Valid: Sunday 23rd September 2012

Issued For: Heavy Rain, Strong Winds


  • Area of Low Pressure moving up from the South-West heading North-East
  • Potential to bring heavy rain
  • Warmer airmass ahead could produce thundery conditions
  • Very uncertain at this stage

Forecast Detail:

Through the course of Saturday night and into Sunday some models are predicting an area of Low Pressure moving up from the South-West bringing a period of heavy, persistent rainfall into Southern England with the potential for strong winds across Eastern, Western and Southern coastal areas, ahead of this  Low Pressure system will be an area of warm, moist air and this has the potential to bring embedded thunderstorms within an area of heavy rainfall.

There is currently a great deal of uncertainty over the exact tracking and intensity of this system with models tending to contain a fair amount of disagreement even at this stage, the models are only really beginning to model this system consistently where as a few days ago it wasn’t appearing at all on some of the model runs. A weather advisory has therefore been issued until things become clearer, there is currently a moderate chance of this advisory being upgraded to a weather warning in the coming days.

Forecast Models

GFS Model showing the area of Low Pressure across Southern parts of England
ECM model showing a much weaker system further South, this disagrees with the GFS and thus lowers confidence within the forecast
UKMO Model showing the low pressure system close to the UK, but a weaker system than the GFS model is showing, again, this model shows a slightly different evolution to the previous two
Met Office FAX Charts showing the Low Pressure system approaching the UK along with the entangled weather fronts
Met Office FAX Chart showing the Low Pressure system just to the East of the country, weather fronts continuing to bring outbreaks of rain/longer spells of rain through into Monday