OT Weather Musing...Atlantic Bath

[simonjk]

Good afternoon all,

I know it's last thing on a Friday afternoon, but I wanted to draw your attention to how warm the North Atlantic is compared to normal.

I've been pondering about what effect this might have on our weather. There are people more expert than me on this, but take a look at the chart at http://www.osdpd.noaa.gov/PSB/EPS/SST/data/anomnight.9.19.2005.gif
On this charts yellow colours show temperatures above normal, whilst the blue are below (no surprises there then!).

Now, my thinking is that all that extra warmth must trigger additional convection. The northern latitudes are cooling down now and so combined the cooler air aloft with the warm air at the surface and there must be the potential for low pressure to dominate the weather over the UK for the next while at least (see http://expert.weatheronline.co.uk/cgi-bi...d2f62be115e1bd)

One other thing the warm water could mean is that warm air gets pumped north and may well build high pressure simply because of the amount of warm air above one particular location. Overall this fits in with my long range forecast of a very mixed end to September/start to october, then high pressure building mid-month.

One thing that is certain is that the warmer waters are responsible for the cat 4Hurricane Rita, which briefly got to a cat 5 yesterday.

It will be interesting to see how this weather pattern develops, but with all that warm water around, I can't help thinking we are in for an unsettled couple of weeks.

Sorry to bore you!

Have a great weekend,
Simon

Simon Keeling.

 

[StephenSails]

Interesting stuff, I was wondering what if any pattern of bad weather in our Autumn here can be correlated with the more intense tropical storm/hurricane season we are seeing? Do you think we are likely for another wet and stormy autumn?

 

[Bergman]

Well yes -

But whats "normal"

how long have comprehensive records of ocean temp been taken - a few tens of years at most.

Compared to 10s of thousands of years of weather.

What are the "normal" cyclic variations not on a year by year base but on a level of 100s of years - No way on knowing.

I get fed up with all this scaremongering.

Why not just get on with living

 

[bilbobaggins]

I learned quite a lot about weather forecasting - and forecasters - in the 70's, when based on an airfield in Cornwall. We had to assemble for 'morning prayers' at 0800, and the first of several short briefings was The Met Brief. We knew as soon as the Senior Forecaster came in the door what was in store for the day....

If he was in shirt sleeves, it would be warm; if he had an overcoat on, it would be cold; if the overcoat was wet, it was raining; and if he didn't turn up at all - it was foggy.......

The same canny Senior Forecaster told us that many of the other forecasters further east in England would have a look at what he - being well west - was offering, then forecast the same for their guys, with a suitable time-lag allowing for the west-east distance.

Sometimes he'd ask the Squadron Boss to have the first takeoff of the day climb out to the west, radio-ing back at 5000-foot intervals the cloud type and amount, the temperature, precipitation and wind direction and velocity. Occasionally, he'd have three jets going in separate directions, giving him bespoke 'ascents' with which to fine-tweak his input to the Big Computer at Bracknell. Seems he had 'star rating' among his peers.

Me, I just look out the window - and maybe phone somewhere 50-100 miles to windward, and ask! /forums/images/graemlins/smirk.gif

 

[BrendanS]

Doesn't always work though. There is a front and huge bank of associated rain moving in from Ireland to UK over Saturday, and early Sunday. By the time it reaches the Channel mid late Sunday, the rain will have largely died out, so the forumites returning from the annual Cherbourg jolly should have no more than scattered showers

 

[bilbobaggins]

Yer right! That's why we fairly often ended up 'weather diverted' for the night from St Mawgan/Cornwall to Waddington/Linconshire or Leuchars/Fife, wearing only a heavy immersion suit and furry fleece underwear. And, more than just occasionally, one would wake up in the morning in Fife or East Lincs, to find dense fog/viz. less than 10 metres. Even if could find aircraft, couldn't find runway! So we'd have to stay another b****y night....
Got good at the Telegraph crosswords, though!

Which raises a thot - how's about our pet forecaster Simon giving us all some practical tips on predicting imminent fog-fall, when out on the water somewhere?

I have some ideas of my own, including a wet 'n dry thermometer ( the Bermuda race ), dew forming on the aluminium ( several RORC races ), Radio 4 198MHz longwave) , and the strands of my desiccated Japanese seaweed-in-a-bottle.....

 

[simonjk]

Hi Chaps,

Apologies for the delayred reply to your comments, been craxy here over the past few days.

To pick up on a couple of points, it is possible to attribute, at least partly, the more active hurrican season in the US to the current breakdown to autumn conditions. However, this isn't always so. If a blovking high built west of the UK, we'd see few, if any, of these systems coming through. The patterns this year though are such that the lows can be "transported" over the Atlantic on their favoured track between Scotland and Iceland, thus producing windy weather in the UK.

What is interesting is that on my 30 and 90 day forecasts (issued to private clients such as utilities and retailers) I've been calling for a major build in pressure around the 6th to 9th October. We've stuck rigidly to this line, and it's interesting that bnow the numerical models are starting to pick up on this. If this happens, then we are predicting a cold, more severe winter, than recent years. However, I'll try to pu a seperate post together on this.

Likewise, good suggestion about fog forecasting. Let me have a think about how best to structure it and I'll post a few hints and tips here. I've also offered (several times) to write regular Weather School features for the Mags on YBW (similar to those I do for Todays Pilot) giving tips to sailors on reading the weather charts, forecasting etc... but none have responded, so perhaps this might spur them into action!

If you'be any more ideas for "tips sheets" let me know and I'll see what I can pull together.

Cheers,
Simon

 

[bilbobaggins]

Here are a couple of thoughts you might amplify: Where around the UK coasts pools of cold fog-forming water are to be found e.g. off the Channel Isles/Solway/Northumberland in summer; how 'burnt-off' radiation-type fog re-forms more quickly as the air temp falls, come late afternoon/early evening, and implications for end-of-passages which were started late; characteristic conditions/places where fog forms frequently; the 'stirring' effect of light breeze; warming effects of cities/industrial areas e.g. Plymouth, Swansea, So'ton Water, on pools of fog....