Early October Severe Weather

Hello all,

Something that I have done for quite a few years now is utilize the OrganicForecasting method, or OFM, to predict severe weather.  Below you will find the composite of SPC high & medium risk days during a neutral fall seasons between 1991-2016.

Large trough in the lee of the Rockies and Western Plains with a anomalous ridge centered over Montreal, Canada.

The BSR website showed the same depiction. Trough West with SW Flow aloft an East Ridge with a hint of NE trough.

Next up is the daily Southern Oscillation Index. The composite below is for day 14 after a 20pt drop of three days centered on 22SEP18.

With day 0 on the 23rd, I get this with my spreadsheet...

Now, the composites for Days 14-16...

Day 16 gets muted because immediately following, we had a rise with day 0 being the 26th of September.

Now, look at the EAR depiction...

A trough west and ridging East with nice vorticity moving from Texas into the Tennessee Valley.

Latest modeling...

01OCT18 12z GFS

00z 01OCT18 ECMWF


So, I will leave you with how various aspects of OFM showed the signals of severe weather and can be an asset to a forecaster.