Data health

Storm Mode / Tracked area

Flash flooding: California

Wall mode

0 warnings total · 0 tornado warnings · 0 alerts including watches and advisories

Current alert feed · checked

Warnings in area

0 of 0 alerts

No active alerts reported by the current feed in this monitoring area.

Watched places

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Layers

Map

NWS’s polygons as issued, or the zones a zone-issued alert names; SPC’s watches by their counties. Checked . Data: NOAA/NWS, NOAA/SPC.

Agency warning geometry · no observed imagery displayed
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Interactive imagery loads separately. Missing radar does not remove warnings or imply clear weather.

Alert outlines: NOAA/NWS; cell points/observed segments: IEM/NEXRAD. A warning polygon is not a tornado footprint.

Lightning activity — GOES GLM

Total lightning, including in-cloud activity. Not ground-strike locations or a safe-to-go-outside signal.

Cached lightning observations have not loaded. An empty map is not zero lightning.

Cached lightning source details and text readings

Snow analysis — NOHRSC

Source-rendered snow depth and snow water equivalent for the lower 48. History changes this snow picture only; warnings and radar keep their own clocks.

Stored snow depth · footprint valid 2026-10-18 06:00:00 UTC, picture retrieved 2026-10-18 12:23:04.796 UTC.

No NOHRSC picture displayed on the interactive map.

  • 0 - 0.39 in
  • 0.39 - 2.0 in
  • 2.0 - 3.9 in
  • 3.9 - 9.8 in
  • 9.8 - 20 in
  • 20 - 39 in
  • 39 - 59 in
  • 59 - 98 in
  • 98 - 197 in
  • 197 - 295 in
  • 295 - 394 in
  • 394 - 787 in
NOHRSC snow analysis for the lower 48; see the adjacent source legend and time qualification
NOAA/NWS/NOHRSC’s original picture and legend. No station or address value is inferred.

NOHRSC footprint times are metadata; pixel analysis time is not independently verified. Snow-depth pixels have previously differed from the footprint time. This is modeled/assimilated snow analysis, not a measurement at a place. Unshaded and no-data areas do not establish zero snow.

Snow pictures, retained history and source provenance

Change time or forecast product

Replay uses retained source bytes. Recording begins with activation; missing history is not clear weather.

Live sources keep independent clocks.

Replay coverage and interpretation

Rolling target: 24 hours; cells: six hours. Radar: NOAA MRMS national overview, 8-minute tolerance. Satellite: original GOES GeoColor day/night picture, hourly sampling, 75-minute tolerance. No interpolation or latest-image fallback. Warning and source checks retain their own clocks. “Recorded by” is collector acquisition evidence, not exact browser publication history.

Current GLM density, velocity and specialist layers are hidden during replay. Snow uses retained footprint metadata with unverified pixel time. Forecast uses one pinned issuance/run and exact valid time.

No observed replay frame displayed.

Open the complete replay reader (works without scripting or WebGL)
Radar-derived cells (0) · current

Collector checked ; feed generated . Zero cells does not establish coverage or clear weather. Observations from different radars are not merged.

    Station and river observations (103)

    Surface source current; observed water-level source current. Each reading keeps its own time. Map markers show at most 500 stations and 500 gauges; the complete source directory is paginated.

    Circle: surface station; square: water-level gauge. Filled: current reading and source; hollow: stale, unconfirmed or missing observation. Marker color is not a hazard category. Enable “Stations and gauges” in Layers to inspect them on the map.

    Showing 100 of 103 listed sources. All surface stations and retained trends · All supported gauges and forecasts

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    Water-level gauge CNJC1

    unavailable · No observation in the latest cached source list. Retained readings below are historical; an absent gauge may have fallen below action stage or stopped reporting.

    River gauge · Highway 101 · Conejo Creek · -118.964722, 34.236667000000004. Units ft; datum not supplied.

    Source checked 2026-10-18 16:55:05.239Z · current.

    Stage in this gauge’s units, not a regional flood depth. Tide/lake gauges remain water levels; datum is not supplied by this feed. Historical observations and the latest forecast keep separate times.

    Retained observations: 12; target 24 hours, at most 96 reports per station. Recording began 2026-10-17 06:15:05.234Z; oldest available reading 2026-10-17 17:15:00 UTC.

