diff --git a/Project.toml b/Project.toml
index c3331782..735622b8 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "CLIMAParameters"
 uuid = "6eacf6c3-8458-43b9-ae03-caf5306d3d53"
 authors = ["Climate Modeling Alliance"]
-version = "0.8.4"
+version = "0.8.5"
 
 [deps]
 DocStringExtensions = "ffbed154-4ef7-542d-bbb7-c09d3a79fcae"
diff --git a/src/parameters.toml b/src/parameters.toml
index a84e9498..9f1df313 100644
--- a/src/parameters.toml
+++ b/src/parameters.toml
@@ -1109,7 +1109,7 @@ value = 29180
 type = "float"
 description = "Coefficient for calculating J_hom parameterized by Koop 2000 [-]. From Koop 2000. DOI: 10.1038/35020537."
 
-# Microphysics - Luo 1995 H2SO4 vapor pressure 
+# Microphysics - Luo 1995 H2SO4 vapor pressure
 
 [p_over_sulphuric_acid_solution_T_max]
 value = 235
@@ -1181,6 +1181,25 @@ value = 0.2285
 type = "float"
 description = "Coefficient in power law for the area of ice side plane, column, bullet, and planar polycrystal aggregates in Mitchell 1996--used in P3 Scheme (Morrison and Milbrandt 2015) [μm^(2-σ_M1996)]. To adjust units into m and m2, see the P3 Scheme documentation."
 
+[Heymsfield_mu_coeff1]
+value = 0.00191
+type = "float"
+description = "Coefficient for shape parameter mu for ice in P3 scheme. See eq 3 in Morrison and Milbrandt 2015. Units: [m^0.8]"
+
+[Heymsfield_mu_coeff2]
+value = 0.8
+type = "float"
+description = "Coefficient for shape parameter mu for ice in P3 scheme. See eq 3 in Morrison and Milbrandt 2015. Units: [-]"
+
+[Heymsfield_mu_coeff3]
+value = 2
+type = "float"
+description = "Coefficient for shape parameter mu for ice in P3 scheme. See eq 3 in Morrison and Milbrandt 2015. Units: [-]"
+
+[Heymsfield_mu_cutoff]
+value = 6
+type = "float"
+description = "Limiter for shape parameter mu for ice in P3 scheme. See eq 3 in Morrison and Milbrandt 2015. Units: [-]"
 
 # Microphysics - Aerosol activation