Correct answer is all are the same. mb = hPa, and these are all the same value of the standard atmosphere pressure.

Shifted to the left so it has backed. In modern usage, this does not depend on hemisphere.

Oregon, or at times any state on the West Coast. Sea breeze is any wind coming from the sea — more specifically from any region that has more water into a region that has less water.

National Data Buoy Center. All data are online for easy access or can be reached by cell phone or satellite phone.

Knots = 1.94 × m/s

Widely spaced isobars mean the pressure drops slowly across them, so the pressure gradient force is small and the wind is weak. A spacing of 300 miles is wide; 60 miles is close. Sky cover and precipitation cannot be inferred from isobar spacing alone.

Can't say from this alone. At any one place, even the summer/winter averages can vary as much as the spread shown here. Check US Coast Pilot, Meteorological Tables, Pilot Charts, or Climate Forecast System model predictions out to 6 months.

Pressure tendency is always given over the past 3 hours. e.g. if pressure now is 1024 and 3 hours ago was 1022, the tendency is +2 mb.

Buys Ballot's law (NH): with your back to the surface wind, put your left arm out and slightly forward (10–30°); it points toward the center of the low (or, more precisely, in the direction of decreasing pressure).

The barometer is a crucial instrument and you get most out of it with practice and calibration. But even an uncalibrated instrument is useful for detecting pressure CHANGES — what matters most for forecasting. Place it near the nav station for easy frequent reading.

Lows generally reach peak depth as their fronts occlude — the occlusion process cuts off the source of warm moist air which is the storm's fuel. The Low begins to dissipate after.

All listed factors can contribute. In practice the Low moving across you is usually the biggest contributor. Watch for a steady drop lasting at least two 3-hour periods. "Meteorological bombs" deepen ~24 mb in 24 h.

Falling pressure. Steady usually means no change; rising pressure usually means improving weather (with rare exceptions like a bent-back occlusion). Wind speed depends on the gradient, not the direction of change.

All we know is the true wind is aft of the apparent wind, so 070R is the only solution. 310R is 50° on the port side, which is not possible.

15° to 30° across the isobars, into the low and out of the high.

See trade winds, horse latitudes, and doldrums; the global wind belts in the World Atlas explain the pattern.

Temperature drops about 4°F per 1,000 ft and the wind veers (over the first ~2,000 ft, total veer 10–40°).

Stratiform — stable air produces flat layered clouds. See section 3.4 on stability.

See Coriolis force; discussed in detail in Chapter 2 on wind.

Because there are intervening land masses interrupting the corresponding latitude range in the Northern Hemisphere that are not present in the Southern Hemisphere.

Get into the white caps — they mark an area with current going with you. Current flowing into the wind makes notably steeper waves that break more often.

Heated air rises at the equator and is forced poleward; Coriolis bends the wind to the right (NH), setting up rivers of strong eastward winds aloft. These are the steering winds that move surface patterns to the east.

Warm moist air is called maritime tropic. See trade winds and air-mass classification.

In the NH, squalls move in a direction veered from the ambient surface winds because they are driven by the higher (veered) winds aloft.

80°F is the accepted value based on research cited in the course materials.

Strong winds come with the initial downburst, which brings the rain and wind together. See Chapter 4 on squalls.

Squalls need a vertical updraft to start formation. Over warm waters typical of frequent squalls, daytime air can be cooler than the water; at night the warmer near-surface air starts to rise — these are 'air-mass' thunderstorms and they're more likely at night than in the afternoon.

Wind builds as the front approaches, suddenly veers at the frontal surface, then remains more or less steady as the warm sector passes. (West Coast wind often backs as it builds; East Coast is less consistent.)

Cold front: short heavy rain, cumulonimbus, larger veer. Warm front: long light rains, stratus clouds, smaller veer.

34 to 47 kt. There are different historical gale classifications, but they are rarely used these days. The NWS glossary is online.

See Chapter 4 or the NHC website. Peak season is easy to specify, even though start/end dates are less consistent.

All points are true, but the direction of the wind into the storm's path is the most important.

Isobars in the warm sector are usually straight and evenly spaced (steady wind), and the entire frontal system tends to move parallel to those isobars.

Secondary lows often develop more intense than the primary that created them. Secondaries can also form at the tip of the occlusion once it forms.

