WhiteFox

I think the recent extreme cold in Canada would help the ice to form fairly quickly; there were rivers starting to freeze in Canada last week!

After two consecutive below average months, November was particularly mild: Quite a contrast from both October and the start of December!

The winter of 1977-78 was the coldest on record for a large portion of the Midwest. I also believe that there were some heavy snowfalls on the East Coast. It would be interesting to see the charts for that period if I could find anything for the US! This would help to give an indication of what to look out for over here, and the position of the jetstream.

Looks like Eastern Long Island and up towards Boston to be honest. The exact path of the low is still uncertain, but Eastern LI is high odds with points further West having lower odds.

Interesting map showing minimum temps in North America overnight Monday into Tuesday (don't forget to allow for the time difference!). Can anyone spot where the snow fell in the Midwest?? Just goes to show the difference that a snow pack can make to minimum temperatures; something we have missed in the UK for a few years now. Anyway, as you can see from the chart below, another cold front drops down from Canada over the Great Lakes and reinforces the cold air over the upper Midwest and Great Lakes region: The 510dm thickness is over most of Wisconsin and Northern Michigan, with the 528 as far south as the northern edge of Arkansas. By Monday, a potential Nor'Easter is developing for the East Coast: Forecast is still uncertain for this one as the exact path of the Low will make all the difference. At the moment it's looking like New York may get an inch or two of snow, with Boston receiving up to four inches. Upper air temps look marginal as does thickness, but dewpoint is comfortably below freezing. Wait and see on this one! Whatever happens with the storm, New York is odds on for the first cold blast of the winter. By Tuesday we're sitting under what they call frigid air over here: It's about time we had some decent frosts in NYC! November has produced some unseasonably warm weather; whilst I was feezing in Chicago and defrosting the car, New York was up near 21oC with a tornado watch on Friday! Incidentally, looking at those charts, I'd fully expect Lake Effect Snow watches to be out in upstate New York; Buffalo, Watertown and Syracuse and the surrounding areas could be looking at 6 inches to a foot of snow. Always hit and miss with LES though; be great for snowchasing so long as you have the ability to see a radar!

No special tyres. I believe they enforce snowchains or studs in the high country and through passes. Illinois is as flat as a pancake (as is much of the MidWest) and they clear the major roads extremely quickly. Saying that, I was surprised to find that they don't grit the roads when there is frost forecast. Anyway, I managed to take a coup0le of shots. Unfortunately I was working for most of the daylight hours... The view from my hotel window at about 7.20am: The same view when I got back from work. Shows how poor visibility was at one point. Thundersnow was reported in places: Had to dig out my car. Made me miss my train into town! My car this morning (Saturday). This was taken just after 10am with the car sitting in bright sunlight for 3 hours. I had to chip the ice from around the boot and lever it open! Extremely slight thaw with any liquid freezing again instantly: And finally, a lovely view this morning. It was only two months ago that I watched the most severe thunderstorm I've ever witnessed from exactly the same windows (albeit about four floors higher). The flattish area you can see to the bottom left is the green for a par 3 hole on the Oakbrook Hills golf course. Guess the course will be closed until about April!

Just back from Chicago; my decision to book into the hotel for Friday night was a good one! The storm was interesting in that there was a very clear cut-off point. The North and Western suburbs outwards all received something like 10-15 inches. Downtown Chicago received about 3 inches I think. Oak Brook came in at six inches. Warmth pumped into the system meant that the ppn stayed as freezing rain for longer in those areas. To the North and West, the ppn changed to snow very quickly. The real story there now is the intense cold. I believe that 3oF was recorded to the West of Chicago last night. Highs look like being in the low to mid twenties (about -5oC I'd guess). I learnt a lesson in Chicago: clean the snow off your car straight away. If you don't, the snow freezes hard and flies off when driving on the freeway; I had to prise the boot open this morning! 23oF at 10am... Looks like a developing system off the Eastern Seaboard could bring some interest to New York early this week...

