New Record Low Pressure for Non-Tropical Storm System

[Drew.Gardonia]

Today's storm system appears to have been one for the data books. Preliminary readings indicate that a new record was set for the lowest pressure in a nontropical storm in the mainland United States, said Chris Vaccaro of the National Oceanic and Atmospheric Administration.

The minimum central pressure of 28.22 inches of mercury was equivalent to the pressure of a major Category 3 hurricane, without the corresponding wind scale, he said. If confirmed, the reading would break the current record of 28.28 inches, set on January 26, 1978, during what became known as the Blizzard of 1978.


converted that comes to 955.6350983719999 MB


http://www.cnn.com/2010/US/10/26/midwest.weather/index.html?hpt=T1

 

[GPhillips]

They must not have liked the Big Forks AWOS observations (site KFOZ) in north central MN since the altimeter setting got down to 28.20.

[SIZE=-1]METAR KFOZ 261933Z AUTO 02007KT 10SM RA SCT002 BKN008 OVC018 13/12 A2825 RMK AO2 P0018
METAR KFOZ 261953Z AUTO 36004KT 10SM +RA BKN010 OVC013 13/12 A2824 RMK AO2 P0002
METAR KFOZ 262013Z AUTO 33003KT 10SM -RA OVC010 13/12 A2822 RMK AO2 P0005
METAR KFOZ 262033Z AUTO 35005KT 7SM RA BKN007 OVC012 13/12 A2822 RMK AO2 P0008
METAR KFOZ 262113Z AUTO 34004KT 4SM +RA OVC007 13/12 A2821 RMK AO2 P0002
METAR KFOZ 262133Z AUTO 00000KT 5SM RA OVC007 13/12 A2821 RMK AO2 P0005
METAR KFOZ 262213Z AUTO 06005KT 5SM -RA OVC005 11/10 [COLOR=Blue]A2820[/COLOR] RMK AO2 P0004
METAR KFOZ 262233Z AUTO 14004KT 4SM +RA BKN005 OVC013 11/09 A2822 RMK AO2 P0008
METAR KFOZ 262253Z AUTO 24011G21KT 223V293 10SM RA SCT005 SCT009 OVC017 09/08 A2823 RMK AO2 P0001
METAR KFOZ 262333Z AUTO 24015G23KT 10SM -RA OVC009 08/06 A2825 RMK AO2 P0002[/SIZE]

[SIZE=-1]

[/SIZE]

 

[Drew.Gardonia]

They must not have liked the Big Forks AWOS observations (site KFOZ) in north central MN since the altimeter setting got down to 28.20.

[SIZE=-1]METAR KFOZ 261933Z AUTO 02007KT 10SM RA SCT002 BKN008 OVC018 13/12 A2825 RMK AO2 P0018
METAR KFOZ 261953Z AUTO 36004KT 10SM +RA BKN010 OVC013 13/12 A2824 RMK AO2 P0002
METAR KFOZ 262013Z AUTO 33003KT 10SM -RA OVC010 13/12 A2822 RMK AO2 P0005
METAR KFOZ 262033Z AUTO 35005KT 7SM RA BKN007 OVC012 13/12 A2822 RMK AO2 P0008
METAR KFOZ 262113Z AUTO 34004KT 4SM +RA OVC007 13/12 A2821 RMK AO2 P0002
METAR KFOZ 262133Z AUTO 00000KT 5SM RA OVC007 13/12 A2821 RMK AO2 P0005
METAR KFOZ 262213Z AUTO 06005KT 5SM -RA OVC005 11/10 [COLOR=Blue]A2820[/COLOR] RMK AO2 P0004
METAR KFOZ 262233Z AUTO 14004KT 4SM +RA BKN005 OVC013 11/09 A2822 RMK AO2 P0008
METAR KFOZ 262253Z AUTO 24011G21KT 223V293 10SM RA SCT005 SCT009 OVC017 09/08 A2823 RMK AO2 P0001
METAR KFOZ 262333Z AUTO 24015G23KT 10SM -RA OVC009 08/06 A2825 RMK AO2 P0002[/SIZE]

[SIZE=-1]

[/SIZE]

did that reading occur today?

 

[Robert Dewey]

did that reading occur today?

According to the time stamp, that was today.

 

[John Farley]

Yes. The metar code means that the pressure was 28.20 at 2213z today, i.e. 5:13 p.m. CDT.

 

[Jeff Snyder]

Just to briefly mention, the 28.20 inHg may actually represent anything between 28.195 and 28.2049. In millibars, this converts to a range of 954.79 mb to 955.13 mb. Since we don't know for sure, it MAY have gotten down to 945.8 mb. All of this, of course, assumes that the altimeter observation is errorless / without bias. The true pressure minimum likely was lower, since there's a good chance that the exact min wasn't exactly sampled by a surface observation site.

