Tornado Forecast for Saturday, April 27

I believe Saturday presents a major tornado risk to residents of southeast Kansas and much of the east half of Oklahoma. 

The color code:
  • The area in red has (on my 4-point scale of significant/enhanced/high/extreme) a high risk of strong tornadoes. Strong is defined as EF-2 or stronger.
  • Yellow, hatched has an enhanced risk of tornadoes.
  • The brown area has a significant risk of tornadoes. 
Below are enlargements of the enhanced and high risk areas:

Tornadoes could occur any time Saturday and/or Saturday night. I recommend you monitor the weather throughout the day in these areas. 

The entire enhanced and high risk areas are likely to receive giant hail (defined as 2" or larger) with any strong thunderstorms, tornado-producing or otherwise.

If you live in a mobile home or a home, in the strongest way possible, please locate -- today -- a nearby community shelter. You can find them here

If you shelter at home, please remember:
  • Have a least three independent ways of receiving tornado warnings.
  • Fresh batteries for your weather radio; fully charged smartphone and laptop but disconnect them when you first hear thunder (risk of power surge damaging the devices). 
  • Turn the Wireless Emergency Alerts (on an iPhone, go to "Notifications" and scroll down to the bottom to "activate."
  • Make sure your storm sheltering area is ready to go (clear cobwebs, etc.), add a couple of bottles of water and diapers, if appropriate. 
  • Always wear shoes into shelter. If the worst happens, you won't want to walk across broken glass and metal shards.
  • If a tornado watch is issued, move family heirlooms, etc., into the shelter at that time. Don't wait till the last minute. Remember, the watch is a forecast of tornadoes, a warning means it is time to take cover. 
I will update the forecast tomorrow morning. In the meantime, I do live updating on Twitter @usweatherexpert. If you have friends/relatives in the threatened area please forward this forecast to them. Thank you. 


Discussion for Meteorologists

As this forecast differs from some others, I'm including a discussion for meteorologists for any that are curious. 

The discussion about morning rain/thunderstorms, if they occur -- which is likely -- does not diminish the likely number or intensity of tomorrow's tornadoes. From a synoptic climatological point of view, the majority of violent tornadoes are preceded by rain. It seems to lower the LCL. SWEAT index runs about 570 (500 the threshold for tornadoes) even behind the initial line of showers/thunderstorms. 

One of the reasons for last week and yesterday's over-forecast of tornadoes was the ECMWF and other models was too fast with the upper atmospheric low. Given that apparent bias, I have slowed the system's location ~100 miles for 7pm Sunday. 

The 250 mb winds in polar jet are exceptionally strong for late April. Some of the models have max winds of 165 mph with central KS and north central OK in the right read quadrants. 


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