Severe weather outlook – forecast across Europe. This forecast features areas of organized severe weather with risk levels and severe weather threats across the European continent.

SEVERE WEATHER OUTLOOK – DAY 1

 
Valid: 09/08/2020 06 UTC – 10/08/2020 06 UTC
Issued by: Severe Weather Europe
Forecaster: Marko Korošec
 

SUMMARY

 
Isolated severe storms with a threat for severe winds, large hail, and torrential rainfall are possible across England, France, Spain, the southern Balkan peninsula and western Turkey on Sunday.
 

Overview of the risk areas across Europe

 
weather forecast

 

Explanations for abbreviations (TSTM, SLGT, ENH, etc.)
 

 

SYNOPTIC OVERVIEW

 
Much of Europe will be under the influence of an extensive upper-level ridge. The upper low over Greece continues weakening while drifting into Turkey.

FORECAST DISCUSSION

 

+++ Serbia, North Macedonia, Greece, Bulgaria and western Turkey +++

 
weather forecast
 

SLGT risk has been issued for southern Balkan countries into western Turkey with an isolated threat for severe storms, capable of producing severe winds, large hail, and torrential rainfall.

MRGL risk has been issued for areas surrounding the SLGT risk area across much of south-central Balkans, including Greece, Romania, and central Turkey for storms with a limited threat for some strong winds, marginal hail, and heavy rainfall.

A moderate to strongly unstable air mass remains across the region under a weakening upper-level low. Only a marginal deep-layer shear will be in place, supporting some multicell storms across the SLGT risk area.

Slow-moving storms should locally enhance torrential rainfall and flash floods threat. Higher instability should also support some large hail events. Cold mid-levels could support the waterspout threat over the Aegean Sea.

+++ Spain and south France  +++

 
weather forecast
 

SLGT/MRGL risks have been issued for northeast Spain int southern France with a threat for a few isolated severe storms, capable of producing severe winds and large hail.

A moderate instability under weak winds and shear could support some organized daytime driven storms with strong winds and some large hail events. 

+++ England and France +++

 
weather forecast
 

SLGT risk has been issued for southern England across the English Channel into France with a threat for isolated severe storms, capable of producing severe winds and marginally large hail.

Strong instability builds up until the peak time heating hours on the western edge of the ridge. A few isolated storms should form after capping erodes. Despite the limiting shear, some large hail and severe wind events will be possible. 

+++ other areas +++

 

TSTM risk areas have been placed across Germany, Poland, Czechia, Slovakia, the Alps, Baltic region, and eastern Finland. Daytime driven storms are likely to occur but should remain sub-severe.

Follow & report severe weather events on our Facebook page:

Severe Weather Europe Facebook page

 

*******************
 

 

Understanding Severe Weather Outlook

 

Severe Weather Outlook features areas of organized severe weather with risk levels and severe weather threats. Risk levels are divided into seven categories:

TSTM – Thunderstorms
MRGL – Marginal risk
SLGT – Slight risk
ENH – Enhanced risk
MDT – Moderate risk
HIGH – High risk
SIG – Significant risk
WNTR – Winter risk

Risk categories stand for the coverage and intensity of organized severe weather. Those could include supercells, squall lines, mesoscale convective systems, wind storms, flooding, snowstorms, or ice storms.

Severe weather threats include:
  • large hail (of at least 2 cm in diameter)
  • Tornadoes (including waterspouts)
  • Wind gusts (convective or non-convective) above 25 m/s (or above 90 km/h)
  • Torrential convective precipitation / Flash floods
  • Excessive rainfall (100 mm within 12 hours) / snowfall (50 cm within 12 hours)
Extremely severe weather threats include:
  • Large hail (of at least 5 cm in diameter)
  • Tornadoes of F2 intensity or stronger
  • Wind gusts (convective or non-convective) above 33 m/s (or above 119 km/h) or 12 Bft
  • Torrential convective precipitation / Flash floods
  • Excessive rainfall (150 mm within 12 hours or above ) / snowfall (above 100 cm within 24 hours)

Categories in the forecast represent the chance of severe weather occurring within a 40 km radius from a location. The used level is based on the conversion table of probabilistic risk into the outlook categories. A threat level is upgraded into a higher category if probabilities meet the threshold criteria for the specific threat (e.g. tornado, wind, hail, or rainfall threat).

Each individual threat area includes a detailed forecast map and discussion on the potential of severe weather threats.

Read more: Explanations for abbreviations (TSTM, SLGT, ENH, etc.)