The 1925 Tri-State Tornado What If It Happened Today? Pat Spoden NOAA/NWS WFO Paducah, Kentucky John Hart NOAA/NWS Storm Prediction Center Norman, Oklahoma

The 1925 Tri-State Tornado

What If It Happened Today?

Pat SpodenNOAA/NWS WFO Paducah, Kentucky

John HartNOAA/NWS Storm Prediction Center

Norman, Oklahoma

Forecasting the Tri-State Tornado…

Anticipating This Historic Event

• This tornado was quite possibly the “greatest”tornado in recorded history.

• It is natural to assume that such an event wouldbe obvious to forecasters today.

• FACT: The Tri-State Tornado would not havebeen an easy forecast.

• What would our forecasts have looked like? This is purely hypothetical!



• US Weather Bureaudid not issue watches orwarnings in 1925.

• NOAA/NWSStorm Prediction Centerformed in early 1950s.

• What would our forecasts have looked like? This is purely hypothetical!



• Researchers have attempted to re-createthe environmentleading up to thisevent.

• Records are sparse and incomplete. But…we have a reasonably good idea of what the pattern looked like.



Our best guess… 6am Wed Mar 18th

• Morning temperaturesin the 50s.

• Dewpoints in the 50s.

• Widespread rain beforesunrise.

• Warm front lifting northward

• A typical windy Marchmorning.




• Strong upper trough approaching from the west.

• 60+ knot 500mb wind max over Arkansas.

• Cold aloft. Steep lapserates.

• Relatively weak instabilitydue to limited low levelmoisture.




• Day2 Outlook would havebeen concerned aboutlack of low level moistureand weak instability.

• ENHD risk, centered overparts of Kentucky.

• Tornadoes a concern overthe ENHD risk area.

DAY2 SPC Convective Outlook




• Here is one possibleconvective outlook.

• MDT risk, centered overparts of Kentucky.

• Concern for tornadoesfocused on late afternoonand evening across MDTrisk area.

• Some risk ahead of the surface low.

OvernightSevere Tstmwatch until

9am

DAY1 SPC Convective Outlook




• Morning storms in southwest MO are weakening. Watchexpiring soon.

• Relatively quiet morningat SPC.

• Monitoring surfaceanalyses, radar, models for trends regarding whenstorms will intensify.



Our best guess… Noon Wed Mar 18th • Warm front continues

to lift north.

• Small area of unstableair now forming nearsurface low.

• First thunderstormsare probably beginningto develop in south-central MO.

Tornado watchuntil 6pm



Our best guess… Issued around Noon • TORNADO WATCH

• Uncertainty on how farsouth storms will develop.

• East edge is the PaducahCWA boundary.

• North edge based on where warm-front mightmake it before lowpasses. (Also CWAboundary).

• Initially would probably not include WFO IND

Conference Call :• WFO Paducah• WFO St. Louis• WFO Little Rock• WFO Memphis• WFO Central IL

Valid until 6pm



• A total of 9 strongtornadoes

• F2: 2• f3: 4• F4: 2• F5: 1

• 747 total fatalitiesSignificant Eveningtornado outbreak.



In summary, SPC would have probably issued…

* DAY2 Enhanced Risk Outlook

* DAY1 Enhanced/Moderate Risk Outlook

* Tornado watch for Tri-State area would have likely been issued around Noon.

* Several more watches would have been issued through the evening over IN, OH, KY, TN.

* Local NWS office, TV/radio stations, and local emergency managers would have kept everyone informed.

Early On

http://ejssm.org/ojs/public/vol8-2/map/map.php

A Likely Warning for SEMO

Once we know there is a large Tornado on the Ground

http://ejssm.org/ojs/public/vol8-2/map/map.php

First Warning for Southern IllinoisTornado Emergency

Tornado Emergency

Large tornado observed on the ground Reports of significant damage Expect the tornado to continue Call-to-Action would be strongly worded

How we Handle Warnings

A “group” of forecasters would focus on that storm only Numerous updates

Would call ahead to upstream county EM’s Work closely with EM’s/Media Social Media would play a big role

1 or 2 forecasters focus on this only

If This Event Happens Again

Outlook probably a Slight or Moderate Watch in place

Lots of tornado warnings Try not to warn for the same location twice Once we get a confirmation and expect the

tornado to be on the ground for a long time – may move to Catastrophic (Emergency) wording

Reports would be critical Social Media would be critical How long do we go with “Catastrophic”

wording?

Documents

The 1925 Tri-State Tornado What If It Happened Today? Pat Spoden NOAA/NWS WFO Paducah, Kentucky John Hart NOAA/NWS Storm Prediction Center Norman, Oklahoma