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.
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
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.
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.
Collector checked ; feed generated . Zero cells does not establish coverage or clear weather. Observations from different radars are not merged.
Station and river observations (22)
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.
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.”
WPC’s Probabilistic Winter Precipitation Forecast, to , issued . Outlines, as WPC draws them. Data: NOAA/NWS/WPC.
Winter watches, warnings and advisories
Freeze Warning22 not yet in effect · until · NWS Baltimore MD/Washington DC, NWS State College PA
Frost Advisory33 not yet in effect · 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.
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.
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.
Frost Advisory issued by NWS Mount Holly NJ: Morris; Hunterdon; Somerset; Middlesex; Mercer; Berks; Lehigh; Western Chester; Eastern Chester; Western Montgomery; Eastern Montgomery; Upper Bucks; Lower Bucks
Freeze Warning issued by NWS Baltimore MD/Washington DC: Frederick; Carroll; Culpeper; Northern Fauquier; Southern Fauquier; Western Loudoun
Frost Advisory issued by NWS Baltimore MD/Washington DC: Northern 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 Park
WPC heavy snow and icing discussion issued
Freeze Warning issued by NWS State College PA: York
Frost Advisory issued by NWS State College PA: Lebanon; Lancaster
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
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.
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