Data health

Storm Mode / Tracked area

Maryland

Wall mode

2 warnings total · 0 tornado warnings · 7 alerts including watches and advisories

Current alert feed · checked

Warnings in area

7 of 7 alerts
  1. Freeze WarningYorkNWS State College PA · until warning · alerts checked
  2. Freeze WarningFrederick; Carroll; Culpeper; Northern Fauquier; Southern Fauquier; Western LoudounNWS Baltimore MD/Washington DC · until warning · alerts checked
  3. Coastal Flood WatchInland WorcesterNWS Wakefield VA · until watch · radar-alerts checked
  4. Coastal Flood WatchMaryland Beaches; Accomack; NorthamptonNWS Wakefield VA · until watch · radar-alerts checked
  5. Frost AdvisoryNorthern Baltimore; Northwest Montgomery; Central and Southeast Montgomery; Northwest Howard; Central and Southeast Howard; Northwest Harford; Greene; Madison; Rappahannock; Orange; Fairfax; Eastern Loudoun; Northwest Prince William; Central and Southeast Prince William/Manassas/Manassas ParkNWS Baltimore MD/Washington DC · until advisory · radar-alerts checked
  6. Frost AdvisoryLebanon; LancasterNWS State College PA · until advisory · radar-alerts checked
  7. Frost AdvisoryMorris; Hunterdon; Somerset; Middlesex; Mercer; Berks; Lehigh; Western Chester; Eastern Chester; Western Montgomery; Eastern Montgomery; Upper Bucks; Lower BucksNWS Mount Holly NJ · until advisory · radar-alerts checked

Watched places

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Layers

Map

  • Freeze Warning 2
  • Coastal Flood Watch 2
  • Frost Advisory 3

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
North ↑

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 2026-10-19 00:00:00 UTC, picture retrieved 2026-10-19 06:23:06.202 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 (24)

    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 24 of 24 listed sources. All surface stations and retained trends · All supported gauges and forecasts

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    Water-level gauge CAMM2

    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.

    Tide gauge (coastal water level) · Cambridge (IN MLLW) · Chesapeake Bay · -76.068333, 38.573333000000005. Units ft; datum not supplied.

    Source checked 2026-10-19 08:25:06.268Z · 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: 0; target 24 hours, at most 96 reports per station. Recording began 2026-10-17 06:15:05.234Z; oldest available reading none.

    No retained observations yet. Reload after the existing scheduled source pass runs.

    NWS forecast · current

    Highest listed forecast: 3.5 ft at 2026-10-22 05:00:00 UTC; issued 2026-10-19 07:36:00 UTC. Minor flooding.

    NWPS’s record held is for another issuance of the forecast; the newer one has not been read yet.

    Gauge thresholds: action 3 ft; minor 3.5 ft; moderate 4 ft; major 4.5 ft.

    Observed reports as a table (0)
    Observed (UTC)Stage / unitsSource category / water
    No retained observations.
    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.

      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 2026-10-18T08:34:43.338Z through 2026-10-19T08:34:04.394Z
      • outlooks: retained from 2026-10-18T08:34:43.338Z through 2026-10-19T08:30:06.937Z
      • hydro: retained from 2026-10-18T08:34:43.338Z through 2026-10-19T08:25:08.947Z
      • analysis: retained from 2026-10-18T08:34:43.338Z through 2026-10-19T08:30:07.047Z
      • winter: retained from 2026-10-18T08:34:43.338Z through 2026-10-19T08:23:05.970Z

      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.

      Analysis and model context

      Current cached context, independently dated. Regional reference: MD; a reference within a wider monitoring area does not replace the complete warning geography. This section remains separate from the historical replay cursor and official cyclone forecast. Use Forecast to pin a retained model package.

      Surface: what stations observe and WPC analyses

      37374123322332323937323141413736373345373634413841383838343434333636434030293331412036363434323233324038323034345644373231313332323241264240
      Maryland: one station shown in each small area of the map, so it stays legible; the table lists every station in a state.

      On the map

      • Observed temperature, °F, above-left of the station
      • Observed dew point, °F, below-left
      • Observed temperature and dew point are left off the map on a screen this narrow: the table below lists every station’s.
      • Observed wind: the staff points to where it blows from; a full barb is 10 kt, a half 5, a pennant 50; a ring is calm
      • Analysis cold front
      • Analysis warm front
      • Analysis stationary front
      • Analysis occluded front
      • Analysis dry line
      • Analysis trough
      • Analysis high and low pressure centres, with their pressure in millibars

      WPC’s bulletin does not say which side of a front its symbols go, so this map draws no triangles or half-circles; each front is named on the map and in the list.

      Observed 2,042 stations, each at its own time, most between and . Airport and other automated stations’ reports (METARs), as AviationWeather.gov decodes them. Left out: 629 reports flagged by the station for maintenance and two reports that cannot be right; no other quality control is applied here.

      Analysis WPC’s surface analysis valid , issued . A forecaster’s analysis of the fronts and pressure centres at that hour, every three hours.

      WPC analyses no front across Maryland; troughs are drawn on the map.

