Severe Weather Discussion for May 23-24, 2011

Severe Weather Discussion for May 23-24, 2011.
Issued:  05/23/2011.

*Significant Severe Weather Today and Tomorrow*

Highlights:

–  Active severe weather day is likely across much western, northern, and central Oklahoma.  Tornadoes, destructive hail, and damaging winds are likely.

–  Significant severe weather day is possible on Tuesday much of Oklahoma.

Discussion:

In 22 years of living in Oklahoma I have never had a three day chase potential, although I’m sure there have been setups but none I can remember.  We used to talk about the Day 1 and Day 2 high risks back in 1991 but forecasting and other things are much different in today’s world.

There is little change to prior forecasts.  Currently there is a dryline from west of Hollis to Alva.  This feature will likely continue to mix slowly east over the next few hours and will be the primary focus for initial development this afternoon.  Just east of the dryline the atmosphere is extremely unstable with CAPE values AOA 5500 J/Kg.  In northern Oklahoma there is an outflow boundary from Westville to Alva, currently crossing through Tulsa.  This boundary should lift a little north today but likely still partially in Oklahoma late this afternoon.  Storms will also develop along this boundary later today.  Wind fields favor supercells and cap favors discrete development.  As such, a tornado threat will exist with any mature storm.  A tornado watch is likely by 2pm and local models indicate initiation by 3pm.  We’ll see how that latter part goes.

I don’t know enough words to describe tomorrow.  SPC said it best when they led off the new Day 2 with a ‘classic plains tornadic outbreak.’  The forecast setup is the same, a shortwave trof is expected to impinge upon Oklahoma at peak heating.  CAPE values are expected to be AOA 5000 J/Kg owing to an extremely unstable atmosphere.  Wind fields will increase across the state as the system approaches and a strong cap should keep the atmosphere down much of the day.  As such, explosive thunderstorm development should occur by 4pm along a dryline in western Oklahoma.  There is a lot of focus on the dryline reaching I-35 and I agree with SPC pulling the risk area west.  As always there is the threat of early morning convection that may modulate the event.  No one can accurately forecast such and for now I’m forecasting the potential.

Probabilities:

Risk area for any part of OK (valid:  05/24 Day 1):

Slight:  100%
Moderate:  100%
High:  90%

Chase Status:

Level 1 – looking to head west or southwest today.

Facebooktwittergoogle_plusredditpinterestlinkedinmailby feather
This entry was posted in Severe Weather. Bookmark the permalink.

Leave a Reply

Your email address will not be published. Required fields are marked *