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Thunderstorm/Convective Watch: Summer 2010
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Here some footage from my old hometown
http://www.dumpert.nl/mediabase/1037441/0863455f/heftige_storm_in_groningen_7_12_2010_.html
Almost scary .....
Does Ireland get storms like this??
Fantastic!!
I have seen squalls like that here which usually happen between late October through to January but they tend to be short lived.0 -
Just for my own education MT, as I seem to have underestimated things for Thursday, what will be the trigger for such deep convection? With an almost verticaly stacked low, will upper QG forcing not be minimised? I was looking at the 00Z GFS forecast sounding for around the Portlaoise area and it to me looked like a strong cap around 750-600hPa, so despite the steep low-level lapse rates and dry mid-level, will the roughly 20m/s 0-6km DLS be enough to overcome that, even with a surface temp/dewpoint of 20/10°C, and CAPE of 80J/kg, as forecast?
I'm not questioning you at all, I'm just trying to learn from your vast experience.
File start time : 10 7 13 0 0
File ending time: 10 7 20 12 0
Chosen date in meteorological file: 10 7 15 15
YR: 2010 MON: 07 DAY: 15 HOUR: 15 AT POSITION: 8.5 144.0 LAT.: 53.00 LON.: 7.50
PRSS: 0.1011E+04
MSLP: 0.1012E+04
TPP6: 0.0000E+00
UMOF: -0.5329E+00
VMOF: -0.5906E+00
SHTF: 0.1130E+03
DSWF: 0.5240E+03
RH2M: 0.5600E+02
U10M: 0.3430E+01
V10M: 0.3620E+01
T02M: 0.2934E+03
TCLD: 0.7050E+02
SHGT: 0.1791E+02
CAPE: 0.8000E+02
CINH: 0.0000E+00
LISD: 0.2817E+03
LIB4: 0.8938E+01
PBLH: 0.1968E+04
MT, I've just realised I'm a total idiot (yes, I know, took me a while), when I put in the coordinates I should have put in a minus for the longitude (West), but didn't, so the sounding earlier was for NW Germany!! :rolleyes:
Here's the correct one this time, though only showing under 200J/kg of CAPE, but a degree or two of surface heating will bring that up nicely. (Incidently, is there a way to measure CAPE from a sounding? If you take different parcel temperatures, and want to calculate the CAPE for each one, how do you physically measure the CAPE area between the parcel and environment curves? I've always wondered that)
File start time : 10 7 13 0 0
File ending time: 10 7 20 12 0
Chosen date in meteorological file: 10 7 15 15
YR: 2010 MON: 07 DAY: 15 HOUR: 15 AT POSITION: 353.5 144.0 LAT.: 53.00 LON.: -7.50
PRSS: 0.9808E+03
MSLP: 0.9953E+03
TPP6: 0.1465E-02
UMOF: -0.5485E+00
VMOF: -0.5749E+00
SHTF: -0.2700E+02
DSWF: 0.2000E+03
RH2M: 0.9350E+02
U10M: 0.3930E+01
V10M: 0.5370E+01
T02M: 0.2872E+03
TCLD: 0.1000E+03
SHGT: 0.1299E+03
CAPE: 0.1760E+03
CINH: 0.0000E+00
LISD: 0.2727E+03
LIB4: -0.1250E+00
PBLH: 0.8477E+030 -
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Sorry I am a little tardy replying to some posts earlier.
I tend to do my severe weather forecasts from a somewhat different set of "tools" than the conventional forecasters use, although I'm familiar with those and in most cases it works out to be a case of two different techniques following similar paths. With CAPE values, quite often the actual severe weather will lie off to one side or another of the higher CAPE values, so it gets back to analyzing where the energy centres from fronts, troughs and any other features may set up and how air mass properties will change over time when they encounter different terrain or ocean influences.
It's probably also the case that because I have been making forecasts for about 35 years now, that I have stored up (informally by memory) a rather large analogue set and tend to be on the lookout for warning signs of a false tell from a given pattern (not always successfully, have to say). Pattern recognition in forecasting can be a help and a hindrance, sometimes one pattern looks very much like another event that's perhaps etched in your memory, but some subtle difference throws the perfect analogy off course (and then also no two systems will be quite the same).
With this one coming in now, I used the reasoning outlined below, and we can go back and do a post-mortem on the reasoning later, but also if the models are wrong then any amount of accurate reasoning will be wasted or at least the results will be shifted to where the models should have depicted the pattern (this is not often a problem nowadays on the 1-3 day time scale, as much as it was perhaps 30-40 years ago).
