Unusually Large Number of 90 Degree Days Through June

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PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE CHICAGO IL
415 AM CDT SUN JUL 1 2012 /515 AM EDT SUN JUL 1 2012/

...UNUSUALLY LARGE NUMBER OF 90 DEGREE DAYS SO FAR THIS SUMMER...

THROUGH JUNE 30TH...THERE HAS NEVER BEEN A YEAR IN CHICAGO THAT
HAS SEEN MORE 90 DEGREE DAYS TO DATE THAN THIS SUMMER. SO FAR THIS
YEAR CHICAGO HAS OFFICIALLY HAD 17 DAYS WITH HIGH TEMPERATURES AT
OR ABOVE 90 DEGREES. THIS TIES 1954 AND 1977 WITH THE GREATEST
NUMBER OF 90 DEGREE DAYS THROUGH JUNE 30TH.

IN ROCKFORD THERE HAVE BEEN 15 DAYS AT OR ABOVE 90 DEGREES SO FAR
THIS YEAR...WHICH PUTS 2012 IN 4TH PLACE FOR MOST NUMBER OF 90
DEGREE DAYS THROUGH JUNE 30TH. THE MOST NUMBER OF 90 DEGREES DAYS
THROUGH JUNE 30TH IN ROCKFORD IS 27 BACK IN 1934...WITH THE SECOND
MOST BEING 24 IN 1921...AND 3RD MOST IS 20 IN 1933. DURING EACH OF
THOSE YEARS CHICAGO`S OFFICIAL TEMPERATURES WERE RECORDED MUCH
CLOSER TO LAKE MICHIGAN WHICH IS THE REASON FOR THE LARGE
DISPARITY BETWEEN ROCKFORD AND CHICAGO FOR NUMBER OF 90 DEGREE
DAYS THOSE YEARS.

ON AVERAGE...THROUGH JUNE 30TH CHICAGO WILL HAVE SEEN ABOUT 5 DAYS
WITH HIGHS IN THE 90S AND ROCKFORD 4 DAYS. THE AVERAGE NUMBER OF
90 DEGREE DAYS IN A YEAR FOR CHICAGO IS ABOUT 17 WHILE ROCKFORD
AVERAGES NEARLY 15 DAYS. HISTORICALLY SPEAKING...ROCKFORD HAS
ALREADY SEEN MORE 90 DEGREE DAYS THROUGH JUNE 30 THAN THEY ENDED
UP HAVING THE ENTIRE YEAR 42% OF PREVIOUS YEARS. IN CHICAGO...THIS
YEAR HAS SEEN MORE 90 DEGREE DAYS THROUGH JUNE 30TH THAN 58% OF
ENTIRE PREVIOUS YEARS.

WHILE WHAT HAS HAPPENED SO FAR THIS WARM SEASON IS NOT
NECESSARILY AN ACCURATE PREDICTOR OF WHAT WILL HAPPEN THE
REMAINDER OF THE SUMMER. HOWEVER...STATISTICALLY SPEAKING EVERY
ONE OF TOP 10 YEARS FOR NUMBER OF 90 DEGREE DAYS THROUGH JUNE 30TH
IN CHICAGO WENT ON TO PRODUCE A GREATER THAN AVERAGE NUMBER OF 90
DEGREE DAYS DURING THE REMAINDER OF THE YEAR. THE JULY THROUGH
OCTOBER PERIOD IN CHICAGO AVERAGES 12.2 DAYS WITH HIGHS AT OR
ABOVE 90...YET DURING THE TOP 10 YEARS FOR NUMBER OF 90 DEGREE
DAYS THROUGH JUNE 30TH THE AVERAGE WAS 19.8 DAYS.

IN ROCKFORD THE STATISTICS ARE SIMILAR WITH ONLY ONE OF THE TOP 10
YEARS FOR NUMBER OF 90 DEGREE DAYS THROUGH JUNE 30TH NOT GOING ON
TO PRODUCE AN ABOVE AVERAGE NUMBER OF 90 DEGREE DAYS FOR THE
REMAINDER OF THE YEAR. IN AN AVERAGE YEAR...ROCKFORD SEES AN
ADDITIONAL 11.3 DAYS ABOVE 90 DEGREES AFTER JUNE 30TH...WHILE THE
AVERAGE FOR THE YEARS WITH THE TOP 10 NUMBER OF 90S THROUGH JUNE
30TH IS 23.4 ADDITIONAL 90 DEGREE DAYS.
HERE ARE THE TOP 10 90 DEGREE DAY PRODUCING YEARS IN ROCKFORD:
 # OF 90SYEAR
1621921
2521934
3491936
4461988
 461937
6451933
7441931
8421916
9401941
 401947
HERE ARE THE TOP 10 NUMBER OF 90 DEGREE DAYS IN A YEAR FOR CHICAGO:

 # OF 90SYEAR
1471988
2461955
3421953
 421983
5391959
6381952
7361954
8351964
9341944
10331977
 331987
$$

IZZI


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