diff --git a/src/tools/other/mode_time_domain/mtd.cc b/src/tools/other/mode_time_domain/mtd.cc
index 45dc13a254..acfe9c3b27 100644
--- a/src/tools/other/mode_time_domain/mtd.cc
+++ b/src/tools/other/mode_time_domain/mtd.cc
@@ -210,18 +210,16 @@ MM_Engine engine;
    //  storage for valid times
    //
 
-unixtime * valid_times_fcst = 0;
-valid_times_fcst = new unixtime [fcst_filenames.n()];
-unixtime * valid_times_obs = 0;
-valid_times_obs = new unixtime [obs_filenames.n()];
+vector<unixtime> valid_times_fcst;
+vector<unixtime> valid_times_obs;
 
    //
    //  read the data files
    //
 
-mtd_read_data(config, *(config.fcst_info), fcst_filenames, fcst_raw, valid_times_fcst);
+valid_times_fcst = mtd_read_data(config, *(config.fcst_info), fcst_filenames, fcst_raw);
 
-mtd_read_data(config, *(config.obs_info),   obs_filenames,  obs_raw, valid_times_obs);
+valid_times_obs = mtd_read_data(config, *(config.obs_info),   obs_filenames,  obs_raw);
 
 if ( fcst_raw.nt() != obs_raw.nt() )  {
 
@@ -446,6 +444,13 @@ for (j=0; j<(fcst_obj.n_objects()); ++j)  {
 
       mask_2d = fcst_obj.const_t_mask(t, j + 1);   //  1-based
 
+      if (t < 0 || t >= (int)valid_times_fcst.size()) {
+	  mlog << Error 
+	       << "\n  " << program_name << ": index " << t << " out of forecast valid times range 0 to " << valid_times_fcst.size()-1
+	       << "\n\n";
+	  exit ( 1 );
+      }
+
       fcst_raw.get_data_plane(t, raw_2d);
 
       att_2 = calc_2d_single_atts(mask_2d, raw_2d, j + 1, config.inten_perc_value);
@@ -480,6 +485,13 @@ for (j=0; j<(obs_obj.n_objects()); ++j)  {
 
       mask_2d = obs_obj.const_t_mask(t, j + 1);   //  1-based
 
+      if (t < 0 || t >= (int)valid_times_obs.size()) {
+	  mlog << Error 
+	       << "\n  " << program_name << ": index " << t << " out of obs valid times range 0 to " << valid_times_obs.size()-1
+	       << "\n\n";
+	  exit ( 1 );
+      }
+
       obs_raw.get_data_plane(t, raw_2d);
 
       att_2 = calc_2d_single_atts(mask_2d, raw_2d, j + 1, config.inten_perc_value);
@@ -695,7 +707,14 @@ if ( have_pairs )  {
 
          // cout << "j = " << j << ",   vol = " << mask_2d.object_volume(0) << '\n';
 
-         fcst_raw.get_data_plane(t, raw_2d);
+	 if (t < 0 || t >= (int)valid_times_fcst.size()) {
+	    mlog << Error 
+	       << "\n  " << program_name << ": index " << t << " out of forecast valid times range 0 to " << valid_times_fcst.size()-1
+	       << "\n\n";
+	    exit ( 1 );
+	 }
+
+	 fcst_raw.get_data_plane(t, raw_2d);
 
          att_2 = calc_2d_single_atts(mask_2d, raw_2d, j + 1, config.inten_perc_value);
 
@@ -736,7 +755,14 @@ if ( have_pairs )  {
          // mask_2d = mask.const_t_mask(t, j + 1);   //  1-based
          mask_2d = mask.const_t_mask(t, 1);   //  1-based
 
-         obs_raw.get_data_plane(t, raw_2d);
+ 	 if (t < 0 || t >= (int)valid_times_obs.size()) {
+	     mlog << Error 
+	       << "\n  " << program_name << ": index " << t << " out of obs valid times range 0 to " << valid_times_obs.size()-1
+	       << "\n\n";
+	     exit ( 1 );
+	 }
+
+	 obs_raw.get_data_plane(t, raw_2d);
 
          att_2 = calc_2d_single_atts(mask_2d, raw_2d, j + 1, config.inten_perc_value);
 
@@ -882,9 +908,6 @@ mlog << Debug(2)
 
 do_mtd_nc_output(config.nc_info, engine, fcst_raw, obs_raw, fcst_obj, obs_obj, config, path.c_str());
 
