Case: 14 March 2018

Summary

Cold air open cell cumulus that transitioned to a closed cloud deck over ENA

Description

This was a postfrontal cold air outbreak open cell cumulus event. The melting level was at approximately 1.5 km AGL, well below the observed cloud top heights for these days. The event on March 15th was more than a day removed from the associated frontal passage over the ENA site, however SEVIRI observations indicated frequent upper level clouds advecting over the site as associated with the larger scale system. Lower level flows were modest (30 kts on March 14th, decreasing to under 20 kts by March 15th) and northwesterly. Precipitating cumulus were common throughout both days. There was a final transition in this cloud field to a closed stratocumulus deck by the end of the event on March 15th. The inversion height by midday on March 15th was at approximately 2.0 km AGL.

Available assets

Standard ARM profiling assets, SEVIRI. RLPROF-FEX. SACR. The event only collected the 12 UTC sounding on March 15th.

Critical period: 03:00-09:00

Open cell cumulus over the ENA site

Figure 32 True color afternoon MODIS AQUA image with overlaid LES domains. The image domain corresponds to the size of the model forcing domain.