diff --git a/sorc/ncep_post.fd/CALVIS_GSD.f b/sorc/ncep_post.fd/CALVIS_GSD.f
index ca9028294..c2795a6e5 100644
--- a/sorc/ncep_post.fd/CALVIS_GSD.f
+++ b/sorc/ncep_post.fd/CALVIS_GSD.f
@@ -91,13 +91,15 @@ SUBROUTINE CALVIS_GSD(CZEN,VIS)
 !   2021-05        Wen Meng  - Add checking for undefined points invloved in computation
 !   2021-08        Wen Meng  - Restrict divided by 0.
 !   2021-10        Jesse Meng - 2D DECOMPOSITION
+!   2023-11        Tim Corrie, Eric James - addition of attenuation for blowing snow
 !                           
 !------------------------------------------------------------------
 !
 
+      use vrbls2d, only: sno, si, ustar
       use vrbls3d, only: qqw, qqi, qqs, qqr, qqg, t, pmid, q, u, v, extcof55, aextc55
-      use params_mod, only: h1, d608, rd
-      use ctlblk_mod, only: jm, im, jsta_2l, jend_2u, lm, modelname, spval,&
+      use params_mod, only: h1, d608, rd, g
+      use ctlblk_mod, only: jm, im, jsta_2l, jend_2u, lm, modelname, spval, method_blsn,&
                                     ista_2l, iend_2u
 
       implicit none
@@ -109,6 +111,10 @@ SUBROUTINE CALVIS_GSD(CZEN,VIS)
       REAL RHB(ista_2l:iend_2u,jsta_2l:jend_2u,LM)
       REAL CZEN(ista_2l:iend_2u,jsta_2l:jend_2u)
 
+      real :: z, ustar_t, u_p, lamda, r_bar, alpha
+      real :: rho_sno
+      real :: z_r, Q_s, C_r, c_z, c_alpha, vis_blsn, BETABLSN
+
       real celkel,tice,coeflc,coeflp,coeffc,coeffp,coeffg
       real exponlc,exponlp,exponfc,exponfp,exponfg,const1
       real rhoice,rhowat,qrain,qsnow,qgraupel,qclw,qclice,tv,rhoair,  &
@@ -300,6 +306,45 @@ SUBROUTINE CALVIS_GSD(CZEN,VIS)
           if (t(i,j,lm)< 270. .and. temp_fac==1.)          &
              write (6,*) 'Problem w/ temp_fac - calvis'
 
+! Key calculation of attenuation from blowing snow -- updated 5 August 2022 by Tim Corrie
+! Framework is from Letcher et al (2021)
+
+        ustar_t = 0.2
+        u_p = 2.8*ustar_t
+        lamda = 0.45
+        z = 2.0
+        alpha = 15.0
+        r_bar = 0.0002
+
+!        print *, i,j
+
+
+        if (si(i,j)<spval .and. si(i,j) .ge. 1.0) then
+            z_r = 1.6*(ustar(i,j)**2./(2.*g))
+            Q_s = max((0.68/ustar(i,j))*(RHOAIR/g)*(ustar(i,j)**2.-ustar_t**2.),0.0)
+            C_r = (Q_s/u_p)*(lamda*g/ustar(i,j)**2.)*exp(-lamda*z_r*g/ustar(i,j)**2.)
+            c_z = max(C_r * exp(-1.55*((0.05628*ustar(i,j))**-0.544 - z**-0.544)),1e-15)
+            c_alpha = alpha/(alpha+2) !simplified version of (6) in Letcher et al (2021)    
+            rho_sno = sno(i,j)/(si(i,j)/1.0e3)
+            rho_sno = rho_sno*2. + 10.*max(0.,rho_sno-0.15)
+            vis_blsn = (5.217*rho_sno*r_bar**1.011)/(1.82*c_z*c_alpha)
+            BETABLSN = 3.912/(vis_blsn/1000.0)
+            ! print to ensure quality
+            !print *, "z_r", z_r
+            !print *, "Q_s", Q_s
+            !print *, "C_r", C_r
+            !print *, "c_z", c_z
+            !print *, "c_alpha", c_alpha
+            !print *, "sno/SWE", sno(i,j)
+            !print *, "si/SNOD", si(i,j)/1.0e3
+            !print *, "rho_sno", rho_sno
+            !print *, "vis_blsn", vis_blsn
+            !print *, "BETABLSN", BETABLSN
+        else
+            BETABLSN = 0
+            !print *, "BETABLSN", BETABLSN
+        end if
+
 ! Key calculation of attenuation from each hydrometeor type (cloud, snow, graupel, rain, ice)
         BETAV=COEFFC*CONCFC**EXPONFC                            &
              + coef_SNOW*CONCFP**EXPONFP                        &
@@ -309,6 +354,9 @@ SUBROUTINE CALVIS_GSD(CZEN,VIS)
 ! Addition of attenuation from aerosols if option selected
         if(method == 2 .or. method == 3)then ! aerosol method
             BETAV = BETAV + aextc55(i,j,lm)*1000.
+            if(method_blsn) then ! BLSN method, updated 8 August 2022 by Tim Corrie
+                BETAV = BETAV + BETABLSN
+            endif
         endif
 
