Deutscher Wetterdienst Central Forecasting DWD ECMWF Forecast Product Users Meeting 15 - 17 June...
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Transcript of Deutscher Wetterdienst Central Forecasting DWD ECMWF Forecast Product Users Meeting 15 - 17 June...
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
1
Predicting severe weather by EPS tools - current results
Thomas Schumann, Deutscher Wetterdienst, Zentrale Vorhersage D-63067 Offenbach,
GermanyE-Mail: [email protected]
NOAA12, 03 June 2005, 15:33 UTC (University of Bern)
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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Outline
1. Introduction - current situation
2. EPS products used for severe weather prediction
3. Case studies
4. Preliminary verification results
5. Conclusions
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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1. Introduction - current situation
Forecaster: a great variety of products
ECMWF EPS and derivedproducts www.ecmwf.int
ECMWF EPS and derivedproducts www.ecmwf.int
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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SRNWP PEPS
PEPS Udos model market (DWD Intranet, in future included into NinJo)
COSMO-LEPS
Decision, which EPS tool will be used, depends from
• Purpose of my forecast (overview,
• ECMWF• GME• GFS• UKMO• LFPW• CMC (still not used)
Plots for global models:
Availableparameters:Z500T850MSLP
detailled view, ... severe weather) • lead time• expected scale of the event
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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Problems (or advantages?):
Forecaster has to keep in mind:
• Clustering always provides a compromise. Different clustering methods could lead to different results.
• selection of available models allows to create a EPS as well from global models as from LAMs (different model physics, parametrisation scheme and resolution, ...)
---> SRNWP EPS
• No model is perfect, models more or less inconsistent („jumping“, caused from changes in initial and boundary conditions).
• The EPS mean / the best populated cluster / the majority of global • models not always shows the szenario that finally will happen.
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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EPS product lead time used for ... able to predictECMWF Clusters/Tubes, EPSmean
H+72 ... 168 General overview ( ... the most likely szenario) –main synoptic pattern
Multi - plots fromUdo´s modelmarket (Intranet)
H+72 ... 168 Planetary waves, Blocking situations, longpersisting anomalies, central low, largethrough, . . .
EFI H+24(36)...H+168(240)
Patterns provided by the EPS related to possiblesevere weather or rare events. Highly scalable in
Stamps, plumes,EPSgrams
H+24(36)...H+168(240)
parameter and timeEvents in synoptic scale (major synopticstorms, cold outbreaks, heat waves,
Probabilities H+36 ... 168...240
large-scale precip events, snow melt...)
COSMO-LEPS H+24 ... 120 High spatial resolution. Allows to evaluateorographic effects (overestimated ?)
SRNWP EPS H+12 ... 42 Events of sub-syn scale, effects trigerredby orography (catabatic winds, heat islands)
2. EPS Products used for severe weather
prediction
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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3. Case studies
A) Late frost - 20/21/22 April 2005
B) Heavy precipitation - 14 May 2005
C) „Hot day“ .... 03 June 2005
D) Thunderstorm - Squall line 03/04 June 2005
How did COSMO-LEPS and SRNWP-PEPS perform
• against observations ?
• against probabilities of the „pure“ (uncalibrated) ECMWF EPS?
SRNWP-PEPS (PEPS): http://www.dwd.de/en/FundE/Projekte/ PEPS/index.htm (forecasts password-protected)
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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A) Late frost - 20/21/22 April 2005
MSLP analysis, 20 April, 06 UTC
Tmin Observations, 20 April, 06 UTC(NE-Part of Germany)
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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PEPS forecast, 19 Apr 05, 12 + 18 ... 30 H(EPS-mean)
COSMO-LEPS,17 April 05, 12 + 42 ... 66 H
COSMO-LEPS, 18 April 05, 12 + 18 ... 42 H
SRNWP-PEPS: Temp below 3C in the N-partof Germany likely, frost 2 m above sfc not !
COSMO-LEPS: Frost in theNE-part of Germany likely !
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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ECMWF EPS probabilities for Tmin > 0 C18 April, 12 + 36 H
ECMWF EPS probabilities for Tmin > 0 C19 April, 00 + 24 H
Frost in the NE-part of Germany likely !
Frost in the NE-part of Germany likely !
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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MSLP analysis, 22 April, 06 UTC
Two days later... The climax of the cold outbreak
Tmin Observations, 22 April, 06 UTC
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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COSMO-LEPS, 17 April 05, 12 + 90 ... 114 H
COSMO-LEPS, 18 April 05, 12 + 66 ... 90 H
Event well predicted by COSMO-LEPS as well as by the ECMWF EPSeven in the early medium-range !
ECMWF EPS, 17 April 05, 12 + 96 ... 120 H
ECMWF EPS, 17 April 05, 12 + 96 ... 120 H
18 April 05, 12 + 72 ... 96 H
18 April 05, 12 + 72 ... 96 H
ProbabilitiesTmin < 0 C22 April, 06 UTC
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
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B) Heavy precipitation - 14 May 2005
Precip (obs, 24 hr-accumulated), 15 May 2005, 06 UTC
MSLP analysis, 14 May, 18 UTCPrecip locally above 50 mm / 24 hin the W-part above 30 mm
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
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PEPS, 14 May, 00 + 06 ... 30 H24 hr-acc precipprobab > 50 mm
PEPS, 14 May, 00 + 06 ... 30 H24 hr-acc precipprobab > 20 mm
PEPS, 14 May, 00 + 06 ... 30 HEPS mean
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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COSMO-LEPS forecasts: probab´s > 50 mm / 24 h (top) and > 20 mm / 24 h (bottom)11 May 12 + 66 ... 90 H 12 May 12 + 42 ... 66 H 13 May 12 + 18 ... 42 H
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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ECMWF-EPS forecasts 15 May 12 UTC (24 hr accum precip: probab´s > 20 mm / 24 hSignal became weaker with decreasing lead time and approaching of the event
11 May 12 + 72 ... 96 H 12 May 00 + 60 ... 84 H 12 May 12 + 48 ... 72 H
13 May 00 + 36 ... 60 H 13 May 12 + 24 ... 48 H 14 May 00 + 12 ... 36 H
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
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C) „Hot day“ .... 03 June 2005
MSLP analysis, 03 June, 15 UTCTmax (Obs), 03 June, 18 UTCFew stations in SW-Germany > 30°C !