I'll skip over Wednesday because there seems to be more of a question of why did I speak of severe storm potential near the closed low on Thursday; the outcome on Wednesday should be governed mostly by how unstable conditions become in the vicinity of the occluded front and various troughs following it cyclonically at intervals of probably 50-100 miles.
For Thursday, at this time of year, the conditions are likely to become very unstable from any heating around breaks in the overcast near the closed low, and from that point on, convection will easily penetrate the freezing levels down to about 3500 metres or so. This will assist in hail development and that generates better conditions for thunder/lightning to develop. But I also factored in an external energy peak that might add some spark to the mix, and the general look of the system as being well organized and somewhat tighter than many Atlantic depressions -- when you see large masses of rather featureless grey cloud on the imagery out near the low centres, this often translates to onshore flows of stratocumulus and weak or absent convection, but when you see sharp frontal structures and breaks in the overcast it suggests that the system will move onto land with some definition already and this will rapidly increase as the air mass now encounters a source of surface heating absent over the 15-16 C water (land can heat to 20-22 C quite rapidly). As you know from studying profiles, this will tend to shoot up the lapse rate which will otherwise stay about the same above say 800 metres, and assist in breaking through mild inversions or other caps to convection.
And then also it's St Swithin's Day and I hope to see that proven wrong on this one occasion just for fun (lots of rain Thursday then forty days of dry weather).
But I should probably not go against the saints in these matters.
For me, a lot depends on numerical values of 500 mb features too, I tend to think of 550-560 dm lows in July as average and 540-550 as rather deep, while in March it might be more like 530-540 being average and 510-530 being deep. It's a rather crude logic compared to modern meteorology, but many "old hands" tend to think in these antiquated terms, however, much depends on the actual pattern too, things like track, wind shear and uniformity or otherwise of the height pattern. Thickness is even more important than height, and the general rule is that the sharper the thickness contour gradient, the more dynamic the weather. However the position of the most dynamic weather may be shifted away from the thickness "ribbon" to some boundary outside the core of the jet stream.
Some locations that I'm expecting might do well for thunderstorm development would be generally eastern Mayo/Galway southeast to Carlow. I'm doing a real-time comparison of how the western Canada upper low performs compared to the Irish upper low (looking for pattern similarities after factoring in climatic range). Quite often I've noticed that heavy to severe weather will tend to occur very close to the centre of the stacked low around 3-6 pm local time then will tend to distort away to the southeast like a sort of repelled charge.0 -
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Another Level 3 has been issued by ESTOFEX for Benelux today, but this time we're also down for some action, and a Level 1 warning is out for tornadoes in England and Wales.
(Click on picture)
That really puts things in perspective. We really don't have much to look forward to in terms of severe weather compared to our Euro neighbours at the moment.
Looks like a good time for chasing supercells in the Benelux region. :pac:0 -
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One of you guys might be the owner of this....
http://www.laoisweather.com/index.php?option=com_content&view=article&id=48&Itemid=57
Just wondering if it is also accurate for strikes?
Or where else can I look?
Thanks
Ian
Hi Ian, yup, that's my page there. For a better view try... http://live.laoisweather.com and on that page is a full euro view at the bottom of the page.
There are three other detectors in Ireland...
ANTRIM: http://sproule.co.uk/weather/svlightning.html
WESTMEATH: http://www.irlweather.com/wxStormVue.php
and CORK: http://www.corklightning.com/
I am in the process of moving mine... again. I have difficulty in finding a suitable site here for the detector that can be easily accessed for fine-tuning. I had it mounted on the roof, but it was too much bother hiring a heist every time I needed to service it. Then I moved it to the garden on a 5m pole but nearby metal buildings caused strikes from the E showing up on the W etc... reflection issues and also farmers electric fences caused non-existant strikes to show up!
At the moment it is indoors on the second floor, but strikes to my E and NE are poorly recieved. Over the coming week or so, it is going back outdoors onto a mast that can be taken down easily if the need to adjust it arises. The mast will be above roof level so hopefully all directions will be clearly recieved. Wish me luck! :pac:
At the moment, all strikes recieved are genuine for their direction but the distance will not be spot on as we need strong thunderstorms (over 10 strikes per minute) to home in on it's distance. This is true of all Irish detectors. The best way is to view all four at once and work out the directions and the mid-point between strikes should prove reasonably accurate.
New software is being developed at the moment and should be available within 8 to 16 months that uses more intellegent software to plot strikes on the map. Exciting times ahead... IF we get the storms to go with it! 0 -
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