Just driven back from downtown to Oak Brook. Currently heavy freezing rain falling; very strange! Driving along, it sounds like it's absolutely pouring with rain, but nothing appears to be hitting the windscreen. I reckon there's about 2 or three centimetres of ice on the ground right now. Should provide a good base for when the ppn turns to snow in a bit. Still going for 8-12 inches here in the Western Suburbs with downtown getting slightly less - probably about 8-10 inches. Outlook is cold for the forseeable future up here: maximum of 1oC on Saturday, followed by maxima of -5oC for Sunday and Monday with the temperature not forecast to get above freezing for most of the week. Looks like the snow will be sticking around for a while.

I'm in Oak Brook and have to drive to a station to commute downtown. Hoping for a heavy fall so I can call in and say I'm working remotely... Would suit me nicely! Have booked Friday at the hotel as I'd rather stay here than spend the night at O'Hare airport. Will try and get some pics. Looks like being rather a large winter storm. It's been a long time since a ten inch snowstorm hit before January in Chicagoland.

Latest forecasts are going for light snow starting around 3pm, becoming heavy later. Accumulations between 5-10 inches, with 8-12 inches possible to the SW of Chicagoland. This storm has been giving the forecasters real headaches; yesterday morning it looked as if it was heading to the East of the area; during the day it was forecast to be much worse and it finally looks like they have nailed it (maybe!). No doubt I'll be stuch in O'Hare airport tomorrow, so I'll report back then. No sign of snow for New York yet, but it does look rather windy for tomorrow as they are on the Eastern side of the Low pressure system with the warm temperatures.

Haven't seen any tornado reports yet. I think the tornado watches for Oklahoma and Northern Texas are due to expire in the next couple of hours. Just to show how quickly the weather can change here, All areas from Dallas to Chicago are under Winter Storm Watches! Kansas City is under an Ice Storm watch. They just showed pictures of accumulating sleet (believe it or not!). Sleet had accumulated on car windscreens and froze solid. All a bit more interesting than winter in Reading! Addit: Current readings show temperature in Oklahoma City at 29oF (-2oC) and Dallas at 73oF (23oC). Quite a powerful cold front! High of 80oF in Dallas today, high of 34oF tomorrow... 12-18 inches of snow forecast for Missouri from the developing storm. I wonder how the board would cope with that in the British Isles?

A Winter Storm Watch has been issued for the Chicago area for Thursday night into Friday. This means accumulating snow, with between 5 and 7 inches possible, locally heavier: /O.NEW.KLOT.WS.A.0003.061130T2100Z- 061201T1500Z/ WINNEBAGO-BOONE-MCHENRY- LAKE ILLINOIS-OGLE-LEE-DE KALB-KANE- DUPAGE-COOK-LA SALLE-KENDALL-GRUNDY- WILL-KANKAKEE-LIVINGSTON- IROQUOIS- FORD-LAKE INDIANA-PORTER-NEWTON-JASPER- BENTON- INCLUDING THE CITIES OF... ROCKFORD...WOODSTOCK...WAUKEGAN... OREGON...DIXON...DEKALB...AURORA... CHICAGO...OTTAWA...OSWEGO... MORRIS... JOLIET...KANKAKEE...PONTIAC... WATSEKA...PAXTON...GARY... VALPARAISO...MOROCCO...RENSSELAER... FOWLER 326 PM CST WED NOV 29 2006 /426 PM EST WED NOV 29 2006/ ...WINTER STORM WATCH IN EFFECT FROM THURSDAY AFTERNOON THROUGH FRIDAY MORNING... THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A WINTER STORM WATCH...WHICH IS IN EFFECT FROM THURSDAY AFTERNOON THROUGH FRIDAY MORNING. A STORM OVER THE LOWER MISSISSIPPI VALLEY THURSDAY WILL MOVE INTO CENTRAL INDIANA FRIDAY MORNING. COLD AIR IS EXPECTED TO DEEPEN OVER NORTHERN ILLINOIS LATER TONIGHT AND THURSDAY LEADING TO SNOW THURSDAY NIGHT. A MIX OF PRECIPITATION IS EXPECTED FURTHER EAST IN NORTHWEST INDIANA. A WINTER STORM WATCH MEANS THERE IS A POTENTIAL FOR SIGNIFICANT SNOW... SLEET...OR ICE ACCUMULATIONS THAT MAY IMPACT TRAVEL. CONTINUE TO MONITOR THE LATEST FORECASTS. So, latest forecasts for Chicago showing a maximum of 34oF (1oC) for tomorrow, followed by an ice day on Friday (0oC) and lows of -5oC Friday night. Saturday barely climbs above freezing, and Sunday/Monday are both forecast to be below. The ongoing forecast shows temperatures maxing out at 2-3oC over the next week. Don't want to make anyone jealous in the UK! Bear in mind that we had a temperature of 67oF (19oC) just yesterday (Tuesday)! This is going to come as a shock. The ensembles show the tumble quite nicely: Just look at the depth of cold air available aloft: As I said before, this is snow I actually don't want! I have to fly out of O'Hare tmorrow night, and a day of snow will almost certainly mean delays or cancellations.