-if ( valid_times_fcst )  { delete [] valid_times_fcst;  valid_times_fcst = 0; }
-if ( valid_times_obs )  { delete [] valid_times_obs;  valid_times_obs = 0; }
-
    //
    //  done
    //
@@ -1066,14 +1089,13 @@ ConcatString path;
    //  storage for valid times
    //
 
-unixtime * valid_times = 0;
-valid_times = new unixtime [single_filenames.n()];
+vector<unixtime> valid_times;
 
    //
    //  read the data files
    //
 
-mtd_read_data(config, *(config.fcst_info), single_filenames, raw, valid_times);
+valid_times = mtd_read_data(config, *(config.fcst_info), single_filenames, raw);
 
    //
    //  copy forecast name/units/level to observation
@@ -1177,7 +1199,15 @@ for (j=0; j<(obj.n_objects()); ++j)  {
 
       mask_2d = obj.const_t_mask(t, j + 1);   //  1-based
 
+      if (t < 0 || t >= (int)valid_times.size()) {
+	  mlog << Error 
+	       << "\n  " << program_name << ": index " << t << " out of valid times range 0 to " << valid_times.size()-1
+	       << "\n\n";
+	  exit ( 1 );
+	}
+
       raw.get_data_plane(t, raw_2d);
+      //raw_2d.set_valid(valid_times[t]);
 
       att_2 = calc_2d_single_atts(mask_2d, raw_2d, j + 1, config.inten_perc_value);
 
@@ -1243,8 +1273,6 @@ mlog << Debug(2)
 do_mtd_nc_output(config.nc_info, raw, obj, config, path.c_str());
 
 
-if ( valid_times )  { delete [] valid_times;  valid_times = 0; }
-
    //
    //  done
    //
diff --git a/src/tools/other/mode_time_domain/mtd_file_base.cc b/src/tools/other/mode_time_domain/mtd_file_base.cc
index 4295a2ba85..f73e88f4ea 100644
--- a/src/tools/other/mode_time_domain/mtd_file_base.cc
+++ b/src/tools/other/mode_time_domain/mtd_file_base.cc
@@ -91,6 +91,8 @@ Nx = Ny = Nt = 0;
  
 StartValidTime = (unixtime) 0;
 
+ActualValidTimes.clear();
+
 DeltaT = 0;
 
 Filename.clear();
@@ -292,7 +294,6 @@ return;
 
 }
 
-
 ////////////////////////////////////////////////////////////////////////
 
 
@@ -306,6 +307,19 @@ return;
 
 }
 
+////////////////////////////////////////////////////////////////////////
+
+
+void MtdFileBase::init_actual_valid_times(const vector<unixtime> &validTimes)
+
+{
+
+ActualValidTimes = validTimes;
+
+return;
+
+}
+
 
 ////////////////////////////////////////////////////////////////////////
 
@@ -349,6 +363,25 @@ return ( StartValidTime + t*DeltaT );
 
 }
 
+////////////////////////////////////////////////////////////////////////
+
+
+unixtime MtdFileBase::actual_valid_time(int t) const
+
+{
+
+  if ( (t < 0) || ( t >= (int)ActualValidTimes.size()) )  {
+
+   mlog << Error << "\n\n  MtdFileBase::valid_time(int t) -> range check error\n\n";
+
+   exit ( 1 );
+
+}
+
+ return ( ActualValidTimes[t] );
+
+}
+
 
 ////////////////////////////////////////////////////////////////////////
 
diff --git a/src/tools/other/mode_time_domain/mtd_file_base.h b/src/tools/other/mode_time_domain/mtd_file_base.h
index 205b5feb92..98d30f10a1 100644
--- a/src/tools/other/mode_time_domain/mtd_file_base.h
+++ b/src/tools/other/mode_time_domain/mtd_file_base.h
@@ -85,9 +85,11 @@ class MtdFileBase {
 
       int Nx, Ny, Nt;
 
-      unixtime StartValidTime;
+      unixtime StartValidTime;   // useful for constant time increments
 
-      int DeltaT;   //  seconds
+      int DeltaT;   //  seconds, useful for constant time increments
+
+      vector<unixtime> ActualValidTimes; // useful for uneven time increments
 
       IntArray Lead_Times;
 
@@ -113,8 +115,11 @@ class MtdFileBase {
       void set_grid(const Grid &);
 
       void set_start_valid_time (unixtime);
+
       void set_delta_t          (int);   //  seconds
 