I'm still amazed that the sfc low was 985-983 mb in the Dakotas yesterday, and the 995 mb isobar encompassed a huge area of the central US. On most any other day, even a 985 mb sfc low in the Plains would be a big deal, and this was actually just the "starting point" for the bombing the occurred today. Oh, and all with a relatively low amplitude trough aloft and with a rather limited area of very cold air near the surface (these two are related, obviously).

 

[Drew.Gardonia]

Yes. The metar code means that the pressure was 28.20 at 2213z today, i.e. 5:13 p.m. CDT.

well I'm not sure when that article was posted but I'm willing to bet it was prior to that reading, so I'm sure it'll be updated later on.

 

[Robert Dewey]

I'm still amazed that the sfc low was 985-983 mb in the Dakotas yesterday, and the 995 mb isobar encompassed a huge area of the central US. On most any other day, even a 985 mb sfc low in the Plains would be a big deal, and this was actually just the "starting point" for the bombing the occurred today.

I found that interesting as well. This storm started out almost as deep as the Edmund Fitzgerald storm before it even started to bomb. With such a deep system, I would expect stronger surface winds than what we're seeing. As someone else noted in one of the other threads, this probably has to do with relatively low pressure across the North America (1020mb high over the SW). During the Superstorm of 1978 (which dropped to 950-955mb), there was a 1030mb high over Saskatchewan, Canada. That's an additional 10mb of gradient.

Other weaker storms, such as the Armistice Day storm, featured high pressure centers buffering both sides of the storm on the order of 1040mb, which would actually give it an equal or slightly stronger pressure gradient than today's ~955mb low.

 

[John Farley]

The Duluth NWS has issued a report confirming the 28.20 reading (just under 955 mb) at Big Fork. That is a Minnesota record low pressure. Not clear to me whether or not it is a record for the U.S. for a non-tropical system, as I have seen conflicting information on what the previous record was.

Here is the PNS from the Duluth NWS:

http://kamala.cod.edu/offs/KDLH/1010271347.nous43.html

The PNS from the Chicago NWS linked below would suggest that the previous record was lower than what is mentioned in the statement Andrew posted above; if this statement is correct then yesterday's pressure would probably be the second-lowest. Not sure what is the source of the confusion among different NOAA sources on the previous record (though both sources appear to associate it with the same 1978 storm). Here is a link to the Chicago PNS:

http://kamala.cod.edu/offs/KLOT/1010261609.nous43.html

 

[rdale]

NWS Cleveland has a presentation on their website which says 28.28 is the 1978 Blizzard lowest value (which I'd trust more than other offices posting) but also contains a reference that it's the second lowest CONUS on record. It has the source's name but no full document, and I sent them a message asking what the lowest is per that study and have not heard.

 

[mikegeukes]

Low Pressure Records Set on October 26, 2010

THE AUTOMATED WEATHER OBSERVING SYSTEM AT BIGFORK MINNESOTA
RECORDED A 954.96 MILLIBAR /28.20 INCHES/ PRESSURE. THIS BREAKS THE
ALL TIME MINNESOTA STATE RECORD FOR THE LOWEST OBSERVED PRESSURE.

http://www.crh.noaa.gov/images/dlh/StormSummaries/2010/october26/pressurerecord.pdf

5:13 PM 51.8 °F 50.0 °F 94% 28.20 in 5.0 miles ENE 5.8 mph - 0.04 in Rain Light Rain
METAR KFOZ 262213Z AUTO 06005KT 5SM -RA OVC005 11/10 A2820 RMK AO2 P0004

Mike

 

[Mike Kovalchick]

NWS Cleveland has a presentation on their website which says 28.28 is the 1978 Blizzard lowest value (which I'd trust more than other offices posting) but also contains a reference that it's the second lowest CONUS on record. It has the source's name but no full document, and I sent them a message asking what the lowest is per that study and have not heard.

I note that on another forum, somebody posted that the non-tropical storm pressure record in the continental US occurred at Block Island, RI where 28.20" was recorded on 3/7/1932. So perhaps yesterday's storm tied the record? (It should go without saying that readings in the Gulf of Alaska or over the Aleutian Islands have readings much lower than this on a regular basis..just not recorded by a land based observation site. But for a mid-continent storm-wow-impressive indeed!)

A reference to the RI record can be found here: http://extremeweatherguide.com/records.asp#United%20States%20Barometric%20Pressure%20Records

 

[Zach Chappell]

Just to mention quick this storm has produced Near 80 mph winds so far if not higher with 75mph winds being measured at Grand River Raws in SD http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=abr&storyid=59069&source=0 and lots of Obs across SD high end 60mph with another 70mph in western SD

 

[GPhillips]

Not sure about the 28.05 mentioned in the LOT PNS, but the always reliable wikipedia says 28.28 in the United States for the Jan 78 storm.

 

[Josh Durkee]

For your entertainment: http://blog.ametsoc.org/columnists/but-not-the-bomb/