Indeed there is. I'm about to update in the American Weather Thread.

Winter is definitely making it's presence felt in the US this week! Some bitterly cold air in Canada, as I'm sure CanadianCoops will testify, is heading this way. Some rivers have started icing in Canada, so that's a taste of the depth of cold. Personally, I'm watching a potential development here in Chicago for this Friday. I'm flying out of O'Hare airport on Friday night to New York; a bad enough journey at the best of times! The situation is this: The cold air currently filtering down over the North West is heading over North Dakota, to the South and East. By Friday, it looks like a developing system wil be over Michigan pulling in North Easterly winds: These winds are dragging in increasingly cold air over Lake Michigan, which is still relatively warm, particularly as November has not been overly cold. This will increase the instability and enhance precipitation: Air Thickness looks marginal, but dew points are forecast below freezing. At the moment this is a developing situation which could still come to nothing. It all depends on exact positioning. For once I don't want it! Strange to think it's currently about 15-16oC in Chicago!

Getting closer to the time now and the snowstorm is still on for the High Plains. Ensembles for Chicago show a really potent cold front coming through still: More than 20oC drop over a very short period of time! That's the American Midwest for you! New York is still showing a disappointing lack of snow, but some real cold finally looks like arriving on the back of the same cold front coming through Chicago: winter proper will be here soon! As for now, in New York a coastal storm has moved up the east coast and we've had rain for about 12 hours or so. It's as cold as it can be with the ppn still being liquid. Thoroughly horrible weather!

Indeed. Since the pattern change around the end of October there has been no chance of snow in the North East beyond a small amount of Lake Effect snow in the usual areas. The Weather Channel are looking at the first major snowstorm of the season moving across the upper Midwest next week. Will keep posted on developments as I'll be in Chicago; I just hope it doesn't come through on Friday when I'm trying to fly out of O'Hare!

Very mild for Chicago Thanksgiving. Only 16% of Thanksgivings record temperatures in the 50s F. This is going to be one of them. Going forward, spot the cold front: As for New York, the signal for colder conditions also exists: Still a bit in the future, but this has been pciked up for a few days now. I'm hopinh it's not a phantom cold spell! Elsewhere, Charlesston South Carolina recorded trace snowfall yesterday, with parts of East Georgia recording an inch or so. Doesn't sound remarkable until you realise that these places aren't so far north of Florida! In the North East, this Autumn has been noticeable by the singular lack of snowfall. None at all in Boston or New York. I'm currently in Albany, which would have expected four inches by now, where only trace has so far been measured. I hope it's not a signal for the coming winter!

First frontal snow for Chicago this winter? Ensembles have been picking up on a colder spell in FI for the last few runs: Well into FI at the moment, but I will be keeping a close eye as I'm in Chicago from November 26th for a week. 850 temps of -10 coupled with precipitation has to be a dream come true for a snow lover from Reading who has been deprived for the past ten years or so. Will be keeping a close eye out, and should anything come of it, will take some pics. The great thing is that even if this disappears closer to the time as usually happens in the UK, it should only be a matter of time over here. Not that I want to make anyone jealous... Would be intersting if the orange outlier verified! As for New York, this week was extremely wet with a mild Nor'Easter Sunday into Monday and now much drier I believe. Looks like the first air frost may be recorded early next week going by the ensembles. There is also a lot of cold air being bottled up in the North East of the continent, hopefully just waiting to be tapped when the jet stream calms down a bit...