+      void init_actual_valid_times(const vector<unixtime> &validTimes);
+
       void set_lead_time(int index, int value);
 
       void set_filetype(MtdFileType);
@@ -143,6 +148,8 @@ class MtdFileBase {
 
       unixtime valid_time (int) const;
 
+      unixtime actual_valid_time (int) const;
+
       int lead_time (int index) const;
 
          //
diff --git a/src/tools/other/mode_time_domain/mtd_read_data.cc b/src/tools/other/mode_time_domain/mtd_read_data.cc
index 9872ab23ef..1f327fc5cd 100644
--- a/src/tools/other/mode_time_domain/mtd_read_data.cc
+++ b/src/tools/other/mode_time_domain/mtd_read_data.cc
@@ -27,9 +27,8 @@ using namespace std;
 ////////////////////////////////////////////////////////////////////////
 
 
-void mtd_read_data(MtdConfigInfo & config, VarInfo & varinfo,
-                   const StringArray & filenames, MtdFloatFile & raw,
-		   unixtime valid_times[])
+vector<unixtime> mtd_read_data(MtdConfigInfo & config, VarInfo & varinfo,
+			       const StringArray & filenames, MtdFloatFile & raw)
 
 {
 
@@ -45,7 +44,7 @@ int j, k;
 Met2dDataFile * data_2d_file = 0;
 Met2dDataFileFactory factory;
 DataPlane plane;
-
+vector<unixtime> valid_times;
    //
    //  read the files
    //
@@ -73,7 +72,7 @@ for (j=0; j<(filenames.n()); ++j)  {
 
    }
 
-   valid_times[j] = plane.valid();
+   valid_times.push_back(plane.valid());
 
    if ( j == 0 )  {
 
@@ -95,48 +94,51 @@ for (j=0; j<(filenames.n()); ++j)  {
 
  varinfo.set_valid(valid_times[0]);
 
+    //  store the valid times vector into the raw data for later use in do_2d_txt_output()
+ 
+ raw.init_actual_valid_times(valid_times);
+
    //
    //  check the time intervals for consistency
    //  Store the time differences between succesive valid times in an array
    //  See if differences are constant or not, and if not see if all diffs are months
    //
 
-unixtime dt_start, dt, *dtArray;
-int numDt = filenames.n() - 1;
-dtArray = new unixtime [numDt];
+unixtime dt_start;
+vector<unixtime> dtVector; 
 
 dt_start = valid_times[1] - valid_times[0];
-dtArray[0] = dt_start;
+dtVector.push_back(dt_start);
 
-for (j=2; j<(filenames.n()); ++j)  {
-   dtArray[j - 1] = dt = valid_times[j] - valid_times[j - 1];
+for (size_t k=2; k<valid_times.size(); ++k) {
+  dtVector.push_back(valid_times[k] - valid_times[k - 1]);
 }
 
 bool variableTimeIncs = false;
-for (j=0; j<numDt; ++j) {
-   if (variableTimeIncs) {
+for (size_t k=0; k<dtVector.size(); ++k) {
+  if (variableTimeIncs) {
+     break;
+  }
+  for (size_t k2=k+1; k2<dtVector.size(); ++k2) {
+    if ( dtVector[k] != dtVector[k2])  {
+      variableTimeIncs = true;
       break;
-   }
-   for (k=j+1; k<numDt; ++k) {
-      if ( dtArray[j] != dtArray[k])  {
-         variableTimeIncs = true;
-	 break;
-      }
-   }
+    }
+  }
 }
 if (variableTimeIncs) {
-   // compute the mode and use it as the actual delta, by storing it to dt_start
-   NumArray na;
-   for (j=0; j<numDt; ++j) {
-      na.add((double)dtArray[j]);
+  // compute the mode and use it as the actual delta, by storing it to dt_start
+  NumArray na;
+  for (size_t k=0; k<dtVector.size(); ++k) {
+    na.add((double)dtVector[k]);
    }	     
    dt_start = (unixtime)na.mode();
 
