Data health

Storm Mode / Tracked area

Coastal flooding: Guam

Wall mode

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

Current alert feed · checked

Change time or forecast product

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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.

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Warnings in area

4 of 4 alerts
  1. Typhoon WarningGuam; Rota; Guam Coastal Waters; Rota Coastal WatersNWS Tiyan GU · until warning · alerts checked
  2. Coastal Flood WarningGuam; RotaNWS Tiyan GU · until warning · alerts checked
  3. High Surf WarningGuam; RotaNWS Tiyan GU · until warning · alerts checked
  4. Flood WatchGuam; RotaNWS 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 2026-10-18 00:00:00 UTC, picture retrieved 2026-10-18 06:23:06.237 UTC.

No NOHRSC picture displayed on the interactive map.

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  • 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) · 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 (0)

    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.

    • No readable station in this monitoring area. Missing does not mean calm or low water.

    Showing 0 of 0 listed sources. All surface stations and retained trends · All supported gauges and forecasts

    Selected details

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    Current NWS warning

    Guam; Rota; Guam Coastal Waters; Rota Coastal Waters

    Typhoon Warning

    Issued
    Updated
    Ends as issued
    Office
    NWS Tiyan GU
    As frequent damaging tropical storm-force gusts continue, do not go outside to check for damage or to implement temporary repairs, even as sustained winds diminish through the next few hours. Occasional strong tropical storm-force gusts will maintain dangerous conditions outdoors. Do not open the doors of your home or shelter until high winds fully subside. Wait for the all-clear signal. Passing showers will bring very strong gusts without warning.

    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

    Typhoon Warning issued October 18 at 3:01PM ChST by NWS Tiyan GU

    ...SUPER TYPHOON CHAMPI CONTINUES WEST, AWAY FROM GUAM WATERS...

.NEW INFORMATION...
None.

.AREAS AFFECTED...
This local statement provides important information and
recommended actions for people in Guam and the Northern Marianas.

.Watches/Warnings...
A Typhoon Warning continues for Guam and Rota.

Although tropical cyclone watches or warnings are not in effect
for Tinian and Saipan, possible impacts from related hazards are
still a concern.

A Flood Watch is in effect for portions of Guam and the Northern
Marianas. Please listen closely for any Flood Warnings that might
be in effect for your area.

Please check the latest public and marine forecasts for detailed
information about additional hazards.

.STORM INFORMATION...
At 2 PM ChST...the center of Super Typhoon Champi (29W) was
located near latitude 13.0N...longitude 142.6E. This was about
150 miles west of Guam. Storm motion was west, 260 degrees, at 12
mph. Storm intensity was 150 mph.

.SITUATION OVERVIEW...
Super Typhoon Champi continues to move generally westward with a
slight southward turn over the last few hours, and a slight
decrease in forward speed. The eye remains very small and compact,
appearing to fill in with cloud cover in the latest visible
satellite imagery, with a width of around 5 miles across. It looks
to be going through an eyewall replacement cycle. GLD network
data shows frequent lightning within the deep convection along the
southern eyewall, which is beginning to exit radar range. Surface
observations from Guam International Airport show strong sustained
winds of 25 to 30 mph with frequent tropical storm-force gusts up
to 60 mph. At Saipan, winds are fresh to strong with gusts to 35
mph.
    As frequent damaging tropical storm-force gusts continue, do not
go outside to check for damage or to implement temporary repairs,
even as sustained winds diminish through the next few hours.
Occasional strong tropical storm-force gusts will maintain
dangerous conditions outdoors. Do not open the doors of your home
or shelter until high winds fully subside. Wait for the all-clear
signal. Passing showers will bring very strong gusts without
warning.
    Warning-message history (6)

    Data: NOAA/NWS · PGUM.TY.W.4029

    Recent source changes

    Recording coverage and limits
    • warnings: retained from 2026-10-17T06:32:50.037Z through 2026-10-18T06:32:03.267Z
    • outlooks: retained from 2026-10-17T06:32:50.037Z through 2026-10-18T06:30:06.875Z
    • hydro: retained from 2026-10-17T06:32:50.037Z through 2026-10-18T06:25:07.255Z
    • analysis: retained from 2026-10-17T06:32:50.037Z through 2026-10-18T06:30:07.583Z
    • winter: retained from 2026-10-17T06:32:50.037Z through 2026-10-18T06:23:05.341Z

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

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    Spotlight: Radar

    1 of 1

    Radar

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

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    What changed, last 60 minutes

    since , when this server began watching this area

    Nothing has changed since 06:32Z.

    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
    Coastal 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 1

    1. Coastal Flood Warning1until 18:00Z
    Every alert in this area, most urgent first
    1. Coastal Flood WarningGuam; 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.