The TOR:CON Index
from Dr. Greg Forbes' Facebook Page

Severe Weather Expert, Dr. Greg Forbes developed the TOR:CON index to estimate the risk of a tornado on a given day or night near your area.

The TOR:CON index ranges from 0 to 10. Multiply the value by 10 to get your percentage chance of a tornado within 50 miles of a location. For example, a TOR:CON index of 6 means there's a 60% chance of a tornado within 50 miles of any location in the indicated area.

Note: By definition, a severe thunderstorm contains one or more of the following: hail at least 1 inch in diameter, wind gusts 58 mph or higher, or a tornado.

TOR:CON Value Descriptions

8+
Very high probability of a tornado
High probability of a tornado
Moderate chance of a tornado nearby, but hail and/or high wind gusts possible
Low chance of a tornado, but hail and/or high wind gusts possible
Near-zero chance of a tornado or a severe thunderstorm

Sunday May / 27th Last Updated: 05/27/18 12:56:33 PM

Isolated tornado threat from Alberto in FL, possibly extending into extreme south AL overnight

TORCON - 3

Isolated severe thunderstorms in east WY, southeast SD, west NE, west KS, OK and TX panhandles, northeast CO

TORCON - 2 to 3

Subtropical storm Alberto is over the Gulf of Mexico west of central FL with rainbands to its east and southeast where low-level winds of about 40 mph are giving enough shear for a tornado

The forward right quadrant will move into the FL panhandle this evening and tonight

The leading edge of an upper low centered over NV and UT will bring a surface low over east CO and pull enough moisture into areas to its north, east, and south for severe thunderstorms, although limited moisture and high cloud bases will limit the tornado threat

Monday May / 28th Last Updated: 05/27/18 12:56:06 PM

Isolated severe thunderstorms in north FL, southeast and east-central AL, south and central GA, south SC

TORCON- 3

Scattered severe thunderstorms in southeast MT, southwest ND, west SD, west NE, west KS, northwest OK, east TX panhandle, northeast CO, east WY, spreading overnight across southern ND, into central SD and central NE

TORCON - 3 west KS, west NE

2 to 3 rest of area

Alberto makes landfall in the western FL panhandle and moves into AL, with a trough of low pressure to its east and low-level winds strong enough for a few tornadoes

A surface low pressure trough from western SD to the western TX panhandle gives a focus for severe thunderstorms as an upper trough moves toward the area

Moisture increases and cloud bases lower, somewhat increasing the tornado threat

Tuesday May / 29th Last Updated: 05/27/18 1:44:36 PM

Isolated severe thunderstorms from Alberto remnants in central KY, middle and southeast TN, north and central GA, northeast AL

TORCON - 3

A chance of severe thunderstorms in east KY, extreme southwest VA, southwest NC, west SC, south GA

TORCON - 2

Isolated severe thunderstorms in central and east SD, northwest MN, central and east SD, southwest, central and northeast NE, east KS

TORCON- 2 to 3

Alberto's remnant low moves over northern AL toward TN with low-level winds and shear still strong enough for a tornado

An upper trough moves into the Northern and Central Plains with a surface low over ND and a trough to the TX panhandle

Low-level wind shear appears relatively weak

Wednesday May / 30th Last Updated: 05/27/18 1:44:13 PM

A chance of severe storms from Alberto remnants over OH, south MI, IN, KY, middle and east TN, east IL

TORCON- 2

A chance of severe thunderstorms in east MN, north WI, western UP of MI

TORCON- 2

Alberto's remnant low moves across KY toward the IL/IN border with still winds aloft marginally strong enough for a damaging gust or tornado

An upper low iand surface low in east ND bring some severe threat, but low-level winds are weak and hold down the threat

Thursday May / 31st Last Updated: 05/27/18 1:43:46 PM

A chance of a severe thunderstorm from Alberto remnants in lower MI except southwest, east OH, northwest WV, west PA, southwest NY

TORCON - 2

The remnant low from Alberto moves into MI, with a trough of low pressure to its southeast

Low-level winds continue to slowly weaken, so tornado threat may diminish

Friday Jun / 1st Last Updated: 05/27/18 1:43:17 PM

Scattered severe thunderstorms in west, central and southeast ND, east SD, northeast NE

TORCON - 3

The leading portion of an upper trough over WA and OR brings a surface low over western ND

Low-level winds look strong enough for a tornado threat

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