Warm front thunderstorms - May 2001

[SummerShower]

Does anyone remember the overnight storms of 9/10 May 2001?  

Where I was at the time (Northampton) this storm was one of the most violent I've ever experienced in this country - perhaps only bettered by the one in Hampshire in September 2016.  

It started between 1 and 2am and went on without a break until 430am with several close CGs, a period of heavy hail, and at least 4 homes in the town struck by lightning.  Car alarms were being set off and the thunder was extremely loud for a prolonged period.

The unusual thing about this storm was that it occurred along a warm front.  The previous day (9th) had been grey and cool with North Sea stratus spreading way inland and lasting all day.  The next day, 10th May, was much warmer and very humid.  There was perhaps up to a 10C temperature rise from the previous day!  This goes against the normal pattern of storms as we all know, where it cools off afterwards.  Also, forgive me as I cannot remember the name of who published a paper - about thunderstorm setups in the UK- but this event is an example used in it.  The storms were widespread, and not forecast to the extent to which they occurred either.

There were other storms in this period too but they were more scattered I think.  There was a much less severe one on the evening of Sunday 13th in Northampton, for example.

I believe the only other time I've experienced big storms along a warm front was in France in August 1994.  However, I'm sure there are other examples of this that others know of.

Use this thread to discuss this event, and other warm front thunderstorms.

Edited April 4, 2023 by SummerShower

[Weather-history]

11 hours ago, SummerShower said:

Does anyone remember the overnight storms of 9/10 May 2001?  

Where I was at the time (Northampton) this storm was one of the most violent I've ever experienced in this country - perhaps only bettered by the one in Hampshire in September 2016.  

It started between 1 and 2am and went on without a break until 430am with several close CGs, a period of heavy hail, and at least 4 homes in the town struck by lightning.  Car alarms were being set off and the thunder was extremely loud for a prolonged period.

The unusual thing about this storm was that it occurred along a warm front.  The previous day (9th) had been grey and cool with North Sea stratus spreading way inland and lasting all day.  The next day, 10th May, was much warmer and very humid.  There was perhaps up to a 10C temperature rise from the previous day!  This goes against the normal pattern of storms as we all know, where it cools off afterwards.  Also, forgive me as I cannot remember the name of who published a paper - about thunderstorm setups in the UK- but this event is an example used in it.  The storms were widespread, and not forecast to the extent to which they occurred either.

There were other storms in this period too but they were more scattered I think.  There was a much less severe one on the evening of Sunday 13th in Northampton, for example.

I believe the only other time I've experienced big storms along a warm front was in France in August 1994.  However, I'm sure there are other examples of this that others know of.

Use this thread to discuss this event, and other warm front thunderstorms.

The storms were not well forecast

 

[Row w]

Yes I remember these storms very well, awoken at around 2-3ish by loud thunder and heavy rain pelting down, assuming I haven't got my years mixed up. I remember watching the weather after the 10 o clock news and seeing storms forecast for down London way and asking my mum if there was a chance of them coming anywhere near Telford to be told no, proving just how these storms were not well forecast.

[Summer8906]

I remember this being forecast for certain parts of the UK, though it did not affect where I was in Hampshire.

The sequence of events was: the bank holiday weekend had been sunny and dry but with temps around the average for early May. There was then a forecast of warmer air arriving from the east behind a warm front, and thunderstorms would mark the boundary. The warmer air arrived, but without storms here - it remained sunny.

I wonder if it's worth devoting a thread to thundery warm fronts in general (might need to separate this out?)

Similar examples of thundery warm fronts occurred on May 7/8 1993, in which once again the weather had been sunny but not especially warm beforehand, then a front was forecast to move in from the east and introduce warmer, but on this occasion more humid and cloudier air. Again storms were forecast on this, but nothing happened.

Another occasion from the same era was June 1 1997, in which once again the air was sunny, and slightly warm before hand (May 31 had been warm to hot, and June 1 cooler) On the evening of June 1 a thundery warm front arrived from the SE and this time did produce some short-duration, elevated storms - followed by more humid air behind.

Finally on August 7 1992 a thundery warm front moved up from the S this time (IIRC) followed by a humid warm sector on August 8 and then a thundery cold front from the W that night.

Interesting most of these occur in late spring or very early summer. Wonder what triggers storms on a warm front? It's certainly counter-intuitive.