Weather and Climate Project
ispaulo33
Group Project #2: Analyzing Weather
Data for Severe Weather This project begins in Module 6 and is due by the end of Module 7.
You were introduced to material for this project in Module 3. Here, you are to manage the same
information meteorologists use to determine if the atmosphere on a particular day can generate
severe weather. Return to thinking about a lifted parcel of air and how it will cool by the dry
adiabatic and moist adiabatic lapse rates. To perform this analysis, meteorologists use a special
chart called a thermodynamic diagram or, more specifically, a SkewT-LogP chart. This chart
consists of several sets of lines, each of which represents specific meteorological variables in the
atmosphere. These include lines for: barometric pressure, temperature, mixing ratio, dry adiabats,
and moist adiabats. In reality, the lines are arranged to show how lifting occurs under the laws of
the adiabatic approximation. Each varies with respect to each other thermodynamically as a
parcel of air is lifted from the surface into the lower stratosphere. This means the arrangement of
lines on the chart balances heat and energy flows within the atmosphere.
Samples of triggering mechanisms that can generate thunderstorms. (Figure 5.11 from text: Essentials of Meteorology)
Temperature and dew point temperature values from a radiosonde (or a sounding as
meteorologists call it) are plotted on the chart. Then, by using the other lines, and a variety of
numerical indices, the potential of severe weather can be determined. A numerical indication that
storms are likely does not mean they will occur because the atmosphere is always in a quasi-
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balanced state and air flowing in and out of a region, plus solar heating, can change conditions.
Most weather scenarios leading to thunderstorms require a physical feature to be present in an
area to generate the lifting required for a parcel to reach the level where it will be buoyant and rise
on its own. The meteorologist must seek out these natural triggering mechanisms that can initiate
convection and include that information in formulating a weather forecast.
To complete this project, you will need these instructions for reading a SkewT-LogP chart
(https://excelsior.instructure.com/courses/21780/pages/instructions-for-reading-a-skewt-logp-chart) .
Project Instructions
In this activity, you will assess a SkewT-LogP diagram near a weather system that generated
thunderstorms and tornadoes. To allow sufficient time for your work, this activity has a two-week
period for completion. However, there is a significant amount of work involved in this activity.
Thus, start as early in the two-week period as possible. You must coordinate with each other’s
schedules. Budget your time carefully.
Use the M6D2 discussion board to communicate within your group – this is a graded discussion.
The project involves both individual and group work. Here’s a basic outline of what you will be
responsible for:
During this module (Module 6):
Agree on different “storm days” and complete your Individual Work (see description below).
Reach out to group mates if you need any help.
Read over the requirements for Group Work portion of the project, and then
Divvy up the 4 indices (LIFT, KINX, CAPE, and CINS) among your group (one each)
Organize a process to check each other’s individual work
Share your Individual Work within this discussion board by Sunday midnight of Module
6.
Start reviewing each other’s Individual Work
During next module (Module 7)
Continue to communicate within M6D2 to
Complete your review of each other’s Individual Work
Complete the Group Work assignment (see description below)
Merge all individual work, plus the Group Work, into a single final project document
Each group member will submit a copy of the final project in M7A1
Please sure to leave time at the end of Week #7 to edit the final document for consistency in
such items as presentation, format, and font types. Understand that this final project
document will be identical between all group members, but will be submitted individually so
grading can be accomplished.
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Conducting Individual Work
While Module 6 is mostly Individual Work, be sure to coordinate with your group members on
storm dates. Also, divvy up the 4 indices (LIFT, KINX, CAPE, and CINS), and organize a process
to check each other’s reports, so that you’re ready for Module 7 Group Work.
Before you begin Individual Work, be sure you have reviewed the instructions for reading a
SkewT-LogP chart (https://excelsior.instructure.com/courses/21780/pages/instructions-for-reading-
a-skewt-logp-chart) .
The following table shows a list of days and sites where thunderstorms and tornadoes occurred in
recent years. Each member of your team will choose a different day to use for analysis in this
activity.
