Can someone recommend a site that can explain in lay terms how to read and make sense of changes in barametric pressures. Or is the only key to worry about whether or not there is a change in pressure (dropping or rising) More specifically when I'm on the water and hear the pressure is 30.10 and falling or rising I would like to know what that means and what's about to happen or what to expect regarding precipitation I KNOW !! I'm probably the only guy that wasn't in science class that day.....(OUT Sailing instead) Ha Ha Thanks
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simplest answer
The way that it was explained to me was that if it is rising it 's going to clear up .If it's falling then there is moisture ,rain,coming.The actual pressure isn't as important as the change
The way that it was explained to me was that if it is rising it 's going to clear up .If it's falling then there is moisture ,rain,coming.The actual pressure isn't as important as the change
That's part of what I understood
Thanks TimmR Also a curiosity I have is whether or not drops in the tenths, hundreds, or whole numbers will ever indicate the severity of the storm or just that it is going to and possibly how soon.
Thanks TimmR Also a curiosity I have is whether or not drops in the tenths, hundreds, or whole numbers will ever indicate the severity of the storm or just that it is going to and possibly how soon.
Great Link for an explanation
Hi RC. This link has a great little explanation of the barometer and its meaning in relation to weather prediction Scott
Hi RC. This link has a great little explanation of the barometer and its meaning in relation to weather prediction Scott
Not so sure Tim
The pressure changes are very very important for you can then make a decision as to if you stay out, reef or stick it out. If my barometer starts to drop quickly it does not always mean rain on the way but what it will idicate that with the sudden drop in pressure a low is approaching rapidly meaning in most cases stronger winds and rough conditions.
The pressure changes are very very important for you can then make a decision as to if you stay out, reef or stick it out. If my barometer starts to drop quickly it does not always mean rain on the way but what it will idicate that with the sudden drop in pressure a low is approaching rapidly meaning in most cases stronger winds and rough conditions.
Weather Hints
Goto http://cruisersforum.com/showthread.php?s=&postid=9524#post9524 for a short piece on weather hints.
Goto http://cruisersforum.com/showthread.php?s=&postid=9524#post9524 for a short piece on weather hints.
So, Gordon...
It's analogous to the stock market: Falling numbers suggest a drop. Rising numbers don't necessarily mean a rise.
It's analogous to the stock market: Falling numbers suggest a drop. Rising numbers don't necessarily mean a rise.
Graphing Barometer
is always handy so you can see the changes over a long period of time. When I bought my Humminbird fishfinder it had an optional accessory that I got that allows you to display a graph of the pressure for the past 24 hours. Evidently its handy to know for catching fish as well as predicting the weather. My Casio Sea-Pathfinder watch also has a button that you press that gives the current barometric pressure as well as show a graph for the past 24 hours but the graph is very hard to read.
is always handy so you can see the changes over a long period of time. When I bought my Humminbird fishfinder it had an optional accessory that I got that allows you to display a graph of the pressure for the past 24 hours. Evidently its handy to know for catching fish as well as predicting the weather. My Casio Sea-Pathfinder watch also has a button that you press that gives the current barometric pressure as well as show a graph for the past 24 hours but the graph is very hard to read.
right !
Good analogy, Bill, and exactly right !!!
In general, falling air pressure means that clouds and precipitation are likely. Rising air pressure signals that clear weather is likely (but not certain) . See also the (new) second post at: http://cruisersforum.com/showthread.php?s=&postid=9524 HTH Gord May
Good analogy, Bill, and exactly right !!!
In general, falling air pressure means that clouds and precipitation are likely. Rising air pressure signals that clear weather is likely (but not certain) . See also the (new) second post at: http://cruisersforum.com/showthread.php?s=&postid=9524 HTH Gord MayStorm Glass???
