1. Convective basics and ESTOFEX
Convective basics and ESTOFEX
Speaker: Helge Tuschy 1

2. Short vita studied Meteorology / Geophysics at the Leopold-Franzens
University of Innsbruck, Austria
2002, 2007 internship National Weather Service Amarillo, Texas
2004, internship Storm Prediction Center ( SPC )
talks: ECSS, ICAM, media …
forecaster at ESTOFEX / member of ESSL
Since 2010 working at the DWD (RZ Leipzig, E-Germany)
favorite sport: baseball and soccer
favorite food: Italian style 2

3. The outline Basics about organized convection Overview about ESTOFEX
Case study (15th August 2008)
Future of ESTOFEX 3

4. Convective forecast parameters and signatures
@ EUMETSAT
9-11 km
SBCAPE
MLCAPE
MUCAPE
Low-level CAPE
0-6 km
0-3 km
0-3 km
Lifted Condensation Level (LCL)
0-1 km
Speed shear
Storm relative helicity
- mixing ratio (0-1 km)
- 0-1 km mean wind streamlines
- real time T/Td data 4

5. Convective available potential energy
Surface based (SB) CAPE
Mean / Mixed layer (ML) CAPE
Surface dewpoints / temperatures
realistic layer depth for thunderstorm
inflow ?
Magnitude highly! variable in
space and time
Pro: e.g. winter with thin low-level
moisture
Contra: - in summer often way too
high
- decays too fast
Mean/Mixed temperatures / dewpoints
within lowest 50 – 100 hPa
realistic layer depth for low topped
supercells ?
Pro: often most reliable parameter
Contra: in winter often underestimates
true magntiude 5

6. Speed shear a) b1) b2) d) c) Cyclonic rotation Anticyclonic rotation
@ Eye on the
Twister
@ LakeErieWX

7. Directional shear (helicity)b)
@ A REVIEW FOR FORECASTERS ON THE
APPLICATION OF HODOGRAPHS TO
FORECASTING SEVERE THUNDERSTORMS
by Charles A. Doswell III c)
@ Dynamics of tornadic thunderstorms
by Joseph B. Klemp 7

8. Storm relative helicity
180 °
Storm relative winds
Horiz. Vort. vector
Storm relative winds (arrow) and storm relative helicity (colored area); here: 1-3 km SRH
Thunderstorm motion
e.g. 320° 12 kn
270 °
90 °
15 kt
30 kt
Sfc. To 1 km (tornadogenesis)
Sfc. To 3 km (mesocyclones)
0 °

9. Be careful of composed parameters
Supercell composite parameter (SCP)
Significant Tornado Parameter (STP)
Energy Helicity Index (EHI)
Derecho Composite Parameter (DCP)
e.g. highly fluctuating
Each parameter has its positive and negative side
Composed parameters mix those aspects; negative ones
can multiply 9

10. European Storm Forecast Experiment (ESTOFEX) www.estofex.org

11. Forecasters of ESTOFEX
Dr. Pieter Groenemeijer
Dr. Johannes Dahl
Dr. Oscar van der Velde
Christoph Gatzen
Helge Tuschy
Oliver Schlenczek
Tomas Pucik
Marko Korosec

12. 1st outlook of ESTOFEX
VALID 06Z THU 10/ Z FRI 11/ ISSUED: TUE 08/10 23:10Z FORECASTER: HAVEN

13. European Storm Forecast Experiment (ESTOFEX)
What is ESTOFEX?
An initiative of a team of European meteorologists and students in meteorology and serves as a platform for exchange of knowledge about severe convective storms in Europe and elsewhere. ! !
ESTOFEX offers a GUIDANCE where organized convection is forecast. This guidance can be used by local forecast offices for daily warning preparation.

14. Which risk of (extremely) severe convective weather phenomena does ESTOFEX forecast ?
tornado (waterspouts)
hail with a diameter of at least 2.0 cm
wind gusts with a speed of at least 25 m/s (92 km/h or about 49 knots)
excessive rainfall of at least 60 mm
Extremely severe convective weather phenomena:
tornado; (E)F 2 or stronger
hail with a diameter of at least 5.0 cm
wind gusts with a speed of at least 33 m/s (119 km/h or about 65 knots)

15. The meaning of the level areas
41 km radius of a chosen point
verification by EUCLID/ESWD
R = 25 miles
= 41 km
A ~ 5085 km2
Severe wind gust report
Tornado report
Below, we see a 91-day (roughly providing a continuous look at the
season) running mean of forecast and observed severe thunderstorm
coverage (observed area multiplied by 40). The big signal is the annual
cycle, with greater coverage in the warm season. Note that the two warm
seasons have similar observed coverage, but that the 2007 warm season
forecast areas were larger, leading to a larger forecast bias. Also, note that
the large forecast areas persist later in the season than the observed area.
This is qualitatively similar to what is seen from the SPC forecasts in the US
where a large area of scattered severe reports are frequently seen in late
summer.
Heavy rain report
Large hail report
Evaluation of ESTOFEX forecasts: Severe thunderstorm forecasts
H.E. Brooks et al.

