9/2 – Rob Knight’s “Cold Frontal Passage” Thursday Morning Forecast
A mid-level disturbance will dip southward over the frontal zone and this will start an initial round of scattered showers and thunderstorms in coastal MS counties through the late morning hours. The frontal zone will shift further southwest into southern Ms through the day, bringing scattered to numerous thunderstorms into the I-10 corridor this afternoon. Activity will persist into the evening south of I-10/I-12 as the front shifts toward the Gulf coast. A much drier airmass will make inroads behind the slowing front as it stalls along the coast or in the open Gulf waters late tonight.
There will be plenty of moisture available to for the potential for heavy rain with rates in the range of 2-3″ per hour. Ongoing flooding in the wake of Ida may exacerbated by activity this afternoon. In addition to heavy rain and frequent lightning, dry air aloft, will increase the potential for strong downbursts.
Despite the passing of the front, there will not be any noticeable cool off with highs staying in the upper 80s to low 90s through the weekend. Slightly drier air will help lower heat index values to the upper 90s to near 100 each afternoon. An influx of moisture is likely early next week, if not already beginning by Sunday, as a frontal system to the northwest approaches the forecast area.