13th October, 2025

Hi All,

Well 2025 is definitely a mast year, you have probably heard this term banded around a lot on the news lately. It refers to a bumper crop of seed, nuts, fruits produced by certain trees according to specific climatic conditions that occur in the spring.

Reading the Woodland Trust's explanation about a Mast year is interesting, (find it here) it isn't (as I thought) that a favourable climate promotes more fruit production, rather that the flowers preceding the fruiting stage are pollinated more effectively in the spring. So the warm, dry spring of 2025 which we know was beneficial for insect populations, was the driver behind the masses of acorns, sooth berries, hawthorns, etc that we now behold when we venture into the countryside. Presumably then the occurrence of a Mast year is a sign that we have a healthy population of pollinating insects ?

Walking in Fineshade Wood yesterday, on the edge of Corby, the masses of acorns crunched pleasingly under my boots, but my attention was drawn higher up, to a flock of birds I saw right at the top of some pine trees. I'd heard their call before but I had never successfully identified them.

Image courtesy of Cornell Lab Bird Identification

I quickly turned on the Merlin Bird I.D app to get a recording and a hopeful I.D. I was chuffed to see it come through as Red Crossbills. Standing quietly watching them feed, you could hear the crack of pinecones as they prised open the cones with their uniquely shaped beaks (there's a clue in their name, see pic) and then flew to their young to feed them. Brilliant.

One of the objectives of the walk was to look for fungi, but the ground not surprisingly was bone dry. We need some rain and we need it in large amounts and fast if we aren't going to be in a hyper-critical water situation in 2026. The latest update from the E.A below makes worrying reading.

Image reproduced courtesy of The Environmental Agency https://www.gov.uk/government/publications/dry-weather-and-drought-in-england-summary-reports/dry-weather-and-drought-in-england-26-september-to-2-october-2025

No area is marked as being in recovery note.

So in this short blog this week (as I have to get myself ready to attend the Meteorological World Technology Expo event in Vienna) I look for any sign that our dry start to October is likely to change ?

Image courtesy of tropicaltidbits.com

General Weather Situation

So last week I discussed the formation of an Omega blocking event that would bring dry and settled weather to the U.K, Ireland and Denmark. We have seen some lovely days, some cold foggy ones and even the occasional frost. I was down in The New Forest area for a couple of days in the campervan pursuing Mullet and Bass and it was lovely. Incidentally whilst fishing looking over to The Isle of Wight, I heard a familiar sound above and there was a small flock of House Martins and Swallows, no doubt just about to make the crossing to France. That's the latest I have ever seen them.

I digress, back to the weather.

Well the Omega Blocking Event is doing what it says on the tin and effectively preventing a westerly airflow and low pressure, rain-bearing systems from influencing our weather. This situation will continue for the whole of this week but as we approach the end of the week, a subtle change will take place as you can see from the animated GIF above as the high pressure gets squeezed eastwards between an approaching Atlantic low pressure and an Eastern Europe low pressure. The leading edge of this low pressure looks to bring a change to southerly winds and rain pushing into Ireland during Saturday. This system will then move eastwards bringing rain to the western coasts of England and Wales on Sunday and inland later the same day, accompanied by strong southerly winds turning westerly as it progresses further east.

So a big contrast between the start of this week and next. This week, it'll be on the cool side during the day, with plenty of low cloud courtesy of a north easterly airstream pulling cloud off The North Sea. We will also see very little wind, mists and fog patches slowly burning of during the day and some isolated patches of drizzle as well. Next week, it'll be much windier and they'll be rain and the pressure will plummet from its current (pauses to walk across the kitchen and tap the barometer) 1026mb.

One of the consequences of this change is that the jet stream position will drop further south and that means an effective 'open door' to Atlantic low pressure systems. Indeed as the first arrival moves east across The North Sea into Denmark on Monday / Tuesday next week, we see another deep Atlantic low pressure hot on its heels. So a brief hiatus next week before another band of strong winds and heavy rain pushes into Ireland and then the U.K for the second half of next week. It may just be strong enough to be the second named storm system of the 2025/26 season, maybe. We will know more next week.

Tropicaltidbits.com have recently added the North Atlantic as a region to the areas within the GFS / ECMWF forecasting sphere, so now I / we can see what's coming before it arrives. Here is a long run showing the blocking high over the U.K & Ireland on the far right of the image and the Atlantic low pressure systems ganging up on the left.

Image courtesy of tropicaltidbits.com

The sharper-eyed amongst you may have noticed this isn't the GFS version (Global Forecasting System), it is from the ECMWF version (European Centre for Medium-Range Weather Forecasts). Last week, I attended an RMets (Royal Meteorological Society) evening lecture on the forecasting of thunderstorms.

To say I was out of my depth knowledge-wise is maybe an understatement, but I learnt two key lessons quite early into the talk. The first is that meteorologists love to use bloody acronyms whenever they can and the second is that they expect everybody else to understand them. Certainly myself and the lady sitting next to me didn't. I'll talk about that lecture next week but what I also learnt is that machine-learning won't have an immediate effect on forecasting accuracy, that we cannot forecast thunderstorms accurately and we don't even understand all of the processes that take place within the formation of a thunderstorm. About from that we are fine and dandy !! The lecturer did answer my question about the merits of GFS vs. ECMWF and he made a strong case for the latter, so I have heeded it.

So if you look at the ECMWF gif above, they are predicting 3 low pressure systems on their way to affect our weather in the second half of October before the possible arrival of a mild and humid, high pressure ridge just in time for Halloween. This has happened many times before and if it comes about, it will I think represent a significant disease pressure period. So if you're sitting here questioning why I find this interesting and why I consider it relevant (There you are John, that bloody word again !!), there's your answer. Two weeks before it may occur, we have a potential heads up on a disease pressure peak. Now we know a lot can change, it may not happen the way it is portrayed now, but it is one to keep an eye on.

So there we are, a quiet week in store before we see a marked change in the weather over the weekend progressing from west to east and bringing some hopefully much-needed rain.

All the best for the coming week.

Mark Hunt