Tuesday, 19 April 2011

Tornadoes soon in the Midwest

Another day, another outbreak of severe weather is expected in the USA. This time it's portions of the Central Plains and Midwest, especially Missouri and Illinois.

This chart shows the latest SPC mesoanalysis for sea level pressure and surface dewpoint. There is a well-marked warm front to the east of surface low, which is currently in central Missouri. Latest satellite imagery shows a deepening cumulus field around the low, the warm front, and down the trailing cold front to the south-west of the low.

Scattered thunderstorms should develop very shortly, especially INVOF the low and warm front. The low will move in the direction shown by the arrow, and low-level shear/helicity will be maximised just ahead of the low. The red polygon shows my interpretation of the highest risk of tornadoes in the next several hours, along the path and just ahead of the surface low.

Storms should develop down the cold front too, eventually turning into a line of severe storms, although initially some supercells are possible. Large hail, severe winds, and isolated tornadoes likely with these.

Thus, in short, another outbreak of severe thunderstorms will develop shortly, and the highest tornado risk, at least in the short term, in my opinion, is central Illinois.

No comments:

Post a Comment