    // test if the differences are all months (in seconds)
    bool isMonths = true;
    int secondsPerDay = 24*3600;
-   for (j=0; j<numDt; ++j) {
-      int days = dtArray[j]/secondsPerDay;
+   for (size_t k=0; k<dtVector.size(); ++k) {
+      int days = dtVector[k]/secondsPerDay;
       if (days != 28 &&	days != 29 && days != 30 && days != 31) {
 	 isMonths = false;
 	 break;
@@ -144,7 +146,8 @@ if (variableTimeIncs) {
    }
 
    if (isMonths) {
-     mlog << Debug(2) << "\n\n mtd_read_data() -> file time increments are months (not constant), use MODE of the increments, mode=" << dt_start << " seconds = " << dt_start/(24*3600) << " days\n\n";
+     mlog << Debug(1) << "File time increments are months (not constant), use MODE of the increments, mode=" << dt_start
+	  << " seconds = " << dt_start/(24*3600) << " days\n\n";
    } else {
       // compute some measures that might be used to exit with an error, for now just show them to the user and go on
       double mean, var, svar;
@@ -153,12 +156,11 @@ if (variableTimeIncs) {
       unixtime umean = (unixtime)mean;
       unixtime uvar = (unixtime)var;
       unixtime suvar = (unixtime)svar;
-      mlog << Warning << "\n\n mtd_read_data() -> file time increments are not constant, could be problematic\n";
-      mlog << Warning << " mtd_read_data() -> use MODE of the increments, mode=" << dt_start << "\n";
-      mlog << Warning << " mtd_read_data() -> time increment properties: mean=" << umean << " variance=" << uvar << " sqrt(var)=" << suvar << "\n\n";
+      mlog << Warning << "\n\n mtd_read_data() -> File time increments are not constant, could be problematic\n";
+      mlog << Warning << " mtd_read_data() -> Using MODE of the increments, mode=" << dt_start << "\n";
+      mlog << Warning << " mtd_read_data() -> Time increment properties: mean=" << umean << " variance=" << uvar << " sqrt(var)=" << suvar << "\n\n";
    }
 }
-delete [] dtArray;
  
    //
    //  load up the rest of the MtdFloatFile class members
@@ -178,7 +180,7 @@ raw.calc_data_minmax();
    //  done
    //
 
-return;
+return valid_times;
 
 }
 
diff --git a/src/tools/other/mode_time_domain/mtd_read_data.h b/src/tools/other/mode_time_domain/mtd_read_data.h
index 69d82caa88..a9e08d13f9 100644
--- a/src/tools/other/mode_time_domain/mtd_read_data.h
+++ b/src/tools/other/mode_time_domain/mtd_read_data.h
@@ -26,10 +26,12 @@
 
 ////////////////////////////////////////////////////////////////////////
 
+//
+// returns the actual valid times
+//
 
-extern void mtd_read_data(MtdConfigInfo &, VarInfo &,
-                          const StringArray & filenames, MtdFloatFile &,
-			  unixtime valid_times[]);
+extern vector<unixtime> mtd_read_data(MtdConfigInfo &, VarInfo &,
+                        const StringArray & filenames, MtdFloatFile &);
 
 
 ////////////////////////////////////////////////////////////////////////
diff --git a/src/tools/other/mode_time_domain/mtd_txt_output.cc b/src/tools/other/mode_time_domain/mtd_txt_output.cc
index 23967d2624..8da256f4bb 100644
--- a/src/tools/other/mode_time_domain/mtd_txt_output.cc
+++ b/src/tools/other/mode_time_domain/mtd_txt_output.cc
@@ -399,8 +399,8 @@ return;
 
 void do_2d_txt_output(const MtdFloatFile & fcst_raw,
                       const MtdFloatFile &  obs_raw,
-		      const unixtime valid_times_fcst[],
-		      const unixtime valid_times_obs[],
+		      const vector<unixtime> &valid_times_fcst,
+		      const vector<unixtime> &valid_times_obs,
                       const SingleAtt2DArray & fcst_simple_att,
                       const SingleAtt2DArray &  obs_simple_att,
                       const SingleAtt2DArray & fcst_cluster_att,
@@ -496,11 +496,9 @@ for (j=0; j<(fcst_simple_att.n()); ++j)  {
 
    table.set_entry(r, fcst_lead_column, sec_to_hhmmss(fcst_simple_att.lead_time(j)));
 
-   //table.set_entry(r, fcst_valid_column, unix_to_yyyymmdd_hhmmss(fcst_simple_att.valid_time(j)));
-   table.set_entry(r, fcst_valid_column, unix_to_yyyymmdd_hhmmss(valid_times_fcst[j]));
+   table.set_entry(r, fcst_valid_column, unix_to_yyyymmdd_hhmmss(fcst_simple_att.valid_time(j)));
 
