Valid: Mon 05 Feb 2018 06:00 to Tue 06 Feb 2018 06:00 UTC
Issued: Mon 05 Feb 2018 02:09
Forecaster: VAN DER VELDE
A level 1 was issued across the coastal regions of NE Spain and S France mainly for excessive convective rainfall.
SYNOPSIS / DISCUSSION
The European map is dominated by two systems: a large anticyclone over the eastern side of the European continent, and a low over the Iberian Peninsula. Under an extensive area of cold upper air across southwestern Europe steep lapse rates create marginal instability for convective developments. Since moisture is lacking over land, CAPE remains below a few tens of J/kg. On the Balearic Sea and northern Mediterranean Sea mixing ratios are significantly higher, leading to decent (but still low-end) CAPE, which advects towards shores of Catalonia and Languedoc. Convergence and synoptic scale lifting create a long-lasting episode of rain, partly convective, where cores can add tens of millimeters of rainfall in a short time. These can develop also land-inward over the lower Ebro Valley. Although deep layer shear is 15-25 m/s, low-level shear is limited, which does not benefit chances of other severe weather phenomena.