Long Island Sound near New London Harbor (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.No secondary data available. Transformations for Flow data and a secondary Y axis cannot be made at this time.
Traces and Thresholds Click to turn on/off display
Observed (OBS) 06/27/2025 6:06 PM EDTOfficial Forecast (FCST) 06/27/2025 2:54 PM EDTLow Threshold: -1.8 ftCATEGORY STAGE 
Major Flooding 7.8 ft Moderate Flooding 6 ft Minor Flooding 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.
Tide Forecasts are a total water level forecast referenced to mean lower low water. 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
- 8 - Along low lying portions of the Long Island Sound, two to three feet of inundation is possible a few blocks inland with one to two feet of inundation possible north of I-95 in several low spots around waterways such as the Niantic River in Niantic, the Mystic River in Mystic. Nearly fifteen miles inland along the Connecticut and Thames Rivers, inundation is also possible with major damage in regions such as West End Drive and Seaside Lane in Old Lyme.
- 6.5 - Inundation of one to two feet of water occurs on streets and several properties in Saybrook Point, as well as in the Marina where several feet of water is possible, as water reaches over the seawall.
- 6 - Coastal flooding causes Niantic River Road to close between 1st and 2nd Avenue.
Gauge Info
| Coordinates | 41.3610, -72.0956 |
| RFC | NERFC |
| State | CT |
| WFO | OKX |
| County | New London |
| Data Provider(s) | |
| NOAA National Ocean Service | NOAA National Ocean Service |
| USGS | 8461490 |
Gauge Location
Recent Crests
| 1. | 8.04 ft | on 10-29-2012 |
| 2. | 9.58 ft | on 08-31-1954 |
| 3. | 7.58 ft | on 11-25-1950 |
| 4. | 7.08 ft | on 09-14-1944 |
| 5. | 10.58 ft | on 09-21-1938 |
Recent Crests
| 1. | 8.04 ft | on 10-29-2012 |
| 2. | 9.58 ft | on 08-31-1954 |
| 3. | 7.58 ft | on 11-25-1950 |
| 4. | 7.08 ft | on 09-14-1944 |
| 5. | 10.58 ft | on 09-21-1938 |
Historic Crests
| 1. | 10.58 ft | on 09-21-1938 |
| 2. | 9.58 ft | on 08-31-1954 |
| 3. | 8.04 ft | on 10-29-2012 |
| 4. | 7.58 ft | on 11-25-1950 |
| 5. | 7.08 ft | on 09-14-1944 |
Historic Crests
| 1. | 10.58 ft | on 09-21-1938 |
| 2. | 9.58 ft | on 08-31-1954 |
| 3. | 8.04 ft | on 10-29-2012 |
| 4. | 7.58 ft | on 11-25-1950 |
| 5. | 7.08 ft | on 09-14-1944 |
Vertical Datum Table
| type | MLLW* |
|---|---|
| major Flooding | 7.80 ft |
| moderate Flooding | 6.00 ft |
| minor Flooding | 5.00 ft |
| action | N/A |
| Latest Value | 0.65 ft |
| Gauge Zero | 0.00 ft |
Gauge Photos
No Images Found
Probability Information
No Images Available
Unique Local Info
|
Potential Tide Levels Used to Estimate the Chance of Flooding and the Range of Possible Tide Levels |
||
| GFS Based Guidance (ETSS) | GEFS Based Guidance (P-ETSS) | NAEFS Based Guidance (P-ETSS) |
 |
 |
 |
Note: Use the official hydrograph at the top of this web page for tide levels within the next 72 hours.
The Potential Tide Level graphics above are from an EXPERIMENTAL web site. It is supported on an 8x5 basis, and has no guarantee of availability in the future. Please see information HERE to understand the strengths and weakness of the Potential Tide Level graphics. Click individual graphics to enlarge.
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.