UK Weather Forecasts, Reports and Discussion WC 17/05/10

A summery week is in store for most this week with temps on the up at last.
Low to mid 20s certainly possible a little later in the week for many.
Talk of maybe some T/Storms breaking out as well.
Will add more detail in the Mini-Forecast which i will start in a minute.

So for now heres a quick overview of current temps...courtesy Netweather.

London / Heathrow Airport 18°C
Bournemouth Airport 17°C
Exeter Airport 17°C
Luton Airport 16°C
Filton Private 16°C
Yeovilton 16°C
Wyton Royal Air Force Base 16°C
Boscombe Down 16°C
Wittering 16°C

So heres my take on what todays 06z of GFS is showing for the coming week.
And as expected temps are going to rise as the week progress's with temps in the region of 25C for many later in the week with a few areas even seeing something slightly higher. So thats certainly some good news and to add to that there looks to be an increasing chance of some T/Storms later in the week as that heat starts to get things going at long last.

Day by day to start with so....

Tuesday will see High Pressure beginning to build nicely from the S/SE with light winds for the majority . Temps will range from 13 in the N to 19 in the S/SE with some light rain possible for more Western areas and Ireland. As yet CAPE and LI are absent.

Wednesday will see the High continuing to build over the country wthl very light winds and again any light rain confined to more Western areas. Temps creep up another few degrees with them ranging from 14-20C.

Thursday will see the High, 1032mb, centered just off the SW of the country. Again winds will be very light generally with any rain during the day being light. Into the late afternoon and evening there looks to be a chance of a few heavy downpours/storms breaking out, CAPE and LI are currently showing to be minimal but wouldnt be surprised to see something of interest. Temps again increasing for many with a range of 14-23C.

Friday will see the heating up process continue with temps now ranging from 15-25C.
Again winds will be very light and there looks to be increasing chances of some T/Storms late afternoon/evening. CAPE and LI values improve slightly on what was there during Thursday and currently Ireland/Central and SE regions look best.

Saturday sees the High to continue to dominate things with the trend of afternoon/evening showers continuing and again some of these may well be T/Storms with CAPE in the region of 900 and LI of -2 on offer in some areas. Again Ireland looks best at this point in time but i wouldnt rule out a T/Storm anywhere given the conditions showing. Liking what i see as the W looks quiet favourable as well !
Temps during the day will again reach 24C.

Into Sunday which is maybe too far out to be holding anything too firm GFS wise but current data shows large areas of CAPE over 1000 and LI of -4.


And a few graphics to illustrate some of the detail above..

SLP 15.00 Wednesday.



SLP 15.00 Saturday.



Max Temps 18.00 Friday.



CAPE and LI 18.00 Sun.



Thats it for now from me, enjoy the warmth and heres hoping we get to see a T/Storm or two later in the week

Still some way off , well +150 on GFS actually but things if anything have improved with the 12z Run. Lapse Rates look average in comparrison to whats shown on the following graphic but if this does hold then things could look good for some T/Storms during late avro early evening Sunday.



This is showing an area with CAPE in the 1200-1300s and LI of -5
Although i would add that GFS is noted for being overly agressive on these big + Runs and nearer the time i would expect things to show as much lower.
Looking at the basic UK Storm Risk graphic it shows much of the above area at 50% with one smaller area of 60%(right over Somerset). Would maybe expect something higher with the CAPE and LI as it is but maybe those %'s reflect the average Lapse Rates.
As it is M4 corridor would again look very favourable as a base area should anything get going. Still some time to go, far too long even to expect these numbers to hold but in general quite hopeful of something later this week.

Beauty of a forecast there mate.

Looking good for the weekend eh. Hope things do come off for some storms, had a look at GFS earlier and I agree with what you have said totally. Always that M4 area.

Here's hoping!

Something i should have mentioned which illustrates perfectly how GFS Runs vary so greatly in such short times is the vast difference between the 2 CAPE and LI graphics posted above.
The first 06z graphic shows a very broad area of the UK under good values at 18.00 Sunday but the next Run 6hrs later has a far more confined area with increased values much further South for the very same time frame.
Fully expecting to see these Runs continue to change and wouldnt really expect to be making any plans until maybe late Fri or early Sat when i will then be looking at the High Res NMM Models anyway.

