'Summer' slipping away for good as low pressure moves in?
Rather fittingly the weather has performed like clock work with the arrival of Autumn Equinox, tomorrow, heralding the start of astronomical autumn and for many marks end of summer. The rain and gloom is here but is it here to stay? After following weeks of high pressure influence and very little in way of rainfall - bringing particularly dry conditions to SE England which has seen a fifth (20%) of expected monthly total. This is set to change a breakdown as of now is occurring this did not prevent a warm day in east in which Norwich reached 26C in afternoon, in contrast London saw its high temp 23C late morning before cold front arrived.
From this point onwards through the new week the weather takes a distinctly more changeable flavour and potentially beyond....
However, I personally do not believe this unsettled period will carry much at all into October viewing the guidance. While there will be Atlantic weather systems giving some very wet weather to all in between some drier and sunnier spells are likely, additionally nights are likely to be mild, We see the remnants of ex hurricane Humberto move in on Tuesday and indeed this serves as a catalyst reinvigorating jet stream for unsettled weather to truly break through.
Monday sees outbreaks of rain and increasingly gusty winds spread across Wales, Ireland, SW England however elsewhere it will be a rather nice day, dry with sunny spells with temperatures lifting into the 20s in the London area.
Tuesday will be a windy and overcast day for most the showery rain seen early in the morning will clear all areas, however then an area of more persistent rain will push in across England and Wales and for southern counties including the SE the first substantial rain in quite some time. The Met Office currently have a yellow severe weather warning for rain covering areas to south/southeast of London extending all the way west to Pembrokeshire, Wales.
Midweek onwards ongoing theme of slow moving low pressure so remaining unsettled pluvial flooding is unfortunately likely and perhaps set to come too much at once. 12Z GFS is forecasting 60mm of rain come the start of October in London area this might be overboard but this does suggest some high rainfall totals may be seen in capital away from NW Scotland which often sees drenching rains a rain shadow is likely to be seen to east of London however still I'd expect some good rain for East Anglia but not as much.
The start of October is likely to see more settled conditions but it may do so unconvincingly away from Southern England, recent model output has backed off on much cooler conditions, courtesy of blocking area over Greenland dragging in cool northerly winds. American model (GFS) however remains keen on much cooler feel to end September and open October while European (ECM) lost scent. High lat blocking however is still likely to be seen north and northwest of British Isles, MJO (tropical forcing) orbiting phase 7-8-1 tends to give a rise of pressure in Greenland locale and as such higher risk of cool northerly airstreams. Some unusually cold and crisp mornings could be seen early October but it is not entirely clear yet.
Thanks for reading