Status: Ongoing analysis Material from: Linus, Zied
1. Impact
On 17 and 18 August parts of central Sweden was hit by extreme rainfall. On station in Gavle measured 161 mm/24h and many stations recorded more than 100 mm/24h.
2. Description of the event
The plots below show analyses of z500 (contour) and T850 (shade) from 14 August 00UTC to 18 August 00UTC, every 24 hour.
The plots below show analyses of MSLP and 6-hour forecasts of precipitation from 16 August 00UTC to 18 August 00UTC, every 12 hour.
The plot below shows the 24-hour gridded precipitation observations from SMHI, ending on 18 August 06UTC.
3. Predictability
3.1 Data assimilation
3.2 HRES
The plots below show observations from SYNOP (first plot) and HRES forecasts of 24-hour precipitation valid 17 August 06UTC - 18 August 06UTC, from different initial dates. The black hourglass marks Gavle, which got 161 mm on one station and 117 mm on another station.
3.3 ENS
The plots below show EFI for 1-day precipitation 17 August, from different initial times. Some signal started to appear in the forecast from 13 August for eastern-central Sweden.
The plot below shows the forecast evolution plot for 24-hour precipitation valid 17 August 06UTC - 18 August 06UTC over Gavle, Sweden. HRES –red, ENS CF – purple, ENS blue box-and-whisker, Model climate – red box-and-whisker. Triangle marks the maximum in the model climate based on 1200 forecasts.
The plots below show the crossing-point forecast (CPF) for 1-day precipitation 17 August, from different initial times.
The plots below show the cyclone feature plots valid 18 August 00UTC, with the features coloured after the maximum rainfall within 300 km.
