WX 395P Hurricanes Mid Term Quiz Answers

Use the Tropopause Temperature (TT) and Sea-Surface Temperature (SST) maps below. Based on available TT and SST data, identify the location where the minimum pressure for a tropical cyclone would theoretically be the lowest.

D

Correctly identify, in numerical order, the three weather features (inside the yellow-dashed circles) that are depicted on the attached GOES-16 Infrared (IR) Weather Satellite image, valid at 1205 UTC 14 September 2022. (select the most correct answer)

(1) tropical wave; (2) extratropical low pressure system; (3) Bermuda-Azores high pressure system

Use the Enhanced Infrared (EIR) Curved Band pattern shown in Figure A and the Data-T number (DT) scale in Figure B. The Log 10 spiral band overlay depicts _________ banding, which yields a DT of ________.

0.60 or 6/10's; 3

The National Hurricane Center uses a _____________ wind speed at _________ elevation to indicate the intensity of tropical cyclones.

1-minute average; 10-meters

the intensity threshold for a major hurricane is

100kts

A tropical cyclone is moving toward the United States. Using the Power Law Equation (below) for boundary layer winds over the ocean, a 1-minute average wind speed of 100 kt (U1) at 4.1 meters elevation is approximately equal to a _________ wind speed (U2) at 10-meters elevation. U2 = U1 (Z2/Z1)P where, P = 0.11

110kts

There have been _____ Category 5 hurricanes landfalls in the United States.

4

Use the Enhanced Infrared (EIR) Embedded Center pattern shown in Figure A and the Central Feature number (CF) scale in Figure B. Relative to center position (red circled-X), the Embedded Center pattern yields a CF and Data T-number (DT) of ________.

4.5

Use the Enhanced Infrared (EIR) Eye pattern shown in Figure A and the Eye Number & Eye Adjustment charts in Figure B. Assume an eye temperature of +5 degrees C or Off White (OW) shade. This Eye Pattern produces a Central Feature (CF) and Data T-number (DT) of ________.

6.0

major hurricanes are responsible for ____% of damage that occurs

90

Use the Tropical Cyclone "Maximum Potential Intensity" (i.e, minimum pressure) nomogram below. Given an inflow temperature of 30OC and an outflow temperature of -60OC, the minimum pressure that a tropical cyclone could theoretically achieve would be _____ mb .

930

Use the Tropical Cyclone "Maximum Potential Intensity" (i.e, minimum pressure) nomogram below. Given an inflow temperature of 25OC and an outflow temperature of -60OC, the minimum pressure that a tropical cyclone could theoretically achieve would be _____ mb .

960

Use the Enhanced Infrared (EIR) Shear pattern shown in Figure A and the Data-T number (DT) scale in Figure B. Relative to the center position (red circled-X), the shear pattern yields a DT of ________.

<3/4 degree or <45 nmi; 2.5

A________ cell is a thermally _________ circulation and a ________ cell is a thermally _________ circulation. (select the most complete answer)

Hadley, direct; Ferrel, indirect

Tropical Cyclones

Possess all of the following characteristics

What month has the most hurricane activity in the north atlantic

September

Which of the following weather systems is NOT a pre-existing disturbance that could trigger tropical cyclone formation: ________ .

Upper-level anticyclone

Weather satellites are the first "line of defense" for tracking, assessing, and forecasting tropical cyclones, especially when these storm systems are located over open ocean areas where reconnaissance aircraft data are unavailable for various reasons. Geostationary satellites can observe __________ of the tropical regions at a _______ resolution, whereas polar-orbiting satellites can observe __________ of the tropical regions at a _______ resolution.

all areas, lower; limited areas, higher

A low pressure system that has a frontal system through the center of the low would be ___________________ cyclone.

an extratropical

The Advanced Dvorak Technique (ADT) utilizes longwave-infrared, temperature measurements from geostationary satellites to estimate tropical cyclone (TC) intensity, and is __________________ process that requires ________________ user input.

an objective; no

Tropical Waves are a combination of two wind fields: ________ and ________.

background easterly gradient flow; eddy flow

A device called the Stepped-Frequency Microwave Radiometer (SFMR) onboard Hurricane Hunter reconnaissance aircraft indirectly determines near-surface wind speeds by measuring upwelled microwave radiation emitted by ocean foam that is created by surface winds. These wind data ________ be contaminated/inflated by rainfall.

can

Which of the following is NOT a significant factor in producing storm surge: _________.

central pressure

The Walker Circulation is an east-to-west-oriented Hadley Cell near the equator that forms as a result of ______________ over the _________ Pacific Ocean and _________________ over the _______________ Pacific Ocean. (select the most complete answer)

cold air sinking, eastern; warm air rising, western

The image below is a schematic of the northern hemispheric mid- and high-level flow pattern on Earth. Superimposed onto the global-scale, circular background flow pattern are __________ circulations that produce ____________________ and __________ circulations that produce _________________ . (select the most complete answer)

cyclonic eddy, troughs of lower pressure; anticyclonic eddy, ridges of higher pressure