Great to have a bit of anticipation at long last

Looks good guys. That's pretty high CAPE for your region and given the -5 it should promote some decent storms. I would check the model run say 12 hours prior to any anticipated chase to make sure your target area is active.

Check the wind profiles to locate possible convergence areas - do you have a low level jet or anything? If not then just nail the areas where winds will be strongest for any shear properties. Also if these numbers hold closer to the weekend try and get the temps for 700mb from your sounding or GFS model. The colder the better.

Given the instability this could be a successful chase opportunity for you guys to team up and hunt. But like I mentioned, see how the convection is forming on satellite and radar then make your move. If you are able to successfully nail a target area where the winds will be more favorable for the trough then go there...

Usually areas with mountainous topography can fire up storms after they pass over them using upslope winds.

Time to put that experience down under into practice mate! Different location but the homework is the same! Good luck!

PS: the GFS shows lifted index and not lapse rates....kinda...you can find the lapse rate on the sounding but you will only get the midnight or 11:30am sounding online - so whist the sounding may look juicy then, it may change dramatically by the time you chase - keep all the info up-to-date a day out of the expected chase - if the numbers hold then go for it. Thing is to anticipate the likely target area that will maximise your storm potential. If it means leaving a favored area pre-planned then do it - go to where the weather has the means of being more unstable!

Cheers Mike!

Looking at the latest runs though, it doesn't look as good as the centre of the High is going to be sat over the south of the country, meaning the winds aren't coming from where I'd like to see them coming from for our area. Northern most parts would be more favourable to see anything.

Still early days though, and shifting in the weather patterns could happen. I'm unable to post any graphics right now as at work but I'm sure me ol mate Uppie may help me out!

Whilst the positioning of the High is changing only slightly the GFS seems to be running amok with what its showing CAPE and LI wise with every Run.
Expected to see a certain degree of change but making any plans at all would be impossible at the moment. Of course wouldnt be making firm plans so far out anyway but hope to see soem sort of pattern gradually forming...which it isnt !

Will keep watching the Models and hopefully see something coming together nearer the weekend.

Mike, nice read there with the advice, certainly getting a touch desperate to get out in the field and try to use some of the knowledge thats allegedly there.
Im sure that things will happen eventually although im already starting to sound just like i did all of last summer as the storms evaded me so many times.

defo time to keep the fingers crossed and hope for some consitency with these runs.
whatever happens with them tho, it sure looks like somwhere in the uk is gonna get what we've been looking for since last year and thats a nice T-storm.

for some reason i cant get the soundings on netweather to work

With you all the way in hoping for something JP, seems a very long time ago since there has been some excitement for us all.

Thankfully it does seem to be generally accepted that some T/Storms will break out later this week but im sure theres going to be some disappointed people amongst us as there always is, and as ever im putting myself as one of the favs to miss out as usual

Latest models not giving any hope at all for the S/SW which is a bitter pill to swallow after seeing 1000+ and -5 within range on yesterdays runs.

But as ever im sure we will keep viewing each days models with anticipation

For sure!

JP - what sorta trouble are you having with the soundings? Try University of Wyoming for soundings, I've found this very useful.

for some reason wazza the soundings wont load for tyne & wear
i use the university of wyoming too but just like to check them both to compare.

latest GFS is showing a bit more consistancy with CAPE and LI showing good numbers and just slightly to my W/NW. will start feeling a bit more confident nearer the time and if the models keep going the way they are.......party time

Could this finally be the storms we've been waiting for? Geeesh, it's about time if so! Looks good Fri/Sat and Sun for various parts of the country in the afternoon. Surely one of the 3 days will give us something!?

GFS now seems to be a little more consistent and to me things currently look far more favourable farther North. Still some way to go before anyone is sure but during Sat possibly but more than likely Sun there will be some T/Storms about.
Looking at data for here in the SW or S even i really cant see anything at all until Mon perhaps and again thats just too far out.

But generally most will see temps in the region of 25C during the weekend if not before and nightime temps will be a sultry 13/14C which by comparrison will actually be higher than the daytime temps most of last week !

