Gavin P

Does that mean an unsettled August?

Met Office is forecasting a medium to strong La Nina this summer. Don't write it off yet.

Just for fun, Aberdeen; October 10th. Manchester; October 25th. Birmingham; November 15th. London; November 21st. I'm expecting an autumn differant to the last couple of years.

It just goes to show how things have switched around. In 2006 all talk was of drought, but 2007 has definatly been the year when the Atlanitc came back.

Doesn't the cold anomoly often weaken in 1 & 2 Regions and then reappear in 3 & 3.4 Regions a week or two later? Certainly if we don't see a significant loweing of temps in 3.4 Region, within the next two or three weeks, then I would say La Nina will fail to arrive yet again.

The shallow waters around the UK are so warm on the May 2007 chart, because the weather has been so warm. As soon as temperatures drop consistently, they will drop. The interesting things is that both charts have got a tripole look to them. Both charts have cold waters down the eastern seaboard, with warmer waters to both the north (around Greenland) and the South-West. The differances are that in 1995 the Azores region was warmer and in 2007 the area south of Greenland is warmer than it was in 1995. Nevertheless, I think the May 2007 chart definatly has the look of a -NAO pattern about it.

Vorticity posted this anomaly chart in TWO forums earlier; http://poet.jpl.nasa.gov/tmp/281511.gif Which, does bear some similarity to the anomaly for May 1995; http://poet.jpl.nasa.gov/tmp/281661.gif Interesting.

I think another concerning aspect of this summer is increasingly the SST set-up in the Atlantic; http://weather.unisys.com/surface/sst_anom.html Cooler waters from the eastern seaboard are increasingly moving into the mid Atlantic now, and with still exceptionally warm waters surrounding western Europe, I would have thought the differance between the warm and the cold water could generate instability and low pressure, with the cool waters in the mid Atlantic also possibly helping to promote Atlantic ridging

A don't remember it being a complete disaster like that SB? From memory they was calling cold right from the very beginning? What made them go mild in September 2005?

Remember the 2005 forecast (the -NAO one) wasn't released until September. I think they held it back until the saw what the dynamic model was predicting for winter. If this years SST's point towards a -NAO they may hold back longer than they did last year. Another advantage of waiting is to see what happens with La Nina.

Thanks SB. So, we could be in for a very cool and wet August?

It always looked to me like June would be the warmest (compared to average) month of the summer. I think July and AUgust will also be warmer than average, but I don't think the anomoly will be as great as June. Infact depending on how La Nina and other Atlantic SST's play out, I think August could come out very slightly under par.

Summer Forecast from me is as follows (Its very vague, but I don't feel confident to go into any detail) JUNE: A very warm and thundery month. High pressure frequently to the east and low pressure to the west. A lot of southerly plumes and thundery periods. JULY: A wet and cool first half, with high pressure migrating into the Atlantic leaving slow moving low pressure over the the UK. Much hotter in the second half with high pressure coming back. Probably thundery and cooler by the end of the month. Temps finishing up a little above average. AUGUST: This is the month thats causing the most problems. Generally I think we'll have a pretty zonal month, with a west to east flow. I think England and Wales probably has quite a bit of dry weather, with the Azores High usually close by. Scotland and Ireland has a very wet month, with frequent bands of rain and strong winds coming in from the Atlantic. I would say theres a small, but significant risk of the Azores High being much weaker and then all areas will have a very wet month with low pressure really dominating. If its option one, temps will be a little above average in the south and below average in the north. If its option two, temps may be near or below average for all.

17.2 Very hot month.

Regarding La Nina, I agree. It looks to me as though the massive cold anomoly thats been down the Pacific Coast of the US is now heading towards the Equatorial regions of the Pacific. Definatly looks like La Nina is developing to me.

Heres the anomoly charts for now in 2005, 2006 and 2007; http://www.osdpd.noaa.gov/PSB/EPS/SST/data...t.5.10.2005.gif http://www.osdpd.noaa.gov/PSB/EPS/SST/data...t.5.13.2006.gif http://www.osdpd.noaa.gov/PSB/EPS/SST/data...t.5.10.2007.gif As you can see 2005 is quite clearly a -NAO pattern, with definatle warm, cold, warm bands. 2006 is quite obviously a +NAO pattern, with no distinct cold band around newfoundland. 2007 looks to be somewhere in the middle at this point, but if I had to choose one side or the other, I would agree with SB that it looks closer to 2005 than 2006. At this stage though, with quite a bit of May to go, it could still go either way, I think.

I still have a suspicion that for Europe and Western Europe in particular, Interdecadel Warming of the Atlantic may he exagerating the undoubted Global Warming trend thats going on. From the 50-80's, whilst it was in its cool phase, I think it actually lessened the warming trend that was beginning to develop across the world, now I think it may be exagerating the effect. I mean, 3 record warm CET months out of 9 is pretty amazing, even if you accept AGW is going on (which I do) So, the question is, when will this "Interdecadel Warming Period" end? Thats what we can't answer. In the first half of the 20th century, I believe it went on for a good 30yrs, from the 1920's to the 1940's (its interesting that even with IW of the Atlantic, we still managed to have a series of severe winters in the 40's) So, we may have a while of this Atlantic warming to go. However, just because that warm phase lasted for 3 decades, doesn't mean the current warm phase will last for that period. It could last longer or shorter than 3 decades. If it was to end fairly promptly, and the cool phase start up quite quickly, then I think we *may* see temps reverting back to a more sensible level of warming, for a couple of decades. I personally don't believe we could ever go back to a 1960's climate pattern, but I do believe an 88-96 type climate may still be possible, if the Atlantic goes into it's cool phase in the next 5-10 years. A lot of if's and but's there, though.

14.7. Exceptionally warm and sunny again, increasing risk of thunderstorms later in the month, when temps may reach 90f.

"The 90s were salvaged by an excellent Feb 91 and the year 95/96 as a whole with the best winter we have seen since . Not too much else, but better than nothing." Don't forget 1993. 5 consecutive months (July to November) below average. I remember thinking at the time what an awful month July 1993 was, but I would LOVE to see a July like it now, just to see if we could still see one. Likewise September. Infact I would love to see a September like 1993 more than a July, because of how bizzarely warm September has become in recent years. Its certainly hard to imagine a run of 5 cesecutive below average months now. Its hard to imagine 1 below average month, really.

I'm not going to be around for the run up to May, so when the May CET thread is opened can you put me down for a May CET of 14.7 please? Cheers.

Nights look like warming up quite a bit next week and with days getting even warmer, I expect that by this time next week to CET will be above 9c. However, that will still leave plenty of room for it to drop back again in the second half of the month, should we get any cooler/unsettled weather. This week has just shown what a massive differance low minimums can make to the CET, even when your having maximums that are up to 5c above average.

The April CET isn't going through the roof though, summer blizzard. The cool nights are keeping it at a sensible level, and if the weather turns a lot cooler after mid-month I would say theres still the outside chance of at least getting an average April.

LOL! It doesn't mean anything for winter 2008. Its only April.

It has to be said that August 2006 is one of those months where the CET is pretty deceptive. I actually recorded my lowest ever August mean temperature (15.6) with my records going back to and including 1993 (where the mean for August 93 was 15.7) I believe that large parts of the coutry also achieved lower mean temps that month, than the final CET ended up being.

If Ian's forecast comes off, an 11c+ CET for 2007 will be a certainty. A hot August. September to match last year. What sounds like a record breaking November. It just goes on and on, doesn't it?