Northwest Branch Patapsco River at Baltimore/Fort McHenry (IN MLLW)
Future / Actual / Minor
OWP 2.0 WWA Modal Title
01/11/2021, 10:04 PM UTC through 01/11/2021, 10:04 PM UTC
Sender
Sent
- Upstream gauge unavailableDownstream gauge unavailableWarning: no valid ratings curve available. Transformations to and from FEET/CFS/KCFS will not happen.
Traces and Thresholds Click to turn on/off display
Observed (OBS) 06/20/2025 6:06 PM EDTOfficial Forecast (FCST) 06/20/2025 2:34 PM EDTRecord: 8.2 ftCATEGORY STAGE 
Major Flooding 6 ft Moderate Flooding 4.6 ft Minor Flooding 3.4 ft Action 2.5 ft Reliability of the Forecast: Forecast data shown here are guidance values only. Please refer to your local NWS office.
NOTE: Forecasts are issued routinely year-round.
Please refer to Coastal Flood Advisories and Warnings for official water level forecasts during periods of coastal flooding. During tropical cyclones, please refer here for additional storm surge information.
National Water Model Hydrograph
Official NWS streamflow forecasts are produced by NWS hydrologic forecasters for river gauge locations using hydrologic models which are calibrated to that location. This process considers additional guidance and information, including local expertise and experience, to produce the best forecast possible. The NWM output provides supplemental guidance to NWS forecasters and should not be considered an official NWS river forecast.
Flood Impacts
- 6.5 - Water approaches Caroline Street.
- 6 - Water reaches the corner of Ann Street and Thames Street.
- 5.5 - Water begins to cover the Pier 4 promenade on the west side and Pier 5 on the west side.
Gauge Info
| Coordinates | 39.2700, -76.5800 |
| RFC | MARFC |
| State | MD |
| WFO | LWX |
| County | Baltimore City |
| Data Provider(s) | |
| National Ocean Service | National Ocean Service |
Gauge Location
Recent Crests
| 1. | 5.85 ft | on 05-28-2025 | (P) |
| 2. | 5.31 ft | on 12-16-2022 | (P) |
| 3. | 4.92 ft | on 10-30-2021 | (P) |
| 4. | 4.24 ft | on 04-30-2020 | (P) |
| 5. | 4.17 ft | on 04-13-2020 | (P) |
Recent Crests
| 1. | 5.85 ft | on 05-28-2025 | (P) |
| 2. | 5.31 ft | on 12-16-2022 | (P) |
| 3. | 4.92 ft | on 10-30-2021 | (P) |
| 4. | 4.24 ft | on 04-30-2020 | (P) |
| 5. | 4.17 ft | on 04-13-2020 | (P) |
| 6. | 3.61 ft | on 11-19-2019 | (P) |
| 7. | 4.05 ft | on 10-12-2019 | (P) |
| 8. | 4.16 ft | on 10-12-2019 | (P) |
| 9. | 3.49 ft | on 12-21-2018 | |
| 10. | 3.66 ft | on 11-27-2018 | |
| 11. | 3.85 ft | on 09-21-2018 | |
| 12. | 3.57 ft | on 09-18-2018 | |
| 13. | 3.62 ft | on 09-11-2018 | |
| 14. | 3.61 ft | on 09-10-2018 | |
| 15. | 3.72 ft | on 09-10-2018 | |
| 16. | 3.80 ft | on 09-09-2018 | |
| 17. | 3.66 ft | on 04-16-2018 | |
| 18. | 3.56 ft | on 03-07-2018 | |
| 19. | 3.89 ft | on 03-07-2018 | |
| 20. | 3.31 ft | on 03-06-2018 | |
| 21. | 3.37 ft | on 11-10-2017 | |
| 22. | 3.04 ft | on 11-05-2017 | |
| 23. | 3.79 ft | on 10-24-2017 | |
| 24. | 3.11 ft | on 10-14-2017 | |
| 25. | 3.02 ft | on 10-13-2017 | |
| 26. | 3.05 ft | on 09-21-2017 | |
