Update: Record Extended to Entire Mainland U.S.; All-Time Record Low Pressure in Minnesota and Wisconsin

October 29 Update: The status of the pressure record has been updated as a result of further review.

8:30 PM CDT Update: The St. Cloud daily record precipitation has increased to 1.42".

The Illinois State Climatologist quotes the National Weather Service:

New record set today for the lowest pressure in a non-tropical storm in the mainland U.S. The massive storm system barreling across the central U.S. had a minimum central pressure of 28.24″ or 956 mb (equivalent to the minimum pressure of a Category 3 hurricane). This breaks the old record of 28.28″ (958 mb), set on Jan. 26, 1978, during the Blizzard of 1978 (aka the Cleveland Superbomb). This is also lower than the March 1993 Superstorm (aka “The Storm of the Century”), or the “Witch of November” storm that sank the Edmund Fitzgerald in 1975, or even the Columbus Day Storm of Oct. 1962.

Note that the Big Fork report apparently exceeded that reading by an additional 0.04".

5:40 PM CDT Update: Big Fork and Orr appear to have bottomed out with slight rises back to 28.22" shortly after 5:30.

St. Cloud has set a rainfall record for the second consecutive day. The 1.38" today broke the old record of 1.33" set in 1941.

5:15 PM CDT Update: Big Fork forges onward to a new low of 28.20".

4:40 PM CDT Update: Although the storm is centered in Minnesota, it's strong enough to break the all-time record in the neighboring state of Wisconsin, as well. The National Weather Service reported earlier this afternoon that the low pressure of 28.38" (961.1 mb) at Superior broke the previous record of 28.45" at Green Bay on April 3, 1982.

4:30 PM CDT Update: The Weather Channel is twitching that the Orr reading is the "Record lowest U.S. land-based pressure! . . . [B]esting the record from 'Superbomb of Jan '78'!" Presumably, this means the lowest reading from a non-tropical storm. Meanwhile, Big Fork has slightly surpassed that with a pressure of 28.21" at 4:13 pm.

4 PM CDT Update: The image (click to enlarge) shows the surface weather map at 1 pm CDT this afternoon, as barometric pressures approached new all-time record lows in Minnesota. The central pressure of the intense storm is shown as 957 mb (28.26").

3:45 PM CDT Update: Big Fork and Orr are tied at 28.22".

Bloomberg reports that the strong winds from the storm have "knocked out power to thousands in Illinois, Indiana and Michigan and forced the cancellation of hundreds of flights at Chicago airports."

3:15 PM CDT Update: The drop continues: Big Fork 28.22", Orr 28.23".

3 PM CDT Update: Orr and Big Fork are both down another notch to 28.24".

2:15 PM CDT Update: Grand Rapids has tied Orr at 28.27", but Orr has come in with a late report of 28.25" at 1:54.

2 PM CDT Update: The latest hourly readings show 5 official stations all at 28.28": Big Fork, Cook, Eveleth, Grand Rapids, Hibbing.

1:40 PM CDT Update: Orr has continued to fall, now at 28.27"; Eveleth at 28.28"; Cook, Hibbing, and Grand Rapids all at 28.29".

1:30 PM CDT Update: Orr has now tied the 28.29" reading as of 1:14.

The storm also brought record daily rainfall yesterday to Minneapolis. The 0.67" exceeded the old record of 0.62" in 1875. St. Cloud's 0.61" also broke the daily record of 0.50" set in 1956.

1 PM CDT Update: As of 1 pm local time, Eveleth was reporting a new low of 28.29" with pressure still falling. Other new lows included:

HIBBING      28.30
GRAND RAPIDS 28.32
COOK         28.33
LONGVILLE    28.33
ELY          28.35
ORR          28.35
AITKEN       28.35
MCGREGOR     28.35  

Original Post:
As predicted yesterday, a strong storm has intensified rapidly over Minnesota, bringing with it an unofficial all-time record low pressure for the state. At noon CDT, Longville in north-central Minnesota was reporting a barometric reading of 28.36" (960.4 mb), and the pressure was continuing to fall. Hibbing also recorded the same reading. According to the National Weather Service, the previous record low pressure for the state was 28.43" (962.8 mb) in 1998.

Other stations reporting pressures below 28.50" include:

BEMIDJI           28.41
THIEF RIVER FALLS 28.49
FOSSTON           28.45
PARK RAPIDS       28.45
BAUDETTE          28.47
INTL FALLS        28.46
BIG FORK          28.42
GRAND RAPIDS      28.38
COOK              28.41
DULUTH            28.39
ELY               28.41
GRAND MARAIS      28.49
AITKIN            28.38
PINE RIVER        28.44
BRAINERD          28.42
STAPLES           28.48
LITTLE FALLS      28.49
MORA              28.49
MOOSE LAKE        28.38
HINCKLEY          28.45
CLOQUET           28.39  

It appears that at least 10 of these locations broke the old record.