Storms......maybe

Have you any graphics to show guys and the sounding might be kinda useful...might give a clue as to how much instability is around. How about a sat image loop - pref current - so we can see anything with the convection forming?

Cheers!

Graphics as requested. Firstly here is a sounding taken from yesterday. No instability and very "tacky"! Cape, CIN etc dont show on here for some reason which is annoying!



Thursday is seeing Ireland as having the best chance of a thundery shower. Instability reasonable. Just a shower though I believe. Friday/Saturday seeing the area moving into northern UK down to the Midlands, but i'm more interested in Sunday. This is "at the moment" though, as we all know, it will change and probably see the values drop, but the very high values are catching my eye right now. My only niggle is the winds not coming from the south, so anything big isn't going to happen in my opinion. But for thundery showers this is far more favourable. The jetstream is far to the north, and West as is the convergence area if I have gotten this area right. Temps aloft will be cooler too given the northerly airflow leading to those reasonable lapse rates. Cape pushing 2000 and Li -5?? Cool!

Oh... and bang over my area! Sweet! If anything does happen, I will be going out there as it is my day orf!

itsa loverly warm day here in st neots, its about 19 degrees, sunshine occasionally but its still warm without the sun.

summer is here! (sort of)

Glad to hear it Mark! It's a stonkingly nice day up here too and now pushing 21C. (And I'm off today, which is amazing those two event's have co-incided!). I'm going to walk the wee boy up to School Nursery and then I'm off for a long walk in the warm sun.

All very pleasant out and about today, really feeling like that cold winter is now firmly behind us at long last. And as we know the week will continue to heat up, near to 80F for some over the weekend.

Still a chance of a few T/Storms but as already mentioned the North is still looking the most likely if anything does get going. Could be worse i suppose, could be raining right now.....because of a T/Storm

Too may late nights and early mornings for me i think

I was just about to post up a graphic and see the very same garphic already here that Wazza had posted earlier...yes the CAPE and LI one for Sunday
Had posted earlier but totally missed the post lovingly put together with lots of detail and graphics on it.
My apologies mate.

Will now have a look through whats there albeit a little later than i should or could have. But as far as Sun 18.00 and the CAPE and LI , im not getting in the slightest excited yet given whats been shown so far this week on GFS.
Next run will probably be totally different again.

Hope im wrong of course.

Hehe not a problem mate! :-)

Yes looking interesting but still one or two factors making me reserve my opinion.

Deffo going to be one to keep an eye on, for me I'll have a lookski Saturday morning before work and Saturday night/early hours Sunday morning whatever time I get in! Of course I have my iPhone to look here and see the latest etc.

im slightly hopeful for a touch of the good stuff this afternoon. CAPE and LI are on the up and theres a wee N breeze coming in of the N sea with Wley's aloft. its 20c already and lapse rates are steepining a touch.

etofex have a 15% chance of lightning for my part of town and north into scotland.

...British Isles...

Diurnal heating may create a few hundred J/kg CAPE over parts of UK and Ireland which may lead to some showers and briefly organised thunderstorms. Severe weather is not expected. courtesy of estofex.

fingers crossed for something to fire today and if things come together the weekend could be juicy

Most deffo JP!

Looking like today the northern most areas may see an isolated storm or two. Humidity building too, very "tacky"!

Theres a few storms going up...cool as...if you live in Scotland

Also note the UKASF watch on the left of the Forum pages.

Details from this are as follows....

Storm Forecast Issued: 2010-05-20 21:36:00
Valid: 2010-05-21 00:00:00 - 2010-05-21 23:59:00

Regions Affected
E/NE Scotland (Wales, N England, S Scotland & Northern Ireland included in the WATCH)

Synopsis

A broad area of HIGH pressure, "Siegbert", situated across the United Kingdom will dominate the weather on Friday.

Local convergence zones are forecast to develop across some parts of Scotland, N England, Wales and Northern Ireland during the day in response to daytime heating. This will provide focus for scattered, fairly isolated, sharp showers with a low risk of a localised thunderstorms.

Any showers will be very slow moving and this, combined with torrential downpours, increases the risk of flash flooding. Showers will gradually ease in intensity and coverage during the evening hours after sunset.