Will Midwest Storm Break Pressure Records?
UPDATE: The National Weather Service has added this list of all-time lowest pressures with storms over the entire Great Lakes... and they project this will be #2 of all-time, the worst since 1978!
The numbers that the computer forecast models are printing out for pressure in tomorrow's storm are just incredible:
4-KM WRF: <28.50"NMM: <28.40"GFS: <28.30"
These low readings speak to the potential power of the low pressure system (if it were a hurricane, it would qualify as Category 3 at these pressures).
If the models are right, it may be the strongest storm to ever pass through the state of Minnesota in recorded history. If you get photos or video of the storm, upload it to AccuWeather.com Facebook!
Data that I accessed indicates that International Falls, MN's lowest pressure since 2005 was 28.93" in June 2007. Their all time record low was 28.70" in 1949; the state record is 28.47" at Rochester. International Falls record would be slammed at the model's predicted readings tomorrow and the state record would likely be broken as well. Michigan's record is 28.30" and is probably safe.
Already this afternoon pressures have fallen to 29.00" at Jamestown, South Dakota! It's possible that state's all-time record of 28.63" could also be broken.
Get more details on the high winds in our news article quoting potential power outages and damage. A squall line will also spin off from the storm, bringing winds high enough for the SPC to issue a Moderate Risk for the Ohio Valley. Although the line will fade as it reaches my area in Central Pennsylvania, it may still contain high winds. See our severe thunderstorm article for more on the thunderstorm threat tomorrow.
Winds on the Great Lakes could cause a seiche (something I have blogged about before) on Lake Michigan or possibly Lake Superior tonight, and wave heights will be over 7 feet there. I'm no seiche forecaster but if all you need is high winds over a long "fetch," tomorrow afternoon would seem to qualify (according to this NWS model from Sunday night):