There is an old device called a Storm Glass(I think) that is basically a container with an inlet tube submerged in water. Rising pressure causes bubbles inside the glass and falling pressure causes the liquid(water) to squirt out. I work in a lab where we use squirt bottles of alcohol for disinfection. When a strong front is approaching the alcohol will be dripping out of all the bottles. Usually I'll notice and loosen the caps to prevent a fire hazard. On a boat slow bubbles or nothing means fair weather. If it starts to squirt you'd better hunker down or get to the dock fast. Tom
There is an old device called a Storm Glass(I think) that is basically a container with an inlet tube submerged in water. Rising pressure causes bubbles inside the glass and falling pressure causes the liquid(water) to squirt out. I work in a lab where we use squirt bottles of alcohol for disinfection. When a strong front is approaching the alcohol will be dripping out of all the bottles. Usually I'll notice and loosen the caps to prevent a fire hazard. On a boat slow bubbles or nothing means fair weather. If it starts to squirt you'd better hunker down or get to the dock fast. Tom
Fitzroy's Storm Glass
Admiral Fitzroy’s Storm Glass: Observing the liquid in the storm glass is supposed to indicate changes in the weather. If the liquid in the glass is clear, the weather will be bright and clear. If the liquid is cloudy, the weather will be cloudy as well, perhaps with precipitation. If there are small dots in the liquid, humid or foggy weather can be expected. A cloudy glass with small stars indicated thunderstorms. If the liquid contains small stars on sunny winter days, then snow is coming. If there are large flakes throughout the liquid, it will be overcast in temperate seasons, or snowy in the winter. Crystals at the bottom indicate frost. Threads near the top mean it will be windy. Here are instructions for constructing a storm glass, attributed to a letter published in the June 1997 School Science Review. Ingredients for Storm Glass * 2.5 g potassium nitrate * 2.5 g ammonium chloride * 33 mL distilled water * 40 mL ethanol * 10 g camphor Dissolve the potassium nitrate and ammonium chloride in the water; add the ethanol; add the camphor. Place in corked test tube. The reader is advised to use proper care in handling the chemicals ;-) The premise of the functioning of the storm glass is that temperature and pressure affect solubility, sometimes resulting in clear liquid; other times causing precipitants to form. The functioning of this type of storm glass is not fully understood. In similar barometers, the liquid level, generally brightly colored, moves up or down a tube in response to atmospheric pressure. Certainly temperature affects solubility, but sealed glasses are not exposed to the pressure changes that would account for much of the observed behavior. Some people have proposed that surface interactions between the glass wall of the barometer and the liquid contents account for the crystals. Explanations sometimes include effects of electricity or quantum tunneling across the glass. Additional Reading ADMIRAL FITZROY'S RULES FOR FORETELLING THE WEATHER. http://www.thebritishclockmaker.com/forsale/barometers.html UNUSUAL WEATHER INSTRUMENTS: http://www.orgonelab.org/cgi-bin/shop.pl/page=yweather.htm
Admiral Fitzroy’s Storm Glass: Observing the liquid in the storm glass is supposed to indicate changes in the weather. If the liquid in the glass is clear, the weather will be bright and clear. If the liquid is cloudy, the weather will be cloudy as well, perhaps with precipitation. If there are small dots in the liquid, humid or foggy weather can be expected. A cloudy glass with small stars indicated thunderstorms. If the liquid contains small stars on sunny winter days, then snow is coming. If there are large flakes throughout the liquid, it will be overcast in temperate seasons, or snowy in the winter. Crystals at the bottom indicate frost. Threads near the top mean it will be windy. Here are instructions for constructing a storm glass, attributed to a letter published in the June 1997 School Science Review. Ingredients for Storm Glass * 2.5 g potassium nitrate * 2.5 g ammonium chloride * 33 mL distilled water * 40 mL ethanol * 10 g camphor Dissolve the potassium nitrate and ammonium chloride in the water; add the ethanol; add the camphor. Place in corked test tube. The reader is advised to use proper care in handling the chemicals ;-) The premise of the functioning of the storm glass is that temperature and pressure affect solubility, sometimes resulting in clear liquid; other times causing precipitants to form. The functioning of this type of storm glass is not fully understood. In similar barometers, the liquid level, generally brightly colored, moves up or down a tube in response to atmospheric pressure. Certainly temperature affects solubility, but sealed glasses are not exposed to the pressure changes that would account for much of the observed behavior. Some people have proposed that surface interactions between the glass wall of the barometer and the liquid contents account for the crystals. Explanations sometimes include effects of electricity or quantum tunneling across the glass. Additional Reading ADMIRAL FITZROY'S RULES FOR FORETELLING THE WEATHER. http://www.thebritishclockmaker.com/forsale/barometers.html UNUSUAL WEATHER INSTRUMENTS: http://www.orgonelab.org/cgi-bin/shop.pl/page=yweather.htm
Thanks Gord MAy
But your Storm Glass isn't what I was referring to. Another name is a Glass Barometer. Your's is much cooler!!!! Mine works on the simple principle of air pressure. High pressure makes bubbles as air goes into the container and low pressure makes water go out. Often the water is colored for visablity.