Date Site Date Site
4/6/2010 Topeka, KS (TOP) 4/15/2011 Slidell, LA (LIX)
4/23/2010 Shreveport, LA
(SHV) 4/15/2011 Jackson, MS (JAN)
4/24/2010 Jackson, MS (JAN) 4/20/2011 Birmingham, AL
(BMX)
5/10/2010 Norman, OK (OUN) 4/25/2011 Shreveport, LA
(SHV)
5/12/2010 Norman, OK (OUN) 4/26/2011 Birmingham, AL
(BMX)
5/20/2010 Jackson, MS (JAN) 4/26/2011 Shreveport, LA
(SHV)
5/24/2010 North Platte, NB
(LBF) 5/22/2011
Springfield, MO
(SGF)
5/24/2010 Dodge City, KS
(DDC) 5/18/2013
Dodge City, KS
(DDC)
5/28/2010 Blacksburg, VA
(RNK) 5/19/2013
Springfield, MO
(SGF)
6/1/2010 Omaha, NE (OAX) 5/20/2013 Norman, OK (OUN)
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6/2//2010 Corpus Christi, TX
(CRP) 5/28/2013 Topeka, KS (TOP)
6/5/2010 Lincoln, IL (ILX) 5/29/2013 Norman, OK (OUN)
6/15/2010 Birmingham, AL
(BMX) 5/29/2013
North Platte, NB
(LBF)
6/23/2010 Birmingham, AL
(BMX) 5/30/2013 Norman, OK (OUN)
1. Begin formulating an individual report. Add to this report as you move through the project.
This report must be shared to the Discussion Board by midnight on Sunday of Module #6.
2. Collect severe weather reports for the day and site you selected.
Severe weather reports are located at the Storm Prediction Center
(http://www.spc.noaa.gov/) . Click on Storm Reports at the top of the page. Scroll down to
Past Storm Reports and enter the date of your selected event (yymmdd). Click the Get Data
This shows a map of severe weather reports on the chosen day from across the country.
Individual reports are given in text tables below the map. The type of event (tornado, large hail,
and strong wind) is categorized into separate sections. Keep this webpage handy for later use.
3. Download a radiosonde sounding for your chosen day and site.
A radiosonde sounding on the day and area of your selected thunderstorm activity can be
located at the University of Wyoming (http://weather.uwyo.edu/upperair/sounding.html)
weather sounding website. Under Type of Plot, select GIF: Skew-T. In Year and Month,
select your chosen date. In From and To, select your chosen day and the 12Z time on both.
Click on a 3-letter ID site near the region of the thunderstorms you have chosen for this
activity. (Write down this 3-letter ID; it will be needed later.) This will display the SkewT-LogP
thermodynamic diagram for that site and time. Start your search with the 3-letter ID supplied
with the site. But if the Storm Reports coverage is a large area, you may want to look at
several radiosonde sites in the general area to see if one looks better than another in reporting
severe weather events. If possible, choose a site closest to tornado activity in the area shown
on the main map of Storm Reports for that day.
The valid time for a 12Z sounding is 0700 EST. Hopefully, you will be seeing the condition of
the atmosphere within the same air mass of the thunderstorms that occurred later in the day,
but prior to the time storms began. Since weather systems in the U.S. typically move from west
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to east, it is more likely that you will observe a conditionally unstable sounding if you choose a
site at or just east of where thunderstorms began.
4. Write your individual report:
a. Copy and paste your selected SkewT-LogP chart as the first item of your individual
report for Week #6. Be sure the variables listed on the right-hand side of the figure are
included in what you copy. Introduce the figure in your report with appropriate text so a reader
can understand what is being presented. Include your name as well as the date and site you
selected for this activity.
b. Describe the weather event you selected and summarize the severe weather that
occurred close to your selected sounding site. Go through each text table in Storm
Reports on tornadoes, large hail, and strong wind events. Entries include the city, county, and
time of the event (UTC) and comments on the kinds of damage, deaths, and injuries reported.
