Using The Short Fuse Composite to Forecast Using The Short Fuse Composite to Forecast Severe Convection:Severe Convection:

Part II – “The Next Generation,” Updating the Technique

By Jim Johnson & Mike UmscheidNWS Dodge City, KS

““Next generation” Short Fuse Next generation” Short Fuse Composite (SFC)Composite (SFC)

Objective analysis routines NWS AWIPS MSAS and LAPS

Gridded display software NWS-FSL Graphical Forecast Editor (GFE)

Updated techniques Low-level Lapse Rate replaces “Cap”

parameter as convective initiation tool

Components of the SFC Components of the SFC

Surface Moisture Flux Convergence Calculated from hourly MSAS grids (g/kg/hr * 100)

Potential Temperature Advection Native pot. temp. adv. grid from hourly LAPS (K/hr *

100)

CAPE and ThetaE CAPE- Native grid from hourly LAPS (J/kg) ThetaE- Native grid from hourly LAPS (K)

Low Level Lapse Rate (0 to 2.5km AGL) Calculated from hourly LAPS grids (C/km * 10)

The ChartsThe Charts

weather.gov/ddc/short.html

““Threat Area” ComponentsThreat Area” Components

axis of highestmoisture flux convergence

Downwind of positive pot. temp. axis

within axis of greatest surface based instability

Threat Area: Threat Area: 19 Aug 2005 @ 2000 19 Aug 2005 @ 2000 UTCUTC

3 components from Chart 1 SB Conv. Inhib component from Chart 2

19 Aug 2005: 19 Aug 2005: Great Bend Great Bend TornadoesTornadoes

SFC Threat Area Analysis 2000 UTC

2004 21042159

© Henry Diehlwith permission

Just northeast of Great Bend around

2120 UTC

A few more 2005 cases. . .A few more 2005 cases. . .

April 10 (local tornado outbreak) “cold core” upper low setup with advancing dry

intrusion

June 9 (local tornado outbreak) Traditional southwest flow setup ahead of broad

upper trough

July 3 (long-lived monster supercell) Elevated supercell transitioning to surface based

supercell

Threat Area: Threat Area: 10 Apr 2005 @ 1800 10 Apr 2005 @ 1800 UTCUTC

Radar imagery 1904 UTC

1900 UTCweak tornado west of

Scott State Lake

3 components from Chart 1

Threat Area: Threat Area: 10 Apr 2005 @ 2000 10 Apr 2005 @ 2000 UTCUTC

3 components from Chart 1

Radar imagery 2059 UTC

Multiple tornadoes from 2 storms in

Trego County from 2135 to 2205 UTC

Threat Area: Threat Area: 10 Apr 2005 @ 2200 10 Apr 2005 @ 2200 UTCUTC

Radar imagery 2259 UTC

3 components from Chart 1

Gorham-Russell Tornadic Supercell (large tornado at

2308 UTC)

Toulon-Catherine Tornadic Supercell

(large tornado crosses I-70 at 2252

UTC)

Threat Area: Threat Area: 9 Jun 2005 @ 1800 9 Jun 2005 @ 1800 UTCUTC

Satellite imagery 1932 UTC

3 components from Chart 1

Convective Initiation

Threat Area: Threat Area: 9 Jun 2005 @ 2000 9 Jun 2005 @ 2000 UTCUTC

Large Tornadic Supercell – “Hill City” tornado

2120 to 2148 UTC rated F2

3 components from Chart 1

Radar imagery 2101 UTC

© Eric Nguyenwith permission

Threat Area: Threat Area: 9 Jun 2005 @ 2100 9 Jun 2005 @ 2100 UTCUTC

Large Tornadic Supercell –

“Zurich-Stockton” tornadoes 2225 to

2240 UTC

New SupercellsDeveloping

Radar imagery 2201 UTC

3 components from Chart 1

© Eric Nguyenwith permission

Threat Area: Threat Area: 9 Jun 2005 @ 2200 9 Jun 2005 @ 2200 UTCUTC

Large Tornadic Supercell – “Stockton”

tornado 2257 to 2306 UTC rated

F1

Radar imagery 2301 UTC

Tornadic Supercell – “Trego Center” tornado 2300 to 2310 UTC rated

F3

Tornadic Supercell – several tornadoes

between 2330 and 2400 UTC

3 components from Chart 1

© Amos Maglioccowith permission

Threat Area: Threat Area: 3 Jul 2005 @ 1700 3 Jul 2005 @ 1700 UTCUTC

Radar imagery 1803 UTC

Chart

1C

hart

2

Baseball size hail @ 1830 and 1855

UTC in Rush County… no wind

reports

Threat Area: Threat Area: 3 Jul 2005 @ 1900 3 Jul 2005 @ 1900 UTCUTC

Radar imagery 2002 UTC

Chart

1C

hart

2

Golfball size hail numerous reports + 70mph winds

1925 to 2015 UTC in Barton-Rice

Counties.

Threat Area: Threat Area: 3 Jul 2005 @ 2100 3 Jul 2005 @ 2100 UTCUTC

Radar imagery 2230 UTC

Chart

1C

hart

2

3 tornado rpts, 2 golfball or larger

hail rpts, and numerous wind

damage rpts from est. 80 to 90mph

winds.

2220 to 2330 UTC

Future WorkFuture Work

Network of local office SFC Operational version 1.0 on AWIPS LAD NWS Goodland, KS first office outside of

DDC to implement http://weather.gov/gld/short

Improvements Web-based looping feature Chart 3: Empirical “Threat Area”

development?NWS DDC Short Fuse Composite website – http://weather.gov/ddc/short.html

Questions & Comments?Questions & Comments?

Thank You!Thank You!

© Mike Umscheid