But your Storm Glass isn't what I was referring to. Another name is a Glass Barometer. Your's is much cooler!!!! Mine works on the simple principle of air pressure. High pressure makes bubbles as air goes into the container and low pressure makes water go out. Often the water is colored for visablity.
Barometers
BAROMETERS 101: Water Barometer: (Tom's Glass Barometer) Rise and fall of the water level in the glass spout reflects changes in atmospheric pressure. The spout is open to the atmosphere. NOTE: When pressure falls, the water level in the spout rises forecasting deteriorating weather conditions. A high water level indicates a low-pressure area, and a low level indicates high pressure. Counter-intuitive, ain't it? Torricelli (Mercury) Barometer: The Torricelli Barometer uses a long glass tube closed at one end, which is upside down in an open container holding liquid. The pressure of the air, bearing down on the liquid in the container forces it up the tube, and the measurement of the various lengths of the column of liquid expresses the changes in air pressure . In order to have a tube of manageable length, the heaviest of all liquids, mercury, is now used. Aneroid Barometer: An aneroid is a flexible metal bellow that has been tightly sealed after having some air removed. Higher atmospheric pressures squeeze the metal bellows while lower pressures allow it to expand. The aneroid barometer is operated by a metal cell containing only a very small amount of air, or a series of such cells joined together. Increased air pressure causes the sides of the cell or cells to come closer together. One side is fixed to the base of the instrument while the other is connected by means of a system of levers and pulleys (which multiply the changes in capsule thickness) to a rotating pointer that moves over a scale on the face of the instrument. E. & O. E. Gord May
BAROMETERS 101: Water Barometer: (Tom's Glass Barometer) Rise and fall of the water level in the glass spout reflects changes in atmospheric pressure. The spout is open to the atmosphere. NOTE: When pressure falls, the water level in the spout rises forecasting deteriorating weather conditions. A high water level indicates a low-pressure area, and a low level indicates high pressure. Counter-intuitive, ain't it?
Torricelli (Mercury) Barometer: The Torricelli Barometer uses a long glass tube closed at one end, which is upside down in an open container holding liquid. The pressure of the air, bearing down on the liquid in the container forces it up the tube, and the measurement of the various lengths of the column of liquid expresses the changes in air pressure . In order to have a tube of manageable length, the heaviest of all liquids, mercury, is now used. Aneroid Barometer: An aneroid is a flexible metal bellow that has been tightly sealed after having some air removed. Higher atmospheric pressures squeeze the metal bellows while lower pressures allow it to expand. The aneroid barometer is operated by a metal cell containing only a very small amount of air, or a series of such cells joined together. Increased air pressure causes the sides of the cell or cells to come closer together. One side is fixed to the base of the instrument while the other is connected by means of a system of levers and pulleys (which multiply the changes in capsule thickness) to a rotating pointer that moves over a scale on the face of the instrument. E. & O. E. Gord MayAneroid barometer
Q: How to determine the height of a building with an aneroid barometer? A: Take barometer to roof. Record barometer reading. Lower barometer to ground with rope. Measure length of rope.
Q: How to determine the height of a building with an aneroid barometer? A: Take barometer to roof. Record barometer reading. Lower barometer to ground with rope. Measure length of rope.
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