Valid: Sun 22 Nov 2015 06:00 to Mon 23 Nov 2015 06:00 UTC
Issued: Sat 21 Nov 2015 13:05
A level 1 was issued for E Adriatic and E Ionian Sea mainly for severe wind gusts and in lesser extent for excessive precipitation (mainly Albania).
SYNOPSIS and DISCUSSION
A strong undulation of a polar jet stream reaching N Africa provides and influx of cold air mass (850 hPa temperature ~ -5) to most of the Central Europe. Jet extends from Iceland trough Iberian Peninsula, encircles W Mediterranean and runs further to W Russia. A main mid-level low of this wave is centered over Germany. Except SE Europe, most of the continent is covered with dry air mass (mixing ratios ~ 2-4 g/kg). Within this flow, a steepening lapse rates locally exceeding 8 C/km (especially over warmer sea surface) provide marginal instability that together with PV advection may result in a shallow convective clouds capable of producing lightning. Due to low instability, shallow free convective layer and lack of overlap with strong wind dynamics severe convective storms in most of the lightning probability areas are unlikely.
Some isolated severe wind gusts are although possible over E Adriatic and E Ionian Sea coast where a 200-300 J/kg CAPE overlaps with 35-40 m/s DLS. However, due to shallow free convective layer, storms will presumably be able to benefit only from 15-20 m/s MLS shear. Although NWP model predicts CI signal along the coastal areas and orographic lift takes place, QG-lift seems to be not favorable. A weak PV advection passes Albania where superimposing stratiform and convective precipitation create threat for the excessive precipitation and local flash flooding. However, due to not significant values of PW and boundary layer's mixing ratios this threat is low.