We've heard of polar vortex and derecho, but a new weather term is sure to make the rounds in Minnesota and Wisconsin as forecasters are already talking about a Predecessor Rain Event (PRE) later this week.
"Looking for a different weather topic to learn about to pass some time today while you're working from home? Check out Predecessor Rain Event (PRE). One of these events is possible up here Thursday night as the remnants of [Laura] are heading for southern Missouri," tweeted the Twin Cities office of the National Weather Service.
Hurricane Laura is expected to hammer the coastlines of Texas and Louisiana in the Wednesday-Thursday timeframe, and while the track of Laura won't come close to Minnesota, a Predecessor Rain Event occurs ahead of the track of a tropical system.
It sounds impressive, and it certainly can be based past Predecessor Rain Events, but there is no guarantee yet as to where the heaviest rain will fall. For now, the Weather Prediction Center (WPC) is monitoring an area of southeast Minnesota eastward into Wisconsin for a slight risk of excessive rainfall, with models hinting at totals in excess of 2.5 inches.
PREs can and have happened in Minnesota, namely in August 2007 when southeast Minnesota was drenched by a PRE ahead of the remnants of Tropical Storm Erin. In fact, that PRE set the state's 24-hour rainfall record as upwards of 12 inches fell in southeast Minnesota, including the record 15.1 inches one mile south of Hokah in Houston County.
The good news this time around is that a PRE associated with Laura is unlikely to produce record rainfall rates in Minnesota.
"It's not looking likely at this time since we wouldn't have as long of a duration of rainfall as we did with Erin," a spokesperson with the NWS Twin Cities told Bring Me The News. "While heavy rain is certainly possible late Thursday into Friday, we're not expecting anything record-breaking like that at this point."
According to the DNR's Climate Journal, the heaviest rain from that the August 2007 PRE fell during the afternoon and evening of Aug. 18 and into the early morning of Aug. 19, with "all portions of 28 counties" getting at least 4 inches of rain.
"Six-inch totals were common across the region, and portions of southeastern Minnesota reported astounding rainfall amounts ranging from 8 to 20 inches. The heaviest rainfall reports came from Winona, Fillmore, and Houston counties, where 36-hour totals exceeded 14 inches. The largest multi-day rainfall total reported (through Monday, August 20) was 20.85 inches observed near the town of Houston in northern Houston County."
There were seven deaths tied to the record storm, including major flood damage to communities and hundreds of homes and businesses.
"Reports of stream flooding, urban flooding, mudslides, and road closures were numerous throughout southern Minnesota," the Climate Journal reads.