Monday, May 28, 2012

Counting Down to the Record: Washington Temperature Approaches Reaches Exceeds 1° Above Warmest Spring, Heads Higher

June 1, 2 PM Update: Charts updated above. Note that the May average of 71.4° was 5.4° above the climatological average and the 3rd warmest May on record, behind 1991 and 2004. It was only the 4th time in history that May averaged over 70°.

June 1, 1 AM Update: The midnight (standard time) temperature is 74°. The daily low remains 69°, and the new record for warmest spring stands at 62.2°. (Charts to be updated.)

May 31, 6 PM Update: Today's high of 85° has exceeded expectations by 3°, and the morning low of 69° is a whopping 11° above the forecast from last evening. That's enough to push the semi-final spring average up another 0.2° to 62.2°, an incredible 1.5° above the old record. With cooling temperatures this evening, however, it all comes down to the midnight temperature (1 am EDT). A reading of 63° or lower would shave off 0.1° and put the final average at 62.1°.

May 30, PM Update: Yesterday's high/low temperatures were 91°/70°. While today's high of 83° as of 5 pm was held down by persistent clouds, the spring average to date has been lifted to 62.0°, exceeding the old record by 1.3°. Tomorrow's cooler readings should still be enough to raise the final average by another 0.1°. (Charts updated above.)

Meanwhile, preliminary indications are still confirming that the U.S. 48-state average spring temperature will crush the old record. See here for the latest update.

May 28, PM Update: Today's preliminary high of 90° brings the month to date average temperature up to 61.7°, a full degree above the old record. The projection remains the same.

Original post:
As noted previously, Washington DC is headed to the record warmest spring by an unprecedentedly large margin. Following the low this morning of 70°, the high temperature so far today (through 1 pm) of 86° is enough to raise the March-May average to date to 61.6°, which is 0.9° above the old record from 1977. Given the forecast temperatures for the next 3 days, the projected final average will be 62.2°. Even without reaching the 90° levels predicted for this afternoon and tomorrow, the average will continue rising. In order to decline from the current level, the average for the next 3 days will have to be at least 8° below the historical average through the 31st. That would mean a high of 71° and a low of 53°. Although that's hardly impossible, it's fair to say: Ain't. Gonna. Happen. While it's bad form to predict records days before before they occur, this one is about as sure as you can get.

Stay tuned as we count down the record.


S.P. Gass said...

Thanks a lot for compiling all of these temperature stats. One correction... I don't think the new DC spring temp record will be by an unprecedented margin. Record in 1945 was 59.3F which stood until 1977 which hit 60.7F, a difference of 1.4F. The spring of 2012 looks to exceed the current standing record of 60.7 by less than 1.4F.

CapitalClimate said...

Well, OK, perhaps "unprecedented" was not the best word. Except for clouds keeping the high down today (81 so far), 62.2 was in reach for the final average, which would have been 1.5 above the old record. As of now, 1.4 is most likely, which would still equal the previous difference.

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