Data health

Storm Mode / Tracked area

Tropical: Guam

Wall mode

3 warnings total · 0 tornado warnings · 4 alerts including watches and advisories

Current alert feed · checked

Warnings in area

4 of 4 alerts
  1. Typhoon WarningGuam Coastal Waters; Rota Coastal Waters; Guam; RotaNWS Tiyan GU · until warning · alerts checked
  2. Coastal Flood WarningGuam; Rota; Tinian; SaipanNWS Tiyan GU · until warning · alerts checked
  3. High Surf WarningGuam; Rota; Tinian; SaipanNWS Tiyan GU · until warning · alerts checked
  4. Flood WatchGuam; Rota; Tinian; SaipanNWS Tiyan GU · until watch · radar-alerts checked

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Map

This map draws the contiguous United States, and Guam is beyond it. What is in force there is listed under “In force in this area”.

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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.

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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 2026-10-16 21:00:00 UTC, picture retrieved 2026-10-17 05:23:07.248 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

Radar-derived cells (0) · unavailable

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

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    Current NWS warning

    Guam; Rota; Tinian; Saipan

    Coastal Flood Warning

    Issued
    Updated
    Ends as issued
    Office
    NWS Tiyan GU
    Everyone should remain out of the water due to life-threatening surf conditions. Stay well away from the coast.

    Official NWS warning ↗

    The polygon is a warned area, not a tornado footprint. NWS detection tags are independent of radar algorithms and reports.

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    Full official message

    Coastal Flood Warning issued October 17 at 10:25AM ChST until October 19 at 4:00AM ChST by NWS Tiyan GU

    * WHAT...For the Coastal Flood Warning, significant coastal
flooding expected. For the High Surf Warning, dangerously large
breaking waves up to 35 feet for Guam, 20 to 25 feet for Rota,
and 15 to 20 feet for Tinian and Saipan.

* WHERE...Guam, Rota, Tinian and Saipan.

* WHEN...From 5 PM this afternoon to 4 AM ChST Monday.

* IMPACTS...Numerous roads may be closed. Low-lying property
including homes, businesses, and some critical infrastructure will
be inundated. Shoreline erosion will occur. Breaking waves can
sweep people off their feet, and into dangerous seas. Life-
threatening swimming conditions and significant beach erosion can
be expected. Coastal inundation of 5 to 7 feet for Guam, 2 to 4
feet for Rota and 1 to 3 feet for Tinian and Saipan is possible
along with coastal flooding and beach erosion.

* ADDITIONAL DETAILS...Surf is expected to rise rapidly to dangerous
levels tonight. Coastal impacts to the western coast of Guam and
Rota are highly dependent on the final track of Champi; passage
south of Guam would be reduced impacts whereas passage over Guam
would result in larger coastal inundation.
    Everyone should remain out of the water due to life-threatening
surf conditions. Stay well away from the coast.
    Warning-message history (2)

    Data: NOAA/NWS · PGUM.CF.W.0003

    Recent source changes

    Recording coverage and limits
    • warnings: retained from 2026-10-16T05:40:59.964Z through 2026-10-17T05:40:05.111Z
    • outlooks: retained from 2026-10-16T05:40:59.964Z through 2026-10-17T05:40:06.098Z
    • hydro: retained from 2026-10-16T05:40:59.964Z through 2026-10-17T05:35:05.479Z
    • analysis: retained from 2026-10-16T05:40:59.964Z through 2026-10-17T05:30:06.960Z
    • winter: retained from 2026-10-16T05:40:59.964Z through 2026-10-17T05:38:04.420Z

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

    Auto-updating checks this site’s cache every minute; each source keeps its own clock.

    Spotlight: The tropics

    1 of 2

    The tropics

    NHC’s and JTWC’s storms, their official graphics and the watches and warnings for them. Storm Mode’s own tropical panels arrive with its tropical events.

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    Data: NOAA/NHC, JTWC.

    Radar

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

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

    What changed, last 60 minutes

    since , when this server began watching this area

    Nothing has changed since 05:40Z.

    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
    Guam (NWS states: GU)
    Hazards
    Tropical 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 1

    1. Typhoon Warning1until 13:15Z
    Every alert in this area, most urgent first
    1. Typhoon WarningGuam Coastal Waters; Rota Coastal Waters; Guam; Rotauntil · NWS Tiyan GU

    Most urgent first, by the Briefing’s ranking. Checked .

    Sources

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    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.