Can you help me understand the weather setup for south alabama?

Question

We are in a slight risk area with moderate probably 100-150 miles to our north. NOAA says 30% storms today 40% storms (poss severe) tonight after 1 a.m., and 50% (poss severe) for Sunday. Weather Channel says 30% (poss severe) today 30% tonight, and 40% for sunday (poss severe). Why are the percentages so low when there is so much talk about the system that will be headed this way? What does the setup look like for severe weather in Southeast Alabama?

Answer 1

Well there could be several reasons.

The most likely reason your chances may be so low is because there's enough warm air aloft (or a cap in place) that prevents the widespread development of nasty thunderstorms. However, they can't rule out a few severe cells popping up and reaching your location given the ample instability and wind shear in place.

Now that the cap has disappated, the best jet stream energy is across northern alabama and there isn't any well defined convergence or forcing zone in the southern portion of the state (the front is stalled out in northern Alabama).

This is a forecast discussion from the NWS in Mobile, Alabama

"LATEST SFC MAP SHOWS A WEAK FRONTAL

BOUNDARY STRETCHING WEST FROM N GA TO N AL INTO N MS. TO THE SOUTH

HIGH PRESSURE WAS CENTERED NEAR S FL STRETCHING WNW OVER MUCH OF THE

EASTERN AND NORTH CENTRAL GULF INCLUDING MUCH OF THE SOUTHERN HALF

OF THE CWFA. THIS PATTERN WILL CONTINUE TO KEEP BETTER RAIN CHANCES

MOSTLY OVER THE NORTHERN HALF OF THE AREA...WITH THE THREAT OF

SEVERE WEATHER DEVELOPING WITH SOME OF THE STRONGER THUNDERSTORMS

OVER NORTHERN SECTIONS OF THE AREA BEGINNING LATER THIS AFTERNOON

CONTINUING THROUGH MUCH OF THE EVENING...THEN SHIFTING SOUTHWARD

TOWARDS THE COAST EARLY SUNDAY MORNING THROUGH EARLY SUN AFTERNOON."

"DUE TO LESS HEATING AND INSTABILITY THUNDERSTORMS SHOULD BE SLIGHTLY

WEAKER DURING THE OVERNIGHT HOURS."

Answer 2

I looked over the models and it looks like it will be a close call for your area in southern AL tonight. I believe that the bulk of the storms shall remain to your north. However, the chance does exist for some storms to develop over your region. Models suggest that a line of thunderstorms will try to move over your area sometime overnight and into tomorrow morning.

The exact positioning of these storms is almost impossible to predict. All I can tell you is that you should keep watching the Weather Channel or the NWS/SPC websites for continued updates. Have a plan in place on what to do just in case. The areas that can be affected today and tomorrow are rather large. Moisture is more than enough in S.AL, instability is there, wind shear profiles look favorable for rotating storms tonight and later on tomorrow.

I will contact you with any new information I receive.