TRAVERSE CITY, Mich. (AP) - Experts say recent wet weather may boost Great Lakes water levels, but it's uncertain by how much - or how long it will last. Drew Gronewold is a hydrologist with NOAA's Great Lakes Environmental Research Laboratory in Ann Arbor. He said Tuesday that runoff from melting snow and rain showers typically causes lake levels to rise in spring. Gronewold said precipitation, runoff and evaporation rates together determine where lake levels go. Keith Kompoltowicz of the U.S. Army Corps of Engineers tells The Holland Sentinel that Lakes Michigan and Huron have risen 6 inches this month. The Great Lakes basin in April has received more than 150 percent of average precipitation. Kompoltowicz says several more wet winters and springs are needed to return the lakes to their normal levels.