Chapter 8 Current Weather Studies

The 500-mb map (Figure 2) also shows that, where contour lines are relatively close, such as across the Central Plains States, wind speeds are ________ compared to where contour lines are more widely spaced. This principle corresponds to the similar relationship between the spacing of isobars and wind speeds on surface maps.

faster

Upper air features result from the general temperature profile of air columns between the surface and 500 mb. The lowest 500-mb heights are generally associated with ________ latitude stations. However, when there is a highly amplified wave pattern, as in Figure 2, that latitude correlation may not hold true. Nashville, TN is technically at a higher latitude than Albuquerque, but in Figure 2 Albuquerque has the lower height at 500-mb of pressure, despite being located south (lower latitude) of Nashville.

higher

Compare the surface (Figure 1) and 500 mb (Figure 2) wind speeds in a general west-east band across the middle of the country at the same locations during this 12Z 10 OCT 2018 event. The wind speed comparison shows that as altitude in the atmosphere increases, wind speeds generally ________. This relationship results in part from the absence of friction in the middle and upper atmosphere.

increase

On the 500-mb map, the plotted report for North Platte shows that, at the 500-mb pressure level over the station, the temperature was ________ °C.

-18

The dewpoint at 500 mb over North Platte was ________ °C.

-22

The highest surface wind speeds at map time were found in the region of stronger horizontal pressure gradients across the Northern High Plains States (North/South Dakota & Minnesota). For example, the sustained wind speed at Huron, in eastern South Dakota, was about ________ knots.

20

The wind at North Platte was generally from the northwest at about________ knots. [Note: When winds of 50 knots or greater are reported, a pennant is used on the station's wind shaft for a 50-kt increment along with the appropriate number of long and short "feathers."]

20

Recalling that the heights plotted at individual stations on 500-mb maps are in tens of meters (place a 0 to the right of the three plotted digits), the coded height at North Platte, in west-central Nebraska, ("557") indicated 500 mb occurred at ________ meters above sea level.

5,570

Compare the temperatures for Stations A, B, and C in Table 1. As you recall from Weather Manual Investigation 5B, the relation of air column temperatures to heights of pressure surfaces was examined using conceptual "pressure blocks." The 500-mb temperature, reflective of the temperature of the column of air beneath that level, was lowest at ________.

Dodge City

Using the 500-mb station values from Table 1, as well as the contour pattern in Figure 2, compare the reported station heights at Albuquerque, Dodge City, and Nashville. The 500-mb height was lowest over ________.

Dodge City

From Table 1, stations A, B, and C represent stations located on the Figure 2 500-mb map: one station in New Mexico, another in Kansas, and yet another in Tennessee. Examining those stations' data on the map identifies Station A in Table 1 to be ________, Station B to be ________, and Station C to be ________.

Dodge City, KS; Nashville, TN; Albuquerque, NM

The station identified in Table 1 with the highest height and warmest temperature was ________.

Nashville, TN

The general contour pattern of the 500-mb map has ________.

a wide trough over the Rocky Mountains into the Southwest U.S.

Surface wind directions at stations near isobars were generally oriented ________ to their nearby isobars. These wind patterns were a result of the combination of horizontal forces acting on air near the surface, including the horizontal pressure gradient, Coriolis, and friction forces.

at an angle

Examine the eastern-most cold front, which extends from roughly Chicago, IL, all the way to Brownsville, TX. Winds in Tennessee, Kentucky, and Indiana were generally _____ the winds in Kansas, Oklahoma, and Iowa on the other side of the front. This flow of surface wind tends to enhance the uplift of air and trigger precipitation.

converging toward

The station identified in question #15 ________ coincide with the lowest height of the three stations identified in Table 1 at 500 mb and your answer to question #14.

did

At upper levels, the wind directions are also related to the contours. Looking at these upper level winds, especially where winds are relatively fast, the winds are generally ________.

more "parallel" to the contours