Flash-flood risk, Day 1
- Marginal
WPC’s excessive rainfall outlook, to , issued : a chance of flash flooding, in four categories. Data: NOAA/WPC.
3 warnings total · 0 tornado warnings · 4 alerts including watches and advisories
Current alert feed · checked
Warnings in area
4 of 4 alerts- Typhoon WarningGuam Coastal Waters; Rota Coastal Waters; Guam; RotaNWS Tiyan GU · until warning · alerts checked
- Coastal Flood WarningGuam; Rota; Tinian; SaipanNWS Tiyan GU · until warning · alerts checked
- High Surf WarningGuam; Rota; Tinian; SaipanNWS Tiyan GU · until warning · alerts checked
- Flood WatchGuam; Rota; Tinian; SaipanNWS Tiyan GU · until watch · radar-alerts checked
Watched places
Places saved on this device appear here with scripting enabled.
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”.
Agency warning geometry · no observed imagery displayed
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.
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 18:00:00 UTC, picture retrieved 2026-10-17 03:08:05.170 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 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.
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.
Inspector
Choose a warning, cell or place
Select a row or map feature for its official details. Overlapping features offer a choice; all peer warnings remain in the list.
Recent source changes
- office-afd · source-revision · Recorded 2026-10-17T04:00:11.185Z
- radar-alerts · source-revision · Recorded 2026-10-17T04:00:09.122Z
- metars · source-revision · Recorded 2026-10-17T04:00:07.920Z
- hrrr · source-revision · Recorded 2026-10-17T04:00:07.920Z
- office-afd · source-revision · Recorded 2026-10-17T03:55:05.244Z
- metars · source-revision · Recorded 2026-10-17T03:45:15.535Z
- office-afd · source-revision · Recorded 2026-10-17T03:45:06.430Z
- gauges-observed · source-revision · Recorded 2026-10-17T03:45:05.684Z
Recording coverage and limits
- warnings: retained from 2026-10-16T04:00:58.253Z through 2026-10-17T04:00:09.122Z
- outlooks: retained from 2026-10-16T04:00:58.253Z through 2026-10-17T04:00:11.185Z
- hydro: retained from 2026-10-16T04:00:58.253Z through 2026-10-17T03:55:04.490Z
- analysis: retained from 2026-10-16T04:00:58.253Z through 2026-10-17T04:00:07.920Z
- winter: retained from 2026-10-16T04:00:58.253Z through 2026-10-17T03:53:02.974Z
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: Chance of Moderate impacts or worse, Day 1
10 of 15River gauges in flood
No river, coastal or lake gauge in this area is in flood, observed or forecast.
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.
Data: NOAA/WPC, NOAA/NSSL MRMS.
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.
Data: NOAA/NHC, JTWC.
SPC Day 1 outlook
- General Thunderstorms Risk
SPC’s Day 1 categorical outlook, valid to , issued . SPC’s categories, as drawn. Data: NOAA/SPC.
Watches
No tornado or severe thunderstorm watch in force in this area.
SPC’s watches, by number, matched by the counties they list. Data: NOAA/SPC.
Mesoscale discussions
No mesoscale discussion reaches this area.
SPC’s mesoscale discussions whose outline reaches the area. Data: NOAA/SPC.
Storm ingredients
SPC’s hourly mesoanalysis, observed soundings and model guidance for the area, on the Analysis tab with its own clocks.
Drawn by the Analysis tab’s own renderer. Data: NOAA/SPC, NOAA/NCEP.
Winter Storm Severity Index
WPC: “WSSI does not depict official warnings and should always be used in context with official NWS forecasts and warnings.”
- Winter Weather Area
- Minor Impacts
- Moderate Impacts
- Major Impacts
- Extreme Impacts
Highest in this area, by day and by cause
- Day 1
- nothing drawn
- Day 2
- nothing drawn
- Day 3
- nothing drawn
- Snow amount, Days 1–3
- nothing drawn
- Snow load, Days 1–3
- nothing drawn
- Ice, Days 1–3
- nothing drawn
- Blowing snow, Days 1–3
- nothing drawn
Each day and cause on the Winter tab, with its own issue time
WPC’s WSSI, overall impact, Days 1–3, valid to , issued . WPC issues each day and cause on its own clock. Not a warning, and not a chance. Data: NOAA/NWS/WPC.
Chance of Moderate impacts or worse, Day 1
WPC: “WSSI does not depict official warnings and should always be used in context with official NWS forecasts and warnings.”
- 5–10%
- 10–20% (not drawn)
- 20–30% (not drawn)
- 30–40% (not drawn)
- 40–50% (not drawn)
- 50–60% (not drawn)
- 60–70% (not drawn)
- 70–80% (not drawn)
- 80–90% (not drawn)
- 90–95% (not drawn)
- 95% or more (not drawn)
Each level and day on the Winter tab
WPC’s WSSI-P, the 24 hours to , WPC’s forecast from . Each band runs to the next. Data: NOAA/NWS/WPC.
Chance of at least 4 inches of snow, Day 1
WPC gives no chance of 4 inches of snow or more in this area over the next three days, so Day 1’s 4 inches is shown.
- Slight: at least 10%
- Moderate: at least 40%
- High: at least 70%
Every day and amount on the Winter tab
WPC’s Probabilistic Winter Precipitation Forecast, to , issued . Outlines, as WPC draws them. Data: NOAA/NWS/WPC.
Winter watches, warnings and advisories
No winter or cold watch, warning or advisory in force in this area.
NWS’s winter and cold alerts in force in the area, by event as issued, each counted once, with the offices that issued them and the latest end. Data: NOAA/NWS.
Snow on the ground
NOHRSC snow depth and snow water equivalent use the source’s original pictures and legends, with qualified footprint times. Open the cached source page for availability and retained history. This wall has no snow picture to rotate; missing imagery does not mean no snow.
Data: NOAA/NWS/NOHRSC. Snow analysis, not a measurement at a place.
WPC’s heavy snow and icing discussion
Issued , for to . WPC’s words, as written. Data: NOAA/NWS/WPC.
Radar
NOAA’s radar for the area, loaded by your browser as on the Radar page.
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
- Guam (NWS states: GU)
- Hazards
- Every kind of warning, watch and advisory this site carries
- 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 4
- Typhoon Warning1until 20:00Z
- Coastal Flood Warning11 not yet in effect · until 18 Oct 18:00Z
- High Surf Warning11 not yet in effect · until 18 Oct 18:00Z
- Flood Watch1until 18 Oct 06:00Z
Every alert in this area, most urgent first
- Typhoon WarningGuam Coastal Waters; Rota Coastal Waters; Guam; Rotauntil · NWS Tiyan GU
- Coastal Flood WarningGuam; Rota; Tinian; SaipanFrom · until · NWS Tiyan GU
- High Surf WarningGuam; Rota; Tinian; SaipanFrom · until · NWS Tiyan GU
- Flood WatchGuam; Rota; Tinian; Saipanuntil · NWS Tiyan GU
Most urgent first, by the Briefing’s ranking. Checked .
Sources
NWS warnings and SPC watches checked
NWS watches and advisories checked
SPC mesoscale discussions checked
SPC Day 1 outlook checked
WPC excessive rainfall checked
NWPS river gauges checked
WPC WSSI checked
WPC WSSI-P checked
WPC snow and ice chances checked
WPC heavy snow and icing discussion checked
Radar live tiles, no last-good copy
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.