June 28 Severe Weather Update...

After some morning clouds, temperatures have skyrocketed into the upper 80s and low 90s across west Alabama with a mostly clear sky. This has allowed the airmass to become very unstable across northwestern sections of Alabama into adjacent portions of northeast MS.

Here's the surface CAPE chart valid right now from the SPC mesoanalysis page. Notice the values exceeding 4500 j/kg from west Alabama to near Memphis, TN. This is an environment that is very unstable, and with an outflow boundary moving south noted in visible satellite imagery, thunderstorms could initiate at any time in this regime. The National Weather Service in Birmingham is particularly concerned with the areas of Fayette, Lamar, Marion, and Winston Counties for potential thunderstorm initiation (seen below; source NWS Birmingham).

However, uncertainty remains to the actual aerial extent and coverage of these storms should they develop. It could be one or two intense storms, or several strong to potentially severe storms. There is, however, some concern about storm coalescence into an MCS and/or bowing segment and accelerating southward. Given northerly flow aloft, these storms would move due south, and if organization occurs, a wind damage threat would certainly be in the cards. Initially, should any storms develop, large hail will also be a potential threat as well.

The 4km WSI RPM develops isolated storms by 3pm over northwestern sections of central AL and moves them southward. Like I said earlier, it remains to be seen if storms can actually develop, but if they do, they will pack quite a punch.

Throughout the afternoon and evening, another thunderstorm complex should develop over portions of Kansas and track southeastward. The 4km and 12km RPM shows this feature making it into north-central MS overnight but dissipates it before it enters west Alabama. This complex will need to be monitored, but for now it appears it will not impact west Alabama.

For tomorrow, a frontal boundary will be sinking in from the north, and as the airmass becomes at least moderately unstable, scattered to numerous showers and storms will develop in association with this feature. Local enhancement of storms may occur where pockets of stronger heating occur and/or where any outflow boundary interactions occur as well and in these areas strong to potentially severe storms will be possible.

Keep an eye to the sky, and God Bless!

IW