Atmospheric response to the orography during cases of precipitation extremes in Iceland

On 10 January 2002 a new precipitation record was set in Iceland, as 293 mm in 24 hrs were observed at Kvísker, Southeast-Iceland. The previous precipitation maximum in Iceland (243 mm in 24 hours) was observed in Iceland in the same place on 1 October 1979. The atmospheric conditions leading to these extreme cases is simulated and analyzed and the cases are compared. The 2002 record occurred in stationary flow from the SSW, while the 1979 extreme was produced in easterly flow. Both cases feature strong low level winds bringing moist flow rapidly from low latitudes. There is very strong response of the airmass to the 2000m high mountain in both cases and the simulations indicate much more precipitation in the mountain itself than at the lowland station where the extremes were observed.