Lowest 500 mb height in history

[Tim Vasquez]

477.6 dam
January 21, 1985 Caribou, Maine
(Lowest on record in the conterminous United States)

http://www.weathergraphics.com/tim/500min.jpg

This deep upper-level low was associated with one of the biggest outbreaks of arctic air into the central U.S. of the 1980s. It also gave the all-time lowest 500 mb height for the conterminous U.S. The day before, Dallas saw a balmy 70-degree afternoon, and by 10 pm it was in the 20s with winds howling out of the north at over 40 mph.

A similar outbreak in 1982 (the month of the AFC Freezer Bowl) gave the second runner up of 478.1 dam on January 18, 1982 at 00Z, also at Caribou.

Tim

[Pat Lawrence]

This is fun! I'm sure the observational data will give a lot of headaches from time to time... but it's always fun to look into data, turned into info, from previous years!

Pat

[Paul Townsend]

1985 was the first January in my database for Appleton, WI. On January 20th we had a high of -5 and a low of -29. This was the lowest temperature in my database (April 1984 to Present) until the string of bitter cold in January of 1994, when on January 18th we had a high of -18 and a low of -30.

[Pat Lawrence]

Just wanted to mention Paul has a great climate database available on his website.. well worth a look!

Pat

[Paul Townsend]

I've updated my climate data for 2006. There are some artifacts due to saving the Excel files in the middle of this month. Also some concatination issues with text strings (some or all of the text does not appear), but you can get the idea. No upper air data, though. Sorry [Red face shrug]

[Andrew Sorce]

Just for kicks, the GFSX shows an extraordinarly deep 500mb low in association with true polar air over the Hudson Bay on Day 10, 0z 2/1/07. I have doubts on this verifying to this extent, but yikes, thats some serious arctic air. The model looks a touch under 4800dm @500mb, pretty sweet.

[Glenn Rivers]

Just lookng at that 500 mb chart causes my hands to hurt, my legs to itch, and imagine the brittle cartledge of my ears snapping off and falling into the gutter

[Glenn Rivers]

477.6 dam
January 21, 1985 Caribou, Maine
(Lowest on record in the conterminous United States)

http://www.weathergraphics.com/tim/500min.jpg

This deep upper-level low was associated with one of the biggest outbreaks of arctic air into the central U.S. of the 1980s. It also gave the all-time lowest 500 mb height for the conterminous U.S. The day before, Dallas saw a balmy 70-degree afternoon, and by 10 pm it was in the 20s with winds howling out of the north at over 40 mph.

A similar outbreak in 1982 (the month of the AFC Freezer Bowl) gave the second runner up of 478.1 dam on January 18, 1982 at 00Z, also at Caribou.

Tim

Another arctic outbreak Just 1 year and 7 days later is one I will never forget.....Challanger exploded due to the effects of the cold on the brittle "O rings" That morning's poler vortex was quite a lot weaker, ~5050 dam futher SW over NY, more negetively tilted and open. Still it seems just like yesterday to me.

[Bob Schafer]

Just for kicks, the GFSX shows an extraordinarly deep 500mb low in association with true polar air over the Hudson Bay on Day 10, 0z 2/1/07. I have doubts on this verifying to this extent, but yikes, thats some serious arctic air. The model looks a touch under 4800dm @500mb, pretty sweet.

Today's 18Z run of the GFS now progs 500mb heights over Canada at <486DAM beginning 1-30 00Z, heights of <480DAM at 1-31 12Z, which continues until 2-1 06Z, then remaining <486 all the way to 2-9 18Z (sometimes <480 during that stretch as well).

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/18/model_mu.shtml

I think the folks in New England and the Midwest are going to be begging for mercy.

*1-28 edit* The GFS paints a different picture this morning. The pressures are now not progged to be nearly so low over that time frame.