April Summary

April 2013 finished with a mean temperature of 40.6 degrees officially, the 13th coldest in Oshkosh history. OSNW3 finished the month at 39.7 degrees which places within the top 10. The coldest April in Oshkosh history occurred in 1907 when the mean temperature was 37.1 degrees.

Precipitation was abundant. 4.20 inches fell at the Waste Water Treatment plant putting the official total in the top 20 all-time. OSNW3 recorded 15 days with precipitation; 1 of those days totaled 2.11 inches while the remaining 14 totaled 2.08 inches. Since 2007 OSNW3 has averaged 4.24 inches of precipitation in the month of April, 147% of the Oshkosh 30 year average.

These extraordinary feats cannot go into the history books without a mention of snowfall. While the amount measured at OSNW3 is outside the top 20 (tied for 25th) the amount of days with measurable snowfall tops the list. We measured snow on 6 days, unofficially overtaking the 5 days that were recorded in 1980.

OSNW3 April 2013 Daily Observations

(click on graph for the month summary data - it will open a new tab/window)

April of 2013 over took the top spot in daily precipitation and minimum temperature at OSNW3 since genesis. See links in below.

Time flies. #OSNW3 "days with sun" tiny.cc/rcsundays and "monthly extremes" tiny.cc/oext are updated. #Oshkosh #wiwx
— Josh Herman (@OSNW3) May 14, 2013

March Summary & Oshkosh Half Marathon Forecast

At OSNW3 March finished 6.8 degrees below the Oshkosh average which was 20.9 degrees colder than last year. Precipitation and snowfall were both above the Oshkosh average, tallying 2.27 inches and 7.0 inches respectively.

Only three days in March experienced average high temperatures, and those days were consecutive, March 9th-11th. With a 25.5 degree monthly mean temperature, March 2013 ranks as the 10th all-time coldest March in Oshkosh history.

OSNW3 March 2013 Daily Observations

(click on graph for the month summary data - it will open a new tab/window)

Oshkosh Half Marathon - April 21st - Wx Forecast
Utilizing Intraseasonal Oscillations (ISO) and applying a cycling weather pattern, Lezak's Recurring Cycle (LRC), I attempt to accurately project weather conditions weeks and months into the future.



The output of the forecast model for April 20-22 in Oshkosh is above. Interpreting the numbers, odds are, temperatures will be around 60 degrees for the daytime high. The 25% chance of precipitation means it has precipitated in 1 of 4 cycles thus far. A zero in the Pcpn column suggests that measured precipitation has been very light. Wind may be more of a factor than precipitation. There is a 50% chance of winds blowing over 10 mph for the entire day. This means in 2 of 4 cycles the average wind speed for the entire day at KOSH was over 10 mph.

A graphical forecast based on the same principles as above, is below.

(Oshkosh April Forecast)


If there are any questions or thoughts on the material presented just let me know in the comments section of the blog. Thanks for reading!