M1.1.2 Define update order in the daily loop

Summary
Define the daily execution sequence for snow, radiation, energy balance, melt, and hydrologic routing.

Purpose
Ensure that snow mass and energy interact with the existing model in a consistent and reproducible order.

Tasks

• Define the daily sequence for processes defined in #1700
• Identify whether the energy balance is solved once per day, per daylight period, or using representative subdaily conditions.
• Document where effective albedo enters the radiation code.
• Document what other surface properties change when snow cover is present.
• Provide either an ordered bullet list or a simple flow diagram.

Acceptance criteria

• A documented update sequence exists.
• There is no ambiguity about whether snow albedo is updated before or after energy-balance calculations.
• The update order for snowfall, albedo refresh, melt, and SWE update is documented.
• The insertion point of hydrologic routing is documented.

Suggested tests

• Walk through one synthetic snowy day and one snow-free day using the documented order to confirm that the sequence is physically consistent.

Start by reading issue #1700 and tracing the existing daily loop. Walk through one synthetic snowy day and one snow-free day, checking the ordering of snowfall, albedo refresh, energy balance, melt, SWE updates, and hydrologic routing. Done means an ordered list or flow diagram removes ambiguity about each insertion point and update dependency.