I'm a bit rusty at Confidence analysis as it's been a long time! The figure for the 10 months of 2006 would be 1.25 +-0.85 where 1.25 is the average difference between actual CET and average CET (1961-90). This is only based on the ten months of the year as it is the topic of the thread. Obviously taking a longer period would produce different results. I realise that using the departure from average CET difference is unusual, but as we were discussing whether or not March is an outlier in the context of this year, I thought it may be a useful comparison. Clearly March is an outlier (which proves the point) as are July, September and October (although I'm sure that surprises no-one). Of course, March may or may not be outside the 95% interval if we took the entire CET dataset; my hunch would be that it is not or very slightly.

I'll try.... Here we have a graph showing the CET by month plotted against the difference from the 61-90 CET for that month: As you can see, most of the months are above average. However, is this significant? Take a look at the next chart: This shows the average CET difference for the year, 0.125 and plots the monthly differences on the same graph. Based on a 95% confidence level, we can see that the Interval is between 0.41 to 2.11 above the mean figure for departure from CET for the year. Based on this figure, March 2006 is outside the 95% confidence level and so can be said to be statistically significantly different from the mean. July, September and October are also significantly different from the mean. Based on these figures you could say that March was significantly below the average difference for the year, whereas July and Sep are exceptionally above. If we go back over a two year period, from Nov 2004 to Oct 2006, we see a slightly different result. The 95% confidence interval for this period is 0.63 to 1.53 degrees either side of the average departure from the CET for the period of 1.08oC. The results are: Jan - Apr are all outside the 95% confidence interval on the downside, with March being 4.16 intervals away from the mean. June, July, September and October are all outside the 95% interval to the upside, with Jul being 5.58 intervals away from the mean. I hope this makes some sense and also goes to demonstrate to some degree just how exceptional this year has been for the UK.

As promised, maps showing below average temperatures in US for October, the second month in a row: For anyone who likes real cold, North Dakota is the state to go for! Fargo averages -1oF during January. Brrrrr! 40oF during October is a reason to get your thermals out:

May I be an honorary SATSIGS member from the US? If so, can I nominate this from the venerable Joe laminate floori?

Looks like a lot of uncertainty still remains with regards to a cold snap this weekend in New York. Scatter on the ensembles gives a range of about 18oC at the 850 level on the 12th. Even after Thursday there is quite a lot of disagreement. All up in the air for the East coast at the moment. The only thing that seems certain is a wet day tomorrow! As it happens I'm off to Chicago again on Sunday and it looks like sub-zero 850s are fairly certain for the whole week going by the pub run: Interestingly, the 0z shows another alternative with warmer air being drawn up followed by an active system crossing through by midweek. Looks like this is one scenario where a strong jet remains fairly flat keeping the coldest air in Canada: So, even in the US we are looking into FI for brief colder spells! Just a matter of waiting for another pattern change.... Meanwhile, Seattle remains very Seattle-like. Quite an amazing amount of rain after a very dry summer:

Without wishing to take sides here (which I realise I am) and recognising the fact that SF is more than capable of arguing his own corner (but he's probably quite sensibly asleep) I have to take you up on these points. I cannot see anywhere in SF's posts where he is commenting on Global trends. As far as I can tell he is making a perfectly innocent point about how exceptional 2006 has been with regards to temperatures. Another perfectly innocent point is that without March being quite below average, 2006 would be far and away the most exceptional year we have seen in perhaps our lifetimes. I really don't see why this is so contentious. Surely you can't disagree that the warmth this year (although I haven't experienced it having been in the US) is exceptional? As for the second paragraph, surely a poster of your experience cannot make the mistake of saying "CET data gathered in other places"? A desperately contrary argument if I've ever heard one, as you know full well that CET stands for "Central England Temperature" so how can it ever come from other places? The point that I think SF was trying to make, and I'm sure he'll correct me if I'm wrong, is that compared to historical records using CET readings (the longest continuous records of temperatures anywhere in the world), 2006 has been exceptional in terms of warmth. No extrapolation was implied to the global temperature. I cannot see where the argument lies...

I've often told people that the UK climate is similar to that of Seattle. Not any more! Take a look at this: There's a pattern change underway here in the US. Looks like the recent Arctic/Canadian visits are gone for now. Current forecasts are pretty confident that the first half of November looks fairly mild. The New York ensembles have been consistent for a while now: After next week the ensembles split, but a new pattern looks to be established, so it seems that I'll have to wait a while before seeing my first real snowfall stateside this winter...