diff --git a/lib/microwaveprop/weather/hrdps_profile.ex b/lib/microwaveprop/weather/hrdps_profile.ex
new file mode 100644
index 00000000..63757fe8
--- /dev/null
+++ b/lib/microwaveprop/weather/hrdps_profile.ex
@@ -0,0 +1,42 @@
+defmodule Microwaveprop.Weather.HrdpsProfile do
+  @moduledoc false
+  use Ecto.Schema
+
+  import Ecto.Changeset
+
+  @primary_key {:id, :binary_id, autogenerate: true}
+  @foreign_key_type :binary_id
+
+  schema "hrdps_profiles" do
+    field :valid_time, :utc_datetime
+    field :lat, :float
+    field :lon, :float
+    field :run_time, :utc_datetime
+    field :profile, {:array, :map}
+    field :hpbl_m, :float
+    field :pwat_mm, :float
+    field :surface_temp_c, :float
+    field :surface_dewpoint_c, :float
+    field :surface_pressure_mb, :float
+    field :surface_refractivity, :float
+    field :min_refractivity_gradient, :float
+    field :ducting_detected, :boolean, default: false
+    field :duct_characteristics, {:array, :map}
+    field :is_grid_point, :boolean, default: false
+
+    timestamps(type: :utc_datetime)
+  end
+
+  @type t :: %__MODULE__{}
+
+  @required_fields ~w(valid_time lat lon)a
+  @optional_fields ~w(run_time profile hpbl_m pwat_mm surface_temp_c surface_dewpoint_c surface_pressure_mb surface_refractivity min_refractivity_gradient ducting_detected duct_characteristics is_grid_point)a
+
+  @spec changeset(t() | Ecto.Changeset.t(), map()) :: Ecto.Changeset.t()
+  def changeset(hrdps_profile, attrs) do
+    hrdps_profile
+    |> cast(attrs, @required_fields ++ @optional_fields)
+    |> validate_required(@required_fields)
+    |> unique_constraint([:lat, :lon, :valid_time])
+  end
+end
diff --git a/priv/repo/migrations/20260429220349_create_hrdps_profiles.exs b/priv/repo/migrations/20260429220349_create_hrdps_profiles.exs
new file mode 100644
index 00000000..582d3916
--- /dev/null
+++ b/priv/repo/migrations/20260429220349_create_hrdps_profiles.exs
@@ -0,0 +1,66 @@
+defmodule Microwaveprop.Repo.Migrations.CreateHrdpsProfiles do
+  use Ecto.Migration
+
+  @disable_ddl_transaction true
+  @disable_migration_lock true
+
+  # Mirror of hrrr_profiles for HRDPS-derived rows. Separate table (not a
+  # unified nwp_profiles) so HRDPS can be dropped/reprocessed without
+  # disturbing the 4500+ HRRR profiles already in prod. Same column set
+  # and indexes; PARTITION BY RANGE (valid_time) with quarterly partitions
+  # starting from the deploy quarter.
+  #
+  # Unlike hrrr_profiles, there's no historical archive to backfill into
+  # — HRDPS is forward-only — so the partition list starts at the deploy
+  # quarter and walks forward.
+  def up do
+    execute """
+    CREATE TABLE hrdps_profiles (
+      id uuid NOT NULL DEFAULT gen_random_uuid(),
+      valid_time timestamp(0) WITHOUT TIME ZONE NOT NULL,
+      lat double precision NOT NULL,
+      lon double precision NOT NULL,
+      run_time timestamp(0) WITHOUT TIME ZONE,
+      profile jsonb[] DEFAULT ARRAY[]::jsonb[],
+      hpbl_m double precision,
+      pwat_mm double precision,
+      surface_temp_c double precision,
+      surface_dewpoint_c double precision,
+      surface_pressure_mb double precision,
+      surface_refractivity double precision,
+      min_refractivity_gradient double precision,
+      ducting_detected boolean DEFAULT false,
+      duct_characteristics jsonb[],
+      is_grid_point boolean DEFAULT false,
+      inserted_at timestamp(0) WITHOUT TIME ZONE NOT NULL,
+      updated_at timestamp(0) WITHOUT TIME ZONE NOT NULL
+    ) PARTITION BY RANGE (valid_time)
+    """
+
+    partitions = [
+      {"2026-04-01", "2026-07-01"},
+      {"2026-07-01", "2026-10-01"},
+      {"2026-10-01", "2027-01-01"},
+      {"2027-01-01", "2027-04-01"},
+      {"2027-04-01", "2027-07-01"},
+      {"2027-07-01", "2027-10-01"},
+      {"2027-10-01", "2028-01-01"}
+    ]
+
