Storms bringing excessive rain to Central & East Europe
Valid: Mon 29 Jul 2019 06:00 to Tue 30 Jul 2019 06:00 UTC
Issued: Mon 29 Jul 2019 02:00
Forecaster: VAN DER VELDE
A level 1 was issued across Poland, Czechia, Slovakia, Austria and Hungary mainly for excessive local convective precipitation.
A level 1 was issued across Albania to Bulgaria mainly for large hail.
A level 1 was issued across S Russia mainly for large hail.
A level 1 was issued across SW UK mainly for tornadoes and severe convective wind gusts,
A small but unseasonally intense low slowly enters the English Channel, accompanied by a strong wind field affecting SW UK and W FR coastal regions. A broad zone of moist unstable air over central and SE Europe is confined by a cold front from Russia on the Baltic, Belarus, Ukraine side, and advances westward as warm front over Germany, Denmark and Austria. To the south, a trough and jetstream move over the southern Balkan.
Significant low-level shear >10 m/s and some CAPE are coming together in the NE flank of the system. In such case storms that form may produce tornadoes.
Slow-moving storms under weak shear present a primary threat of excessive rain production with flash floods. GFS places convective maximum over S Poland with weakly capped 1000 J/kg, whereas ECMWF and WRF models favour them to the south and west in weaker CAPE but more humid conditions. Also along the warm front in N Germany and Denmark, some convective rain threat is not excluded.
Lower CAPE but favourable shear and dynamic triggering during afternoon could produce organized storms which can produce some large hail.
Large hail can be produced here in storms along the cold front thanks to enhanced deep layer shear and relatively high cloud base.
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