Python code for plotting 1-hour and 3-hour precip

[ali_4906]

I'm using wrf-python to plot total precipitation, but I still can't find a way to generate 1-hour and 3-hour rainfall maps. Is there any code available for plotting these, as well as a snow-depth map?

 

[William.Hatheway]

I have some, let me find the codes

 

[ali_4906]

Thanks so much

 

[William.Hatheway]

from datetime import timedelta
import numpy as np
from netCDF4 import Dataset
import wrf
from wrf import to_np


def get_cumulative_rain(ncfile, timeidx):
    """Return total cumulative precipitation (mm) at a given time index."""
    rainc  = wrf.getvar(ncfile, "RAINC",  timeidx=timeidx)
    rainnc = wrf.getvar(ncfile, "RAINNC", timeidx=timeidx)
    rainsh = wrf.getvar(ncfile, "RAINSH", timeidx=timeidx)
    return rainc + rainnc + rainsh


def get_valid_time(ncfile, timeidx):
    """Return Python datetime for a WRF time index."""
    t = wrf.extract_times(ncfile, timeidx=timeidx, do_xtime=True)
    if isinstance(t, np.ndarray):
        t = t.item()
    return t


def compute_3hr_rain(ncfile, timeidx, all_frames):
    """
    Compute 3-hour accumulated precipitation using actual times.

    all_frames = list of (path, time_index) tuples in chronological order
    """
    # Current time
    valid_time = get_valid_time(ncfile, timeidx)
    target_time = valid_time - timedelta(hours=3)

    # Find closest frame ≤ target_time
    prev_path = None
    prev_idx = None

    for path, idx in reversed(all_frames):
        with Dataset(path) as nc:
            t = get_valid_time(nc, idx)
        if t <= target_time:
            prev_path = path
            prev_idx = idx
            break

    # Current cumulative rain
    curr_rain = get_cumulative_rain(ncfile, timeidx)

    # If no suitable previous time found
    if prev_path is None:
        return np.zeros_like(to_np(curr_rain))

    # Previous cumulative rain
    with Dataset(prev_path) as prev_nc:
        prev_rain = get_cumulative_rain(prev_nc, prev_idx)

    return curr_rain - prev_rain

from datetime import timedelta
import numpy as np
from netCDF4 import Dataset
import wrf
from wrf import to_np


INCH_PER_METER = 39.3700787402


def get_valid_time(ncfile, timeidx):
    """Return Python datetime for a WRF time index."""
    t = wrf.extract_times(ncfile, timeidx=timeidx, do_xtime=True)
    if isinstance(t, np.ndarray):
        t = t.item()
    return t


def get_cumulative_snow_inches(ncfile, timeidx):
    """Return cumulative snow depth (SNOWH) in inches."""
    snow_m = wrf.getvar(ncfile, "SNOWH", timeidx=timeidx)  # meters
    return snow_m * INCH_PER_METER


def compute_1hr_snow(ncfile, timeidx, all_frames):
    """
    Compute 1-hour accumulated snowfall (inches) using actual times.

    all_frames = list of (path, time_index) tuples in chronological order
    """
    # Current time
    valid_time = get_valid_time(ncfile, timeidx)
    target_time = valid_time - timedelta(hours=1)

    # Find closest frame ≤ target_time
    prev_path = None
    prev_idx = None

    for path, idx in reversed(all_frames):
        with Dataset(path) as nc:
            t = get_valid_time(nc, idx)
        if t <= target_time:
            prev_path = path
            prev_idx = idx
            break

    # Current cumulative snow
    curr_snow = get_cumulative_snow_inches(ncfile, timeidx)

    # No previous frame found → zero accumulation
    if prev_path is None:
        return np.zeros_like(to_np(curr_snow))

    # Previous cumulative snow
    with Dataset(prev_path) as prev_nc:
        prev_snow = get_cumulative_snow_inches(prev_nc, prev_idx)

    return curr_snow - prev_snow

@ali_4906 it's not my full python code because that has a lot of specific functions for my area but this should help you get started!