feat: add MET Norway provider with normalization

fixtures/providers/met_locationforecast_compact.json

@@ -0,0 +1,136 @@
+{
+  "type": "Feature",
+  "geometry": {
+    "type": "Point",
+    "coordinates": [9.0, 42.4, 0]
+  },
+  "properties": {
+    "meta": {
+      "updated_at": "2025-08-29T06:15:00Z",
+      "units": {
+        "air_pressure_at_sea_level": "hPa",
+        "air_temperature": "celsius",
+        "cloud_area_fraction": "%",
+        "precipitation_amount": "mm",
+        "relative_humidity": "%",
+        "wind_from_direction": "degrees",
+        "wind_speed": "m/s",
+        "wind_speed_of_gust": "m/s"
+      }
+    },
+    "timeseries": [
+      {
+        "time": "2025-08-29T12:00:00Z",
+        "data": {
+          "instant": {
+            "details": {
+              "air_pressure_at_sea_level": 1013.2,
+              "air_temperature": 18.5,
+              "cloud_area_fraction": 85.0,
+              "relative_humidity": 78.0,
+              "wind_from_direction": 220.5,
+              "wind_speed": 6.1,
+              "wind_speed_of_gust": 10.6
+            }
+          },
+          "next_1_hours": {
+            "summary": {
+              "symbol_code": "lightrain"
+            },
+            "details": {
+              "precipitation_amount": 0.4
+            }
+          },
+          "next_6_hours": {
+            "summary": {
+              "symbol_code": "rain"
+            },
+            "details": {
+              "precipitation_amount": 3.2
+            }
+          }
+        }
+      },
+      {
+        "time": "2025-08-29T13:00:00Z",
+        "data": {
+          "instant": {
+            "details": {
+              "air_pressure_at_sea_level": 1012.8,
+              "air_temperature": 19.2,
+              "cloud_area_fraction": 90.0,
+              "relative_humidity": 82.0,
+              "wind_from_direction": 225.0,
+              "wind_speed": 7.5,
+              "wind_speed_of_gust": 12.3
+            }
+          },
+          "next_1_hours": {
+            "summary": {
+              "symbol_code": "lightrainandthunder"
+            },
+            "details": {
+              "precipitation_amount": 1.2
+            }
+          },
+          "next_6_hours": {
+            "summary": {
+              "symbol_code": "heavyrainandthunder"
+            },
+            "details": {
+              "precipitation_amount": 8.5
+            }
+          }
+        }
+      },
+      {
+        "time": "2025-08-29T14:00:00Z",
+        "data": {
+          "instant": {
+            "details": {
+              "air_pressure_at_sea_level": 1011.5,
+              "air_temperature": 17.8,
+              "cloud_area_fraction": 95.0,
+              "relative_humidity": 88.0,
+              "wind_from_direction": 230.0,
+              "wind_speed": 8.9,
+              "wind_speed_of_gust": 15.2
+            }
+          },
+          "next_1_hours": {
+            "summary": {
+              "symbol_code": "heavyrain"
+            },
+            "details": {
+              "precipitation_amount": 3.5
+            }
+          }
+        }
+      },
+      {
+        "time": "2025-08-29T15:00:00Z",
+        "data": {
+          "instant": {
+            "details": {
+              "air_pressure_at_sea_level": 1011.0,
+              "air_temperature": 16.5,
+              "cloud_area_fraction": 75.0,
+              "relative_humidity": 80.0,
+              "wind_from_direction": 235.0,
+              "wind_speed": 5.5,
+              "wind_speed_of_gust": 9.2
+            }
+          },
+          "next_1_hours": {
+            "summary": {
+              "symbol_code": "partlycloudy_day"
+            },
+            "details": {
+              "precipitation_amount": 0.0
+            }
+          }
+        }
+      }
+    ]
+  }
+}

