Windrush Weather

The flow of moist, warm air from far south continued on Wednesday that saw the thermometer rise to 17.1C at 14.05 before dropping back slightly. This maximum was 2.2C above my 40-year average and the warmest day since 26th September.

It was a dry day but overcast and misty. The next rain band arrived at 17.20 producing 12.6mm of precipitation taking the monthly total to 82.0mm, just 9mm below my 40-year October average.

The overnight minimum of 10.8C was logged at 07.27 early Thursday being 3.4C above the long-term average, so another mild night.

The start to Thursday revealed that the dull, dreary beginning to recent days had passed and variable light and high cloud allowed a bright start to the new day. Overnight radiation fog had formed in the River Og valley that had all but dispersed by 07.30. The wind direction has changed from southeast on Wednesday to southwest overnight as the next weather system edges closer.

The Atlantic synoptic charts show a very large low pressure system developing just south of Iceland that is deepening rapidly and slowly heading our way. The forecast pressure at its centre will be an extremely low pressure of 962mb by midnight. However, the extreme wind and rain is likely to have greatest effect over Scotland and Northern England although it will breezy and wet here on Sunday. The wind gusts are forecast to reach 40mph over high,exposed ground locally.

Tuesday gave us another cloudy, damp and overcast day. The difference between that and Monday was the temperature. An air stream from the southeast brought much milder air that saw the thermometer slowly rise during the day to reach a maximum of 15.8C late afternoon at 16.16. This peak was 0.9C above my 40-year average and the warmest day since the 7th (16.9C). The rainfall that started to fall at 19.15, amounted to 4.0mm taking the monthly total to 69.3mm, just 21mm below the average for the whole month.

Once again the thick cloud cover kept in much of the warmth overnight that saw a minimal fall in temperature with a minimum of 14.6C at 05.55 early Wednesday, thus a diurnal range of just 1.2C.

Wednesday revealed another overcast and dull start to the new day, however at 08.00 the thermometer read 15.C, which was 0.8C above the average maximum for October. Although it is very misty with the humidity reading 100% at 08.00, where it was for much of Tuesday, the fog is less dense with visibility limited to 500m as the cloud base is a little higher today.

The warm air is being brought to us on a southerly or southeasterly drift that will back into the southwest during the evening. The track of the airstream can be traced back to Southern France, Spain and the Mediterranean, which is likely to continue for another day or two.

The rain ceased just after 09.00 on Monday but there was persistent light rain and drizzle from the thick, low cloud all day on Monday that limited the temperature rise to a maximum of just 11.4C at 16.00 being 3.5C below my 40-year average. The additional precipitin was 2.1mm taking the monthly total to 65.3mm when the long-term average is 91.0mm.

The thick, low cloud was maintained overnight that produced a mild night as the temperature eased downwards to a minimum of 10.1C at 00.30 early Tuesday before edging upwards to reach 10.5C at 08.00. The past twenty-four hours have been noticeable for not only the cloud but very light winds, a maximum movement of 10mph at its peak, the calmest day and night all month.

The conditions over the past twenty-four hours have produced a very small diurnal range, the difference between day and night extremes, of just 1.3C.

The recent high pressure, now to the east, is blocking the advance of significant rain from the large area of low pressure in the Atlantic. The day will be mainly cloudy thanks to minor weather fronts crossing our area, perhaps lifting allowing a little brightness in the afternoon. The barometric pressure has eased upwards to read 1015.3mb at 08.00.

The pool of cool air over the country on Sunday meant a cold day with the thermometer not rising above 9.8C, logged at 15.40. This maximum was a significant 5.1C below my 40-year average, however, it was a dry day, if cloudy, and the wind from the southeast was light during daylight hours.

The minimum of 6.4C was logged at 02.59 early Monday also being below average at -1.0C. After that time the thicker cloud and yet another weather front began to traverse our area bringing another considerable fall of rain amounting to 11.1mm by 08.00 Monday. That additional precipitation took the monthly total to 63.3mm when the 40-year average is 91.0mm.

Monday struggled to arrive under very low, thick cloud cover that was still bringing rain at 08.00 but the backend of the rain band, associated with the warm weather front, is easing away. A mini depression formed in the English Channel and will drift away towards the Continent, although the rain will cease it will leave legacy of a cloudy day. The humidity at 08.00 was, not surprisingly, 99% thanks to the hours of rainfall and low temperatures. The high humidity will persist all day due to the cool, misty conditions.

The wind from the west picked up as the day progressed that combined with a cloudy morning limited the temperature rise to a maximum of 14.7C 13.49, which was 0.2C below average. There was a brief light shower between 10.20 and 11.05 that amounted to 1.0mm of precipitation. Brief sunny intervals then arrived after midday but were limited. The sky was clear overnight that allowed the thermometer to fall away to reach a minimum of 3.7C at 06.33 being 7.7C below average.

By 06.30 on Sunday thin cloud had arrived from the west and obscured any view of the sun after dawn, which allowed the temperature to show a slight rise to 4.5C by 08.00. The wind has backed into a more southerly quadrant, probably from the southeast for the bulk of the day, and be relatively light. The cool air following a cold night then thin high cloud during daylight will mean a very cool day.