    Observed stage and separate NWS forecast at CNJC1 (ft)Dots are retained observations. Lines break for missing fields, long intervals or changed station location or units. 3 recorded discontinuities. Dashed lines, when present, are the separately issued NWS forecast.20.617.6ft10-17 17:15Z10-18 14:15Z2026-10-17 17:15:00 UTC · 19.01 ft2026-10-17 17:20:00 UTC · 18.97 ft2026-10-17 17:40:00 UTC · 18.84 ft2026-10-17 18:05:00 UTC · 18.98 ft2026-10-17 18:30:00 UTC · 18.99 ft2026-10-17 18:40:00 UTC · 18.9 ft2026-10-17 20:25:00 UTC · 18.61 ft2026-10-17 23:35:00 UTC · 18.62 ft2026-10-18 00:10:00 UTC · 18.89 ft2026-10-18 00:30:00 UTC · 19.57 ft2026-10-18 13:45:00 UTC · 18.62 ft2026-10-18 14:15:00 UTC · 18.61 ft
    Observed stage and separate NWS forecast · 12 retained observations; 3 discontinuities. Lines join reported values only; missing intervals are not interpolated.
    Observed reports as a table (12)
    Observed (UTC)Stage / unitsSource category / water
    2026-10-17 17:15:00 UTC19.01 ftAction stage · River gauge
    2026-10-17 17:20:00 UTC18.97 ftAction stage · River gauge
    2026-10-17 17:40:00 UTC18.84 ftAction stage · River gauge
    2026-10-17 18:05:00 UTC18.98 ftAction stage · River gauge
    2026-10-17 18:30:00 UTC18.99 ftAction stage · River gauge
    2026-10-17 18:40:00 UTC18.9 ftAction stage · River gauge
    2026-10-17 20:25:00 UTC18.61 ftAction stage · River gauge
    2026-10-17 23:35:00 UTC18.62 ftAction stage · River gauge
    2026-10-18 00:10:00 UTC18.89 ftAction stage · River gauge
    2026-10-18 00:30:00 UTC19.57 ftMinor flooding · River gauge
    2026-10-18 13:45:00 UTC18.62 ftAction stage · River gauge
    2026-10-18 14:15:00 UTC18.61 ftAction stage · River gauge
    Capture times, quality and provenance

    Each report keeps its observation time, first capture of this version, and the SHA-256 of the source bulk body. Corrections at the same observation time replace that point and are marked; unrelated bulk-file changes do not freshen a report.

    • Observed 2026-10-17 17:15:00 UTC, captured 2026-10-17 18:05:09.547Z; source body SHA-256 ce9665c1ab24da7c324f37374177f4e5b72455c2ef6565cd5c0d732217d9f0ee.
    • Observed 2026-10-17 17:20:00 UTC, captured 2026-10-17 18:25:06.484Z; source body SHA-256 c7b606972c17b5cf2e0734f800efc19fc6ad3fe42ed2b21f2406a7ee6688b790.
    • Observed 2026-10-17 17:40:00 UTC, captured 2026-10-17 18:45:07.189Z; source body SHA-256 05dd767c85748e9a16ef3da8d862ac7af6f3ea1e46e090022714a47205e48848.
    • Observed 2026-10-17 18:05:00 UTC, captured 2026-10-17 19:05:06.801Z; source body SHA-256 60cf58360af10f2d750469fb7df26158e3c395d26d194c9df905bfff272883be.
    • Observed 2026-10-17 18:30:00 UTC, captured 2026-10-17 19:25:05.413Z; source body SHA-256 8bfe0f6c4fbf418a97ed9a70a42faba76076b63d9ed23ca8958be28ed3e3dfbd.
    • Observed 2026-10-17 18:40:00 UTC, captured 2026-10-17 19:45:07.297Z; source body SHA-256 0c5c2e951418422e829868d6340e946c222cc8c6fefd6061bb657410339e4df2.
    • Observed 2026-10-17 20:25:00 UTC, captured 2026-10-17 21:25:04.659Z; source body SHA-256 587d4b429fdb21364a4a40d69af457e0f516a29baf595199eaa813c8160dfd2a.
    • Observed 2026-10-17 23:35:00 UTC, captured 2026-10-18 00:45:06.728Z; source body SHA-256 afec4416ea0f8de0c9a380660fb699f0e6f2f6de46c7f2306163e8220dd91163.
    • Observed 2026-10-18 00:10:00 UTC, captured 2026-10-18 01:05:05.183Z; source body SHA-256 b4b568ffea5d1284346a71afe8c92556989f3ceaadc7ae4d239f59ab1322b015.
    • Observed 2026-10-18 00:30:00 UTC, captured 2026-10-18 01:25:06.453Z; source body SHA-256 e409fc97034bfb40176782eb786aad2fea65de1c5495bf843e8769c4e41a58d8.
    • Observed 2026-10-18 13:45:00 UTC, captured 2026-10-18 14:35:07.225Z; source body SHA-256 571b293d8f9eb11322235f143f729ad67aad81c71d4573a940b1944493b23dec.
    • Observed 2026-10-18 14:15:00 UTC, captured 2026-10-18 14:45:09.175Z; source body SHA-256 79795e19658e28e4fd1a425003b70165e513705749f51d8055a7d030eb7fe056.

