Make Tempest the primary source for all current-conditions fields

CHANGELOG.md

@@ -1,5 +1,13 @@
 # Changelog
 
+## 1.4.8
+
+- fix dew point reporting `N/A` when the NWS METAR omits it but a Tempest station is active; `_merge_tempest_conditions` now backfills dew point from the Tempest `dew_point` field, with frost-point labeling at and below 0°C to match the NWS path
+- make the Tempest station the primary source for every field it measures in current conditions: `wind_gust` now comes from Tempest (was NWS-only), and `observation_time` reflects the Tempest reading time rather than the NWS METAR time
+- use the Tempest station's own `sea_level_pressure` directly (`pressure_source: tempest`) rather than reducing station pressure locally; the local hypsometric reduction was an approximation that disagreed with the station's value by ~1 mb, and is now a fallback used only when the station supplies no SLP. Also fixes that fallback never running: station elevation is read from `station_meta.elevation`, not the absent top-level `elevation` key
+- add Tempest hyper-local fields to conditions: `wind_lull`, `brightness`, `wet_bulb_globe_temperature`, `delta_t` (°C), `precip_last_hour`, and last-strike distance (shown only when there has been recent lightning)
+- stop labeling NWS station pressure as sea-level when a METAR reports no sea-level pressure; `pressure_source` is now `station` in that case instead of presenting absolute station pressure as SLP
+
 ## 1.4.7
 
 - fix probabilistic tornado/wind/hail outlooks always returning 0% with null valid/expire times; SPC's March 2026 outlook revamp serializes probabilities as decimal fractions (`"0.05"`) and `int()` parsing skipped every feature

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "stormscope"
-version = "1.4.7"
+version = "1.4.8"
 description = "MCP server for real-time US weather data via NWS API, NOAA SPC, and IEM radar"
 readme = "README.md"
 license = "ISC"

src/stormscope/server.py

@@ -50,14 +50,19 @@ async def _lifespan(app):
         "sectors, surface lows/highs, or synoptic surface patterns. Returns "
         "distance and bearing to nearby fronts and pressure centers, plus "
         "warm/cold sector detection relative to the nearest cold front.\n\n"
-        "When a Tempest weather station is configured, get_conditions includes "
-        "hyper-local sensor data from the user's personal station: solar_radiation, "
-        "uv_index, lightning_strikes_1hr, air_density, and wet_bulb_temperature. "
+        "When a Tempest weather station is configured, it is the primary source "
+        "for every field it measures and get_conditions adds hyper-local sensor "
+        "data from the user's personal station: solar_radiation, uv_index, "
+        "brightness, lightning_strikes_1hr, last-strike distance (when recent), "
+        "air_density, wet_bulb_temperature, wet_bulb_globe_temperature, delta_t, "
+        "precip_last_hour, wind_lull. "
         "The data_source field indicates whether primary readings (temperature, "
-        "wind) come from the Tempest station or NWS. All pressure values are sea "
-        "level pressure. The pressure_source field is 'tempest_slp' when Tempest "
-        "station pressure was converted to SLP using station elevation, or "
-        "'sea_level' when NWS altimeter-corrected pressure was used. Forecasts "
+        "wind) come from the Tempest station or NWS. The pressure_source field "
+        "tells you how to read the pressure value: 'tempest' is the Tempest "
+        "station's own SLP, 'tempest_slp' is station pressure reduced to SLP "
+        "locally as a fallback, 'sea_level' is the NWS sea-level pressure, and "
+        "'station' is raw NWS station pressure (not reduced to sea level) when "
+        "no SLP is reported. Forecasts "
         "include a data_source field (NWS/{office} or tempest). When Tempest is "
         "the primary source, original NWS values are retained as nws_* fields for "
         "comparison."
@@ -139,9 +144,16 @@ async def get_conditions(
     Use when: "What's the weather right now?", "How hot is it?", "Is it windy?"
 
     detail="standard": temperature, feels-like, dewpoint (or frost_point when <= 0C),
-    humidity, wind, sky, visibility, pressure.
+    humidity, wind, gust, sky, visibility, pressure.
     detail="full": adds cloud layers, present weather, raw METAR.
 
