Record cold likely for Eastern CONUS next week!

[Tim Gonyo]

Looking on to the ensemble maps, the 850 mb temperature ensemble maps show massive cold building south into the Great Lakes area before modifying and heading towards the East Coast.

 

[Tim Gonyo]

Looking at the 12z operational GFS, during the height of the cold, 850 T's will approach -30c over Northern Wisconsin, with the -27c running along the WI/IL border. Using DT's 850 mb temp rule, we would subtract -2c from the 850 mb temp for the month of February to get the 2 meter temp. (Using my house for example, -28.5c 850 minus 2c equals -30.5c). That equates to -22.9F. That's really close to what I think the temperature will be Monday morning. I think I'll be in the -20F to -25F range. Here is the 850 mb T map for 12Z Monday 02/07/07:

The 2 meter temperature map for the same period only shows my surface temperature around -12F, however, which I think is too warm. Especially seeing I have fresh snowcover of 8" to 10" and a crystal clear sky which will allow for exceptional radiational cooling. 2 meter GFS temperature map for 12Z Monday 02/05/07:

Moving on to Monday afternoon here, the GFS paints a 850 mb temperature of -27C, and using DT's 850 temperature rule again, I would add 7c for February, bringing it up to -20c. That gives me a temperature during the warmest part of the day around -4F. I believe my high temperature to be between -5F and -10F Monday here. Here is a 850 mb temperature map of 18Z Monday 02/05/07:

So far, no one is near as cold as I think it will be. The coldest I can find is the NWS which has me at -7F Sunday night. I think most, if not all of Wisconsin will struggle to hit 0F on Sunday and Monday during the day and will fall to between -20F and -35F at night. Some areas in remote areas could approach -40F I believe. The coldest temperature on record for Milwaukee, WI for the month of February is -26F set in February, 1996. I think if everything falls in place, that record could be in trouble this upcoming weekend.

My very own predictor forecast for this upcoming weekend:

Milwaukee, WI:

Saturday, February 3rd, 2006: High: 3F, Low: -7F
Sunday, February 4th, 2006: High: -6F, Low: -17F
Monday, February 5th, 2006: High: -8F, Low: -26F (ties record set in Feb '96)
Tuesday, February 6th, 2006: High: 8F, Low: -16F

Moderation starts Wednesday.

 

[Paul Knightley]

I always like to look at the US/Canada weather as it often impacts the pattern across Europe in the subsequent days.

The polar vortex is expected to move into the Hudson Bay area over the next couple of days before ending up close to the Great Lakes. The effect of this is to introduce extremely cold air across much of the central and eastern US, especially the northern Plains/Great Lakes states - 850 hPa temperatures of around -35C are expected across parts of MN on Saturday Sunday and Monday, and even in Washington, D.C., they drop to around -20C by Tuesday.

1000-500 hPa thicknesses drop to around 480 dam on Saturday across northern MN!

This whole episode should shove a potent jet out into the Atlantic early next week, but the evolution of this jet will be the big player in the weather of NW Europe - if it bifurcates around the UK, we could be in for some fun!

 

[Jeff Snyder]

It's interesting to see the model forecasts of a 240-260kt 250mb jet streak across the east-central US and western Atlantic this weekend! Given the degree of baroclinic instability, it's not much of a surprise to see the GFS forecasting a <960mb low in eastern Canada this weekend... It's rather remarkable to see how "wrapped up" that cyclone gets --> http://weather.cod.edu/forecast/GFS/gfsUS_850_temp_96.gif ... The warm sector begin to wrap all the way around the west side of the cyclone, and you actually see warm-air advection occurring on the south side of the low... Not too often do you see that the warm sector has rotated almost 270 degrees around the cyclone (compared to the typical wave-cyclone model).

Many locales in the northern-tier of states along the central and eastern USA-Canada border may not rise above 0F for several days. Record cold? Probably not. One of the colder artic intrusions in the past several years? Yup.

 

[Scott Olson]

The most interesting possibility for the Northern Plains would likely be releated to duration of freezing tempatures. There is a possibility that wind chill values may reach into the the -35F range for some locations. No doubt cold but not that unusual for this time of year (our state has experienced several episodes of extreme windchills of fifty to seventy degrees below zero.)

 

[Josh Richardson]

The most interesting possibility for the Northern Plains would likely be releated to duration of freezing tempatures. There is a possibility that wind chill values may reach into the the -35F range for some locations. No doubt cold but not that unusual for this time of year (our state has experienced several episodes of extreme windchills of fifty to seventy degrees below zero.)

I agree with the -50 to -70 windchills, now was that before the change in wind chill index? I'm trying to recall as it seemed to me that it's been less frequent that we have been able to achieve indicies such as that recently. Either way, the values seen across the Northern Plains in the next few days will be downright bone-chilling. As Scott mentioned, the main problem will be the duration. Here in Northern IA we should be steadily below zero for somewhere close to the 96 hr. range or more. We could possibly sneak a degree or two above zero on Sunday or Monday but either way with lows around the -15 range thats good enough for me.

 

[GPhillips]

Tough to get a -70 wind chill since the new index went into effect in 2001. You need something like

40 mph at -30 F
25 mph at -35 F
15 mph at -40 F
10 mph at -45 F

http://www.weather.gov/om/windchill/

 

[B Ozanne]

Tough to get a -70 wind chill since the new index went into effect in 2001. You need something like

40 mph at -30 F
25 mph at -35 F
15 mph at -40 F
10 mph at -45 F

http://www.weather.gov/om/windchill/

And for it to get that cold in that part of the country you'd need calm winds.