fixtures/providers/met_normalized_expected.json

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+{
+  "meta": {
+    "provider": "MET",
+    "model": "ECMWF",
+    "run": "2025-08-29T06:15:00Z",
+    "grid_res_km": 9,
+    "interp": "point_grid",
+    "stations_used": []
+  },
+  "data": [
+    {
+      "ts": "2025-08-29T12:00:00Z",
+      "t2m_c": 18.5,
+      "wind10m_kmh": 22.0,
+      "gust_kmh": 38.2,
+      "precip_rate_mmph": 0.4,
+      "precip_1h_mm": 0.4,
+      "cloud_total_pct": 85,
+      "symbol": "lightrain",
+      "thunder_level": "NONE",
+      "cape_jkg": null,
+      "pop_pct": null,
+      "pressure_msl_hpa": 1013.2,
+      "humidity_pct": 78,
+      "dewpoint_c": null
+    },
+    {
+      "ts": "2025-08-29T13:00:00Z",
+      "t2m_c": 19.2,
+      "wind10m_kmh": 27.0,
+      "gust_kmh": 44.3,
+      "precip_rate_mmph": 1.2,
+      "precip_1h_mm": 1.2,
+      "cloud_total_pct": 90,
+      "symbol": "lightrainandthunder",
+      "thunder_level": "HIGH",
+      "cape_jkg": null,
+      "pop_pct": null,
+      "pressure_msl_hpa": 1012.8,
+      "humidity_pct": 82,
+      "dewpoint_c": null
+    },
+    {
+      "ts": "2025-08-29T14:00:00Z",
+      "t2m_c": 17.8,
+      "wind10m_kmh": 32.0,
+      "gust_kmh": 54.7,
+      "precip_rate_mmph": 3.5,
+      "precip_1h_mm": 3.5,
+      "cloud_total_pct": 95,
+      "symbol": "heavyrain",
+      "thunder_level": "NONE",
+      "cape_jkg": null,
+      "pop_pct": null,
+      "pressure_msl_hpa": 1011.5,
+      "humidity_pct": 88,
+      "dewpoint_c": null
+    },
+    {
+      "ts": "2025-08-29T15:00:00Z",
+      "t2m_c": 16.5,
+      "wind10m_kmh": 19.8,
+      "gust_kmh": 33.1,
+      "precip_rate_mmph": 0.0,
+      "precip_1h_mm": 0.0,
+      "cloud_total_pct": 75,
+      "symbol": "partlycloudy",
+      "thunder_level": "NONE",
+      "cape_jkg": null,
+      "pop_pct": null,
+      "pressure_msl_hpa": 1011.0,
+      "humidity_pct": 80,
+      "dewpoint_c": null
+    }
+  ]
+}

src/app/providers/__init__.py

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+# Providers package

src/app/providers/met.py

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+"""MET Norway LocationForecast provider adapter."""
+
+from typing import Any
+
+
+def ms_to_kmh(value: float) -> float:
+    """Convert m/s to km/h."""
+    return round(value * 3.6, 1)
+
+
+def map_symbol(symbol_code: str) -> str:
+    """
+    Map MET symbol_code to normalized symbol.
+
+    MET symbols may have suffixes like _day/_night/_polartwilight.
+    We strip these and normalize to the canonical symbol set.
+    """
+    # Strip time-of-day suffixes
+    base_symbol = symbol_code.replace("_day", "").replace("_night", "").replace("_polartwilight", "")
+
+    # Direct mapping for known symbols
+    # MET symbols align well with our canonical set
+    return base_symbol
+
+
+def get_thunder_level(symbol_code: str) -> str:
+    """
+    Determine thunder_level from symbol_code.
+
+    According to api_contract.md:
+    - MET: symbol_code contains "thunder" => HIGH, else NONE
+    """
+    if "thunder" in symbol_code.lower():
+        return "HIGH"
+    return "NONE"
+
+
+def normalize(api_response: dict[str, Any]) -> dict[str, Any]:
+    """
+    Normalize MET Norway LocationForecast API response to schema format.
+
+    Args:
+        api_response: Raw MET API response (GeoJSON format)
+
+    Returns:
+        Normalized forecast timeseries conforming to normalized_timeseries.schema.json
+    """
+    properties = api_response["properties"]
+    meta_data = properties["meta"]
+    timeseries = properties["timeseries"]
+
+    # Build meta
+    meta = {
+        "provider": "MET",
+        "model": "ECMWF",  # MET uses ECMWF for most forecasts
+        "run": meta_data["updated_at"],
+        "grid_res_km": 9,  # MET Norway uses ~9km grid resolution
+        "interp": "point_grid",  # Point forecast, no station interpolation
+        "stations_used": []
+    }
+
+    # Build data array
+    data = []
+    for item in timeseries:
+        instant = item["data"]["instant"]["details"]
+        next_1h = item["data"].get("next_1_hours", {})
+        next_1h_details = next_1h.get("details", {})
+        next_1h_summary = next_1h.get("summary", {})
+
+        # Get precipitation (from next_1_hours)
+        precip_1h = next_1h_details.get("precipitation_amount", 0.0)
+
+        # Get symbol (from next_1_hours summary)
+        symbol_code = next_1h_summary.get("symbol_code", "clearsky")
+
+        # Required fields
+        data_point = {
+            "ts": item["time"],
+            "t2m_c": instant["air_temperature"],
+            "wind10m_kmh": ms_to_kmh(instant["wind_speed"]),
+            "precip_rate_mmph": precip_1h,  # 1h amount = rate in mm/h
+            "cloud_total_pct": int(instant["cloud_area_fraction"]),
+            "symbol": map_symbol(symbol_code),
+            "thunder_level": get_thunder_level(symbol_code),
+        }
+
+        # Optional fields (only add if not None)
+        gust = instant.get("wind_speed_of_gust")
+        if gust is not None:
+            data_point["gust_kmh"] = ms_to_kmh(gust)
+
+        if precip_1h is not None:
+            data_point["precip_1h_mm"] = precip_1h
+
+        data_point["pressure_msl_hpa"] = instant["air_pressure_at_sea_level"]
+        data_point["humidity_pct"] = int(instant["relative_humidity"])
+
+        # Fields MET does not provide: cape_jkg, pop_pct, dewpoint_c
+        # We omit them entirely rather than setting to None
+        data.append(data_point)
+
+    return {
+        "meta": meta,
+        "data": data
+    }