In still water ~10 kt; with a knot or more of current with the wind, ~12 kt; with current against the wind, ~8 kt. Use the effect in reverse to read the surface for current direction.

About one day. Rough rule: hours of wind needed for full development ≈ wind speed in knots (for winds < 30 kt). 25 kt → ~25 h ≈ 1 day.

Significant Wave Height (SWH) = the average of the highest one-third of all waves. Universal definition.

Trade-wind belt has the largest waves because the fetch and stability of the wind are very high. The other listed systems have very short fetches.

Classic warm-front approach: backing wind followed by a veer. Helpful rule: the time from the first signs of the front until rain starts is roughly how long it will rain until the front passes.

Winds at cumulus cloud level are veered 10–30° from surface winds over water (more over land), so they appear from the right of the true surface wind by that amount.

High pressure is descending air that evaporates the clouds. This could in principle be stable or unstable air.

Less friction aloft means wind veers as you go up. Land has more friction than water, so wind backs going from sea to land. Going from land out to water it veers (absent other factors).

The key is friction: land has lots, water has much less. Excluding channeled effects, wind on the water is always stronger than nearby land. Factor of 2 is a reasonable working rule.

Sea breeze is the most common land effect on coastal wind, but it is rarely a hazard by itself. Only when channeled does it become dangerous (gap wind).

Sea breezes are usually the resultant of a developing thermal wind and an existing gradient wind. In the NH the building thermal part will veer as it develops (descending from less-friction air aloft).

See sea breeze in Chapter 6 on wind and terrain.

Sea breeze is the most common, but gap or channeled winds are usually the source of the strong winds.

Sea breezes exist on almost all near-coastal waters to some extent.

More from the southeast — sea breezes in the Northern Hemisphere veer as they build (and back in the SH).

8 times the height. A standard rule of thumb for staying out of the wind shadow of an elevated obstacle.

See 500-mb maps. Winds aloft flow along the contours of the 500-mb surface — where the contour is steep, the wind is faster.

Tropical-storm-force at 34 kt. Since 34 > 32.5 it is plotted with 4 feathers (3 long, 1 short). See https://ocean.weather.gov/UsersGuide/UGprint.php (33 kt at 48 h, 34 kt at 96 h).

Coast Pilot is the best starting point for US inland or coastal waters.

Simulated Radar Reflectivity. See textbook.

Pilot chart — useful for both a quick look at High locations and for specific wind probabilities.

All provide the data. Bowditch is a quick lookup; Mariners Weather Log includes extra-tropical and tropical storms summarized by quarter; the NHC is the most comprehensive. The Starpath Weather Trainer software also presents this data clearly.

NOAA weather radio… at least for a year or so, then all bets are off.

To prevent getting caught in a hurricane, avoid the areas the NHC forecasts having winds of 34 kt or more. They are plotted on the Tropical Cyclone Danger Maps (textbook Figure 8.7-7).

All listed indicators can be the most useful indicator of strongest current flow. See text on Gulf Stream plus Forum discussion.

The actual rate of pressure drop depends on many factors. The given answer comes from averaging many published barograph traces of severe lows — this is the initial down-turn 12–24 h before the low arrives, NOT the rate at the low itself (which is much steeper, 6–10 mb per 3 h).

A ring around the sun or moon is the most positive sign — it proves a transparent layer of cirrostratus has been forced over you by an approaching warm front, usually the first step in an approaching mid-latitude Low.

A long low swell would likely be the first sign, especially in tropical waters as an indicator of a tropical cyclone. See sea state and forecasting tips.

Sea breeze comes from land heating more than nearby water (creating a low over land, high over water). If an offshore Low approaches at the same time, the reduced pressure on its fringes can cancel out the land-water differential and kill the sea breeze. Same logic if a fresh sea breeze fades early in the afternoon.

Using the units converter, 331 m/s ≈ 740 mph and 20 s ≈ 0.0056 h, so 740 × 0.0056 ≈ 4.1 miles. Equivalently, every ~5 seconds of delay between flash and thunder ≈ 1 mile.

The Beaufort scale relates wind to sea state — it is not a wind speed scale per se.

In most cases clouds are a valuable asset for judging the weather, but sometimes they are not, and in extreme cases they can be misleading.

See details of fronts. The veering wind shift along with a general period of gusty strong wind, clouds and some form of rain are the common characteristics. The other listed options are not common.