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HOW TO....forecasts and weather links...


rick stoehrer

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Weather and sea state are important considerations for our paddles and a review of forecasts will be a part of the HOW TO…Cam beach briefing.

What we should all do every time we paddle and certainly to best benefit from the discussion on Sunday is to check the forecast.

There are numerous sources to get weather info. NOAA, Magic Seaweed and GoMoos are only a few online sources you can check before you even get to the put-in. Once your there it never hurts to listen to the NOAA weather radio and hear what the latest information is before you launch.

NOAA – National Oceanic and Atmospheric Association if the US Gov agency focused on the condition of the oceans and atmosphere…which makes it a dandy resource for what’s going on “big picture”. If you go to…

http://www.weather.gov/om/marine/home.htm

and click on the region of the US where you’d like to see a forecast (in this instance if you click on “Boston”), it directs you to what it calls a “Quick Glimpse at the Weather”…you can see it breaks the forecast into regions and if you click on the region encompassing Portsmouth, you get a marine forecast for the next few days. At the top it will reference the region for the forecast (in this instance Cape Elizabeth, ME to Merrimack River, MA and out 25nm) and the date of the forecast.

Note that the marine forecast region encompasses a LOT of water!

Other items of interest from NOAA include synoptic charts and forecasts…

http://www.hpc.ncep.noaa.gov/basicwx/day0-7loop.html

In addition to buoy information for real time readings of conditions (wind direction/speed/gusts/wave height/period, water temp, etc.) at various buoys…

http://www.ndbc.noaa.gov/maps/Northeast.shtml

Magic Seaweed is a site more or less catered to surfing. We can use this same information though to check out the surf forecast. There are limited reference stations on the site and that’s a bit of a drag but there is one for rye rocks. Take a look, see how that looks compared to some of the information that you’re getting from NOAA.

http://magicseaweed.com/

Gomoos is the Gulf of Maine Ocean Observing System. The site is focused on our section of the Atlantic here and has links for forecasts for wind/wave, marine weather and real time buoy readings. It has lots of very useful information - a personal favorite site.

http://www.gomoos.org/

There are other sites, Wunderground.com, Cinnamonrainbow.com has/had a real time surf cam for Hampton Beach (and a pretty groovin’ set of tunes playing in the background!) and we all find our favorites.

NOAA / National Weather Service radio is broadcast on VHF frequencies 162.400 thru 162.550 (generally channels 1-7 or so) on your radio and are a loop of the forecasts, high and low tide information and weather alerts for the region. What some of us do is just turn the thing on and put it on the deck while we’re loading our boats and then if anything is going on you’ll hear it before you actually shove off.

Check the weather and paddle with an idea of what to expect. It is an integral part of how we can try to minimize our risks on the water.

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Forecasts are valuable, but even more important is the ability to "read" the sky. Too many times during paddles or during a beach briefing, someone will refer to the forecast as though it was the last word on what the local weather is or will be over the time we paddle. I have seen instances where the weather was fairly obvious and worsening but people relied on what the forecast said instead.

Even getting the "current conditions" on a weather radio does not tell you what the weather is in your vicinity. As we have seen over the last couple weeks, storms can be very localized; one place may have nothing but a freshening wind whereas five miles away there is a severe thunderstorm.

It is always interesting to talk about weather while on a paddle. Ask people: "from what direction is the wind, what may that tell you", "what do the clouds indicate", "are the winds aloft the same as those at ground/sea level", "what do the conditions look like for our destination considering the winds, etc." Many times people are surprised that one can do a good job predicting the local weather over an hour or so, especially where there are active fronts, clouds, and wind. And many times they say: "but that is different than the forecast."

John Huth's excellent talks about weather are a great foundation to understanding weather, but even as he states, you have to put it into practice outside. I think it may be a good thing to add to many beach briefings when there are beginning paddlers. Have everyone simply take a look at the sky and see what it says about the current and immediate future conditions. For experienced paddlers, I think it is a must that they understand how to interpret the sky - and to use forecasts as they are meant, which is a probability of general (not local "where I am") conditions, but nothing more.

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Even getting the "current conditions" on a weather radio does not tell you what the weather is in your vicinity. As we have seen over the last couple weeks, storms can be very localized; one place may have nothing but a freshening wind whereas five miles away there is a severe thunderstorm.

I have found using the weather alert function available on most marine VHF radios useful in alerting me to severe weather in the area and providing adequate info to enable me to make a SWAG on whether a change in plans was needed or the weather would skirt by. I think everyone with a VHF radio should know how to use this function and use it when the sky is telling you something is likely to happen.

