NAVGEM#

This demonstrates how to use public data from the NAVGEM and NOGAPS model from NOMADS or GODAE.

Note: there are not .idx files provided, so you have to download the full file and generate the .idx file with wgrib2 (requires Linux).

NAVGEM on NOMADS#

NOMADS hosts a copy of the the latest NAVGEM forecasts for the last two days.

[1]:

import matplotlib.pyplot as plt

from herbie import Herbie
from herbie import paint
from herbie.toolbox import EasyMap, pc

[4]:

H = Herbie("2024-06-11 00:00", model="navgem_nomads", fxx=6)

✅ Found ┊ model=navgem_nomads ┊ product=none ┊ 2024-Jun-11 00:00 UTC F06 ┊ GRIB2 @ nomads ┊ IDX @ None

[5]:

H.PRODUCTS

[5]:

{'none': ''}

[6]:

H.SOURCES

[6]:

{'nomads': 'https://nomads.ncep.noaa.gov/pub/data/nccf/com/fnmoc/prod/navgem.20240611/navgem_2024061100f006.grib2'}

[7]:

# There is no index file available. Have to download the full file.
H.download()

👨🏻‍🏭 Created directory: [/home/blaylock/data/navgem_nomads/20240611]

[7]:

PosixPath('/home/blaylock/data/navgem_nomads/20240611/navgem_2024061100f006.grib2')

[8]:

# Since we have download the full file and don't have an index,
# we need to filter by keys to open the variable we want.
# (see cfgrib documentation)

ds = H.xarray(
    backend_kwargs={
        "filter_by_keys": {"shortName": "2t", "typeOfLevel": "heightAboveGround"}
    },
)
ds

/home/blaylock/GITHUB/Herbie/herbie/core.py:1097: UserWarning: Will not remove GRIB file because it previously existed.
  warnings.warn("Will not remove GRIB file because it previously existed.")

[9]:

ax = EasyMap(crs=ds.herbie.crs, figsize=[10, 8]).ax
p = ax.pcolormesh(
    ds.longitude,
    ds.latitude,
    ds.t2m - 273.15,
    transform=pc,
    **paint.NWSTemperature.kwargs2,
)
plt.colorbar(
    p, ax=ax, orientation="horizontal", pad=0.05, **paint.NWSTemperature.cbar_kwargs2
)

ax.set_title(ds.t2m.GRIB_name, loc="right")
ax.set_title(
    f'{H.model.upper()}: {ds.time.dt.strftime("%H:%M UTC %d %b %Y").item()} F{int(ds.step.dt.total_seconds() / 60 / 60):03d}',
    loc="left",
)

[9]:

Text(0.0, 1.0, 'NAVGEM_NOMADS: 00:00 UTC 11 Jun 2024 F006')

../../_images/gallery_usnavy_models_navgem_7_1.png

After downloading the full file, you can create an index file. (Only possible if WGRIB2 is installed and in your path)

[10]:

from herbie import wgrib2

[11]:

wgrib2.create_inventory_file(H.grib)

[11]:

PosixPath('/home/blaylock/data/navgem_nomads/20240611/navgem_2024061100f006.grib2.idx')

[13]:

H = Herbie("2024-06-11 00:00", model="navgem_nomads", fxx=6)
H.inventory()

✅ Found ┊ model=navgem_nomads ┊ product=none ┊ 2024-Jun-11 00:00 UTC F06 ┊ GRIB2 @ local ┊ IDX @ None

[13]:

	grib_message	start_byte	end_byte	range	reference_time	valid_time	variable	level	forecast_time	search_this
0	1	421	172266.0	421-172266	2024-06-11	2024-06-11 06:00:00	ACPCP	surface	0-6 hour acc fcst	:ACPCP:surface:0-6 hour acc fcst
1	2	172267	408146.0	172267-408146	2024-06-11	2024-06-11 06:00:00	APCP	surface	0-6 hour acc fcst	:APCP:surface:0-6 hour acc fcst
2	3	408147	643549.0	408147-643549	2024-06-11	2024-06-11 06:00:00	TMP	max wind	6 hour fcst	:TMP:max wind:6 hour fcst
3	4	643550	917714.0	643550-917714	2024-06-11	2024-06-11 06:00:00	HGT	max wind	6 hour fcst	:HGT:max wind:6 hour fcst
4	5	917715	1246460.0	917715-1246460	2024-06-11	2024-06-11 06:00:00	PRES	max wind	6 hour fcst	:PRES:max wind:6 hour fcst
...	...	...	...	...	...	...	...	...	...	...
86	87	18346863	18701766.0	18346863-18701766	2024-06-11	2024-06-11 06:00:00	UGRD	10 m above ground	6 hour fcst	:UGRD:10 m above ground:6 hour fcst
87	88	18701767	19056137.0	18701767-19056137	2024-06-11	2024-06-11 06:00:00	VGRD	10 m above ground	6 hour fcst	:VGRD:10 m above ground:6 hour fcst
88	89	19056138	19432421.0	19056138-19432421	2024-06-11	2024-06-11 06:00:00	var discipline=0 center=58 local_table=0 parmc...	19.5 m above ground	6 hour fcst	:var discipline=0 center=58 local_table=0 parm...
89	90	19432422	19791097.0	19432422-19791097	2024-06-11	2024-06-11 06:00:00	UGRD	19.5 m above ground	6 hour fcst	:UGRD:19.5 m above ground:6 hour fcst
90	91	19791098	NaN	19791098-	2024-06-11	2024-06-11 06:00:00	VGRD	19.5 m above ground	6 hour fcst	:VGRD:19.5 m above ground:6 hour fcst

91 rows × 10 columns

[14]:

H.inventory().attrs

[14]:

{'url': <_io.StringIO at 0x7fdc89a5a800>,
 'source': 'generated',
 'description': 'Inventory index file for the GRIB2 file.',
 'model': 'navgem_nomads',
 'product': 'none',
 'lead_time': 6,
 'datetime': Timestamp('2024-06-11 00:00:00')}

[15]:

H.xarray("TMP:2 m")