ISWS CAS West Nile Virus Project

West Nile Virus Mosquito Crossover Dates

Experimental Data. For Champaign-Urbana Only.

During 2010, the models were run weekly from May 5 until July 28 when the model values converged. Shown below are the model results of July 28, which includes a summarization of the all of the model simulations.

to current
to MRCC

MAXIMUM TEMPERATURE EXCEEDANCE MODEL (Threshold of 81°F):
How to Interpret the Model Results

81°F MAX TEMP MODEL - CURRENT MODEL RUN:	7/28/2010
Based on the current model run there is:
• a 50 percent chance that the crossover date will be later than	July 19, 2010
• a 90 percent chance it will be earlier than	July 19, 2010
• and a 10 percent chance it will be earlier than	July 19, 2010
• The current run of the model has a median crossover date of	July 19, 2010
• The earliest crossover date projected by the current model run is	July 19, 2010
• The latest crossover date projected by the current model run is	July 19, 2010

Model Run History for the Current Year

81°F Max Temp Model
Model Run Date 2010	Probability that crossover will occur earlier than given date
Model Run Date 2010	Earliest	10 percent	25 percent	MEDIAN	75 percent	90 percent	Latest
5/5	7/8	7/23	7/28	8/6	8/17	8/24	9/28
5/12	7/16	7/25	7/30	8/7	8/19	8/28	9/30
5/19	7/12	7/18	7/24	7/31	8/11	8/18	9/17
5/26	7/17	7/20	7/25	8/1	8/11	8/17	9/16
6/2	7/13	7/18	7/22	7/28	8/4	8/11	9/12
6/9	7/17	7/19	7/23	7/27	8/3	8/9	9/5
6/16	7/16	7/17	7/19	7/22	7/27	8/2	8/16
6/23	7/18	7/18	7/19	7/22	7/25	7/30	8/14
6/30	719	7/19	7/19	7/21	7/23	7/25	8/9
7/07	7/20	7/20	7/20	7/20	7/21	7/23	8/4
7/14	7/19	7/19	7/19	7/19	7/19	7/19	7/19
7/21	7/19	7/19	7/19	7/19	7/19	7/19	7/19
7/28	7/19	7/19	7/19	7/19	7/19	7/19	7/19

Graph of 81F Max Temp Model Data

DEGREE DAY MODEL:
How to Interpret the Model Results

DEGREE DAY MODEL - CURRENT MODEL RUN:	7/28/2010

Based on the current model run there is:
• a 50 percent chance that the crossover date will be later than	July 23, 2010
• a 90 percent chance it will be earlier than	July 23, 2010
• and a 10 percent chance it will be earlier than	July 23, 2010
• The current run of the model has a median crossover date of	July 23, 2010
• The earliest crossover date projected by the current model run is	July 23, 2010
• The latest crossover date projected by the current model run is	July 23, 2010

Model Run History for the Current Year

Degree Day Model
Model Run Date 2010	Probability that crossover will occur earlier than given date
Model Run Date 2010	Earliest	10 percent	25 percent	MEDIAN	75 percent	90 percent	Latest
5/5	7/11	7/23	8/1	8/12	8/23	9/1	9/19
5/12	7/14	7/27	8/4	8/14	8/25	9/3	9/20
5/19	7/10	7/22	7/30	8/8	8/19	8/29	9/15
5/26	7/15	7/24	8/1	8/8	8/18	8/27	9/14
6/2	7/13	7/20	7/27	8/3	8/11	8/18	9/7
6/9	7/16	7/20	7/27	8/3	8/10	8/17	9/4
6/16	7/12	7/17	7/21	7/25	7/30	8/3	8/14
6/23	7/13	7/19	7/22	7/25	7/31	8/3	8/13
6/30	7/17	7/23	7/25	7/28	8/1	8/4	8/14
7/07	7/22	7/23	7/24	7/26	7/28	7/31	8/10
7/14	7/23	7/23	7/23	7/23	7/23	7/23	7/23
7/21	7/23	7/23	7/23	7/23	7/23	7/23	7/23
7/28	7/23	7/23	7/23	7/23	7/23	7/23	7/23

Graph of Degree Day Model Data

These graphs show the results of the individual model runs so far this season. As more of the “actual” weather is included in the model runs (i.e. as the summer progresses) and less “probable” weather (i.e. past climatology) is included, the plots of the dates will tend to converge on the crossover date.

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to 2005

NOTE: These models were derived from Champaign-Urbana, Illinois data.
the threshold temperature may vary regionally.