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About this blog

this will be my own forecast ideas

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Lrf Update - Friday 16 July 2010

If you look at my post from last week I suggested that a spell of 7-10 days unsettled weather was likely before it settled down by the end of the month.

The generally unsettled pattern has occurred and will likely last for a few days yet.

However I stick by the suggestion I posted that surface high pressure will become the dominant factor by the end of this month.

On the synoptic scale the 500mb anomaly charts, all 3 versions, have slowly come round to the idea of an upper ridge developing SW of the UK, part of the Azores surface high. This will edge into the UK by the end of the month and into the first week of August. It is likely to keep the south-north divide going but perhaps more SW-NE this time. How far the surface high centre beneath the upper ridge will edge east is far from certain. The major wave lengths suggest that it will be a very slow process. This MAY lead to home grown heat developing as a result for the southern areas, England and Wales and parts of eastern Scotland perhaps. Northern Ireland is less clear probably staying in the more unsettled area most of the period. With a surface high setting up then winds should not feature much other than the occasional fresh to strong in the far North West as weather systems run up the western edge of the ridge. I’m not at all sure about thundery rainfall on its SW’ern flank this far out. It is a possibility if the ridge gets east of about 5 East.

Other factors, QBO, ENSO, AO, NAO etc all seem to me to support something along these lines.

So a more summery spell looking likely for much of the southern half of the UK, and possibly less unsettled for the far North West, certainly than recently.



The proof of the pudding as they say, so I’ll look again, next week, probably be Sunday before I can get round to doing another update.




johnholmes

johnholmes

 

Lrf Ideas-Friday 9 July 2010

Rather than never be sure whether this type of post should be in model or technical I've decided to drop this and any others into my blog area. That way I will know where it is each week!Please add your comments, but I'd appreciate constructive type replies about your belief in it being good or bad let alone right or wrong.I'm always happy to have a chat via pm if you prefer that way.John[attachment=102177:will the hot spell return soon-9 jul10.pdf]

johnholmes

johnholmes

 

The Coming Weekend - 29-30 November

[b]This weekend's outlook, starting from Wednesday 26 November[/b]

We can forget about long term effects over this short time period. Our eyes are turned to the 3 main models at what is now T+72 on Saturday. Indeed we need to start looking from tomorrow when the first hint of the colder air returning will be seen.
The Met O Fax chart for T+36, (currently at 1630), shows it nicely. The cold front moving fairly quickly through most of the UK by dusk or soon after for the far southeast.
[attachment=71632:weekend_1.JPG]
Behind it the coldest air seems set to be for the western half of the UK for quite a little while. So for those snow addicts its looking like Ireland and Scotland along with possibly for a time Wales may see some. Really its only for the hills as we go towards the weekend, perhaps as low as 3000 metres (about 1,000ft) before we have a drier spell developing through Friday after wintry showers for western parts. Friday morning is likely to dawn bright and frosty for a good many it would seem.
See the Extra chart for minimum temperature below
[attachment=71633:weekend_2.JPG]

I'll use NE Extra charts to try and illustrate what, as of the 12z run today, is likely to happen from late on tomorrow into the weekend. Leaving out beyond that for now.

So for the weekend
Again looking at the Met O Fax forecast for 12z Sunday is likely to give a reasonable picture of probable events
[attachment=71634:weekend_3.JPG]
Obviously details will change but the overall idea of a cold north or north west flow, complicated by two features is there to see.
Feature one is the low shown in the Channel area, this may be north/south/east or west of this position by perhaps 50-70 miles, making a lot of difference so its something each update will address and for the same time (12z Sunday)
The second feature is the low in the Iceland region. This will also change in track and probably intensity as well so another feature to keep tabs on.

So there we have a quick situation check. A cold and probably rather wet weekend seems in prospect for many but with twists and turns to come as we count down.
The rainfall charts for Saturday and Sunday at 12z from Extra are shown below
Saturday on the left and Sunday on the right

[attachment=71635:weekend_4.JPG][attachment=71636:weekend_5.JPG]

And below their respective 850 mb temperature charts
[attachment=71637:weekend_6.JPG][attachment=71638:weekend_7.JPG]

Below is the self help will it snow for me link; remember about your height above sea level and the AVERAGE temperature drop being about 3C per 1,000ft (300 metres). One other point to bear in mind, for the winter as a whole, where moderate to heavy rain falls for 2 hours or more, it CAN if other things are in its favour turn the rain to snow. A reasonable guide to this is the wet bulb temperature. If its3C or below is a good guide.
The link
[url="http://www.netweather.tv/forum/index.php?showtopic=27989"]http://www.netweather.tv/forum/index.php?showtopic=27989[/url]

excuse any errors bit of a rush

johnholmes

johnholmes

 

blog 26 what will happen over the weekend?

hi This will do for a start for my view of the various models and the possible outcome. Its by no means certain, apart from being a heck of a lot cooler in the south, and pretty unsettled just what will develop through the latter part of the weekend. As I say, this will do for a start and I'll do a blog from Friday evening on how/where the low(s) are and their predicted paths by the 3 main models. Blog_26_into_the_BH_weekend.doc John

johnholmes

johnholmes

 

blog 24 to the BH weekend

hi This is my take on how the weather will develop from mid week into the weekend. blog_24.doc Monday I'll update this later today. The models coninue to be uncertain just how the weekend breakdown will occur. John

johnholmes

johnholmes

 

blog 22

hi renaming the blog but otherwise content the same. blog_22.doc sorry about the charts and black surrounds, will do blog 23 the correct way I hope. John

johnholmes

johnholmes

 

my annual sun burn warning

hi If you read this please do take note. I would hate you to end up with skin cancer. It can be very minor, just having cuts and stitches but I lost a very good friend when his skin cancer turned into something lethal. May I just make a plea to all you sun lovers, all pretty young, well at least compared to me. Soggy Wales comments about being on chemo - can I ask is that for cancer? To all you others, please, please do take very great care. Some of you mention looking like a lobster, stop allowing that asap, or else you will very probably end up with skin cancer. Use the highest factor possible, in the UK and abroad, the sun burns just as much from about mid Spring into mid autumn as mid summer. It has nothing to do with how hot it feels. Beware, as someone has already mentioned, sunbathing with salt on you from the sea, without applying high value sun tan. Beware the wind, it feels cool but the sun burns just the same. Likewise for skiers and boarders, yes its -1 or maybe -20C but the sun burns far more at altitude than at low level. I have some experience of what can happen when we do some of the things I've mentioned as I have skin cancer, some 14-15 operations and around 65 external stitches so far. All because, up to about 10 years ago I thought it good to have a tan! 50 years ago there was some excuse as I make the point to my skin cancer specialist, there was NO warning other than do not burn. John

johnholmes

johnholmes

 

blog 16 - the T+144 and its actual - now

hi I was not going to issue another until tomorrow but as I seem unable to break into the discussion tonight so I thought I would put my ramblings down as a post for anyone to read it. What I'm trying to get across, and failing on the model thread, is that the model at T+120 is very very close in its predict to what we have today. This is NOT to say its other predicts from that time will be accurate but it is worth just trying to prevent Net Wx lemmings jumping off the cliff for a further 24 hours perhaps! blog_16.doc John

johnholmes

johnholmes

 

blog 8

as in my post in the 06z model thread. this is issued at 1050 on Monday 05/02/07 Blog_8.doc John

johnholmes

johnholmes

 

blog 6

my latest ideas at 1030 on Sunday 4th february 2007 its a big file again with a couple of charts so please be patient whilst it downloads. Blog_6.doc

johnholmes

johnholmes

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