Status:Ongoing analysis Material Status: Finalised Material from: Linus, Fernando
...
| Show If | ||
|---|---|---|
| ||
Discussed in the following Daily reports: |
1. Impact
Report from Zoltan Sipos:
""
| Excerpt |
|---|
On 17 September, 2017 in northern Serbia and western Romania occurred a derecho event, which corresponds to the definition of this phenomenon: wind damage extends for more than 400 kilometers, includes wind gusts of 93 km/h along most of its length, and also includes several, well-separated 121 km/h or greater gusts. There were 8 dead and dozens injured. |
In western Romania, at meteorological or airport weather stations, the wind gusts reached: 25 m/s Sinnicolau Mare, Batos, Sighetu Marmatiei, Bistrita; 26 m/s Zalau, Baia Mare, Ocna Sugatag, Sebes, Alba Iulia; 27 m/s Cluj Napoca, Deva, Toplita, Tg. Lapus, Arad airport; 28 m/s Tebea, Poiana Stampei, Sarmasu, 29 m/s Borod, Holod; 30 m/s Timisoara, Resita; 31 m/s Siria; 32 m/s Varadia de Mures, Rosia Montana; 34 m/s Jimbolia, Gurahont; 35 m/s Stei; 36 m/s Ceahlau Toaca; 39 m/s Banloc, 40 m/s Huedin; 42 m/s Vladeasa 1800. There were 8 dead and dozens injured.
""
Severe weather reports from the European Severe Weather Database for 17th September 2017:
2. Description of the event
...
The plots below show the EFI and SOT for wind gusts valid 17 September.
Convective EFIs for both CAPESHEAR (left) and CAPE (right) for different forecast steps starting from day+1 (top) to day+6 (bottom). CAPESHEAR EFI provided stronger signal of severe convection than CAPE EFI but for both parameters the EFI values are not particularly high over the affected areas in northern Serbia and north-western Romania. It seems that wind shear played a significant role in this severe convective outbreak.
T+000-024h:
T+024-048h:
T+048-072h:
T+072-096h:
T+096-120h:
T+120-144h:
Straight-line winds of 35 m/s have been reported at Stei weather station (see ESWD reports plot at the top of this page) and they caused significant damage. At the same time a bow echo was observed in the radar imagery. CAPESHEAR parameter looks more extreme than CAPE in the forecast. This again suggests that deep-layer wind shear played a major role in the severe convective outbreak. CDFs for CAPE (left) and CAPESHEAR (right) over Stei are shown below.
3.4 Monthly forecasts
3.5 Comparison with other centres
...
4. Experience from general performance/other cases
5. Good and bad aspects of the forecasts for the event
- Good signal in EFI 4 days before the event
- The forecast missed the amplitude