Fall 2012 Thread (September - November) (Iowa, Minneapolis, snow, record)

[Hiromant]

Looks like temperature will be staying below 10°C here for the most part. It's cloudy and rainy though, little chance of frost.

[Mac15]

First frost last night! Temp is surprisingly still 4c at 9am.

[Weatherfan2]

Mean temperature of 7.2°C / 45°F here making it the coldest day since June 4.

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No frost sadly because the wind never died down but got down to 2C anyway. I see most other places had a frost though.

[Weatherfan2]

I looked out of the window at 6:30AM when the temp was 2.6°C and there was no sign of white on anything in the back garden or objects.

[Mac15]

Well the dew point is 35 here so if it stays clear and the wind isn't strong then it may be another cool one but i'm not expecting an air frost again.

[Cambium]

3 Points on the latest GFS.

1st - It keeps showing above normal for Canada and U.S next week and I'm thinking, this is the new trend for now, away from the well below normal temps in Eastern U.S




Then I see this for the long range and Im thinking that warm up is temporary and right back to well below normal for the Mid West again and Canada. This setup is similar to what we have today, with the trough setup there, so it makes sense to happen again. These are COLD temps for Upper mid west and cool for mid section of U.S



Then I see it has this. Its long range but I'm loving the looks of things for the past 3 weeks now. This is phenominal to see if you're a winter fan. Even if theres no snow out of this, this setup is just interesting.

Say hello to the Sub Jet and the Northern Jet. It was nowhere to be seen last year.

[Cambium]

I was looking at the temp departures for DLH (Deluth, MN) and noticed they were 11 & 12 degrees below normal for the lows and out of the last 15 days, only 3 nights were above normal.

The highs have a different look having 12-16 degrees above normal.

Does anyone think the day high and night low spreads are strange? Or is it because the angle of the sun is just keeping things warm still during the day and then the trough coolness takes over at night?

Anyway ..... Mid West Temp Departures last 7 days.
Current Climate Summary Maps - Powered by ACIS - High Plains Regional Climate Center=

[dunno what to put here]

The 'child' of ex-tropical storm Nadine approaching SW Britain now.



Wind will not be an issue, but it will be very wet..




For southern areas it will be a shock to the system given the lack of any decent rainfall amounts. Even up here we haven't had much rain this month, certainly no large totals for over a month. Basically, rain Sunday night, through to Monday night.

[Patricius Maximus]

On all of the first frosts, congratulations to all of our posters that have just now entered the Frost Club. The first frost is always a great event, especially when it's this time of year.

Originally Posted by Cambium

3 Points on the latest GFS.

1st - It keeps showing above normal for Canada and U.S next week and I'm thinking, this is the new trend for now, away from the well below normal temps in Eastern U.S

Then I see this for the long range and Im thinking that warm up is temporary and right back to well below normal for the Mid West again and Canada. This setup is similar to what we have today, with the trough setup there, so it makes sense to happen again. These are COLD temps for Upper mid west and cool for mid section of U.S

That's just what I'm thinking. Weak to moderate positive departures will prevail next week before the same pattern roars back later on. "She's not retreating, she's reloading" greatly applies to the cold pattern's behavior over the next few weeks.

Then I see it has this. Its long range but I'm loving the looks of things for the past 3 weeks now. This is phenominal to see if you're a winter fan. Even if theres no snow out of this, this setup is just interesting.

Say hello to the Sub Jet and the Northern Jet. It was nowhere to be seen last year.

Things are certainly on a great track heading into winter. It can and often does change from September to December, but a winter fan can't ask for a better start than what we've had over the past few days. Frost has penetrated very far south and a widespread early snow (fraction of an inch) has blanketed the Midwest, plus the pattern looks to reload and continue as far as the eye can see. If this pattern continues into winter we shouldn't have any problem.

I did some research into the intensity and timing of this pattern hoping to find analogues, and the only good matches there are in terms of matching the intensity and timing come from before 1920. There aren't any after 1920 (either off in timing or off in intensity), but there's several before 1920 . I believe this conforms to the notion that a cooling climate is emerging; pre-1920 patterns and events are showing up more often (quite a bit now vs. none from c. 1920-2010). Anyway, most of the analogues led to cold winters, but it is still September so it could go either way.

A notable analogue, which isn't included in my previous statement due to being off on timing, is September 1983, which led to a cold winter, as well as the coldest Christmastide ever recorded for the U.S. In the analogues I found, there was a strong tendency for a potent cold period in November or December (the early season). One of the 1900's analogues featured a "step-down pattern" for autumn, where (relative to normal), each month was colder from September through December, as well as similar cold persisting through March. This analogue, as well as what we've seen so far this season (late June to late September), is consistent with the earlier CFS forecasts of the autumn-to-winter pattern.

In the weather data I checked from the South, that same 1900's analogue featured 12 consecutive near-normal or cooler-than-normal months. After the cool September that year the next month that was above normal was the following September. It's possible (and maybe even probable) that this year will not turn out the same way; after all, predicting the next year based on one month is quite a leap of faith, but I think it's interesting because it's the exact opposite from what many sites have seen this year, which is a long string of warmer-than-normal months. We'll have to wait and see.

Back on topic, that huge storm system is very interesting in and of itself, and the snow shown on the model run takes the cake. The same model run features temperatures that are well within the "cold enough for snow" range (as opposed to many fantasy storms), and it shows Minnesota having an extremely cool weather starting around the 5th, with pretty much every morning close to the freezing point. Snow accumulations, though, are restrained, with about 1 inch being the maximum. Still, it's nice for early October.

Could this be the beginning of something big, perhaps the autumn storm I've been wishing for? We'll have to see if it doesn't just disappear on the next model run first .