At the end of the comments is a 3-letter station ID to the National Weather Service (NWS)
Forecast Office responsible for collecting these data. Clicking on the ID usually links you to
the name of the city where the report is located. This may (or may not) be identical to the ID at
your radiosonde site. However, each radiosonde site represents approximately a 200-mile
circle. So, any severe weather close to that distance is important to include in your report.
c. Highlight some major specifics from the Storm Report summaries. You should seek
out news reports for the day, if available. At a minimum, your weather summary should say
something like the following, but feel free to expand on this summary if you find more
extensive information:
The radiosonde site is in Springfield, MO. Over southwestern MO, there were 15
tornadoes, 25 hail events, and 45 damaging wind reports. The largest hail was 2.5
inches in diameter and the highest wind speed reported was 87 mph. One tornado
was rated as EF-3 and caused massive damages in Columbia, MO. There were 5
deaths and 15 injuries within this event, etc., etc., etc.
Please note: The daily timeframe for these 24-hour reports is in UTC from 12 Z to 12 Z or
from 7 a.m. to 7 a.m. Eastern Standard Time. That is, storm reports for say March 23 run from
7 a.m. on March 23 until 7 a.m. on March 24. This structure is used because a “severe
weather day,” when storms are most severe, runs from about noon to midnight. The desire by
NWS is to keep all severe weather reports on a particular day, attributed to a particular severe
weather air mass, centered within the same 24-hour period.
d. Analyze the SkewT-LogP diagram for its ability to indicate severe weather.
1) Was there a positive area? Explain in detail.
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2)Was there a change in wind direction or wind speed with height that would indicate wind
shear was present, which could have enhanced any severe weather that occurred?
Explain in detail.
e. Give the values for the following variables shown on the right-hand side of the chart
in your report. Include a definition of each term. These variables will assist you with the
sounding analysis.
1) LCLP – Lifted condensation level (mb) – This is the level where a lifted parcel reaches
saturation.
2) LFCT – Level of free convection (mb) – This is the level where the lifted parcel
temperature exceeds the sounding temperature, the bottom of the positive area.
3) EQLV – the equilibrium level (mb) – This is the level where the parcel temperature
equals the sounding temperature at the top of the positive area.
4) PWAT – precipitable water (mm) - This is the depth of precipitation that would occur if
the entire amount of water vapor in the sounding were precipitated out and converted to
liquid. A high amount (55 mm) means that very heavy rain is possible.
f. Share your report in the discussion board so that your group mates can start
checking each other’s work. (Do not post it in the Assignment area until the project is
completed).
Conducting Group Work
1. Organize a process to check each other’s individual and group work. Distribute group
work evenly between all of the members in your group.
2. Collate all individual work submitted in the Discussion (M6D2) into a single group
document. Care should be taken to assure consistency of presentation style, format, and font
type. Please prepare as a Word document (or equivalent).
3. Each group member will perform a minimal amount of Internet research to explore how
significant the following indices relate to severe weather in general, and then specifically to
each of the four selected events. Include the range of critical values related to severity of each
index during an occurrence of severe weather. Compare these values with the numbers
observed in the soundings.
Each group member should choose a separate research topic (index) to investigate. If there are
less than four team members, one topic each is still adequate. All topics researched should be
included in your group submission. The indices are as follows:
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LIFT – Lifted index (degrees C)
KINX – K-index (degrees C)
CAPE – Convective Available Potential Energy (joules/kilogram)
CINS – Convective inhibition (joules/kilogram)
4. Add this information into the group report identified with each group member’s names to
the indices chosen.
5. Evaluate the performance of the four indices for each of the four selected soundings.
a. Interpret which index performed better overall than the others in predicting the occurrence
(or no occurrence using CINS) of severe weather.
b. Which index performed the worst in this prediction?
Explain and justify your analyses in detail. For example, was KINX the best index overall
in predicting the severe weather that occurred at all four sites? Or was another index the
best? Explain how the CINS values prevented convection from occurring or may actually have
enhanced convection.
6. Insure that all appropriate references are included at the end of the group document in
the APA reference style. Citations to these references need to appear in the text where the
information is used and also need to follow APA guidelines as well.
Bonus (worth 5 points)
Why does the moist adiabatic rate line on a SkewT-LogP chart become nearly parallel to the dry
adiabatic lapse rate line with height?
Submitting your Project
You will submit your project through the activity M7A1: Submit Project #2 – Analyzing Weather
Data for Severe Weather.
Refer to M6D2 and M7A1 for information on how your project will be evaluated.
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