A unique characteristic of a mature tropical cyclone is the formation of a generally cloud-free 'eye' where winds are nearly calm. Surrounding the eye is a ring of ____________ called the _________ .

deep-convection; eyewall

The African Easterly Mid-Level Jet (AEMLJ) is a band of strong mid-level winds that blows from __________ and lies between the dry Saharan regions and moist sub-Saharan regions. This meteorological feature results in the enhancement of tropical waves to the ______ of the jet axis.

east-to-west; south

Of the various Dvorak satellite intensity estimation technique cloud patterns/scene types, the ______________ pattern is considered to produce the most reliable intensity estimates.

eye

The __________ of a hurricane is a thermally _________ circulation, while the ________ is a thermally _________ circulation.

eye, indirect; outer windfield, direct

Although surface observation platforms/sites are not located at the same elevation above Earth's surface, the data can still be used as is without being adjusted to a standard altitude.

false

On a non-rotating Earth, a global Hadley Cell forms as the result of cold air rising over the Poles and warm air sinking over the Equator.

false

Since 1970, global tropical cyclone frequency (i.e., number of storms) and intensity (i.e., strength) have been increasing.

false

The CIMSS Satellite Consensus (SATCON) product only utilizes tropical cyclone intensity estimates from the ADT and AiDT objective intensity estimation techniques.

false

The Dvorak satellite intensity estimation techniques provide a direct measurement of a tropical cyclone's wind speed, providing output that is as accurate as surface observational or reconnaissance aircraft wind speed data.

false

The visible and enhanced infrared (EIR) Dvorak Satellite Intensity Estimation Techniques are objective processes that involve no user input.

false

Warm-core tropical surface cyclones cannot form sea-surface temps less than 26 degrees celsius

false

wind pressure on structures is linear and is directly proportional to wind speed

false

Wind speeds within the frictional boundary layer __________ with increasing altitude ____________.

increase; logarithmically

"Storm Surge" is an abnormal rise of water generated by a storm, over and above the predicted astronomical tide, which typically occurs on the ________ side where the winds are blowing _________.

left; onshore

A typical tropical wave is characterized by ________ located on the _________ of the wave axis.

low-level convergence, rising motion, and thunderstorms; east side

Over Africa during the northern-hemisphere summer, the Monsoon Trough lies to the __________ of the African Easterly Mid-Level Jet and within a _______ air mass.

north; dry

In a mature hurricane, the eye and eyewall slope ___________ with height, producing a ____________ effect.

outward; stadium

Relative to a landfalling tropical cyclone's forward motion (i.e., direction), the __________ quadrant is most favorable region for tornado development.

right; front

In general, _____-moving tropical cyclones tend to produce _________ rainfall amounts.

slow; heavy

Which tropical cyclone hazard has the greatest potential to cause large loss of life: ____________?

storm surge

Horizontal cyclonic speed shear located on the southern, or equatorward, side of the African Easterly Mid-Level Jet can __________ tropical waves after they develop and move ___________ away from the Ethiopian Plateau.

strengthen; westward

Tropical Waves originate or form over _____________ .

the ethiopian highlands

a major hurricane is defined as a _____ hurricane

three, four or five

Which one of the following parameters does not affect hurricane intensity: _________.

time of year

During El Nino warm-oceanic episodes in the eastern Pacific, the Pacific Ocean Walker Circulation weakens and reverses the normal direction of the wind flow. As a result, upper-level winds across the tropical Atlantic Ocean increase from a westerly direction, which acts to increase vertical wind shear and decrease tropical cyclone activity in the Atlantic basin.

true

Land-based weather radars can track the center of tropical cyclones and also provide rainfall information. Moreover, Doppler radars, such as the NOAA/National Weather Service WSR-88D radars, can also provide velocity data to assess the intensity of tropical cyclones.

true

Latent Heat released by deep convection that flows inward toward the center is concentrated near the convective comma head where upper-level convergences focuses the warmer and less dense air. This forces subsidence which warms the air even more over the surface low, causing pressures to decrease and the tropical cyclone's winds to increase.

true

The Artificial Intelligence (AI) enhanced advanced Dvorak Technique (AiDT) performs better (e.g., has lower RMS errors) than the Advanced Dvorak Technique (ADT).

true

Tropical Cyclones are generally only "warm core" above the 925-mb level due to low-level diabatic cooling effects of rain, cool downdrafts, land, and ocean temperatures.

true

________ is the most important genesis and intensity modulating factor.

vertical wind shear

Which of the following is NOT a necessary ingredient for tropical cyclone development

vertical wind shear > 20kts

For a low pressure system to be classified as a tropical cyclone, it must possess a ____________ structure and have persistent ______________ convection.

warm-core; organized