October 2007

Why this Upper-Level Low? Not an especially severe weather system (near Ireland) Behaviour was a little unusual Surface charts would give you no clue to the evolution Demonstrates the value of some of the Meteosat Second Generation Imagery

Hand-drawn Surface Charts from the Met Eireann Central Analysis and Forecast Office

12Z October 7 th

00Z October 8 th

12Z October 8 th

00Z October 9 th

12Z October 9 th

00Z October 10 th

12Z October 10 th

00Z October 11 th

12Z October 11 th

00Z October 12 th

12Z October 12 th

00Z October 13 th

12Z October 13 th

00Z October 14 th

12Z October 14 th

00Z October 15 th

WV Imagery 00Z 7 th Oct to 00Z 15 th Oct

RGB Image from MSG – 00Z October 8 th

RGB Image from MSG – 12Z October 8 th

CROSS-SECTION

PV at 12Z October 8 th

Relative Humidity at 12Z October 8 th

Consequences over Ireland Some very heavy showers in the north and north-east some time after the passage of the cold front. Isolated thunderstorms A quickly-moving feature, so convection rapidly died down, as system moved southwards over Britain.

RGB Image from MSG - 18Z October 9 th

PV at 18Z October 8 th

Relative Humidity at 18Z October 9 th

Later This weather system became very active on the east coast of Spain Very heavy rain fell near Valencia Floods and one death resulted

Lessons Value of MSG Water Vapour and Airmass RGB imagery as a “first alert” Cross-Sections are a powerful tool to analyse such a case