1 files changed, 52 insertions, 0 deletions
diff --git a/waterspout_radar/_radar.py b/waterspout_radar/_radar.py
new file mode 100644
index 0000000..629ec55
--- /dev/null
+++ b/waterspout_radar/_radar.py
@@ -0,0 +1,52 @@
+import dataclasses
+import datetime
+import typing
+
+import szilagyi
+from geopy import geocoders
+from metpy import calc
+from metpy import units as metunits
+from windy import point_forecast, Windy
+
+_L = point_forecast.Level
+
+
+@dataclasses.dataclass
+class Prediction:
+	time: datetime.datetime
+	swi: float
+
+
+def calculate(config) -> typing.List[Prediction]:
+	units = metunits.units
+	windy = Windy(units)
+
+	def _calculate(latitude, longitude):
+		forecasts = windy.point_forecast(
+			config.key,
+			latitude, longitude,
+			point_forecast.Model.ICONEU,
+			("temp", "dewpoint", "wind", "pressure"),
+			tuple(_L))
+		for cast in forecasts:
+			dt = abs(cast.at("temp", _L.H850) - cast.at("temp", _L.SURFACE))
+			pressure, _ = calc.lcl(
+				cast.at("pressure", _L.SURFACE),
+				cast.at("temp", _L.SURFACE),
+				cast.at("dewpoint", _L.SURFACE))
+			lcl = calc.pressure_to_height_std(pressure)
+			pressure, _ = calc.el(cast["pressure"], cast["temp"], cast["dewpoint"])
+			el = calc.pressure_to_height_std(pressure)
+			ccd = (el - lcl).to(units.ft)
+			try:
+				swi = szilagyi.calculate_swi(dt, ccd)
+			except ValueError:
+				swi = -10
+			yield Prediction(time=cast.timestamp, swi=swi)
+
+	predictions = []
+	locator = geocoders.Nominatim(user_agent="waterspout-radar")
+	for location in config.locations:
+		found = locator.geocode(location)
+		predictions.extend(_calculate(found.latitude, found.longitude))
+	return predictions