A common plot request this time of year is a map showing precipitation departures over some number of days. This departure can be expressed in a number of ways with the featured map presenting this departure in terms of percentage of average. A value of 100% would indicate the total is equal to the average computed over some number of previous years on record for an individual site. Individual point values are then contoured to provide a bit more visual information to the spatial trends over the state. Since there is only about one observation station per county, these maps tend to show smoothed details that may not exist in real life. Since the most significant rainfall events tend to be isolated in the summer season, having one of these events hit a given observation station can skew the map. Having a number of stations generally agree in a given area of the state can help give confidence to the analysis and the featured map shows that northern Iowa continues to be the driest portion of the state. Some needed rainfall did visit the area Monday evening and into Tuesday, so we shall see how those totals added up!

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