40 th annual meeting, national weather association, broadcast meteorology workshop oct. 18, 2015...
TRANSCRIPT
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
Understanding SPC’s Outlooksor
Everything you wanted to know about outlook probability to category conversion but were afraid to ask.
Greg Carbin, Jared Guyer, Bill Bunting, Russ Schneider
NOAA/NWS Storm Prediction Center
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
Severe Thunderstorm Outlook Categories
Bottom line…
It’s about forecasting the overall coverage of severe storms…
…and the intensity of those storms!
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
From Probabilities to Day 2 CategoriesTotal of all hail, wind, & torn events
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
From Probabilities to Day 2 CategoriesTotal of all hail, wind, & torn events
What does Jimthink will happen tomorrow?
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
From Probabilities to Day 2 CategoriesTotal of all hail, wind, & torn events
5%
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
From Probabilities to Day 2 CategoriesTotal of all hail, wind, & torn events
15%
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
From Probabilities to Day 2 CategoriesTotal of all hail, wind, & torn events
15%sig
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
From Probabilities to Day 2 CategoriesTotal of all hail, wind, & torn events
30%
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
From Probabilities to Day 2 CategoriesTotal of all hail, wind, & torn events
30%sig
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
From Probabilities to Day 2 CategoriesTotal of all hail, wind, & torn events
45%
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
From Probabilities to Day 2 CategoriesTotal of all hail, wind, & torn events
45%sig
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
From Probabilities to Day 2 CategoriesTotal of all hail, wind, & torn events
60%
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
From Probabilities to Day 2 CategoriesTotal of all hail, wind, & torn events
60%sig
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
From Probabilities to Day 1 CategoriesHail, wind, & torn events
are considered separately.Significant severe usually
results in a category upgrade.
Why Are These Numbers Important?
Five year sample: 2010 - 2014
Day 1 Probabilistic Outlooks Day 2 & 3 Probabilistic Outlooks
Because SPC Severe Weather Outlooks probabilities are reliable.
Forecast Exercise
Case Studies for Day 2 SWO
Probability Practice
Greg Carbin, Jared Guyer and Patrick Marsh
NWS-NCEP-Storm Prediction Center
Severe Weather Forecast Exercise
- 00Z 500 mb heights, temps (C), isotachs (kt)
- 00Z surface pressure, 2m temps/dewpoints (F), 10m wind (kt)
- 00Z surface pressure, CAPE, HLCY
- What states were most impacted by severe weather on this day?
- Were there significant tornadoes (F2-3)? How many and where?
- Were there violent tornadoes (F4-5)? How many and where?
- What happened?
- 00Z Supercell Composite Parameter (SCP)
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
Case #1 – 500 mb
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
Case #1 – MSLP/T/Td
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
Case #1 – MSLP/CAPE/SRH
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
Case #1 – Supercell Composite
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
Case #2
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
Case #2 – 500 mb
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
Case #2 – MSLP/T/Td
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
Case #2 – MSLP/CAPE/SRH
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
Case #2 – Supercell Composite
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
Case #3
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
Case #3 – 500 mb
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
Case #3 – MSLP/T/Td
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
Case #3 – MSLP/CAPE/SRH
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
Case #3 – Supercell Composite
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
Case #4
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
Case #4 – 500 mb
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
Case #4 – MSLP/T/Td
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
Case #4 – MSLP/CAPE/SRH
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
Case #4 – Supercell Composite
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
Here’s what happened…
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
TOR = 5F2+ = 1F4+ = 1DPI = 4.8
CASE #1 verification
13 July 2004: Roanoke, IL F4 and later derecho. ~400 total reports.
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
TOR = 5F2+ = 1F4+ = 1DPI = 4.8
CASE #1 verification
45% SIGModerate Risk
60% Moderate Risk
13 July 2004: Roanoke, IL F4 and later derecho. ~400 total reports.
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
TOR = 30F2+ = 20F4+ = 7DPI = 1156Fatalities= 89
CASE #2 verification
Infamous 1985 OH/PA tornado outbreak
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
TOR = 30F2+ = 20F4+ = 7DPI = 1156Fatalities= 89
CASE #2 verification
Infamous 1985 OH/PA tornado outbreak
60% SIGHigh Risk
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
TOR = 7F2+ = 4F4+ = 1DPI = 38Fatalities= 6
CASE #3 verification
3 June 1980: “Night of the Twisters!” Grand Island, NE tornado cluster.
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
TOR = 7F2+ = 4F4+ = 1DPI = 38Fatalities= 6
CASE #3 verification
30% SIGEnhanced Risk
3 June 1980: “Night of the Twisters!” Grand Island, NE tornado cluster.
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
TOR = 50F2+ = 27F4+ = 4DPI = 633Fatalities= 21
26 April 1991: Andover, KS and Red Rock, OK. TORNADO OUTBREAK!
CASE #4 verification
40th Annual Meeting, National Weather Association, Broadcast Meteorology Workshop Oct. 18, 2015
TOR = 50F2+ = 27F4+ = 4DPI = 633Fatalities= 21
CASE #4 verification
45% SIGModerate Risk
60% SIGHigh Risk
26 April 1991: Andover, KS and Red Rock, OK. TORNADO OUTBREAK!
Severe Weather Forecast Exercise
- Summary: Why is tornado forecasting so hard?
- A wide range of large-scale conditions…
- Generally poor forecasts of storm-scale conditions…
- Any time of year…
- Just about anywhere…
- Tornadoes kill people and can ruin your day!
