Autumn Storms/Severe Weather Discussion

[Saphira]

Hi guys

Well as you can see i have not been round much IRL does that sometimes. However this Mondays storm event is worth a topic, now as many have gathered yet again the media have over hyped this (but for good reason). Now if this bores you and your not into weather then dont read it

I will explain why now..

Ok so this storm has been monitored by weather enthusiast for about a week now, i myself have done nothing but look at data, graphs, models, GFs, etc..endless tbh. Now the reason for the excellent media coverage is the possible chance of a Sting Jet (will explain more on that later) and also the Low weather front Lorenzo that passed UK will played a big part in how this Storm! can/might/will predictably turn out and how both the northern and southern flanks of this storm will be affected, and its path it takes..Anyway this storm had not even been born yet but with today's technology and data readings us weather bods could see it developing. Now what is unusual is the high temperatures that the UK have been having, this has also played a significant factor with the storm (now named Christian).

Now lets get to the Graphs etc, this is the exciting bit, many wont understand them so i will do my best to explain.



Now on this image you can see the tightly packed isobars as the deepening low passes through the UK, the tighter the isobars the higher the winds, also the potential for severe wind gusts.



On this image you can see the pressure dropping which will increase the wind gusts even more (potential for in excess of 80-90 mph gusts in coastal/exposed areas), now even more concerning is the Sting Jet i already mentioned, this has the potential to develop and if it does we could see wind gust over 90mph, possibility of them reaches 100mph.



Now this is the worrying part that all us weather bods have been banging our heads over, as you can see the pressure bars have dropped to a staggering 966 (hurricane force) as the Low moves NE wards. Now if the sting jet does become existent in this deep depression then things will be stepped a notch or two.



Now this chance signifies the potential for a tornado on the southern flank of this storm, we are not ruling out potential of a tornado to exceed an F3 with its cores reaching 120-150mph. It's shear is impressive.

Jet stream + unseasonably mild weather + wind shear + low pressure system (possible Sting Jet) will all plays major factors in this storm, however the data is still yet coming in and changes are apparent, possible shifting more north, if this happens then the Low will run further over the midlands, and south wont get much of a battering, if the Low stays on course as it is now the south will be somewhat batter, if the Low passes further south then France will get a battering. Expect power lines down, power outages, fallen trees, flying debris, flooding, structural damage to properties etc. On a safe note stock up on candles, and essentials, and more importantly DONT travel unless absolutely necessary (even worse for island as all travel crossings to the island will be suspended) Looks in cupboard, "how many candles do i have", ooops! only one lol...



This is the expected path it will take (if the low does not shift). Now these storm can change course quite rapidly as this time of year our Jet Stream is raging quite fast with speeds off over 200mph.

Right - The Sting Jet

A sting jet is a meteorological phenomenon which is believed to be the cause of the most damaging winds in European windstorms.

The definition of a sting jet -

Originates at mid-levels within the cloud head
Descends along a sloping surface of constant wet-bulb potential temperature
Accelerates and dries during descent
Results in strong winds near the top of the boundary layer
Results in localised strong surface gusts at the surface
Persists for several hours
Distinct from the low-level jets associated with the warm and cold conveyor-belts.

Anyway, the latest models (within past 5 minutes) GFS, NAE etc have put this storm a little further south, so that means it could potential hit out in the English channel and France will take the brunt of it, however this Low has literally only just been born and expect a lot of change in the next 24hrs. Im hoping it will go further south and miss the UK, if it dont im right in its path and also live right on the southern side of the island in quite an exposed area.