Friday, March 14, 2025

Storm Prediction Center Day 2 Outlook (For Saturday)




SPC AC 140600


   Day 2 Convective Outlook  

   NWS Storm Prediction Center Norman OK

   0100 AM CDT Fri Mar 14 2025


   Valid 151200Z - 161200Z


   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF

   LOUISIANNA...MISSISSIPPI...ALABAMA AND THE FLORIDA PANHANDLE...


   ...SUMMARY...

   A tornado outbreak is possible on Saturday across the central Gulf

   Coast States and Deep South into the Tennessee Valley. Numerous

   significant tornadoes, and some long-track tornadoes are expected on

   Saturday afternoon and evening, centered on eastern Louisiana,

   Mississippi, and Alabama. Widespread damaging wind swaths and

   scattered large hail are likely.


   ...Tornado Outbreak Possible Across parts of the Southeast on

   Saturday...

   ...Gulf Coast States/Tennessee Valley/Southern

   Appalachians/Georgia...

   At mid-levels on Saturday, a strong and fast-moving jet streak will

   translate eastward across the southern U.S., as an associated trough

   moves through the Great Plains. Ahead of the system, a moist and

   unstable airmass will be in place across the lower to mid

   Mississippi Valley. Warming surface temperatures in the morning will

   contribute to the development of moderate instability across much of

   the moist airmass. As large-scale ascent increases ahead of the

   approaching jet streak, scattered thunderstorms are expected to

   initiate near the western edge of the moist airmass during the late

   morning, from eastern Louisiana into northwest Mississippi and

   western Tennessee. These storms should become severe rather quickly

   due large-scale forcing, moderate instability and strong deep-layer

   shear. Supercells with large hail, wind damage and a tornado threat

   are expected to develop and move east-northeastward during the

   afternoon across the central Gulf Coast States and Tennessee Valley.


   The exit region of the mid-level jet streak is forecast to move

   across the lower Mississippi Valley and Tennessee during the mid to

   late afternoon, which will be timed well with afternoon max heating.

   Forecast soundings at 21Z across parts of southern and central

   Mississippi have MLCAPE in the 2000 to 3500 J/kg range, with 0-6 km

   shear of 70 to 80 knots. 700-500 mb lapse rates are forecast to be

   near 8 C/km, with 0-3 km storm-relative helicity in the 400 to 500

   m2/s2 range. This will be very favorable for intense severe storms,

   with a threat for tornadoes, wind damage and large hail. Several

   tornadic supercells are expected to develop within this cluster by

   mid to late afternoon as the low-level jet intensifies. Multiple

   long-track high-end tornadoes will be possible. The greatest tornado

   threat is expected to shift into Alabama by early to mid evening,

   with a significant tornado threat also impacting parts of middle

   Tennessee. In addition, supercells are expected to grow upscale into

   a developing MCS, with potential to produce significant severe wind

   gusts above 70 knots and large hail. The severe threat is expected

   to develop eastward into parts of Georgia and the southern

   Appalachians by mid to late evening. A severe threat should continue

   into the overnight.


   ...Ohio Valley/Lower Great Lakes...

   A negatively-tilted mid-level trough will move into the western

   Great Lakes on Saturday, as the southern part of the trough moves

   into the mid to upper Mississippi Valley. Ahead of the system,

   southwest mid-level flow will be in place over most of the Great

   Lakes and Ohio Valley. At the start of the period, a corridor of

   rich low-level moisture is forecast from western Kentucky northward

   into Indiana. Surface dewpoints along this corridor will likely

   range from the mid 50s to the lower 60s F. Early in the period, a

   cluster of strong thunderstorms is forecast to move across the Ohio

   valley. Some of the storms could have severe potential. Wind damage,

   isolated large hail and a few tornadoes will be possible. In the

   wake of this activity, outflow could negatively affect the airmass

   over parts of the Ohio Valley. However, areas that are not affected

   by outflow could re-destabilize, maintaining a severe threat. As the

   exit region of a mid-level jet moves across the Ohio Valley and

   lower Great Lakes during the late afternoon, supercells will be

   possible due to the increasing large-scale ascent and strong

   deep-layer shear. Any supercell could have potential for tornadoes,

   wind damage and hail.


   ..Broyles.. 03/14/2025

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Storm Prediction Center Day 2 Outlook (For Saturday)

SPC AC 140600    Day 2 Convective Outlook      NWS Storm Prediction Center Norman OK    0100 AM CDT Fri Mar 14 2025    Valid 151200Z - 16120...