While we are stuck with the out 25KM forecast for the NH coast, once you get past Muscongus Bay the marine forecast are broken down into smaller areas and include intracoastal regions so the marine forecasts are more "reliable". To backup your point about how localized things can be, you often see quite different wind speeds and on occasion even different directions between Isle of Shoals and the York buoy which is same distance off the coast and only a few miles to the northeast.

Point very well made that contemporary observation trumps forecast. I tend to think local knowledge can trump observation as well.

Ed Lawson

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Point very well made that contemporary observation trumps forecast. I tend to think local knowledge can trump observation as well.

I certainly didn't mean to imply that forecasts are not useful; they are, as are VHF advisories. But the advisories are more for severe weather. Sometimes, depending on the paddle and the participants, other aspects of the weather can be very important.

An example is the L2 paddle during the Solstice. While we were all lounging at Crowninshield and watching the clouds, the wind had shifted and strengthened and was obviously going to be the biggest problem getting back. While some were worried about the threat of a thunderstorm, it was fairly clear from the cloud patterns, the detectable winds aloft and the surface winds, that we were looking at a pretty stiff headwind but with clear skies for the next hour.

I think - as you said also, Ed - that all sources of information have their place, but no one source, especially those based on the "forecast last night" should be relied on completely.

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A good strategy is to work from global to local weather patterns. The timescales for global patterns are several days - as you get closer to the day of the paddle, the relevant distance scales gets smaller, and, at a certain point, you have to rely on your own local observations, particularly in the summer when there is a lot of convection that can lead to thunderstorms and very local conditions that evolve over the timescale of less than hours.

For the large scale information, I like the following website:

http://www.oceanweather.com/data/

You can see little flags that are observations - the number of sticks on the end of the flags represents increments of 10 knots - the half-sizes represent 5 knots. I tried to upload a screen capture of today's observations.

If that actually uploaded properly, here's what you'll see - there's a large and mild low pressure system centered over central Quebec and Labrador. This is causing a counter-clockwise rotation of winds around the low pressure system, ad you can see from the local observations. At the coast of New England, the wind direction is roughly SSW, which will produce some southern swell. You can anticipate the following - as the low pressure system moves east, the wind will begin to shift to the west and then to the NW, following this counterclockwise circulation.

You could easily get this forecast from the NOAA site, but the oceanweather site can help you understand the global conditions that are causing these patterns.

post-100145-1215676383_thumb.jpg

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1505 noaa forecast for area including portsmouth...

TONIGHT

S WINDS 10 TO 15 KT. SEAS 2 TO 4 FT.

SUN

S WINDS 10 TO 20 KT...BECOMING 15 TO 20 KT IN THE AFTERNOON.

GUSTS UP TO 25 KT. SEAS 3 TO 5 FT.

SUN NIGHT

S WINDS 10 TO 15 KT WITH GUSTS UP TO 25 KT. SEAS 4 TO

6 FT. A CHANCE OF SHOWERS AFTER MIDNIGHT.

kickoff at 0830!

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Fortunately Little Harbor as well as Sagamore Creek area are not affected too much by Southerly winds. Paddling out of Little Harbor towards Rye Harbor could pose an exciting chalenge for some. There is a nice protected area in the Lee of Leachs, Pest & Goat or past Wentworth Coolidge and around the back of Lady Isle to play in calmer waters. Since the tide will be high there are plenty of options in the area.

Neil

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1505 noaa forecast for area including portsmouth...
.

And no small craft advisory... yet...maybe for late Sunday afternoon or by the time we are finishing beer and burgers??

Ed Lawson

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To give folks info to help understand how buoy data translates to the conditions likely to be encountered while paddling. The Western Maine Shelf buoy which is 6NM off York Harbor reported waves in the 4 to 5 foot range and sustained winds around 15Kts. Sobering how small those numbers are for the open ocean isn't it given what was found while paddling Sunday? Then again, Isle of Shoals reported winds in the sustained 20-30kt range. Of course wave heights are tricky since the number represents an average of the measured waves and the buoy samples wave heights for 8.5 minutes out of every hour. So some really big or small waves can easily get missed and if not missed, get averaged out. For example, if that buoy shows 2.5 foot waves representing an onshore swell, kayakers along the coast would consider conditions benign and anything less would be essentially a calm sea. 2.5 foot waves generated by a local easterly wind would not be so benign while if from a westerly wind it would be.

Just some things to dial into all the great info given by Rick and others on Sunday to help make future paddling plans/judgments.

Ed Lawson

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