Free CBM Practice Questions

Question 1

A widespread rain shield contains a nearly circular ring of enhanced radar reflectivity. On higher elevation scans, the ring shifts closer to the radar, but a vertical cross section places the enhancement at the same altitude, just below the freezing level. Gauges beneath it report only modest rain rates. What is producing the apparent heavy-rain ring?

Accepted Answer

Melting snow is enhancing reflectivity as the beam intersects a layer of water-coated ice particles.

Answer

Anomalous propagation is bending the beam toward the ground and increasing echoes from terrain.

Answer

A band of embedded convection is producing large raindrops and unusually high surface rainfall rates.

Answer

Partial beam blockage is removing weaker returns and leaving a ring of apparently stronger precipitation.

Question 2

Road crews report small liquid drops freezing on contact with untreated surfaces. A sounding shows a shallow saturated cloud with a top temperature of -7°C, dry air above it, and no above-freezing layer anywhere below cloud top. Cloud observations indicate very few ice crystals. Which growth process accounts for this precipitation?

Accepted Answer

Supercooled cloud droplets grow by collision-coalescence and fall as freezing drizzle.

Answer

Snowflakes melt aloft, and the resulting drops become supercooled in a shallow cold surface layer.

Answer

Ice crystals grow by vapor deposition at the expense of cloud droplets and fall as snow grains.

Answer

Ice particles collect supercooled droplets by riming and fall as small, soft graupel pellets.

Question 3

At 1500 UTC, quality-controlled observations place an advancing cold front 80 km east of every ensemble member's forecast position. Review of the 1200 UTC analyses reveals the same westward position error in all members; their frontal speeds otherwise match the observations. They cluster tightly around a 2100-2200 UTC passage at a city still ahead of the front. How should the afternoon timing forecast respond?

Accepted Answer

Shift passage earlier using the observed position; the small spread misses a shared initialization error.

Answer

Retain the ensemble's passage window because agreement among all members outweighs the position discrepancy.

Answer

Adopt 2100 UTC as the earliest credible passage because it is the fastest solution within the ensemble.

Answer

Withhold a passage window until the next initialization cycle removes the common position error.

Question 4

The 1653 UTC airport observation reads: METAR KXYZ 151653Z 28018G32KT 10SM SCT030 18/10 A2994 RMK AO2 PK WND 27044/18. A graphic highlights the 44-knot wind. Which caption accurately identifies that measurement?

Accepted Answer

A peak wind of 44 knots from 270° true at 1618 UTC.

Answer

A sustained wind of 44 knots from 270° true at 1618 UTC.

Answer

A current gust of 44 knots from 270° true at 1653 UTC.

Answer

A peak wind of 44 knots toward 270° true at 1618 UTC.

Question 5

An offshore hurricane develops concentric eyewalls. Over several hours the inner eyewall erodes, the outer eyewall strengthens, and the maximum sustained wind decreases from 125 to 105 mph. Aircraft measurements also show hurricane-force winds extending farther from the center. Which interpretation reconciles the weakening peak wind with the expanding wind field?

Accepted Answer

An eyewall replacement is reducing peak intensity while expanding the hurricane-force wind footprint.

Answer

The lower maximum wind indicates a contraction of the area exposed to hurricane-force winds.

Answer

The expanding wind field establishes reintensification despite the measured decrease in maximum wind.

Answer

The outer ring marks a frontal boundary replacing the eyewall as the storm becomes extratropical.

Question 6

For a surface parcel, the lifted condensation level is 900 m AGL and the level of free convection is 1,800 m AGL. Forced lifting carries the parcel to 1,200 m, where it is saturated but remains colder than its surroundings. Neglect entrainment and overshoot. What has the parcel achieved at that height?

Accepted Answer

It has formed cloud, but still needs forced ascent through the negatively buoyant layer to reach free convection.

Answer

It has reached neither cloud formation nor free convection; both begin at 1,800 m.

Answer

It has entered free convection because it has crossed its condensation level.

Answer

It has reached its equilibrium level because it is saturated but colder than its surroundings.

Question 7

A small watershed has 1-hour basin-average flash flood guidance of 1.6 inches. A forecast graphic shows a basin-average total of 2.4 inches over six hours, without showing how that rain is distributed in time. A producer proposes 'Flash flooding expected' because 2.4 exceeds 1.6. Before asserting that the guidance will be exceeded, what is the necessary comparison?

Accepted Answer

Compare forecast 1-hour basin-average rainfall amounts with the corresponding 1-hour guidance.

Answer

Compare the full 2.4-inch storm total with the 1-hour guidance and escalate the flooding headline.

Answer

Compare the six-hour average rate of 0.4 inch per hour with the guidance and reduce concern.

Answer

Compare the wettest gridpoint's six-hour rainfall total with the basin-average guidance.

Question 8

Two stations at sea level both report a surface pressure of 1,000 hPa. Their atmospheric columns are hydrostatic, and one column is warmer in virtual temperature throughout the 1,000-500-hPa layer. Where will the 500-hPa surface lie?

Accepted Answer

Higher above the warmer station, because the pressure layer has greater thickness.

Answer

At equal heights, because both surface pressures and both pressure differences are the same.

Answer

Higher above the colder station, because its denser air makes the pressure layer deeper.

Answer

Its relative height cannot be determined without the upper-air wind profiles.

Question 9

On an August afternoon in southern Arizona, thunderstorms develop over mountains east of a desert city. Before any rain reaches the city, a wall of dust advances from the east. Its arrival brings a sharp temperature drop, a pressure jump, and strong easterly gusts. Identify the process driving this dust wall.

Accepted Answer

A thunderstorm cold pool is spreading outward, lifting dust along its leading gust front.

Answer

A Gulf of California moisture surge is spreading northward across the desert.

Answer

Daytime mixing is transporting hot, dry westerly air down to the surface.

Answer

A Pacific cold front is bringing the leading edge of a synoptic-scale marine air mass inland.

Question 10

An isolated thunderstorm's nearly vertical tower appears northeast of its surface position on an uncorrected geostationary satellite image. The satellite's subpoint is southwest of the storm. Coastlines align correctly, the radar and satellite observations are simultaneous, and the feature being located is the tower rather than its spreading anvil. Account for the displacement.

Accepted Answer

Parallax places the elevated cloud top farther from the satellite's subpoint.

Answer

A navigation error shifts the cloud and surface features northeast together.

Answer

Upper-level winds have advected anvil cloud northeast of the updraft.

Answer

A later satellite observation places the cloud farther along the storm's northeastward track.

Free CBM Practice Questions

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