Friday 10th April
After the two very warm days on Tuesday and Wednesday, the latter peaking at 24.1C, Thursday was a shock to the system with a maximum of just 14.6C, down 9.5C on the high of Wednesday, making it feel distinctly cool, however it was still 0.3C above average. That was only part of the story as the maximum was logged at 09.35 with the temperature very slowly falling away as the morning and afternoon progressed under cloud cover, and more quickly in the evening. The brisk wind from the west also added to the cooler feeling. The minimum of 4.0C was logged at 00.28, early Friday.
Friday began dull and gloomy under a thick cover of cloud. There is a battle today between the remains of the ridge of high pressure from yesterday, that is easing away to the east, and a deep low pressure edging in from the Atlantic. The wind will slowly back from west to south then southeast as the day progresses, all the while bringing a cool and moist air stream that, combined with minimal sunshine this morning, will mean a maximum likely to be below average. Overnight, as the depression edges towards Ireland, an associated cold front will cross the country with light showers possible early Saturday morning.
By Sunday temperatures are likely to be edging upwards again, closer to the average, that by Tuesday are likely to return close to our slightly above average due to the wind swinging into the south. The forecast surface pressure charts indicate the depression departing to the north and an Azores high building again.
I add the final part of the Met Office article on pollen
How weather conditions influence pollen
Different elements of the weather affect pollen in different ways. Warm, wet weather earlier in the season supports plant growth and pollen development. Once pollen is ready to be released, warm and dry conditions with a light breeze are ideal for dispersal.
Rainfall has the opposite effect in the short term. During and immediately after rain, pollen levels usually drop as pollen grains are washed out of the air and deposited on the ground.
However, once conditions dry out again, levels can rise quickly, especially if plants have continued producing pollen.
This means pollen levels can fluctuate significantly from day to day, depending on the timing of rain and sunshine.
Is this the worst weather for hay fever?
For most hay fever sufferers, the worst conditions are warm, dry and breezy days. These allow pollen to be released easily and spread efficiently through the atmosphere. Calm, dry days can also lead to high levels locally, as pollen accumulates near the source.