Jackson MS (JAN) — the National Weather Service forecast in plain English · Plaincast

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A limited threat for dangerous heat stress will continue across much of the area through Saturday. Heat stress will increase heading into early next week.

Discussion

Through Saturday: A disturbance/MCV lifting northward from the Gulf Coast will serve as a forcing mechanism for scattered to numerous showers and thunderstorms today, with scattered light showers already ongoing across portions of central and southeast MS early this morning. At the same time, an upper shortwave will shift from the Ozarks into the Mid South today, providing another focus for development over the northwestern portion of the area. Though there will be some morning activity, convective coverage will still primarily be diurnally modulated. Though a few showers may linger into the evening. A belt of marginally stronger upper flow will pass across north MS in association with the shortwave today, and high res guidance does suggest a few strong storms are possible in that area, though any threat looks to remain mostly north of our area. The coastal disturbance will shift east of the area tonight. Meanwhile the trailing portion of the Mid South upper shortwave will linger into Saturday, meaning scattered afternoon and early evening convection is expected again, but coverage should be lesser than today.

With increasing low level moisture, heat stress will become more of a factor over the next few days. For today and Saturday, it appears increased clouds/precipitation will preclude the need for an advisory, though a few spots may still approach or briefly reach advisory thresholds at times. We will maintain a limited heat stress threat outlook during this time frame.

Sunday through next Friday: Upper ridging will build back in across much of the Southeastern CONUS early next week, resulting in a return to higher heat with lower daily rain chances more typical of summer. With a muggy airmass still in place, heat indices may begin rising to critical thresholds each day. Interestingly, the higher heat indices during this period will be driven more by higher temperatures, as dewpoints mix down into the upper 60s in many areas during the day. We will highlight an elevated heat stress threat for much of the area, and heat advisories may ultimately be needed.

Over the second half of the week, there are signs the position of the surface ridge will begin to bring some heat stress relief. There is increasing guidance consensus in drier easterly surface flow wedging around the Appalachians and toward our area as early as Wednesday or Thursday. The eastern half of the area has the highest chance of being a beneficiary of this regime, so it may still be quite hot from the MS River west. We'll keep our fingers crossed for any potential break from this muggy weather. /DL/