Weather or Not?

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Weather or Not?

• Weather basics for sound decision making!
• What to do for bad decision making?

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Resources for Weather

• Good- Before!!
• Newspaper
• TV- Danny Treanor????
• VHF radio-Weather channels
• Computer- Internet-NOAA
• Better- During Trip
• Smart Phone-Accu-weather
• Satellite weather on chart plotter-XM or Sirius
• Radar
• Read the sky?
• BEST- ALL of the above!!!

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Types of Clouds
Cirrus Uncinus High Ice Clouds. Good Weather if
winds from W, NW to N. Precipitation likely
within 20 to 30 hours if winds steady from NE, E
to S
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Types of Clouds
Altocumulus Translucidus Water and ice clouds.
Some precipitation likely within 15 to 20 hours
if wind is steady NE to S Other winds bring
overcast sky
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Types of Clouds
Nimbostratus Rain or snow clouds. Precipitation
of long duration if winds NE to S, or shorter
duration if winds are SW W to N
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CONVECTION
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Lifting by Convergence broad lifting of an
entire layer of air Convergence is an
atmospheric condition that exists when there is
a horizontal net inflow of air into a region.
When air converges along the earth's surface, it
is forced to rise since it cannot go downward.
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Cumulus Congestus If clouds form from SW to NW,
precipitation with gusty winds and thunderstorms
or wind squalls are likely within 5 to 10 hours.
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Stratocumulus at sunset Low to middle water
clouds with gold, pink, amber, lavender or rosy
background. No precipitation likely within 20
-24 hours
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Stratocumulus at Sunset Low water clouds of dark
Indian red color. Precipitation in 12 to 20
hours if winds from NE to S. Other winds bring
overcast sky.
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Forecasting

• Persistence Method
• today equals tomorrow
• There are several different methods that can be
  used to create a forecast. The method a
  forecaster chooses depends upon the experience of
  the forecaster, the amount of information
  available to the forecaster, the level of
  difficulty that the forecast situation presents,
  and the degree of accuracy or confidence needed
  in the forecast.
• The first of these methods is the Persistence
  Method the simplest way of producing a forecast.
  The persistence method assumes that the
  conditions at the time of the forecast will not
  change. For example, if it is sunny and 87
  degrees today, the persistence method predicts
  that it will be sunny and 87 degrees tomorrow. If
  two inches of rain fell today, the persistence
  method would predict two inches of rain for
  tomorrow.

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• Effects of Frontal Lifting
• on forecasted precipitation
• Forecast Tip If there is sufficient moisture in
  the air and a forcing mechanism like a cold front
  (for example) is approaching the area, then there
  is an increased probability that precipitation
  will occur.
• Clouds and precipitation are formed by the upward
  motion of air. Therefore, there must be a
  mechanism present to lift the air. Fronts often
  serve as such a mechanism. Air on one side of the
  front typically blows in a different direction
  from the wind on the other side, causing the air
  to converge, or pile up right along the frontal
  surface.

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How Does this affect me?

• Convergence typical during Winter fronts
• Convection typically during summer afternoon over
  land and move towards water-Less predictable
• Can get a combination of both

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Wind as a Predictor

• Dont be fooled by direction
• Sometimes wind will head toward the storm
  (Remember the convergence model)
• Look at movement of the clouds
• Dead calm in the presence of Cumulus clouds
  indicate a severe thunderstorm soon
• Wind direction coupled with different types of
  clouds can be a good predictor

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Lightning

• If you hear thunder-High possibility of lightning
  strikes at your position
• Lightning can proceed the storm by a long time
• Just because you have blue skies doesnt mean
  that you are not in danger
• A number of strikes each year happen in clear
  skies

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From video of a distant cloud-to-ground strike
near Gothenburg, Nebraska Frames 1 through 4
show the stepped leader descending 5 shows the
intense first return stroke, Frame 6 shows the
decaying first return stroke.
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Strike Prevention

• Lower antennas, fishing rods, outriggers etc..
  For a lower profile
• Dont anchor near high items ie.markers, buoys,
  power lines etc.
• Get to safe haven asap

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Surviving a Strike

• Have a bonded boat
• Keep clear of metal structures on board
• Wear rubber soled shoes

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Bonded Boat

• Major metal component are electrically bonded to
  underwater hardware to create a path for
  lightning discharge
• Bonding is normally thought of a way to prevent
  galvanic corrosion
• Using heavy cable (8 gauge) gives a adequate
  discharge path

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Dos and Donts in a Thunderstorm

• Do slow down if visibility is poor
• Dont anchor in a channel where you can be struck
  by another boater
• Do anchor from the bow is necessary
• Dont anchor in a position where a slipping
  anchor will put you in a worse situation
• Do seek protected waters

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FOG

• Fog-
• Sea fog
• Water is cold air is hot
• You can look straight up and see blue skies
• Can last all day and start at anytime
• Thermal Fog
• Air is cold water is hot
• Predictable
• Will burn off after time

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Fog

• Using a audible signaling device-Preferably a
  bell
• Proceed a speed based on your visibility
• Zero visibility-HOLD your position
• Use radar if you have it
• Listen carefully for breaking waves, other boats
  etc.
• Have all the crew on watch in all directions
• Have the crew report in reference to a clock (Bow
  is 1200)

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Be SMART

• Put lifejackets on early when conditions
  deteriorate.
• Its better to be at the dock wishing you were
  out rather than being out wishing you were at the
  dock
• Learn More- Weatherknowledge.com