    Only observed gauge records enter this history. Forecast maxima and forecast hydrograph points never become observations. A missing datum or unsupported flow value remains unknown.

    Observation source page · Cached readings as JSON · Official source

    Recent source changes

    Recording coverage and limits
    • warnings: retained from 2026-10-17T17:03:28.104Z through 2026-10-18T17:03:04.520Z
    • outlooks: retained from 2026-10-17T17:03:28.104Z through 2026-10-18T17:00:18.532Z
    • hydro: retained from 2026-10-17T17:03:28.104Z through 2026-10-18T16:55:05.859Z
    • analysis: retained from 2026-10-17T17:03:28.104Z through 2026-10-18T17:00:06.399Z
    • winter: retained from 2026-10-17T17:03:28.104Z through 2026-10-18T16:53:04.430Z

    Source-message history is not recorded imagery replay. Recorded radar/satellite imagery is not available in this view.

    Checks every minute; each layer keeps its own time.

    Spotlight: Flash-flood risk, Day 1

    1 of 4

    Flash-flood risk, Day 1

    • Marginal

    WPC’s excessive rainfall outlook, to , issued : a chance of flash flooding, in four categories. Data: NOAA/WPC.

    River gauges in flood

    No river, coastal or lake gauge in this area is in flood, observed or forecast; 1 gauge at action stage.

    NWS’s gauges at flood stage or above in the area, worst first, each with its forecast hydrograph on Rain & rivers. Data: NOAA/NWPS.

    Rain expected and rain that fell

    WPC’s rain forecast and MRMS’s radar estimate of the rain that fell, on the Briefing’s map for the area.

    Open Rain & rivers

    Data: NOAA/WPC, NOAA/NSSL MRMS.

    Radar

    NOAA’s radar for the area, loaded by your browser as on the Radar page.

    Open the radar

    Live tiles; the radar keeps no last-good copy.

    What changed, last 60 minutes

    Nothing has changed in the last 60 minutes.

    The products’ own words and times, and what is no longer in force since the last read. Never written by AI.

    Monitoring area, legacy alert summary and selection rules
    Area
    California (NWS states: CA)
    Hazards
    Flash flood warnings, watches and advisories, and the forecasts for them
    Window
    In force now, with the next days of SPC’s and WPC’s products
    Made by
    This address: anyone can make one, and nothing is stored. Change the area or hazards

    An area you chose, not a storm’s footprint: everything here is in force in this area, never “from this storm”.

    In force in this area

    No warning, watch or advisory for these hazards is in force in this area.

    NWS’s alerts checked : a successful check, so this is none in force, not “can’t tell”.

    Sources

    Choose another storm or areaChange monitoring areaSource status

    Not an official warning service. Warnings and watches are the National Weather Service’s, outlooks and reports the Storm Prediction Center’s and the Weather Prediction Center’s (Data: NOAA/NWS, NOAA/SPC, NOAA/WPC). When a warning is issued for you, act on it, and use weather.gov or a NOAA Weather Radio for where you are.