The models have really upgraded the heat overnight for next weekend and beyond with heatwave conditions again likely to take place over the UK and Ireland though as you'd expect by the timeframe, there are some differences among the models. Here I discuss what the latest runs of the two models, GFS and ECMWF, show.
The GFS 06z shows high pressure from the Azores ridging to us by Saturday 21st July which gradually over time pushes to our east and draws in a southerly to southeasterly flow with hot air from Europe. Low pressure is stalling in the Atlantic as a result of this area of high pressure and if that low were to invade a few days following the establishment of hot weather over us then there'd be some severe thunderstorms. This is a proper hot scenario with temperatures easily getting into the 30s across England and Wales whilst mid to high 20s over Ireland and Scotland. If the wind was to sustain a southeasterly airstream along with the high pressure not going too far east, then 30°C is not out of the woods for Ireland.
ECM 0z is kind of different. It ridges in the high pressure similar to the GFS during next weekend (even hotter air on this model) but the jet stream is closer to the north of Ireland and over Scotland. This would mean it'd be cooler and cloudier up there with temperatures stuck in the high teens and low 20s mainly in any sunshine but generally mid to high teens. Elsewhere, we'd be talking mid to high 20s and low 30s over England & Wales. The high pressure also doesn't push east over to Scandinavia, it stays over top of us. The heatwave conditions dam line (564) is across Ireland on Saturday on the ECM whilst it makes its way to most parts then afterwards.
