Storm Forecast
Valid: Wed 14 Jun 2023 06:00 to Thu 15 Jun 2023 06:00 UTC
Issued: Tue 13 Jun 2023 19:35
Forecaster: GROENEMEIJER
A level 2 was issued across central and southern Italy for excessive rainfall and isolated tornadoes.
A level 2 was issued across a large part of the central Mediterranean region for excessive rainfall, isolated large hail, and tornadoes.
A level 2 was issued for the Caucasus region for large hail, isolated severe wind gusts, and heavy rainfall.
A level 1 was issued for a larger area encompassing the Caucasus and parts of Russia and Ukraine for heavy rainfall and isolated large hail.
A level 1 was issued across Northeast Algeria and Northwest Tunisia for excessive rainfall and large hail.
A level 1 was issued for western Ukraine, East and Southeast Poland, and northern Romania for heavy rainfall and isolated large hail.
A level 1 was issued across Ireland for extreme rainfall and isolated large hail.
A level 1 was issued across southern Turkey for isolated large hail and excessive rainfall.
SYNOPSIS
Across northern Europe, an elongated area of high geopotential stretches from Scotland to western Russia.
The flow across Central Europe is weak and cyclonic around a mid-level low across southern Poland. An unseasonable shortwave trough moves eastward across the Central Mediterranean, following a closed low that translates eastward across Turkey. A tongue of warm, humid, and slightly unstable air affects western France, the southwestern UK, and Ireland.
DISCUSSION
Central and Southern Italy...
A closed surface low is expected to develop ahead of the eastward-moving shortwave trough. Increasing southerly low-level flow is set to aid the initiation of convection and lead to heavy rain rates especially where the ascent is orographically enhanced, especially across Central Italy. In addition, high low-level buoyancy suggests that a few waterspouts or weak tornadoes may occur.
Caucasus...
Scattered to widespread storm initiation is expected ahead of the approaching mid-level low. Profiles with high buoyancy above the -10°C level and strong deep-layer shear are expected across the region, which implies that the convection may easily include supercells with a risk of large or very large hail as well as isolated damaging winds.
Algeria, Tunisia...
Ahead of the shortwave trough, strong vertical motion is expected to be affecting an already unstable airmass across the region on Wednesday morning, leading to high precipitation rates with a convective system lingering on the north side of the Aurès Mountains warranting a level 1. In addition, strong shear and high SRH suggest that a few supercells may develop across northern Tunisia in spite of the limited instability, which gives rise to some risk of large hail.
Ukraine, Poland, North Romania...
On the eastern flank of the low across South Poland, scattered convection is expected to initiate within a very moist airmass. Across the western part of the area, storm motion should be modest, enhancing local rain accumulations. Across Ukraine, shear is stronger and a few better-organized storms may develop with a minor risk of large hail.
Ireland...
NWP guidance suggests that a convergence line acting as an axis of high moisture will be located across southwest Ireland and that widespread storms will form along it leading to high local rain accumulations. As a result, a risk of localized flooding will be present.
Turkey...
Slow-moving storms will form within a very moist troposphere, which suggests that high local rainfall accumulations may occur with an attendant risk of local flooding. The instability may be sufficient for producing small or marginally severe hail as well.
