Weather Info

If heading out from our Norwalk Base, start with the NOAA Marine Forecast for Norwalk Islands & Surrounding Areas in Long Island Sound.

Before sailing, these local weather summaries are your best, quick source of information about winds, weather, small craft warnings (when you should not be out) and other dangers like strong cold fronts with thunderstorms. In general, we find that the marine forecast for the Long Island Sound underestimates the local effect of the sea breeze. Southwest (SW) winds will often kick in sooner and will be 2-4 knots stronger than forecast. If you start to see puffy cumulus clouds forming just north of the Connecticut coast, count on the winds shifting to the south or southwest, even if they are forecast to be out of the North. Any day with clear skies and winds less than 15 knots means that SW breezes are a good bet.

Click for Atlantic Seaboard & Caribbean Forecasts. Scroll down the list until you get to the area you want.  Start with the Synopsis for the big picture, then click on the local forecast. This will give you a fairly detailed forecast for 24 hours, and then winds for the next 4 days, which is very useful in planning your trip.

After we get the basic weather and wind info, we often like to get a little more information. Our favorite basic weather site is the NOAA site for zone forecasts CityName=Norwalk&state=CT&site=OKX  This will bring you to the Norwalk forecast. Type in the zip code or City, State to bring up the local forecast in other area’s. National updates come first, followed by a nice summary of the weather for the next 7 days. The first three days will include wind forecasts in MPH, not Knots.

If you are into weather, the best feature of this site is the Forecast Discussion (located lower left hand corner of the page under Additional Forecasts and Information), where the forecasters discuss what is interesting or uncertain in the forecast and review the big picture data. Weather forecasters use several different computer models to predict the weather such as NAM (North American Model) or GFS (Global Forecast System), and these models do not always agree. When they don’t, the forecasters have to pick which model to use, and they often discuss this process.  Very educational and interesting. Lots of jargon here, but much is explained via links to technical terms. Even more important is that when the models do not agree, the forecast is more uncertain. This is the only place to find out how reliable the forecast is on the web. Note that the government is running massive supercomputers, not the TV forecaster, and the guy who analyzes the model runs is the one writing the forecast discussion.

The NOAA site has good radar data also. Click on the radar box half way down on the right hand side to get into the radar data. First you get a static pic, which is not too useful.  We recommend you select the short range composite loop to start with, to see what direction the weather is moving and what will be passing over you soon (of course, it is almost always moving from the west to the NE, East or SE). The loop runs for about an hour, so you can get a feel for how soon any approaching weather will be here, and how long it will last.

Then we scroll down to the long range images, which separate the US into a series of boxes. The upper right hand box is the one you want for the NE. This allows a look farther to the west, and gives you an idea of the weather 24 hours out. After you click on the box, scroll down to the lower left hand corner of the image and click on the Loop option. This loop is 70 minutes, and allows a look at the weather as far west as Ohio.

Click for NOAA Buoy Data for realtime data of what the wind is doing, and how it’s shifting using the prior 24-hour data. For local information, there will be a highlighted box over the NY metro region. Click on this box, then click on 44065 for the Abrose Light Tower at the enterance to NY Harbor or Robins Reef ROBN4 for a look to the west (for the approaching weather). The UConn bouys in the Long Island Sound 44040 (off Greenwich) or 44022 (Execution Rock) are more local, but often show less wind than we see. The New Haven shoreside station NWHC3 will provide a good comparison, with a better location for picking up the sea breeze.

Many sailors find the Predict Wind to be a useful site, especially for wind predictions You will need to login to access the data.  48 hours of data is free, or you can access 5 days of data for a small charge. Predict wind has it’s own sensors located all around our area, so they have lots more raw data than noaa for wind. However, the forecasts still are based on noaa or US Navy data.

For the big picture, the Navy has lots of cool loops. One such model

We suggest you click on the loop button for surface winds, if the link below does not work.

For more detail, go to the NE regional model

Click on the FNMOC Wave Watch, Over Ocean sfc wind loop. Surface Pressure also shows surface winds

Click for NOAA Tide Information at Bridgeport, CT, station.
Time difference for Norwalk: Add 9 minutes for high tide. Add 15 minutes for low tide.
Height difference for Norwalk: Add 1.05 feet to predicted high tide. Add 1.04 feet to predicted low tide.

Once you begin doing coastal or offshore passages, one of your best sources of weather information will be the NOAA weather charts. Click on to get the latest charts. We normally print out 24, 48 and 96 hour charts before we head out on a trip.This helps make the local forecast more understandable, as you see where the highs and lows that create the weather conditions are heading.

The first charts as you scroll down are the Wind / Wave charts. These give a nice overall picture of what the wind will be doing over the next several days. Note that the arrows point to where the wind is going. The feathers at the back of the arrow indicate the wind strength.A long feather means 10 knots, a short feather means 5 knots, and a triangle means 50 knots. Add them up for the wind strength.

The surface charts that follow the wind charts allow you to see what is causing the wind, and are our favorite charts. Remember: tight isobars = lots of wind; spaced isobars = no wind (typically at the center of a high). For both lows and highs, you will normally see an arrow leading to the H or L, and an arrow leading away. These give the forecast position 24 hours before the forecast time (at the start of the arrow leading in) and 24 hours after the forecast (for the arrow leading away).

After the surface charts come the 500 mb charts, which show the jet stream direction and speed. The upper level winds steer and to a large degree, create the surface highs and lows. A fast moving jet stream that dips deeply over the east coast, then head north again over the Gulf Stream, is the key ingrediant for a “perfect storm” which the weather service calls a rapidly intensifying low.

You may want to look at the users guide at this location for some basic weather info, or take our Advanced Cruising or Ocean Sailing Class, where we spend a fair amount of time looking at these things.

Note: There is normally both older and more recent info (check times) and you will need either a tif or gif viewer.  We suggest using the condensed version of this page, to always have the latest charts. Times given are for GMT or Zulu time, which is 5 hours ahead of the East Coast (or 4 hours when daylight savings time is used). Subtract 5 hours (or subtract 4 hours from EDT) to convert GMT to East Cost Time.

Bermuda Weather puts out a useful set of North Atlantic weather charts for the next 5 days, which combine surface and wind information into one chart. Whereas the NOAA charts err on the side of caution, and may show more wind, the Bermuda Charts are often more realistic. The Bermuda charts also show the same area for all 5 days, and are easier to compare day to day.

The US Navy puts out the basic Gulf Stream charts

Click for USNO Master Clock Time in Standard Time Zones. (Click the “reload” or “refresh” button on your web browser to update.)