16. Probabilities
Verification of severe and significant severe events (1266 forecasts)
Level areas
% coverage of severe events
% coverage of significant severe events
(svr.[%])
(sig.svr.[%])
Level 0
0.40 %
0.01 %
< 5
Level 1
4.90 %
0.80 %
5 – 15
Level 2
14.50 %
2.80 %
> – 5
Level 3
22.20 %
11.10 %
> 5
Lightning probabilities
Marginal lightning probabilities
15.0 %
Enhanced lightning probabilities
50.0 %

17. The meaning of the level areas
E.g. probability of 15 % means a 15 % chance for that event to happen within a radius of 41 km around each point. May seem low, but compared to climatology, it is significant
2) Level 0 expected probability of severe convection appears insignificant
3) Level 1 most common threat level; low threat of severe weather
4) Level 2 large confidence of severe storm occurrence and slight risk for
extreme severe
5) Level 3 major severe thunderstorm outbreak (e.g. 15th August 2008 )

18. 18

19. How do we prepare our outlooks?

20. (Meteox and local data) Soundings: Real time/model
Wind profiler
Surface data
European radar data
(Meteox and local data)
Soundings:
Real time/model
AVHRR SST (spout forecast)
ESTOFEX outlook
Lightning data
(EUCLID)
Ensemble prediction system (EPS) data from global models
EUMETSAT
Satellite data [HVIS !]
Model data:
global models
local / regional models
self-produced outputs for convective forecasts
Climatology
(e.g. thunderstorm days)

21. Structure of a Severe Weather Outlook Day 1 or 2 (SWODY 1 or SWODY 2)
Synopsis
Short overview
upper level streamline pattern (e.g. trough, ridge, jets)
low levels (e.g. sig. boundaries, characteristics of the planetary boundary layer quality regarding moisture, temperature)
possible: short outline of model credibility (e.g. ensembles, EFIs etc.)
if necessary: short side notes for significant weather events like a depression with a potential (sub) tropical character
Discussion
Header
Severe Weather Outlook Day 2 (SWODY 2):
General discussion
Severe Weather Outlook Day 1 (SWODY 1):
Discussions of each area of interest within different paragraphs. The following points are discussed:
kinematic environment (shear)
instability
forcing
storm mode
time frame/duration
Structure of a Severe Weather Outlook
Day 1 or 2 (SWODY 1 or SWODY 2)

22. Tornado outbreak 15th August 2008 (Poland)

23. Pattern recognition ! 23

24. T h H Upper levels White: Green: Yellow: Pink arrow: isohypse isohumid
lapse rates (2-4 km AGL)
Pink arrow:
300 hPa jet wind T h H 24

25. Low levels White: Green: Arrows: t T isobare isohumid
850 hPa jet wind and temperature advection (colorized) t T 25

26. Severe Weather Outlook Day 2: 13th August 2008
SYNOPSIS Active weather pattern continues as a strong upper-level trough shifts to the east over central Europe. […]. At the surface, a quasi-stationary frontal boundary is still in place, running from the Alpes over CNTRL Poland to W-Russia, […].
DISCUSSION ** A major severe-weather event is forecast for parts of central Europe and an outbreak of severe thunderstorms with tornadoes, damaging wind gusts and significant hail can be expected. ** […] m/s 0-6km bulk shear values over the northern central Mediterranean. During the afternoon and evening hours, shear also increases significantly E/NE of the Alpes, with 0-6km DLS values of 25-35m/s all the way to N-Poland. […] LL shear of locally up to 20m/s and also very high SRH values, maximized over Poland, but also augmented all the way down to the N-Adriatic Sea.
Very rich BL moisture and steep mid-level lapse rates along the front result in near 1000 J/kg MLCAPE, with locally higher MUCAPE values. […] Another interesting point is abundant LL CAPE release along the boundary, which could be a backing mechanism for tornado development, which has to be monitored in the upcoming model runs. Forecast soundings from central Italy to Poland indicate that the environment is prime for tornadoes/a few strong ones/large hail/a few damaging events included and severe to damaging wind gusts. […] 26

27. Severe weather outlook day 2 (SWODY 2)
Issued: Wed 13 Aug :18 Z
Level areas:
13th Aug 2008
Lightning data:
15th Aug 2008 27

28. Severe weather outlook day 1
Issued: Thu 14 Aug :16 Z
Issued: Fri 15 Aug :09 Z 28

29. Future of ESTOFEX
More forecasters participating in this experiment, e.g. from the
Mediterranean or E/SE Europe
Platform for forecasters to discuss realtime / past events
To bring more meteorological students on board
Creation of a detailed climatology about European convection
(also push verification of outlooks)
In the long term future: maybe an institution for European convective
forecasts ? 29

30. Thank you very much for your attention ! 30