Sunday, June 3, 2012

Preliminary Data Continue Supporting US Record Warm Spring Estimate

June 7, PM Update: See update for official report from NOAA/NCDC.

June 5, PM Update: Preliminary National Climatic Data Center analysis, based on National Weather Service data, shows an average May temperature departure from normal of only 2.33°F. This would reduce the U.S. spring average about 0.7° from the earlier estimate. However, the adjusted average would still exceed the old record by a wide margin:

June 4, PM Update: Using a larger subset of 237 National Weather Service stations for May 1-31, the average is 3.5°F above the 1981-2012 climatology, so it's very likely that the May average was within 0.1°C of being 2°C above climatology.

Original post:
Now that preliminary data are available through the end of May, earlier estimates of U.S. record warm spring temperatures are being further confirmed. For the meteorological spring months of March through May, temperatures averaged above climatology in nearly the entire country, except for the immediate Pacific Coast:
Much of the Midwest was 3.5°C or more above average, with most or all of 5 states above 4°C.

Looking at the averages from 215 official National Weather Service reporting stations for the weeks ending from May 6 through June 3, the U.S. May temperature would average 3.7°F above the 1981-2010 climatological baseline:

This puts the May 2012 national average temperature at 65.5°, which edges out the record warmest May of 1934 by 0.1°.

Combined with the significantly above-average temperatures of March and April, it's very likely that the final spring temperature will exceed the previous warmest spring of 1910 by as much as 2.4°F. Five of the top 8 warmest springs will now have occurred in the 13 years of this century.

Official U.S. temperature averages will be published by the NOAA National Climatic Data Center in about a week.


Anonymous said...

Can you produce the same map and numbers, but based on 1951-1980?

Pete Dunkelberg

Anonymous said...

UAH published its satellite-based estimates of global temperatures for May 2012 today. Globally, their analysis shows last month was 0.29C above the 1981-2010 mean. For the contiguous US, their analysis shows last month to be 0.95C above the 1981-2010 mean. This is a little lower than your estimate, but in recent months, the satellite-based TLT temperature anomalies for the US have been lower than the actual surface-based instrumental record. I would expect the official NCDC temperature data (based on the 1901-2000 period of record) to finish with a final anomaly of at least 2C above the 1901-2000 normal.

CapitalClimate said...

Unfortunately, the map-generation options don't include a choice of climatology, but the 1951-1980 national averages are 0.7° lower for May and 1.3° lower for spring, so you can add those amounts to the corresponding average departure figures.

Anonymous said...

Looks like the official final tally was 57.1F, or a full 2 degrees above the prior record.

CapitalClimate said...

Right U R; see the update.

Anonymous said...

I hate to argue, but could we take another look at this?
The "mapping program" has three main steps:
1. read in a data file
2. format the data, probably in a standard weather program way
3. send formatted data to graphics routine.

The graphics routine doesn't "know" what data file you started with, and it would be really odd for a programmer to announce "I have a wonderful mapping program but it only works from one data file."
Someone sold you a crippled version.
I'll bet NCAR, NASA or NOAA would give a more flexible program if you asked them.
And consider: using a base period that ends day before yesterday kind of hides the incline.
A base period of 1951-1980 (or perhaps starting a little earlier) shows the comparison to the climate that the people who run everything grew up with. Isn't that worth asking NOAA for an uncrippled program?

Pete Dunkelberg

CapitalClimate said...

The problem is probably not in the program, but in the web interface to it, which limits the base period for climatology. Now that the NCDC data have come out, it is possible to get close to what you wanted. However, the fact of the matter is that this spring is such an extreme outlier that the differences between base periods are much smaller than the 2012 deviations themselves. An untrained eye unlikely to notice any difference.
For example,
1950-1995 base:
1961-1990 base:
1895-2000 base:

Seasonal Outlook

Latest seasonal forecast: Click here.

Latest 3-month temperature outlook from Climate Prediction Center/NWS/NOAA.