Abnormally Dry Spring Weather

While there are a couple chances of rain in the forecast, at this point neither potential precipitation event looks to be all that impressive with respect to potential precipitation totals. Precipitation Analysis data from our AHPS page (http://water.weather.gov/precip)indicates that in our region areas south of I-80 are running less than 50% of normal for rainfall the past 30 days, and arent fairing much better in the 60 and 90 day time frame. In fact, portions of Lasalle and Grundy counties have seen less than 25% of typical rainfall the past 30 days. The abnormally dry weather has even begun to register on the U.S. Drought Monitor which has the portion of our region south of I-80 in Illinois in D0 drought category with a D1 (or moderate drought) now depicted just to our southwest over central Illinois.

 

 

Here is a map showing percentage of normal rainfall for the past 30 days, click on the map to be taken to the AHPS Precipitation Analysis page where you can make your own custom queries...

 

AHPS Precip Analysis

 

 

 

Here is a map depicting the location of the developing drought area over Illinois, again, click on the image to be taken to the website...

 

Accumulated Precipitation

The following images depict the accumulated precipitation so far this year for our NWS Cooperative Observer locations at Watseka and Pontiac Illinois. The dark blue line indicates accumulated precipitation thus far compared to normal (red) along with the wettest (green) and driest (brown) years for that location.
 

 

Watseka accumulated precip Pontiac accumulated precip
Watseka, IL Pontiac, IL

 

 

 

Streamflow

The lack of precipitation is most evident in observed streamflow at U.S.Geological Survey (USGS) river gage stations. In fact, several locations are indicating streamflows that are well below normal for this time of year.

USGS low flow map

The following are streamflow duration graphs produced by the USGS for river gage locations on the Iroquois River and Vermilion River. Typically, locations would be experiencing some of the highest streamflows during this time of year.

Iroquois River at Iroquois, IL Vermilion River at Pontiac
Iroquois River at Iroquois, IL Vermilion River at Pontiac, IL

 

 



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