Remarkably consistent temperatures in Shropshire - but all change from now on!

[Freddie]

The last three days have had both maxima and minima within a few decimal points of each other, here in rural Shropshire:

19th: Tx 22.7; Tn 3.4

20th: Tx 22.9; Tn 3.1

21st: Tx 22.7; Tn 3.3.

The only variation in weather elements appears to have been in the visibility, which has shown a gradual increase over the three days (diurnal variations excluded), and the air pressure which has been steadily falling since the morning of the 20th.

All change from today, though, starting with a noticable increase in gradient wind this morning.  This will probably lead to higher maxima today owing to low-level warm advection from the south - although this will be partially offset by greater mixing in the lowest part of the boundary layer preventing the formation of superadiabatic lapse rates.  There should be an increase in high cloud, too, as moisture advection and slow cold advection occur at medium to high levels, boosted by shortwave upper troughs making their way north through the developing southerly flow.  Further cooling of medium layers over the next 36 hours will destabilise the troposphere, possibly accompanied by unstable medium cloud and maybe some preciptation generated - although the lower troposphere should remain too dry for much if any of this to reach the ground.

Big change on Wednesday, with low level moisture sucked northwards and the atmosphere properly destabilising as the higher level cold advection accelerates - culminating in some heavy rain, possibly with thunder, moving north during the day, followed by a cold front as the pressure pattern pushes Atlantic air in from the southwest and low-level cold advection occurs.  Air pressure will have fallen to around 992 hPa by this point.

Rest of the week looks cool and unsettled with heavy showers - but moisture content lower by this point, so unlikely to be as heavy as thos on Wednesday.

It is going to be fantastic watching this sequence of events over the next three or four days.  Meteorology is endlessly fascinating, IMHO of course :-)

--
Freddie
Dorrington
Shropshire
115m AMSL
http://www.hosiene.co.uk/weather/
Stats for the month so far: https://www.hosiene.co.uk/weather/statistics/201904APR.xlsx

[Julian Mayes]

Hello Freddie, 

I'd been meaning to ask - would you consider your new site to be in a frost hollow ? ( just from the lie of the land - I realise that you would not have any observational evidence yet. ).   

Thanks   Julian   

[Freddie]

Hi Julian,

Not a classic frost hollow, as I live on a low hill consisting of gravel that stands slightly above the general local topography, which is 90-100 m AMSL. Dorrington is on the southern edge of the Shropshire plain, and night time temperatures are probably influenced by katabatic flow off the south Shropshire hills. I have noticed that I have been colder at night than Shawbury during this current spell, but I doubt that would hold true for winter nights with snow cover - Shawbury and its immediate surroundings are notoriously cold on such nights.