diff --git a/utils/analyze_log.py b/utils/analyze_log.py
index c52ae0f..17b938e 100644
--- a/utils/analyze_log.py
+++ b/utils/analyze_log.py
@@ -1,14 +1,16 @@
 #!/usr/bin/env python3
-"""Offline analysis of a log/forecast pair produced by the BrewPi server.
+"""Offline analysis of a log (and optional forecast) produced by the BrewPi server.
 
 Usage:
     python analyze_log.py <date_time> <sud_name> [--log-dir <dir>]
+    python analyze_log.py <path/to/log_*.json>
 
-Example:
-    python analyze_log.py 20260628T184903 Sud-0010
+The two-argument form loads logs/<date_time>_<sud_name>.json and its paired
+forecast file.  The single-argument form accepts a direct path to any
+log_*.json (e.g. a server-session log without a Sud name); the forecast panel
+is shown only if a matching forecast_*.json exists alongside it.
 
-Loads logs/<date_time>_{sud_name}.json (log and forecast) and renders the same
-two plots the PyQt GUI shows: the 3-panel realtime strip chart and the
+Renders the 3-panel realtime strip chart and, when available, the
 forecast-vs-actual comparison.
 """
 
@@ -102,33 +104,42 @@ def plot_forecast(forecast, samples, name):
 
 def main():
     parser = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
-    parser.add_argument('date_time', help='Timestamp part of the filename, e.g. 20260628T184903')
-    parser.add_argument('sud_name',  help='Sud name part of the filename, e.g. Sud-0010')
+    parser.add_argument('date_time_or_path',
+                        help='Timestamp part of the filename (e.g. 20260628T184903) '
+                             'or a direct path to a log_*.json file')
+    parser.add_argument('sud_name', nargs='?', default=None,
+                        help='Sud name part of the filename (e.g. Sud-0010); '
+                             'omit when passing a direct file path')
     default_log_dir = Path(__file__).parent.parent / 'logs'
     parser.add_argument('--log-dir', default=str(default_log_dir),
                         help='Directory containing the log files (default: %(default)s)')
     args = parser.parse_args()
 
-    log_dir = Path(args.log_dir)
-    stem = '{}_{}'.format(args.date_time, args.sud_name)
-    log_path      = log_dir / 'log_{}.json'.format(stem)
-    forecast_path = log_dir / 'forecast_{}.json'.format(stem)
+    if args.sud_name is None:
+        log_path = Path(args.date_time_or_path)
+        stem = log_path.stem[len('log_'):] if log_path.stem.startswith('log_') else log_path.stem
+        forecast_path = log_path.parent / 'forecast_{}.json'.format(stem)
+    else:
+        log_dir = Path(args.log_dir)
+        stem = '{}_{}'.format(args.date_time_or_path, args.sud_name)
+        log_path      = log_dir / 'log_{}.json'.format(stem)
+        forecast_path = log_dir / 'forecast_{}.json'.format(stem)
 
-    for path in (log_path, forecast_path):
-        if not path.exists():
-            print('Error: file not found: {}'.format(path), file=sys.stderr)
-            sys.exit(1)
+    if not log_path.exists():
+        print('Error: file not found: {}'.format(log_path), file=sys.stderr)
+        sys.exit(1)
 
     with open(log_path) as f:
         log = json.load(f)
-    with open(forecast_path) as f:
-        forecast = json.load(f)
 
     name = log.get('Name', stem)
     samples = log['Samples']
 
     plot_realtime(samples, name)
-    plot_forecast(forecast, samples, name)
+    if forecast_path.exists():
+        with open(forecast_path) as f:
+            forecast = json.load(f)
+        plot_forecast(forecast, samples, name)
 
     plt.show()