| 27. | 3.21 ft | on 09-20-2017 | |
| 28. | 3.29 ft | on 08-31-2017 | |
| 29. | 3.02 ft | on 08-18-2017 | |
| 30. | 3.12 ft | on 08-15-2017 | |
| 31. | 8.15 ft | on 09-19-2003 | |
| 32. | 5.16 ft | on 09-07-1996 | |
| 33. | 5.13 ft | on 11-04-1985 | |
| 34. | 5.18 ft | on 09-06-1979 | |
| 35. | 6.39 ft | on 08-13-1955 | |
| 36. | 5.50 ft | on 10-15-1954 | |
| 37. | 4.69 ft | on 09-01-1952 | |
| 38. | 4.89 ft | on 11-25-1950 | |
| 39. | 7.69 ft | on 08-23-1933 | |
| 40. | 5.30 ft | on 08-04-1915 |
Historic Crests
| 1. | 8.15 ft | on 09-19-2003 | |
| 2. | 7.69 ft | on 08-23-1933 | |
| 3. | 6.39 ft | on 08-13-1955 | |
| 4. | 5.85 ft | on 05-28-2025 | (P) |
| 5. | 5.50 ft | on 10-15-1954 |
Historic Crests
| 1. | 8.15 ft | on 09-19-2003 | |
| 2. | 7.69 ft | on 08-23-1933 | |
| 3. | 6.39 ft | on 08-13-1955 | |
| 4. | 5.85 ft | on 05-28-2025 | (P) |
| 5. | 5.50 ft | on 10-15-1954 | |
| 6. | 5.31 ft | on 12-16-2022 | (P) |
| 7. | 5.30 ft | on 08-04-1915 | |
| 8. | 5.18 ft | on 09-06-1979 | |
| 9. | 5.16 ft | on 09-07-1996 | |
| 10. | 5.13 ft | on 11-04-1985 | |
| 11. | 4.92 ft | on 10-30-2021 | (P) |
| 12. | 4.89 ft | on 11-25-1950 | |
| 13. | 4.69 ft | on 09-01-1952 | |
| 14. | 4.24 ft | on 04-30-2020 | (P) |
| 15. | 4.17 ft | on 04-13-2020 | (P) |
| 16. | 4.16 ft | on 10-12-2019 | (P) |
| 17. | 4.05 ft | on 10-12-2019 | (P) |
| 18. | 3.89 ft | on 03-07-2018 | |
| 19. | 3.85 ft | on 09-21-2018 | |
| 20. | 3.80 ft | on 09-09-2018 | |
| 21. | 3.79 ft | on 10-24-2017 | |
| 22. | 3.72 ft | on 09-10-2018 | |
| 23. | 3.66 ft | on 11-27-2018 | |
| 24. | 3.66 ft | on 04-16-2018 | |
| 25. | 3.62 ft | on 09-11-2018 | |
| 26. | 3.61 ft | on 09-10-2018 | |
| 27. | 3.61 ft | on 11-19-2019 | (P) |
| 28. | 3.57 ft | on 09-18-2018 | |
| 29. | 3.56 ft | on 03-07-2018 | |
| 30. | 3.49 ft | on 12-21-2018 | |
| 31. | 3.37 ft | on 11-10-2017 | |
| 32. | 3.31 ft | on 03-06-2018 | |
| 33. | 3.29 ft | on 08-31-2017 | |
| 34. | 3.21 ft | on 09-20-2017 | |
| 35. | 3.12 ft | on 08-15-2017 | |
| 36. | 3.11 ft | on 10-14-2017 | |
| 37. | 3.05 ft | on 09-21-2017 | |
| 38. | 3.04 ft | on 11-05-2017 | |
| 39. | 3.02 ft | on 10-13-2017 | |
| 40. | 3.02 ft | on 08-18-2017 |
Vertical Datum Table
| type | MLLW* |
|---|---|
| major Flooding | 6.00 ft |
| moderate Flooding | 4.60 ft |
| minor Flooding | 3.40 ft |
| action | 2.50 ft |
| Latest Value | 0.55 ft |
| Gauge Zero | 0.00 ft |
Gauge Photos
No Images Found
Probability Information
No Images Available
Unique Local Info
Tidal forecast guidance is now available for this location. This forecast guidance is calibrated for high tide. Low tides may be lower than this guidance indicates.
Collaborative Agencies
The National Weather Service prepares its forecasts and other services in collaboration with agencies like the US Geological Survey, US Bureau of Reclamation, US Army Corps of Engineers, Natural Resource Conservation Service, National Park Service, ALERT Users Group, Bureau of Indian Affairs, and many state and local emergency managers across the country. For details, please click here.