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AEMET – 6/7-November-2018

Alejandro Roa – Head of the Forecasting Techniques and Applications Area Javier Rodríguez – Head of the National Forecasting System. AEMET – 6/7-November-2018. Contents. AEMET organization chart Deterministic-atmospheric NWP used in AEMET Use of HARMONIE-AROME in AEMET

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AEMET – 6/7-November-2018

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  1. Alejandro Roa – Headof the Forecasting Techniques and Applications AreaJavier Rodríguez – Head of the National Forecasting System AEMET – 6/7-November-2018

  2. Contents • AEMET organization chart • Deterministic-atmospheric NWP used in AEMET • Use of HARMONIE-AROME in AEMET • Developments of HARMONIE-AROME in AEMET • Weakenesses of HARMONIE-AROME cy40. • Convective precipitation • Maximum wind gusts • Minimum temperature in radiation frosts HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  3. AEMET organization chart Model adaptation, forecast and subjective verification Model development and objective verification HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  4. Deterministic-atmospheric NWP used in AEMET NWP web page (nottheonlyone): http://www0.aemet.es/wwj/stapwww/fijos/web/visu/index.htm HRES-IFS HARMONIE-AROME Old HIRLAM Res. 0.15/0.05 (Will be deprecated soon) HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  5. Use of HARMONIE-AROME in AEMET Different products and forecast time (every 1, 3, 6, 12, 24 or 48 h) for HARMONIE-AROME c38 and c40 HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  6. Use of HARMONIE-AROME in AEMET http://www0.aemet.es/wwj/stapwww/fijos/web/visu/index.htm • This website is the most used by the operational forecasters. Includes satellite, radar and lightning information, but mainly information of numerical models. First, the ECMWF’s IFS, both deterministic and probabilistic models. Also the “old” HIRLAM, high and low resolution. • HARMONIE-AROME is used in AEMET since around 8 years. At this moment there are two different versions, cycle 38 and cycle 40, the reference cycle. A number of different fields of the model are presented ,for ranges between 00 and 48 hours and four runs per day (00, 06, 12 and 18): cloudiness, base and cloud top, visible and infrared pseudoimages, snow, snow-height, precipitation, wind, etc. HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  7. Developments of HARMONIE-AROME in AEMET Estimation of lightning based on HARMONIE-AROME integrated graupel field http://noreste.aemet.es/pn33/ngiv-r/iberia/ HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  8. Developments of HARMONIE-AROME in AEMET Snow fall limit (To be uploaded in gl) • The probability that a snowfall had completed its transition to rain is calculated by logistic regression applied to a new variable: the phase • This phase is derived from the analysis of the equation of snowflake melting and the Marshall-Palmer distribution. The snowfall limit is defined as the altitude at which this probability is 50% HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  9. Developments of HARMONIE-AROME in AEMET New tool Skew-T used for vertical postprocessing • Made in python only using eccodes and matplotlib as libraries. • It reads BUFR and GRIB (variables at hybrid levels) HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  10. Developments of HARMONIE-AROME in AEMET • Representation of tephigrams and skew-T diagrams. • Plot of hodographs, with left and right supercell motion (Bunkers method) • It computes several index like LIFT, CAPE, SRH... HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  11. Developments of HARMONIE-AROME in AEMET • Comparisonof two soundings, for example observation versus model integration. • Interesting for model developers testing branches or cycles of model. HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  12. Weakenesses of HARMONIE-AROME cy40 1. Convectiveprecipitation • During the 2017 convective season, there were several high impact weather events in which precipitation associated with deep and organized convection was underestimated or directly missed. • Case study of 7th August 2017 (18-24 UTC): HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  13. Weakenesses of HARMONIE-AROME cy401. Convectiveprecipitation HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  14. Weakenesses of HARMONIE-AROME cy401. Convectiveprecipitation HARM Cy40 CAPE = 1927 J/Kg SBCAPE = 2017 J/Kg CIN = 37 J/Kg CAPEv = 2302 J/Kg LCL = 746 hPa ECMWF HRES CAPE = 961 J/Kg SBCAPE = 1407 J/Kg CIN = 229 J/Kg CAPEv = 1336 J/Kg LCL = 782 hPa HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  15. Weakenesses of HARMONIE-AROME cy401. Convectiveprecipitation HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  16. Weakenesses of HARMONIE-AROME cy40 1. Convectiveprecipitation HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  17. Weakenesses of HARMONIE-AROME cy401. Convectiveprecipitation HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  18. Weakenesses of HARMONIE-AROME cy401. Convectiveprecipitation • Only 5-20 mm were registered in the area of interest, although there were high intensities, as most of the precipitation was produced in only 10-20 minutes. • The most severe parameter was hail, with hailstones of an average diameter of 3-4 cm and a maximum diameter of 5-6 cm. • Major impacts were produced in Spanish western Pre-Pyrinees, mainly due to a Splitting Storm and the associated cyclonic supercell (right move). • Major impacts: • Difficulties to drive in the Pyrinees Motorway that connects Pamplona (Navarra) and Jaca (Huesca; Aragon). • Huge damages in cars: broken windscreens and significant damages in sheets. • Major damage to roofs and glass breakages in houses. • Losses in agriculture. HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  19. Weakenesses of HARMONIE-AROME cy401. Convectiveprecipitation HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  20. Weakenesses of HARMONIE-AROME cy40 1. Convectiveprecipitation HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  21. Weakenesses of HARMONIE-AROME cy40 1. Convectiveprecipitation • The report and its main conclusions were sent to the NWP Area and the Area of Forecasting Techniques and Applications: • The precipitation associated with the deep and organized convection in the Western Spanish Pre-Pyrenees was performed better by ECMWF (HRES and ENS) and HARM Cy38 than by HARM Cy40. • It was strange that HARM Cy40 did not solve convective precipitation with CAPEs very high (around 2000 J/Kg) and very low CINs (although quite high LCL). • The problem was transmitted to the Hirlam Consortium. • From the point of view of subjective evaluation, during the 2018 convective season there have been many fewer cases of high impact weather events in which precipitation associated with deep and organized convection has been underestimated or missed by HARM Cy40. • In any case, during 2018 convective season there have been still some cases in which the HARM Cy40 did not have a good performance. HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  22. Weakenesses of HARMONIE-AROME cy40 1. Convectiveprecipitation • 12th June 2018 (03-09 UTC), reported by forecasters of the Forecast and Watch Group of Barcelona. HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  23. Weakenesses of HARMONIE-AROME cy40II. Maximumwindgusts A significant overestimation of maximum wind gusts by HARM Cy40 was detected during spring and summer 2018, especially in the case of convective wind gusts. 3-6th August 2018: the unique heat wave of 2018 in Spain, with some dry downbursts and maximum gusts associated between 60 and 100 Km/h. HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  24. Weakenesses of HARMONIE-AROME cy40. II. Maximumwindgusts HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  25. Weakenesses of HARMONIE-AROME cy40. II. Maximumwindgusts HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  26. Weakenesses of HARMONIE-AROME cy40. II. Maximumwindgusts HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  27. Weakenesses of HARMONIE-AROME cy40. II. Maximumwindgusts HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  28. Weakenesses of HARMONIE-AROME cy40. II. Maximumwindgusts • Some conclusions about these convective episodes: • The observed maximum gusts associated with dry and wet downbursts registered by AWS were between 60 and 100 Km/h. • There is a limited density of AWS but crowdsourcing data were also analysed  There were not estimated gusts higher than those registered by AWS and there were not major impacts. • ECMWF HRES and Hirlam HRES were not able to solve very strong wind gusts (> 70 Km/h) associated with deep convection. • HARMONIE-AROME was able to solve very strong wind gusts associated with deep convection, but it overestimated, although HARM Cy38 overestimated much less than HARM Cy40. • This significant overestimation of HARM Cy40 associated with deep convection, with large areas with forecasted maximum gusts of 100-120 Km/h and in some cases quite large areas of more than 120 Km/h, was a problem (too many false alarms) for bench forecasters. HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  29. Weakenesses of HARMONIE-AROME cy40. II. Maximumwindgusts • The NWP area was informed about this problem and they worked in the recalibration of the maximum wind gust parameter in HARM Cy40. • After this recalibration, no significant overestimations of maximum wind gusts associated with deep convection have been detected. • It will be important to observe the behaviour of this parameter during the next months, in episodes with predominance of larger-scale winds, and the trend to underestimate the strongest wind gusts, those ones above 20 m/s (72 Km/h) and especially above 25 m/s (90 Km/h). Source: NWP Area HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  30. Weakenesses of HARMONIE-AROME cy40. III. Minimum temperature in radiation frosts 6th December 2017: ridge and anticyclonic situation with persistent fog in the Northern Plateau and snow in the surroundings of the Pyrenees and the Cantabrian Mountains. Besides, clear skies and very low winds favoured radiation frosts. HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  31. Weakenesses of HARMONIE-AROME cy40. III. Minimum temperature in radiation frosts • Some conclusions: • All the models and the postprocessing had difficulties to perform well the minimum temperature, with a clear overestimation and in general no detection of strong frosts (Tmin < -8 ºC). • Hirlam High Resolution and HARM Cy38 performed better than ECMWF HRES, postprocessing and HARM Cy40, taking into account both the location and amplitude. • In some large areas (with and without snow on the ground), the ECMWF HRES and HARM Cy40 overestimation of the minimum temperature was around 6-8 ºC. • This weakness of direct NWP output also appeared the two previous days, and it is quite typical of these radiation frosts events, in general with a higher overestimation of Tmin if there is snow on the ground. HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

  32. Thanksforyourattention HARMONIE User Workshop. 6-7h November 2018. AEMET Headquarters

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