+    When a Tempest station is in range it is the primary source for every
+    field it measures (temperature, feels-like, dewpoint, humidity, wind,
+    gust, lull, pressure, observation_time) and adds hyper-local fields:
+    solar_radiation, uv_index, brightness, lightning_strikes_1hr, last-strike
+    distance (when recent), air_density, wet_bulb_temperature,
+    wet_bulb_globe_temperature, delta_t (°C), precip_last_hour, pressure_trend.
+
     Omit lat/lon to use configured primary location.
 
     units: "us" or "si" for base system, with optional field overrides:

src/stormscope/tempest.py

@@ -193,7 +193,8 @@ def normalize_obs(self, obs: dict, prefs: UnitPrefs) -> dict:
         wind_unit = "mps"
 
         # normalize temperature fields
-        for field in ("air_temperature", "wet_bulb_temperature", "feels_like",
+        for field in ("air_temperature", "wet_bulb_temperature",
+                      "wet_bulb_globe_temperature", "feels_like",
                       "dew_point", "air_temperature_high", "air_temperature_low"):
             val = obs.get(field)
             if val is None:

src/stormscope/tools.py

@@ -113,10 +113,23 @@ def _merge_tempest_conditions(
     if uv is not None:
         result["uv_index"] = round(uv, 1)
 
+    brightness = normalized.get("brightness")
+    if brightness is not None:
+        result["brightness"] = f"{round(brightness)} lux"
+
     lightning = normalized.get("lightning_strike_count_last_1hr") or normalized.get("lightning_strike_count")
     if lightning is not None:
         result["lightning_strikes_1hr"] = int(lightning)
 
+    # only surface last-strike distance when there has been recent activity,
+    # otherwise the value is stale (last strike could be days old)
+    strikes_3hr = obs.get("lightning_strike_count_last_3hr") or 0
+    last_dist_km = obs.get("lightning_strike_last_distance")
+    if strikes_3hr and last_dist_km is not None:
+        result["lightning_last_strike_distance"] = _fmt_visibility(
+            last_dist_km * 0.621371, last_dist_km * 1000, prefs,
+        )
+
     air_density = normalized.get("air_density")
     if air_density is not None:
         result["air_density"] = f"{air_density:.3f} kg/m³"
@@ -128,6 +141,18 @@ def _merge_tempest_conditions(
         c_val = wet_bulb_n if prefs.temperature == "c" else None
         result["wet_bulb_temperature"] = _fmt_temp(f_val, c_val, prefs)
 
+    wbgt_n = normalized.get("wet_bulb_globe_temperature")
+    if wbgt_n is not None:
+        f_val = wbgt_n if prefs.temperature == "f" else None
+        c_val = wbgt_n if prefs.temperature == "c" else None
+        result["wet_bulb_globe_temperature"] = _fmt_temp(f_val, c_val, prefs)
+
+    # delta-T (dry-bulb minus wet-bulb) is an agronomy spray metric defined
+    # in °C by convention, so it is reported in °C regardless of prefs
+    delta_t = obs.get("delta_t")
+    if delta_t is not None:
+        result["delta_t"] = f"{round(delta_t, 1)}°C"
+
     trend = normalized.get("pressure_trend")
     if trend is not None:
         result["pressure_trend"] = trend
@@ -140,6 +165,12 @@ def _merge_tempest_conditions(
     # normalized values are already in prefs units
     result["data_source"] = "tempest"
 
+    # the displayed readings are now the Tempest station's, so the timestamp
+    # should reflect the Tempest observation, not the NWS METAR time
+    ts = obs.get("timestamp")
+    if ts is not None:
+        result["observation_time"] = datetime.fromtimestamp(ts, tz=timezone.utc).isoformat()
+
     temp_n = normalized.get("air_temperature")
     if temp_n is not None:
         f_val = temp_n if prefs.temperature == "f" else None
@@ -161,6 +192,20 @@ def _merge_tempest_conditions(
         f_val = feels_n if prefs.temperature == "f" else None
         c_val = feels_n if prefs.temperature == "c" else None
         result["feels_like"] = _fmt_temp(f_val, c_val, prefs)
+
+    dew_n = normalized.get("dew_point")
+    if dew_n is not None:
+        # raw obs dew_point is °C (API is SI); use it for the frost-point
+        # threshold so labeling matches the NWS path regardless of prefs
+        dew_c = obs.get("dew_point")
+        dp_key = "frost_point" if dew_c is not None and dew_c <= 0 else "dewpoint"
+        f_val = dew_n if prefs.temperature == "f" else None
+        c_val = dew_n if prefs.temperature == "c" else None
+        result[dp_key] = _fmt_temp(f_val, c_val, prefs)
+        # the NWS path set exactly one of these; drop the other so the
+        # merged result never carries both labels
+        result.pop("frost_point" if dp_key == "dewpoint" else "dewpoint", None)
+
     humidity = normalized.get("relative_humidity")
     if humidity is not None:
         result["humidity"] = _fmt_humidity(humidity)
@@ -171,15 +216,38 @@ def _merge_tempest_conditions(
         result["wind"] = _fmt_wind(wind_n, cardinal, prefs)
         if "wind_direction" in result:
             result["wind_direction"] = cardinal or "N/A"
-    station_press_mb = obs.get("station_pressure")
-    elevation_m = obs.get("station_elevation")
-    air_temp_c = obs.get("air_temperature")
 
