Tuesday, November 15, 2011

Are November High Temperature Swings More Sharp Recently?

After a severe weather event like last night, the images and sounds become embedded in every one's mind much faster. The inevitable conclusion is that severe weather and wild temperature swings in November are unusual. After all, we associated colder temperatures with November not tornado watches and temperatures near 70!


While the disconnect between huge changes in temperature and tornadoes seem to be vast at first glance, the first often plays a big role in the latter. 

The first question: Have high temperature swings become more drastic in recent years in November?

Look at the last 20 Novembers (Since 1991). The first number is the # of times where daytime highs
varied more than 20 degrees over 24 hours. Specific instances are in parentheses. The second set are the highest high and lowest high for each November.

The 2000s certainly had more days with high temps changing more than 20 degrees! One so far this month.

2011     1 (43 to 61)
2010     0                                     69  34
2009     0                                     71  40
2008     0                                     72  28
2007     0                                     66  33
2006     1  (62 to 42)                    66  37
2005     4  (57 TO 70 TO 48)      70  29

                 67 TO 29; 58 TO 35)
2004     0                                     64  40
2003     2  (69 to 39; 71 TO 51)  79  45   TORNADOES
2002     1  (45 TO 65)                 67  30    TORNADOES
2001     1  (69 TO 48)                 69  42

2000     0                                     66  28
1999     1  (64 to 37)                    73  35
1998     1  (49 to 70)                    71  40
1997     0                                     60  31
1996     1  (70 to 45)                    70  30
1995     0                                      71  33
1994     0                                      72  39
1993     0                                      63  33
1992     3 (56 TO 36; 61 TO 39   65  33   TORNADOES
                63 TO 41)
1991     0                                      69  29

Normally with huge swings in high temperatures, a cold front lies in the middle which is often the firing line for severe storms and sometimes tornadoes. The maps of November tornadoes in Ohio is below. Notices the cluster of tornadoes in northeastern Ohio in 2002 and 2003. Then check above at the list of huge high temp swings. 2003 has 2 instances of  high temps changing more than 20 degrees. One was 30 degrees in 24 hours!


November is a month of wild weather for sure. This decade seems to have had more instances than in the 1990s.  

We are still waiting for the pattern to switch. The snow is falling out west. Denver was hit hard earlier this week. Its just a matter of time. Once it does, lake effect snow will begin and the mild stretches for us hiking in the Metroparks will be over!

In case you were wondering, here are the overall temperature averages through November over the last 5 years:

2011  +3.4         1 time below 32
2010  +1.4       16 times below 32
2009  +5.9         6 times below 32
2008   -1.6       15 times below 32
2007   -0.5       14 times below 32
2006   +3.1        7 times below 32

Will we make up for it in December? More on this coming up in my next post!!!

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