The main causes for the heavy spring rains area:
1. Stronger than normal and more amplified jet stream (deeper troughs and stronger ridges). This has made it cool in the west and warm in the east (recent east coast heat wave).
2. A stationary front has been a persistent feature across the Midwest. This front serves as the lifting mechanism the air needs to rise, cool and condense to make clouds and precipitation
3. Strong high pressure over the southeast US and western Atlantic brings what meteorologists call "return flow" to the Midwest, which is southerly winds on the western side of the surface high pressure system that pump moisture rich air from the Gulf of Mexico up into the central states.
4. The above three processes have been a persistent feature in the weather patters for nearly 30 days.
Below are 3 images that show the Doppler radar observed precip amounts (inches), the departure from normal (inches) and the percentage of normal (%). These images report that Champaign - Urbana and surrounding areas have seen over 10 inches of rain which is nearly 500% of the normal amount of rainfall for these last 30 days. Check out this image from the NWS office in Lincoln. The Hydrologic Information Center has also released and interesting article reporting river flooding across the midwest.
NOAA released a report last week that found March-May to be one of the wettest March-May periods on record in the Midwest. At the same time, this years preliminary tornado count is incredibly high and setting records as well! What a fun season!