-    if station_press_mb is not None and elevation_m is not None and air_temp_c is not None:
-        slp_mb = station_pressure_to_slp_mb(station_press_mb, elevation_m, air_temp_c)
+    gust_n = normalized.get("wind_gust")
+    if gust_n is not None:
+        result["wind_gust"] = _fmt_gust(gust_n, prefs)
+
+    lull_n = normalized.get("wind_lull")
+    if lull_n is not None:
+        result["wind_lull"] = _fmt_gust(lull_n, prefs)
+
+    # last-hour precipitation accumulation; raw obs value is mm (API is SI)
+    precip_mm = obs.get("precip_accum_last_1hr")
+    if precip_mm is not None:
+        result["precip_last_hour"] = _fmt_accumulation(precip_mm, prefs)
+
+    # Tempest reports its own sea-level pressure, reduced with the proper
+    # (mean-column-temperature) method, so prefer it. Reduce station pressure
+    # ourselves only when the station does not supply SLP directly: our
+    # instantaneous-temperature reduction is an approximation that can differ
+    # from the official value by ~1 mb.
+    slp_mb = obs.get("sea_level_pressure")
+    source = "tempest"
+    if slp_mb is None:
+        station_press_mb = obs.get("station_pressure")
+        elevation_m = obs.get("station_elevation")
+        air_temp_c = obs.get("air_temperature")
+        if station_press_mb is not None and elevation_m is not None and air_temp_c is not None:
+            slp_mb = station_pressure_to_slp_mb(station_press_mb, elevation_m, air_temp_c)
+            source = "tempest_slp"
+    if slp_mb is not None:
         slp_pa = slp_mb * 100
         result["pressure"] = _fmt_pressure(pa_to_inhg(slp_pa), slp_pa, prefs)
-        result["pressure_source"] = "tempest_slp"
+        result["pressure_source"] = source
 
     return result
 
@@ -515,7 +583,10 @@ async def _fetch_tempest_obs(lat: float, lon: float) -> dict | None:
             return None
         # attach station name for display
         obs["station_name"] = station.get("name") or station.get("public_name")
-        obs["station_elevation"] = station.get("elevation")
+        # elevation lives under station_meta; the top-level key is absent, so
+        # without this the SLP computation silently never ran
+        meta_elev = (station.get("station_meta") or {}).get("elevation")
+        obs["station_elevation"] = meta_elev if meta_elev is not None else station.get("elevation")
         return obs
     except Exception:
         logger.debug("tempest observation fetch failed", exc_info=True)
@@ -554,7 +625,13 @@ async def get_conditions(
         gust_kmh = _obs_value(obs, "windGust")
         humidity = _obs_value(obs, "relativeHumidity")
         vis_m = _obs_value(obs, "visibility")
-        pressure_pa = _obs_value(obs, "seaLevelPressure") or _obs_value(obs, "barometricPressure")
+        # seaLevelPressure is reduced to sea level; barometricPressure is the
+        # absolute station pressure, so it must not be labeled sea_level
+        slp_pa = _obs_value(obs, "seaLevelPressure")
+        if slp_pa is not None:
+            pressure_pa, pressure_source = slp_pa, "sea_level"
+        else:
+            pressure_pa, pressure_source = _obs_value(obs, "barometricPressure"), "station"
 
         temp_f = c_to_f(temp_c)
         feels_like_c = heat_index_c if heat_index_c is not None else wind_chill_c
@@ -580,7 +657,7 @@ async def get_conditions(
             "sky_condition": obs.get("textDescription", "N/A"),
             "visibility": _fmt_visibility(m_to_miles(vis_m), vis_m, prefs),
             "pressure": _fmt_pressure(pa_to_inhg(pressure_pa), pressure_pa, prefs),
-            "pressure_source": "sea_level",
+            "pressure_source": pressure_source,
             "station_name": station.get("name", "Unknown"),
             "observation_time": obs.get("timestamp", "N/A"),
         }