Late evening storms over SW France and N Spain in the testbed visualization of the RDT (rapid developping thunderstorm) product from EUMETSAT NWC-SAF and MeteoFrance:

 RDT product screenshot: growing cells with red borders, mature cells with magenta. Mouse-over function provides a selection of additional cell properties.

Here one of the new products from DWD to be tested this year:

The DWD COSMO DE EPS visualization of the “condensate in column below -10 degrees Celsius 1 hour track” shows interesting signals to be verified later today over Germany.

This first week of the ESSL Testbed was a very fruitful one, also because of the weather setups that we have experienced. The testbed will have a break of one week now and will be back on 19 June for additional 3 weeks.

Today’s forecasting team for day 1 found a significant threat for severe weather over western Turkey in the coming hours: level 2 there.

Here is what their experimental Testbed forecast says:

Day 1 Forecast

Valid: Thu 08 Jun 2017 09:00 to Fri 09 Jun 2017 06:00 UTC

Issued: Thu 08 Jun 2017 08:53

Forecaster: ESSL TESTBED

A level 2 was issued across W Turkey mainly for large hail and to lesser extend isolated tornadoes, severe wind gusts and extreme rainfall.

A level 1 was issued across Bulgaria, Greece and soroundings for large hail and extreme rainfall.

DISCUSSION

Turkey

Approaching trough from the Mediterranean push a strong southwesterly mid level jet into W-Turkey. Large scale lift/height falls expected. Broad overlap of a steep lapse rate and low level moisture as indicated by the latest observations will create a favorable environment for initiation in the afternoon hours. First storms are expected over the mountains. Strong deep layer sheer and favorably veering profiles supports supercells (deep layer sheer ~ 20 m/s or more). First stroms are capable of producing very large hail (5 cm), later on highest storm coverage poses of threat of large hail and locally excessive precipitation and severe windgusts. In the evening increasing low level sheer can be sufficient for a few tornadoes as well.

Image: Interesting EUMETSAT NWCSAF product for today. Discussion showed that there is substantial moisture available not only in the typical very thin mediterranean coastal layer, but also inland over western Turkey with ongoing advection from the south (green to yellow to orange colours in the precipitable water product).

You can also follow our updates on Facebook and Twitter – also via our Twitter newsfeed on the ESSL homepage.

The team forecasting for yesterday was quite pleased (not in terms of damage, but in terms of forecast quality) with the verification of their forecast. The same is true for the team perfectly nowcasting a tornado in northern Italy:

This afternoon teams are busy with the evaluation of NWCSAF and DWD products.

Today’s day 1 forecast (valid until Wed 06 UTC) – made by a team at the ESSL Testbed – foresees a considerable risk for severe weather:

There will be interesting and very active Nowcasting sessions this afternoon.

You can follow our daily activities via regular online sessions during the testbed period:

Tue – Thu at 9 UTC: Online severe weather briefings and daily expert lecture.
Fri at 9 UTC: Severe weather online briefing only.

At the online meeting times you can join us here in WebEX with the session number “953 698 353” and the password “testbed”. This service is kindly provided by EUMETCAL.

Already on the first full Testbed day the situation is very interesting regarding low level moisture. We are assessing what role for example the EUMETSAT Nowcasting SAF total precipitable water (TPW) products can play in detecting local moisture differences:

The ESSL Testbed 2017 welcomes all participants of this years’ edition.

We are proud to present you again an interesting selection of leading-edge forecasting and warning tools. New this year are for example a number of products from the EUMETSAT Nowcasting SAF.

Pieter Groenemeijer and Tomas Pucik observing high precipitation storms at lunchtime in Wiener Neustadt on the day before the testbed starts.