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
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PEPSmean, 02 June, 12 + 06 ... 30 H 03 June, 00 + 06 ... 30 H Probabilities not available !
PEPS forecasts based on 02 June, 12 UTC and 03 June, 00 UTC didn´t show Tmax above 30 C over SW Germany (EPSmean) !
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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COSMO-LEPS probabilities T > 30 C30 May 12 + 90 ... 114 H31 May 12 + 66 ... 90 H
01 June 12 + 42 ... 66 H
Tmax above 30 C over SW-Germany very likely !Persistent signal
EPS (ECMWF) withoutof any signal !
02 June 12 + 18 ... 42 H
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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ECMWF EPSprobab´s Tx > 30 C(03 June, 18 UTC)
ECMWF EPSprobab´s Tx > 25 C(03 June, 18 UTC)
02 June, 00 + 36 ... 42 H 02 June, 12 + 24 ... 30 H
Tmax underestimatedcaused from the„lower“ resolutionof the EPS
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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D) Thunderstorm - Squall line 03/04 June 2005
Observed gusts (m/s), 03 June, 18 UTC 04 June, 00 UTC
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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Damages by the storm in theforests near Offenbach(picture by Klaus Paetzold)
Hail in Northern Germany(picture by Matthias Jaenicke)
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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PEPS, prob fx > 20 m/s03 June, 00 + 06 ... 18 H
prob fx > 20 m/s03 June, 00 + 18 ... 30 H
PEPS, prob fx > 20 m/s, 03 June, 12 + 06 ... 18 H
Most severe gusts over NW and N-Part of Germany ?
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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COSMO-LEPS fx > 20 m/s30 May 12 + 96 ... 120 H31 May 12 + 72 ... 96 H
01 June 12 + 48 ... 72 H
Weak signals for gusts over the W- and S-part of GermanySignal over N-Germanyfor lead time > 48 h only
02 June 12 + 24 ... 48 H
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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ECMWF EPS probabilities for gusts > 20 m/s (03 June, 18 ... 24 UTC)
01 June, 00 + 66 ... 72 H 01 June, 12 + 54 ... 60 H
02 June, 00 + 42 ... 48 H 02 June, 12 + 30 ... 36 H
Signal over N-partof Germany not consistent
Increased prob´slater...
No indications overthe central part ofGermany !
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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4. Preliminary verification results
COSMO-LEPS: • still subjective verification, carried out by the medium-range shift meteorologist• Tables: Verification against observations
Main results:
• Tmin, Tmax: useful, able to add value to forecasts (improved)• Wind gusts: good, orographic effects overestimated• Conv wind gusts: signals mostly too weak (Improvement ?)• Large-scale precip: good, orographic effects overestimated• Convective precip: not useful• CAPE: still under evaluation• Snow: good, orographic effects overestimated
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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PEPS: • operational experimental suite since beginning of this year • Forecaster collecting experience • Set of forecasts (weather parameter, leading time) will be increased
Parameter: 24h-accumutated precipitation (00 UTC +06...+30h)Observations: Max. 217 synoptical stationens of the DWD (06...06 UTC)
N: Sample sizePOD: Probability of Detection (hit rate). Perfect score: 1FAR: False Alarm Ratio. Perfect score: 0HSS: Heidke Skill Score. Perfect score: 1TS: Threat Score. Perfect score: 1
HSS=100*(a+d-R)/(a+b+c+d-R)R=((a+b)(a+c)+(c+d)(b+d))/(a+b+c+d)
TS=100*a/(a+b+c)
. Obs yes Obs nofc yes a bfx no c d
. Obs yes Obs nofc yes a bfx no c d
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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PEPS - "Probability of Detection" and "False Alarm Rate"
0,00
0,10
0,20
0,30
0,40
0,50
0,60
0,70
0,80
0,90
1,00
Date
POD
FAR
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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Categorical verification of PEPS - Heidke skill score, Threat Score and Correlation Coefficient
0,00
0,10
0,20
0,30
0,40
0,50
0,60
0,70
0,80
0,90
1,00
Date
HSS
TS
r²
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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5. Conclusions
• Forecaster hat to deal with and to check a great collection of products in a limited time frame before making a decision
• EPS-products: more and more accepted by the forecaster - content has to be condensed and compressed
- products valid for different temporal and spatial scales- tailored products predicting severe weather in the meso-scale -----> COSMO - LEPS, SRNWP PEPS
• preliminary verification results of COSMO - LEPS and SRNWP PEPS encouraging (daily use by the forecaster, case studies)
- COSMO - LEPS: quasi-operational use, improvements to be seen- SRNWP PEPS: experimental, first results promisingly
Problem presenting EPS forecast customer-friendly not been solved
DWD ECMWF Forecast Product Users Meeting 15 - 17 June 2005
Deutscher WetterdienstDeutscher WetterdienstCentral Forecasting
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CentralForecasting
That´s it ! Thank you for your attention!
Headquarterof the DWDin Offenbach