Catalogue Severe Weather Netherlands today and ERA-40 Geert Groen ECMWF June 2005

Who does not want to learn from the past…. GALE Februari 1, 1953: 1836 people killed, cattle drowned people killed, cattle drowned. August 25, 1972 and Nov 6, 1990: Fogaccidents 23 dead, 42 injured FOG STORM Tornado: August 23, 1950, Veluwe, cm trees June 25, 1967, Chaam and Tricht, 11 dead Aug 11, 1972, Ameland, campers, 4 dead Oct 6, 1981, airplane F28 Moerdijk 17 dead Aug 26, 1986, Slochteren and Appingedam Aug 5, 1993, Burgum (Gr), camping Winterproblems Snow and Freezing precipitation: 1958, 1963, 1969, 1978, 1981, 2002,….

My presentation: Background Objectives Examples Experience with ERA40 Plans My presentation: Background Objectives Examples Experience with ERA40 Plans

Background for this project: Severe Weather leads to Weather Alarm, 3-5 cases/year...slow growing experience Severe Weather leads to Weather Alarm, 3-5 cases/year...slow growing experience Solution: look back in history….the catalogue Solution: look back in history….the catalogue Disaster 1953, excellent reanalysis ECMWF/NCEP Disaster 1953, excellent reanalysis ECMWF/NCEP Inspired to use ERA-40, 4D-reanalysis up to 6 days before event Inspired to use ERA-40, 4D-reanalysis up to 6 days before event

Objectives: Increasing knowledge on a synoptic scale of severe weather Open all information (incl. ERA) Open all information (incl. ERA) Increase (my) experience Increase (my) experience Improve model Improve model Operational knowledge Operational knowledge Simulate severe weather events Simulate severe weather events Stimulate (E-)learning Stimulate (E-)learning

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Typical chart-display

Experiences sofar: Positive Exploring ERA and historical material good combination Exploring ERA and historical material good combination Inspired use of operational knowledge Inspired use of operational knowledge ERA: good pressure reconstruction ERA: good pressure reconstruction ERA: thetaw mirror of fronts/troughs ERA: thetaw mirror of fronts/troughs ERA: PV315K illustrative ERA: PV315K illustrative In general: ERA OK for large-scale In general: ERA OK for large-scale

Experiences sofar: Negative ERA-resolution 6 hrs, 1.5 deg for smaller scale events ERA-resolution 6 hrs, 1.5 deg for smaller scale events Windspeed 1-3 Bft to low Windspeed 1-3 Bft to low No profiles and precipitation No profiles and precipitation

Plans and wishes……. More cases (upto 10 cases/year?) More cases (upto 10 cases/year?) Good historical material Good historical material Investigating by keyparameters Investigating by keyparameters E-learning modules E-learning modules Weather-simulator Weather-simulator Use of ECMWF and HIRLAM-forecast Use of ECMWF and HIRLAM-forecast Reanalysis of cases in HIRLAM Reanalysis of cases in HIRLAM

Suggestions, questions and remarks? Suggestions, questions and remarks? Demonstration part of the test- catalogue (7 dec 1959) Demonstration part of the test- catalogue (7 dec 1959)