13th April, 1999

[Dave J]

http://www.wetterzentrale.de/archive/ra/19...00119990413.gif

http://www.wetterzentraleforum.de/archive/...cka19990413.gif

As you can see, the 13th April 1999 was characterised by a typical unstable showery N'ly flow which often happens during this month and can probably explain the well used phrase "April showers", but can also bring about some sharp late frosts.

However on this particular day one shower around 4pm was much more violent than most and I believe produced a tornado or at least a very strong gust front near to my parents house.

The Nottingham ascent for the day (see below) shows that the atmosphere was moist in the lower layers and had an ELR that fell sharply with height- creating instability and the generation of rain/hail/snow showers with no doubt some thunder mixed in too. Tops were relatively (though not greatly high) at around 450hPa.

Also note the wind shear on the skew-T with a great change between the nr surface (250deg 17knots) to the what is known as Level 6 height (925hPa) where winds are 290deg 37knots!

In my weather diary for the day which I kept when I was at Middle and Upper School it reads:

Sunshine and heavy showers of sleet, hail and snow- very strong gusts afternoon

Max: 9.1C

Min: 2.6C

Precipitation: 5.0mm

Wind direction: North

Wind speed: 6mph

Max wind gust: 57mph

Wind chill: 0C

Min wind chill: -11C

Pressure: 999mbars

Now I remember clearly, when I got home from school- getting myself a drink in the kitchen and both me and my mum were talking. Quite suddenly the wind REALLY got up and I mean REALLY. The oak tree at the bottom of the garden was blowing fully like it was being pulled out of it's roots. The direction of movement was to the northwest (i.e. the wind gust was from the southeast) despite the synoptic wind being Northerly.

I hurried upstairs to see what the weather station had logged and saw the 57mph and couldn't believe it- to date that is the highest gust I have recorded with even the strongest Autumn storms only reaching 50mph (although in October 2002 it may have reached higher however it was down for repair at the time ironically).

The next day I spoke a few people who live in the village and heard numerous reports of wind damage including my friend's shed door which for some bizarre reason was propped shut by a brick, being flung open hurling the brick across the garden by the gust. I also heard about some damage to the local St. Matthew's church spire and talk of a possible tornado, but really thought nothing else of it at the time.

To this date I never solved the mystery of the Leavenheath "freak gust", only knowing that atmospheric conditions were very unstable on the day and that it was not that unusual to see such a gust occur.

Does anyone have any particular memories of this day, especially living in the south Suffolk/ north Essex area?

[Thundery wintry showers]

As for the gust, it sounds like it was a very freak occurrence but such gusts are known along squall lines and in the vicinity of particularly vigorous shower clouds.

I remember the day in the North East. A polar trough of some kind produced a spell of more persistent precipitation between about 10am and 2pm, which started off as rain at 3-4C, but soon turned to snow as temperatures fell to around 2C. Despite temperatures staying well above freezing the snow accumulated for a time, producing a dusting on the ground (although inland areas had up to a couple of inches) After 2pm the trough cleared, the snow thawed and a mix of clear intervals and snow showers ensued, with another accumulating snow shower at around 8Pm.

The day's maximum was only 4.9C which is the lowest maximum I have ever recorded during April- and the following night's minimum, -3.3C, was also the lowest I have ever recorded in April. For some inland parts of the region it may well have been the deepest snow cover they saw during the whole 1998/99 season.

[Dave J]

Looking through some old Journal of Met. articles and the TORRO database I found out that a tornado was reported from Pentlow (on the Essex/Suffolk border just NW of Sudbury) on this day. This is only about 12 miles from Leavenheath as the crow flies.

[agowerguy83]

http://www.metoffice.com/climate/uk/1999/april.html

We had a light dusting of snow from the 14/4 polar low, not what you'd expect in the Easter holidays.