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: 26/08/2020 06 UTC – 27/08/2020 06 UTC
Issued by: Severe Weather Europe
Forecaster: Marko Korošec
 

SUMMARY

 
Severe storms are possible along the fast-moving surface from Poland into Belarus and Ukraine on Wednesday. Storms could bring large hail, torrential rainfall, and severe winds. Isolated storms are also possible over northwest Russia, western Turkey, eastern Spain ann north Morocco.
 

Overview of the risk areas across Europe

 
weather forecast
 

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

SYNOPTIC OVERVIEW

 
A deep upper trough over western Europe weakens while moving east. An associated surface front is pushed towards the east. Another upper wave is moving east across the North Atlantic, approaching Ireland and UK on Wednesday night. The shallow short-wave over southern Balkans finally vanishes moving into Turkey. An upper-level ridge is gradually developing over the southern half of Europe.

FORECAST DISCUSSION

 

+++ Czechia, Slovakia, Poland, Lithuania, Belarus and Ukraine +++

 
weather forecast area 1
 
ENH/SLGT risks have been issued for far eastern Czechia, northern Slovakia, eastern and southern Poland, southern Lithuania, west-central Belarus and northwestern Ukraine with a threat for isolated to scattered severe storms with severe winds, torrential rainfall, and large hail.

A fast-moving surface front will provide lift for convective initiation during the daytime into evening hours. Strong shear but only marginal to moderate CAPE should allow some organized storms to develop. Including a few supercells.

The main threat will be severe winds and marginally large hail. Some large hail could form with the stronger cells, as well as torrential rainfall. A forced line of storms could develop, racing east across the ENH risk area through afternoon and evening hours.

The activity could extend into nighttime with clustering storms.

+++ Turkey, Finland and northwest Russia +++

 
weather forecast area 2
 
SLGT/MRGL risks have been issued for eastern Finland into northwestern Turkey, as well as northern Morocco and western Turkey with mainly an isolated threat for severe storms, capable of producing severe winds, large hail, and torrential rainfall.

While storms over Finland and northwest Russia are possible with the departing wave, some stronger cells could be severe with marginal hail, severe winds, and heavy rainfall.

A few isolated, potentially severe storms are possible over western Turkey and northern Morocco. The isolated threat for large hail and severe winds exists.

+++ other areas +++

 

TSTM risks have been issued for eastern Spain, the Alps, northern Turkey into Georgia, and part of the North Atlantic with a threat for daytime driven storms. Limited shear is present, so the storms 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.)