 !  Calculation of visibility based on hydrometeor and aerosols.  (RH effect not yet included.)
diff --git a/sorc/ncep_post.fd/CTLBLK.f b/sorc/ncep_post.fd/CTLBLK.f
index 224742918..663a6d6eb 100644
--- a/sorc/ncep_post.fd/CTLBLK.f
+++ b/sorc/ncep_post.fd/CTLBLK.f
@@ -18,6 +18,7 @@
 !>  2023-04-04 | Li(Kate Zhang) | Add namelist optoin for CCPP-Chem (UFS-Chem) and 2D diag. output (d2d_chem) for GEFS-Aerosols and CCPP-Chem model.
 !>  2023-04-17 | Eric James | Adding 160 and 320 m above ground to HTFD for RRFS output.
 !>  2023-08-16 | Yali Mao   | Add gtg_on logical option
+!>  2023-11-24 | Eric James | Add method_blsn logical option
 !-----------------------------------------------------------------------
 !> @defgroup CTLBLK_mod Sets default parameters that are used throughout the UPP code
 !-----------------------------------------------------------------------
@@ -73,6 +74,7 @@ module CTLBLK_mod
   logical :: aqf_on        !< Turn on Air Quality Forecasting (CMAQ-based).
   logical :: slrutah_on    !< Calculate snow to liquid ratio (SLR) using method from University of Utah.
   logical :: gtg_on        !< Turn on GTG (Graphical Turbulence Guidance)
+  logical :: method_blsn   !< Turn on blowing snow effect on visibility diagnostic
 !
   logical :: SIGMA      !< No longer used/supported.
   logical :: RUN        !< No longer used/supported.
diff --git a/sorc/ncep_post.fd/WRFPOST.f b/sorc/ncep_post.fd/WRFPOST.f
index d2b0ef546..01a63baa1 100644
--- a/sorc/ncep_post.fd/WRFPOST.f
+++ b/sorc/ncep_post.fd/WRFPOST.f
@@ -37,6 +37,7 @@
 !         and 2D diag. output (d2d_chem) for GEFS-Aerosols and CCPP-Chem model.
 !> 2023-05-20 | Rahul Mahajan             | Bug fix for fileNameFlat as namelist configurable
 !> 2023-08-16 | Yali Mao                  | Add gtg_on logical option
+!> 2023-11-29 | Eric James                | Add method_blsn logical option
 !> @author Mike Bladwin NSSL/SPC @date 2002-06-18
 !---------------------------------------------------------------------
 !> @return wrfpost
@@ -127,7 +128,7 @@ PROGRAM WRFPOST
               mdl2agl_tim, mdl2std_tim, mdl2thandpv_tim, calrad_wcloud_tim,nasa_on,gccpp_on,         &
               fixed_tim, time_output, imin, surfce2_tim, komax, ivegsrc, d3d_on, gocart_on,rdaod,    &
               readxml_tim, spval, fullmodelname, submodelname, hyb_sigp, filenameflat, aqf_on,numx,  &
-              run_ifi_tim, slrutah_on, d2d_chem, gtg_on
+              run_ifi_tim, slrutah_on, d2d_chem, gtg_on, method_blsn
       use grib2_module,   only: gribit2,num_pset,nrecout,first_grbtbl,grib_info_finalize
       use upp_ifi_mod, only: write_ifi_debug_files
 !- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
@@ -153,7 +154,7 @@ PROGRAM WRFPOST
 !
       integer      :: kpo,kth,kpv
       real,dimension(komax) :: po,th,pv
-      namelist/nampgb/kpo,po,kth,th,kpv,pv,fileNameAER,d3d_on,gocart_on,gccpp_on, nasa_on,gtg_on,popascal &
+      namelist/nampgb/kpo,po,kth,th,kpv,pv,fileNameAER,d3d_on,gocart_on,gccpp_on, nasa_on,gtg_on,method_blsn,popascal &
                      ,hyb_sigp,rdaod,d2d_chem, aqf_on,slrutah_on, vtimeunits,numx,write_ifi_debug_files
       integer      :: itag_ierr
       namelist/model_inputs/fileName,IOFORM,grib,DateStr,MODELNAME,SUBMODELNAME &
@@ -261,6 +262,7 @@ PROGRAM WRFPOST
         aqf_on      = .false.
         slrutah_on  = .false.
         gtg_on   = .false.
+        method_blsn = .true.
         popascal    = .false.
         fileNameAER = ''
         rdaod       = .false.