1 Convective basics and ESTOFEX Speaker: Helge Tuschy 1.

1

Convective basics and ESTOFEX

Speaker: Helge Tuschy

http://www.estofex.org/

http://www.dwd.de/

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 parametersand signatures

9-11 km

0-6 km

0-3 km

0-1 km0-3 km

SBCAPEMLCAPEMUCAPE

Low-level CAPE

Speed shear

Storm relative helicity

Lifted Condensation Level (LCL)

- mixing ratio (0-1 km) - 0-1 km mean wind streamlines- real time T/Td data 4

@ EUMETSAT

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

@ Eye on the Twister

Cyclonic rotation

Anticyclonic rotation

@ LakeErieWX

a)

b1)

c)

d)

b2)

7

Directional shear (helicity)

@ A REVIEW FOR FORECASTERS ON THE APPLICATION OF HODOGRAPHS TO FORECASTING SEVERE THUNDERSTORMS by Charles A. Doswell III

@ Dynamics of tornadic thunderstorms by Joseph B. Klemp

a)

b)

c)

7

8

15 kt30 kt

Storm relative winds

Thunderstorm motion

e.g. 320° 12 kn

Storm relative winds (arrow) and storm relative helicity (colored area); here: 1-3 km SRH

Storm relative helicity

Sfc. To 1 km (tornadogenesis)

Sfc. To 3 km (mesocyclones)

dzzVk

kmCVH )ˆ3

0()(

Horiz. Vort. vector

90 °

270 °

180 °

0 °

9

Be careful of composed parameters

Supercell composite parameter (SCP)Significant Tornado Parameter (STP)Energy Helicity Index (EHI)Derecho Composite Parameter (DCP)

Each parameter has its positive and negative side

Composed parameters mix those aspects; negative ones can multiply 9

11221 150

200

20

6

100

1

1500

2000

1500 Jkg

sbCIN

ms

BWD

sm

SRH

m

sbLCL

Jkg

sbCAPESTP )(

e.g. highly fluctuating

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

Oliver Schlenczek

Marko Korosec

Tomas Pucik

Helge Tuschy

12

1st outlook of ESTOFEX

VALID 06Z THU 10/10 - 00Z FRI 11/10 2002ISSUED: TUE 08/10 23:10ZFORECASTER: 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 ?

Severe convective weather phenomena:

• 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

Large hail report

Heavy rain report

Tornado report

Severe wind gust report

Evaluation of ESTOFEX forecasts: Severe thunderstorm forecasts

H.E. Brooks et al.

16

ProbabilitiesVerification 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 % >15 3 – 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

1) 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

ESTOFEX outlook

Surface data

AVHRR SST (spout forecast)

European radar data

(Meteox and local data)

Wind profiler

Soundings:

Real time/model

Lightning data

(EUCLID)

Ensemble prediction system (EPS) data from global models

Model data:

- global models

- local / regional models

- self-produced outputs for convective forecasts

EUMETSAT

Satellite data [HVIS !]

Climatology

(e.g. thunderstorm days)

21

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:

isohypse

Green:

isohumid

Yellow:

lapse rates (2-4 km AGL)

Pink arrow:

300 hPa jet wind

24

25

T

t

Low levels

White:

isobare

Green:

isohumid

Arrows:

850 hPa jet wind and temperature advection (colorized)

25

26

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. **

[…]35-40 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. […]

Severe Weather Outlook Day 2: 13th August 2008

26

27

Severe weather outlook day 2 (SWODY 2) Issued: Wed 13 Aug 2008 21:18 Z

27

Level areas:

13th Aug 2008

Lightning data:

15th Aug 2008

28

Severe weather outlook day 1 Issued: Thu 14 Aug 2008 21:16 Z Issued: Fri 15 Aug 2008 18:09 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 !

30Email: [email protected]