclamation that "Dewey Beats Truman!"

Why not wait until the end of the month? Perhaps ratings might have something to do with it? I don't know, but I'd wait until all the data is in--and that it is accurate--before making such pronouncements.

Of course, you did not have the data to recognize that there might be some problems with the Station's information. So, in no way, am I criticizing you. I am critical of the station for passing off inaccurate information and making a possibly premature judgment. Now, if the Station had mentioned that if August sees no more 90° days... then it would have done better.

Clearly, forecasts can be incorrect. But when one cites past data, one has all the results and some proofreading should avoid the kind of errors that resulted e.g., the number of 90° days this June through August, thus far. Through yesterday, we're talking about 82 days and that's not a huge number. The number of 90° days for June-August 2004 should have been correct.

[W13]

It has been a hot summer here, but it has recently cooled down. With that cooling, it also brought rain. Hopefully as the monthes progress we will see that turning over to snow.

The Farmer's Almanac says that the Pacific Northwest should see one of the first winter storms. They are also predicting a cold winter. Just my kind of weather.