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Medium/Long Range Discussion Part 3


IWXwx

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The GFS still wants to bring the coldest air since 1994 to the continental US... If the future would even catch up to the present.

 

According to the 12z.  looks like a seasonable week thru next weekend, then the historic arctic outbreak makes it's pluge around hour 216 (a week from monday).

 

Will be interestin to watch how it all evolves or if it continues to push back and moderate.   We were suppose to be in the deep freeze this coming week too according to previous model runs from a week or two ago.   

Either way, no storms anywhere....even when the the fantasy arctic air plunges in.  LES folks will do well however.

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Sorry just have to share even though it's from pay site since they adjust their contours and post the min. temp...this might be once in life time run to see a forecast run with -40.2C 850's just north of the border.

Yeah, -40C doesn't happen often. I know it happened in the Feb 1996 outbreak and it's been close at other times but definitely something you don't see very often.

P.S. In case anyone was wondering, Wright is ok with an occasional map being posted.

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I'm cautiously optimistic this could happen. I just need to see it predicted to happen within 200 hours. Like I said, the cold shot that was originally supposed to be quite intense around the 17-19th no longer looks very impressive. The GFS, for one thing, doesn't seem to know whether to bring the front through on the 16th or 17th.

Not surprised. Gfs starting to model what I envisioned a couple weeks ago with coldest 850 temps remaining above -15c for 15-19 event. Josh is spot on about ssw timing. And I think models will continue to perform the same way through early Feb and not really having even a decent handle on anything until we get within 84-96 hours

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Yeah, -40C doesn't happen often. I know it happened in the Feb 1996 outbreak and it's been close at other times but definitely something you don't see very often.

P.S. In case anyone was wondering, Wright is ok with an occasional map being posted.

Cool good to know. btw ct rain in new England thread posted great link to historical 850 temp distribution histogram generator I think. Looks like could be fun to play with to see how many times -35c etc has occurred over anyone's local
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Cool good to know. btw ct rain in new England thread posted great link to historical 850 temp distribution histogram generator I think. Looks like could be fun to play with to see how many times -35c etc has occurred over anyone's local

Yeah, cool tool. Just gotta replace the number in the URL with whatever RAOB site you want. Here is DVN...I wanna know when they had an 850 mb temp of +32C.

hist_74455_850.jpg

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A very cool graph, definitely. I did a little fumbling around with numbers and I think each 'observed frequency' unit is representative of 12 hours. So, in White Lake's case, there's been just one 12-hour period in which the 850-hpa temperature got down to -34 since 1956. 


hist_72632_850.jpg

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That is some sick cold showing up. Surprised nobody mentioned it but the 12z GFS also has a blip of -40 at 240hrs just north of the border AND again at 252hrs just to the nw of Mankato MN. :blink: Don't think i have ever seen -32 850s over my head till this run anyways. brrrrrr

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Even though the models bring it forward and back off from run to run. It still seems to be on the maps..... When was the last time something this cold even showed up in fantacy land. To me it is comming perhaps alittle overdone, but some very cold temps are in our future.

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Even though the models bring it forward and back off from run to run. It still seems to be on the maps..... When was the last time something this cold even showed up in fantacy land. To me it is comming perhaps alittle overdone, but some very cold temps are in our future.

 

I think its safe to say, we will see some double digit negatives in lower Michigan... Probably single degree high temps.

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That is some sick cold showing up. Surprised nobody mentioned it but the 12z GFS also has a blip of -40 at 240hrs just north of the border AND again at 252hrs just to the nw of Mankato MN. :blink:Don't think i have ever seen -32 850s over my head till this run anyways. brrrrrr

What would that translate to at the surface?

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I have only seen sub zero high temps twice in my lifetime... I would like to see it happen once more. Last time I was a high school student, this time the heat bill is on me... Hmm.

I am really hoping that this arctic outbreak takes Toronto below -20 celcius at night. The lowest temperature I have ever recorded on my thermometer at my place in Toronto is -26 celcius on January 14,1999.

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What would that translate to at the surface?

 

Not sure to be honest? Problem here is if the flow is westerly ( which it looks to be per THIS run ) we may have Lake effect snow and or clouds at the very least. Have seen a few times when this sort of thing happened ( not as cold though ) and it was around 0 here and like -10/-12 below south of here/away from the lake influence. Coldest i have seen here is -19 back in Jan 2009 i think it was.. 850s were not -32 though but it did clear out some as the flow turned more northerly and light.

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I am really hoping that this arctic outbreak takes Toronto below -20 celcius at night. The lowest temperature I have ever recorded on my thermometer at my place in Toronto is -26 celcius on January 14,1999.

I'll never forget that morning. Windchills approaching -40, 20" of snowpack, WSW for 8-12" of fresh snow, all us little kiddies were sent home from school at 11am. What a great two weeks.

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I think -35 was the magic 850 number for southern Mich in 94 and coldest over night lows for Ann arbor and Jackson were in the -25f range. Overnight lows are tough to gauge off 850 since you have lots of other factors as Brewer mentioned... decoupling , what the dew points, winds clouds snow cover etc. Whose effects on temp are amplified compared to during the daytime . But as Josh said there was a snow pack for that one. I know -35c at 850 would get you up to -5f on a sunny day and only -13 if by some miracle it was cloudy

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I think -35 was the magic 850 number for southern Mich in 94 and coldest over night lows for Ann arbor and Jackson were in the -25f range. Overnight lows are tough to gauge off 850 since you have lots of other factors as Brewer mentioned... decoupling , what the dew points, winds clouds snow cover etc. Whose effects on temp are amplified compared to during the daytime . But as Josh said there was a snow pack for that one. I know -35c at 850 would get you up to -5f on a sunny day and only -13 if by some miracle it was cloudy

So, realistically for a place in suburban Toronto I could maybe expect a high of -15C (5F) if the coldest air moves in the week of the 21st? With the December 26, 1993 outbreak, Toronto managed a high of -18C (0F) with bare ground. Ottawa saw a high of -26C (-15F)!

 

I wouldn't mind seeing a morning low of -15F just to tie or surpass my previous thermometer record.

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Might be a silly question but what effects will this significant ssw event have later down the road...say during the summer months?

I have no idea, they seem to last through the winter quite often... Patterns don't die easy.. The ling range shows the polar vortex rooted into place for the most part.

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I have no idea, they seem to last through the winter quite often... Patterns don't die easy.. The ling range shows the polar vortex rooted into place for the most part.[/quote

Wouldnt take much but a significant stratosphere cooling event to "reset" things so to say. Happened in Novemeber.

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A little snowcover goes a huge way for determining how low a temp will go. Im talking, you lay as little as  a 1-2" snowcover down and it will be way colder than if ground is bare.
A little snowcover goes a huge way for determining how low a temp will go. Im talking, you lay as little as  a 1-2" snowcover down and it will be way colder than if ground is bare.

True..something like 80% of the effect is in the first four inches (thats what she said lol)

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