-   //table.set_entry(r,  obs_valid_column, unix_to_yyyymmdd_hhmmss(obs_raw.valid_time(t)));
-   table.set_entry(r,  obs_valid_column, unix_to_yyyymmdd_hhmmss(valid_times_obs[t]));
+   table.set_entry(r,  obs_valid_column, unix_to_yyyymmdd_hhmmss(obs_raw.actual_valid_time(t)));
 
    table.set_entry(r,  obs_lead_column,  sec_to_hhmmss(obs_raw.lead_time(t)));
 
@@ -512,13 +510,11 @@ for (j=0; j<(obs_simple_att.n()); ++j)  {
 
    t = obs_simple_att.time_index(j);
 
-   //table.set_entry(r, fcst_valid_column, unix_to_yyyymmdd_hhmmss(fcst_raw.valid_time(t)));
-   table.set_entry(r, fcst_valid_column, unix_to_yyyymmdd_hhmmss(valid_times_fcst[t]));
+   table.set_entry(r, fcst_valid_column, unix_to_yyyymmdd_hhmmss(fcst_raw.actual_valid_time(t)));
 
    table.set_entry(r,  fcst_lead_column, sec_to_hhmmss(fcst_raw.lead_time(t)));
 
-   //table.set_entry(r,  obs_valid_column, unix_to_yyyymmdd_hhmmss(obs_simple_att.valid_time(j)));
-   table.set_entry(r, obs_valid_column, unix_to_yyyymmdd_hhmmss(valid_times_obs[j]));
+   table.set_entry(r,  obs_valid_column, unix_to_yyyymmdd_hhmmss(obs_simple_att.valid_time(j)));
 
    table.set_entry(r,  obs_lead_column, sec_to_hhmmss(obs_simple_att.lead_time(j)));
 
@@ -534,8 +530,7 @@ for (j=0; j<(fcst_cluster_att.n()); ++j)  {
 
    table.set_entry(r, fcst_valid_column, unix_to_yyyymmdd_hhmmss(fcst_cluster_att.valid_time(j)));
 
-   //table.set_entry(r,  obs_valid_column, unix_to_yyyymmdd_hhmmss(obs_raw.valid_time(t)));
-   table.set_entry(r, obs_valid_column, unix_to_yyyymmdd_hhmmss(valid_times_obs[t]));
+   table.set_entry(r,  obs_valid_column, unix_to_yyyymmdd_hhmmss(obs_raw.actual_valid_time(t)));
 
    table.set_entry(r,  obs_lead_column,  sec_to_hhmmss(obs_raw.lead_time(t)));
 
@@ -547,8 +542,7 @@ for (j=0; j<(obs_cluster_att.n()); ++j)  {
 
    t = obs_cluster_att.time_index(j);
 
-   //table.set_entry(r, fcst_valid_column, unix_to_yyyymmdd_hhmmss(fcst_raw.valid_time(t)));
-   table.set_entry(r, fcst_valid_column, unix_to_yyyymmdd_hhmmss(valid_times_fcst[t]));
+   table.set_entry(r, fcst_valid_column, unix_to_yyyymmdd_hhmmss(fcst_raw.actual_valid_time(t)));
 
    table.set_entry(r,  fcst_lead_column, sec_to_hhmmss(fcst_raw.lead_time(t)));
 
diff --git a/src/tools/other/mode_time_domain/mtd_txt_output.h b/src/tools/other/mode_time_domain/mtd_txt_output.h
index b172e8a44c..e519eebd7e 100644
--- a/src/tools/other/mode_time_domain/mtd_txt_output.h
+++ b/src/tools/other/mode_time_domain/mtd_txt_output.h
@@ -48,8 +48,8 @@ extern void do_3d_pair_txt_output(const PairAtt3DArray &,
 
 extern void do_2d_txt_output(const MtdFloatFile & fcst_raw, 
                              const MtdFloatFile &  obs_raw, 
-			     const unixtime valid_times_fcst[],
-			     const unixtime valid_times_obs[],
+			     const vector<unixtime> &valid_times_fcst,
+			     const vector<unixtime> &valid_times_obs,
                              const SingleAtt2DArray & fcst_single_att, 
                              const SingleAtt2DArray &  obs_single_att, 
                              const SingleAtt2DArray & fcst_cluster_att,