+    for {from_date, to_date} <- partitions do
+      suffix = from_date |> String.replace("-", "_") |> String.slice(0..6)
+
+      execute """
+      CREATE TABLE hrdps_profiles_#{suffix} PARTITION OF hrdps_profiles
+        FOR VALUES FROM ('#{from_date}') TO ('#{to_date}')
+      """
+    end
+
+    execute "CREATE UNIQUE INDEX hrdps_profiles_lat_lon_valid_time_index ON hrdps_profiles (lat, lon, valid_time)"
+    execute "CREATE INDEX hrdps_profiles_valid_time_index ON hrdps_profiles (valid_time)"
+  end
+
+  def down do
+    execute "DROP TABLE IF EXISTS hrdps_profiles CASCADE"
+  end
+end
diff --git a/test/microwaveprop/weather/hrdps_profile_test.exs b/test/microwaveprop/weather/hrdps_profile_test.exs
new file mode 100644
index 00000000..175eb4b0
--- /dev/null
+++ b/test/microwaveprop/weather/hrdps_profile_test.exs
@@ -0,0 +1,83 @@
+defmodule Microwaveprop.Weather.HrdpsProfileTest do
+  use Microwaveprop.DataCase, async: false
+
+  alias Microwaveprop.Repo
+  alias Microwaveprop.Weather.HrdpsProfile
+
+  describe "changeset/2" do
+    test "valid with required fields" do
+      attrs = %{valid_time: ~U[2026-04-29 12:00:00Z], lat: 53.32, lon: -60.42}
+      cs = HrdpsProfile.changeset(%HrdpsProfile{}, attrs)
+      assert cs.valid?
+    end
+
+    test "rejects missing required fields" do
+      cs = HrdpsProfile.changeset(%HrdpsProfile{}, %{})
+      refute cs.valid?
+      assert %{valid_time: ["can't be blank"]} = errors_on(cs)
+      assert %{lat: ["can't be blank"]} = errors_on(cs)
+      assert %{lon: ["can't be blank"]} = errors_on(cs)
+    end
+
+    test "casts the full set of derived fields" do
+      attrs = %{
+        valid_time: ~U[2026-04-29 12:00:00Z],
+        lat: 53.32,
+        lon: -60.42,
+        run_time: ~U[2026-04-29 12:00:00Z],
+        profile: [%{"pres" => 1000.0, "tmpc" => 12.0, "dwpc" => 7.0, "hght" => 100.0}],
+        hpbl_m: 800.0,
+        pwat_mm: nil,
+        surface_temp_c: 12.0,
+        surface_dewpoint_c: 7.0,
+        surface_pressure_mb: 1000.0,
+        surface_refractivity: 312.0,
+        min_refractivity_gradient: -50.0,
+        ducting_detected: false,
+        duct_characteristics: [],
+        is_grid_point: true
+      }
+
+      cs = HrdpsProfile.changeset(%HrdpsProfile{}, attrs)
+      assert cs.valid?
+      assert Ecto.Changeset.get_field(cs, :surface_refractivity) == 312.0
+      assert Ecto.Changeset.get_field(cs, :is_grid_point) == true
+    end
+  end
+
+  describe "persistence" do
+    test "inserts and reads back via the partitioned hrdps_profiles table" do
+      attrs = %{
+        valid_time: ~U[2026-04-29 12:00:00Z],
+        lat: 53.32,
+        lon: -60.42,
+        run_time: ~U[2026-04-29 12:00:00Z],
+        surface_temp_c: 7.8
+      }
+
+      {:ok, %HrdpsProfile{id: id}} =
+        %HrdpsProfile{} |> HrdpsProfile.changeset(attrs) |> Repo.insert()
+
+      reloaded = Repo.get!(HrdpsProfile, id)
+      assert reloaded.lat == 53.32
+      assert reloaded.surface_temp_c == 7.8
+    end
+
+    test "enforces unique constraint on (lat, lon, valid_time) at the DB level" do
+      # The partitioned table propagates the unique index per partition, so
+      # Postgres rejects duplicate (lat, lon, valid_time) inserts. Schema-
+      # level `unique_constraint/2` matching against changeset errors
+      # doesn't apply because the partition's index name varies per
+      # partition; callers that need upserts go through
+      # `on_conflict: {:replace_all_except, ...}` in the worker.
+      attrs = %{valid_time: ~U[2026-04-29 12:00:00Z], lat: 53.32, lon: -60.42}
+
+      assert {:ok, _} =
+               %HrdpsProfile{} |> HrdpsProfile.changeset(attrs) |> Repo.insert()
+
+      assert_raise Ecto.ConstraintError, fn ->
+        %HrdpsProfile{} |> HrdpsProfile.changeset(attrs) |> Repo.insert()
+      end
+    end
+  end
+end