Over the last week or so it seems I’ve been issuing warning after warning for heavy rainfall and localised flooding. The main reason for all this rainfall is the Jet Stream, usually around this time of year it’s somewhere between Northern Scotland and Iceland, this more Northerly flow allows the Azores high to ridge over the United Kingdom bringing settled, warmer weather. However over the last couple of months the Jet Stream has been taking a more Southerly route and due to the huge kinks within the Jet Stream this is causing Low Pressure to become stuck over us, the Jet Stream chart below shows this.
There is however perhaps a slight glimmer of hope for something warmer and more settled as we move into the second half of the month, however at the moment it is just a glimmer with models in disagreement over this. The 500hPa anomaly charts for both the ECM & GFS can be seen below.
The ECM (chart on the left) shows the Azores high extending Northwards across the UK like it should be doing at this time of year, this would bring warmer, more settled weather particularly towards the Southern half of the UK as we move into next week, more Northern areas would probably hang onto the cooler, damp airflow from the Atlantic. The GFS on the other hand (chart on the right) keeps the Azores high South of the UK and with Low Pressure to our East would keep us in this cool, unsettled flow. There’s also a sign the NAO is going to become more neutral as we move into the second half of the month which again indicates a change.
So whilst there are indications of some sort of change through the second half of the month, there’s also models indicating a continuation of this cool, unsettled theme. It’s going to take a few more days I think before we have a clearer picture. My best guess at the moment for the second half of the month would be for a ridge of High Pressure to extend up into Southern areas turning things a little more settled whilst Northern areas remain cool with outbreaks of rain at times. If this month doesn’t improve, I’m holding a lot of hope for a more settled August.