      Every station in Maryland (15)
      fifteen stations in Maryland, by identifier
      StationObservedTemperatureDew pointWindPressureVisibilityWeather
      K0W337 °F37 °Fcalm—9 mi—
      K2G441 °F23 °F140° 8 kt—10+ mi—
      KBWI39 °F37 °F280° 3 kt1032.1 mb10+ mi—
      KCBE32 °F31 °Fcalm—10+ mi—
      KCGE41 °F41 °F360° 3 kt—10+ mi—
      KCGS37 °F36 °Fcalm—10+ mi—
      KDMH45 °F37 °Fnot given1032.2 mb——
      KDMW36 °F34 °F010° 2 kt—10+ mi—
      KESN41 °F38 °F010° 3 kt—10+ mi—
      KFDK34 °F34 °Fcalm—10+ mi—
      KFME36 °F36 °Fcalm—10+ mi—
      KGAI36 °F36 °Fcalm1033.9 mb10+ mi—
      KMTN40 °F38 °Fcalm—10+ mi—
      KOXB56 °F44 °F040° 12 kt, gusts 20 kt1030.0 mb10+ mi—
      KW2942 °F40 °Fcalm—10+ mi—

      Surface observations checked · Data: NOAA/NWS Aviation Weather Center

      WPC surface analysis checked · Data: NOAA/WPC

      Spotlight: Winter Storm Severity Index

      1 of 15

      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%
      • 20–30%
      • 30–40%
      • 40–50%
      • 50–60%
      • 60–70%
      • 70–80%
      • 80–90%
      • 90–95%
      • 95% or more

      Each level and day on the Winter tab

      WPC’s WSSI-P: no chance drawn for Day 1. 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

      • Freeze Warning 2 until · NWS Baltimore MD/Washington DC, NWS State College PA
      • Frost Advisory 3 until · NWS Baltimore MD/Washington DC, NWS Mount Holly NJ, NWS State College PA

      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.

      NOHRSC snow analysis and retained pictures

      Data: NOAA/NWS/NOHRSC. Snow analysis, not a measurement at a place.

      WPC’s heavy snow and icing discussion

      Southern Sierra Nevada

      Day 3...

      A highly anomalous upper-low off the Southern CA coast (standardized anomalies as much as -4 sigma at 500mb and 700mb by 12Z Wed) will work in tandem with an upper-level ridge over the Nation's Heartland to tap into rich tropical East Pacific moisture and direct this moisture at the Southwest U.S.. 850-500mb mean flow out of the south will provide a favorable setup for upslope- enhanced precipitation rates long the southern Sierra Nevada. That said, the antecedent air-mass is not overly cold and the colder temperatures within the closed low are well offshore. This will keep snowfall confined to the higher elevations of the southern Sierra Nevada on Wednesday (above 9,000ft). The Probabilistic Precipitation Portal (PPP) shows low chances (10-30%) for snowfall totals >4" above 10,000ft. The Probabilistic Winter Storm Severity Index (WSSI-P) also show low chances (10-30%) as low as 9,000ft in elevations. This could result in some slick conditions in the rugged terrain of the southern Sierra Nevada mid-week.

      The whole discussion

      Issued , for to . WPC’s words, as written. Data: NOAA/NWS/WPC.

      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.

      Open the Analysis tab

      Drawn by the Analysis tab’s own renderer. Data: NOAA/SPC, NOAA/NCEP.

      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

      0 major · 2 moderate · 4 minor · 3 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.

      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.

      Open the Tropics page

      Data: NOAA/NHC, JTWC.

      Radar, winter preset

      The Radar page’s winter preset over the area: HRDPS forecast snow with NWS’s warnings on top, loaded by your browser. A forecast, labelled as one there.

      Open the radar

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

      What changed, last 60 minutes

      since , when this server began watching this area
      1. Coastal Flood Watch extended in time by NWS Wakefield VA: Inland Worcester
      2. Coastal Flood Watch extended in time by NWS Wakefield VA: Maryland Beaches; Accomack; Northampton
      3. WPC snow and ice chances issued
      4. WPC snow and ice chances issued
      5. WPC snow and ice chances issued
      6. WPC snow and ice chances issued
      7. WPC snow and ice chances issued
      8. WPC snow and ice chances issued
      9. WPC snow and ice chances issued
      10. WPC snow and ice chances issued
      11. WPC excessive rainfall outlook issued
      12. WPC snow and ice chances issued
      13. WPC snow and ice chances issued
      14. WPC snow and ice chances issued
      15. WPC snow and ice chances issued

      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
      Maryland (NWS states: MD)
      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 7

      1. Freeze Warning2until 13:00Z
      2. Coastal Flood Watch22 new · 2 not yet in effect · until 22 Oct 02:00Z
      3. Frost Advisory3until 13:00Z
      Every alert in this area, most urgent first
      1. Freeze WarningYorkuntil · NWS State College PA · drawn over this area
      2. Freeze WarningFrederick; Carroll; Culpeper; Northern Fauquier; Southern Fauquier; Western Loudoununtil · NWS Baltimore MD/Washington DC
      3. Coastal Flood WatchInland WorcesterFrom · until · NWS Wakefield VA
      4. Coastal Flood WatchMaryland Beaches; Accomack; NorthamptonFrom · until · NWS Wakefield VA
      5. Frost AdvisoryNorthern Baltimore; Northwest Montgomery; Central and Southeast Montgomery; Northwest Howard; Central and Southeast Howard; Northwest Harford; Greene; Madison; Rappahannock; Orange; Fairfax; Eastern Loudoun; Northwest Prince William; Central and Southeast Prince William/Manassas/Manassas Parkuntil · NWS Baltimore MD/Washington DC
      6. Frost AdvisoryLebanon; Lancasteruntil · NWS State College PA · drawn over this area
      7. Frost AdvisoryMorris; Hunterdon; Somerset; Middlesex; Mercer; Berks; Lehigh; Western Chester; Eastern Chester; Western Montgomery; Eastern Montgomery; Upper Bucks; Lower Bucksuntil · NWS Mount Holly NJ · drawn over this area

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

      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.