1. Trenton Davis
The Ohio State University
Atmospheric Science
Weather-Ready Nation
National Weather Service Cheyenne, WY
Mentor: Rob Cox

2. Introduction
 Biography
 National Weather Service
Cheyenne, WY
 The hail…and more hail…
 Lightning and hail interests
 Why I chose CYS
 Hypothesis: Larger flash jump
= Larger hail and extended
lead time

3. Background
 What is SPoRT
 7 Current lightning
mapping arrays
 Goals and research
 NALMA’s conclusions
 GOES-R Proving
Ground
 Geostationary Lightning
Mapper

4. What is COLMA?
 Colorado State University
 First use at CYS in April
2013
 Measures VHF radiation
then sent to NM Tech.
University
 16 sensors-need at least 6
operating
 Location found through
equal time hyperbolas
 RFD vs. FED
 Updated every minute, faster
than radar
 Disseminated to AWIPS at
CYS

5. -
-
-
-
--
-
-
-
+ ++
+
+ +
+
+ ++
+
+ +
+
t1
t2
t3
Ground
LMA time-of-arrival technique
VHF radiation α dI/dt
Cell antenna
E field
Height
Radio antenna
Solar panel
Main
processor
Vertical distribution of
sources?
Colorado State University Dept. of Atmospheric Science

6. The Project
 Familiarization with project/read papers
 Started with SPC Severe Thunderstorm Event Archive
 Next, AWIPS Product History
 Days with Hail ≥2” (15 cases), 1”-2” (15 cases), and <1” in
diameter (14 cases)
 Analyzed radar on GR2Analyst
 From NCDC
 Loaded and viewed COLMA data on WES
 From SPoRT and CSU
 2012 cases-COLMA data not decimated
 Not used in most graphical analyses, so 14, 9, and 9 cases now
 Made graphs and analyzed trends in data
 Visited CSU for background info on COLMA

7. 6-24-14 2232Z Example
 While at work
 Damage on I-25- 2.75” hail
Lightning Jump Starts 2211ZLightning Jump Ends 2215Z Lightning Jump Starts 2216ZLightning Jump Ends 2219Z
1st Hail Report
Radar Indication
2217Z
2nd Hail Report
Radar Indication
2227Z
2210Z2215Z2219Z2224Z2228Z2205Z
209 Sources365 Sources17 Flashes25 Flashes225 Sources343 Sources20 Flashes23 Flashes

8. Results
1. Hail <1" 2. 1" ≤Hail <2" 3. 2" ≤Hail
RFDJump 36.90 55.85 42.44
FEDJump 3.15 4.38 4.22
Time to RadarIndication (min) 8.20 9.85 9.00
Lead-Time (min) 14.10 17.23 17.44
Storm HeightatJump (kft) 38.60 43.62 43.78
MeanResults PerHail Size
0.00
1.00
2.00
3.00
4.00
5.00
Hail<1" 1"≤Hail<2" 2"≤ Hail
HailSize(in)
Hail Size Categories
Hail Size Range by Category
0.00
50.00
100.00
150.00
200.00
Hail<1" 1"≤Hail<2" 2"≤ Hail
SourceJump
Hail Size Categories
Source Jump by Category
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
16.00
Hail<1" 1"≤Hail<2" 2"≤ Hail
FlashJump
Hail Size Categories
Flash Jump by Category

9. Results (cont.)
%Jump=(End Mag.-Start Mag.)/Start Mag.
y = 0.183x + 3.6643
R² = 0.0037
0
2
4
6
8
10
12
14
16
0 1 2 3 4 5
FlashJump
Hail Size (in)
Flash Jump to Hail Size
y = -21.855x + 214.06
R² = 0.0366
0.00
100.00
200.00
300.00
400.00
500.00
600.00
0 1 2 3 4 5
SourceJump(%)
Hail Size (in)
Source Percentage Jump to Hail
Size
y = -2.7956x + 85.016
R² = 0.0019
0.00
100.00
200.00
300.00
400.00
0 1 2 3 4 5
FlashJump(%)
Hail Size (in)
Flash Percentage Jump to Hail
Size

10. Results (cont.)
%Jump=(End Mag.- Start Mag.)/Start Mag.
y = 0.3977x + 9.1814
R² = 0.502
0.00
100.00
200.00
300.00
400.00
0.00 100.00 200.00 300.00 400.00 500.00 600.00
FlashJump(%)
Source Jump (%)
Source Percentage Jump to Flash
Percentage Jump
y = 9.0817x + 143.67
R² = 0.0576
0.00
100.00
200.00
300.00
400.00
500.00
600.00
0 5 10 15 20
SourceJump(%)
Elapsed Time (min)
Source Percentage Jump to
Radar Indicated Hail
y = 1.8958x + 63.364
R² = 0.0337
0.00
100.00
200.00
300.00
400.00
0 5 10 15 20 25
FlashJump(%)
Elapsed Time (min)
Flash Percentage Jump to Radar
Indicated Hail

11. Summary
 RFD and FED jumps greatly vary from storm-to-storm
 Large (%) jumps don’t always = large hail
 Continuously high RFD and FED rates could indicate more
robust updrafts
 RFD and FED are closely related
 Rough 9 minute lead-time for any hail occurrence
 We know the average jump for each hail size category
 Flashes are more valuable than sources
 General trend
 1) Storm top height increase 5-10 min prior to LJ
 2) Radar Indicated hail around 9 minutes after
 3) Storm report 7-8 minutes after
 COLMA is useful as a tool, not the only tool for issuing
warning

12. Next Steps
 Continue as a graduate school project?
 CSU- work with COLMA further
 Compare more variables
 CAPE, Dew Points, Precipitable Water, etc.
 Storm top divergence
 Compare structure of storms
 LMA mode, source initiation, initial height
increase
 SPoRT-LMA data on GR2Analyst?
 Cleaner feed to CYS and FTG

13. Acknowledgements
 Thank you to all who helped make this
project possible!
 Mentor: Rob Cox (Science Operations Officer)
 Co-Mentors: Zach Finch and Rebecca Mazur
(Forecasters)
 Christopher Hammer (Meteorological Intern)
 Dr. Geoffrey Stano (NASA’s SPoRT)
 Dr. Steven Rutledge and Brody Fuchs (Colorado
State University)
 Special thank you to NOAA Scholarships
for this inspiring opportunity!!