1. Overview of Microphysics in NCEP Models Brad Ferrier 1,2 (Thanks to Eric Aligo 1,2 ) 1 NOAA/NWS/NCEP/EMC 2 I.M. Systems Group, Inc (IMSG) “Quick Hits” Session NCEP Production Suite Review (NPSR) NCWCP, College Park, MD 7 – 9 December 2015

2. Microphysics Schemes in EMC Models Model System Microphysics Scheme(s) Advected Variables Within Physics GFS, GEFSZhou/Moorthi et al. Qv, Qcld (Ice/water)Qc, Qi NAM: Parent Nests Ferrier-Aligo (F-A) Qv, Qt (Frain, Fice, RF) Qv, Qc, Qr, Qice, Qice*RF Qv, Qc, Qr, Qci, Qs+g, RF HWRF (all doms)F-AQv, Qt (Frain, Fice, RF)Qv, Qc, Qr, Qci, Qs+g, RF HiResWinF-A* in NMMB WSM6* in ARW Qv, Qt (Frain, Fice, RF) Qv, Qc, Qr, Qci, Qs, Qg Qv, Qc, Qr, Qci, Qs+g, RF Qv, Qc, Qr, Qci, Qs, Qg RAP, HRRRThompsonQv, Qc, Qr, Qci, Qs, Qg, Ni, Nr SREF (details)details Mix of F-A & WSM6 in NMMB members Mix of Thompson, WSM6, & Ferr in ARW members 7 - 9 Dec 2015NPSR2 Qcld = Qc + Qci, Qice = Qci + Qs+g, Qt = Qc + Qr + Qice Frain, Fice are 3D storage arrays used to separate Qc, Qr, Qice from Qt WSM6* - reduced Qg production improved composite dBZ & dBZtop FA* - early version of F-A microphysics, more similar to Ferr

3. Rime Factor (RF)  Variable Ice Density 7 - 9 Dec 2015NPSR3 RF=1 (Unrimed Snow) Liquid accretion (rime) RF>20 (Sleet, hail) RF ~ 2 to 5 (Rimed Snow) RF ~ 10 (Graupel)

4. 22-h Valid at 22Z on 20 May 2013 - Moore, OK Tornado A B A B A B Use of Vertical Cross Sections in Model Diagnostics 7 - 9 Dec 2015NPSR4 “Old” NAM Microphysics F-A Microphysics Observed Reflectivity < 50 dBZ >= 55 dBZ A B A B A B

5. Cross Section from 1.33-km Fire WX Nest 25-26 Feb 2015NCAR-FAA In-Flight Icing5 >0°C <0°C Composite Reflectivity Rimed snow (2<RF<5) Graupel (5<RF<20) Sleet (RF>20) 0°C

6. “ PHYSICS WHEEL OF PAIN ” Radiation Cu Scheme Sfc & PBL Grid Scale Microphysics 1.Phase & optical properties (r eff ), overlap assumptions, horizontal fractions 2.Precipitation (+ phase) and clouds 3.Subgrid transports, detrainment 4.Energy exchanges with land & ocean surfaces 5.Convection (deep & shallow), PBL evolution 7 - 9 Dec 2015NPSR6

7. Additional Challenges with Ice Microphysics We don’t have full, quantitative knowledge of: – Ice nucleation & multiplication – Particle size spectra of various habits in all conditions (esp. <-40C) – Collection/breakup between colliding ice particles – Properties of rimed & mixed-habit ice; e.g. m(D), V(D) All these conditions occur within deep convection Assessing costs/benefits of more advanced schemes is challenging and it should be based on evidence rather than on “conventional wisdom” 7 - 9 Dec 2015NPSR7

8. Improving Cloud Microphysics (1 of 2) Gradual build up of effective analysis tools Evaluate against remote-sensing obs – Ground-based radars + polarization – Passive & active satellite obs e.g., JCSDA-ECMWF Clouds & Precip Workshop – Large variations between advanced schemes Collaborative projects with DTC, ESRL Make use of more cloud info in U/RTMA 7 - 9 Dec 2015NPSR8

9. Improving Cloud Microphysics (2 of 2) Participate in revolving Monday meetings with: – Storm Prediction Center (SPC) – severe local convective storms (mode, evolution) – Weather Prediction Center (WPC) – precipitation, winter storms, flash floods – Aviation Weather Center (AWC) – ceiling & visibility near airports, radar echo tops in transit Participate in NCEP experimental testbeds MEG briefings have also been helpful 7 - 9 Dec 2015NPSR9

10. Solving The Moisture Puzzle We need to go from here… to here! 7 - 9 Dec 2015NPSR10 “Improved processes” are not of interest to forecasters if it does not lead to improved forecasts. Additional constraints we face: Limits in available computing (improving) & bandwidth Most complex production suite in the world