wind chill: a forward approach
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Wind Chill: A Forward Approach . Kelly Balmes , Brian Adams, Justin McCoy . Introduction. Statement of the Problem: When cold temperatures already exist, wind can make the situation much worse. - PowerPoint PPT PresentationTRANSCRIPT
Kelly Balmes, Brian Adams, Justin McCoy
*Wind Chill: A Forward Approach
Statement of the Problem:• When cold temperatures already exist, wind can
make the situation much worse. • Dangerously low wind chill temperatures can cause
serious health concerns such as frostbite, hypothermia, breathing impediments for sensitive groups, and other health complications.
• It is for this reason that having timely forecasts is of the utmost importance for the protection of human life.
*Introduction
*Case Study: January 5-7, 2014
Cold Spell*Air mass of arctic origin draped across the Northern Midwest
*Wind gusts of 25 to 45 mph, wind chill values of -35 to -55 degrees
*Coldest stretch of weather since February of 1996
*Wind Chill Warnings issued 48 hours in advance,all of Iowa, Minnesota, and Wisconsin were under warnings
*All schools closed on Monday the 6th, most remained closed on the 7th.
*Also used data from January 24th-26th, anothersignificant cold spell
• Create plots of probabilities that determine the chance of temperatures exceeding the thresholds for either an advisory or a warning for two different lead times (24 and 48 hours).
• Determine the likelihood of an advisory or warning being issued for the inputted latitude and longitude.
*Objectives
• Collection of SREF ensemble files – provided by Dr. Greybush.• Data from January 4th, 6th, 24th, and 26th, 2014• Actual wind chill advisory and warning events.
*Description of Input Data
• Defined threshold temperatures values for wind chill advisories and warnings.• Wind Chill = 35.74 + 0.6215T - 35.75(V0.16) +
0.4275T(V0.16) • Advisory threshold = -26.111 degrees C• Warning Threshold = -31.667 degrees C
• Calculated probabilities of thresholds being exceeded.
• Calculated how many ensemble members had exceeded the threshold at each grid point.
*Decision Support
Algorithm
• Inputted latitude and longitude read in from the terminal.
• Probabilities were calculated using data from all the ensemble members and thresholds.
• Detailed maps were created, showing which areas were experiencing conditions that were conducive to significantly low wind chill temperatures.
*Implementation Details
• Output came in the form of plotted maps, like the one shown below, for wind chill temperatures.
* Description of Output
• The output also delivers probabilities of advisories and warnings at each grid point.
* Description of Output
• The output also delivers probabilities of advisories and warnings at each grid point.
* Description of Output
*Comparison of Output to Actual Event
• The output also displays to the terminal the likeliness (over or under 50% probability) of a warning or advisory being issued for an inputted latitude and longitude, which can physically be entered by a user of the program.
* Description of Output
• Two cities were chosen in order to test the validity of our program’s ability to determine wind chill advisories and warnings.
• First Test: Madison, WI (43.0667N, 89.4W) – test results yielded likely wind chill advisory and warnings.
* Test Plan and Examples
• Second Test: Dallas, Tx (32.7758N, 96.7967W) – test results yielded unlikely wind chill advisories and warnings.
* Test Plan and Examples
• Can be used as a forecasting tool for forecasters determining wind chill advisory and warnings for particular locations.
• Forecasters will be able to input SREF data for a particular day to enhance their forecasts.
• Emergency management could use it for event cancellations if wind chill advisories or warnings were likely to be issued for the inputted latitude and longitude of an event venue.
*Potential Uses of this Product
• Different categories of likeliness for advisories/warnings (i.e. slight risks, moderate risks, high risks)
• Filtering out temperatures not conducive to significant wind chill conditions (i.e. 80 degrees in Florida)
• Taking different wind chill thresholds into account for each state
• Specifying the forecast lead times via terminal input, instead of just having 24- and 48-hour forecasts
*Future Improvements
• SREF ensemble files used to help determine wind chill advisories and warnings.
• Calculated probabilities of the likelihood of wind chill advisory and warnings.• Program output generates maps of wind chill
advisory/warning probabilities, as well as wind chill temperatures.
• Users of the program may input a specified latitude and longitude value.• Terminal prints to the screen the likelihood of a wind
chill advisory/warning for the desired location.
*In Summary