It is time for another Storm Prediction Center Outlook (SPC). The SPC Outlook post is designed to show where and when severe weather may occur over the next week, in a broad, synoptic sense.
Day 1: Today, The SPC has issued a Marginal Risk for parts of the Gulf Coast. Associated with the Marginal Risk is a 2% Tornado Threat Ring.
A surface low pressure system is moving north from southeastern Louisiana into southern Mississippi and Alabama, though it continues to weaken. The warm sector of this system is full of clouds and rain, limiting the 0-3 km lapse rates and the Convective Available Potential Energy (CAPE). Some boundary layer destabilization is possible in the area of maximum shear, thus the threat of tornadoes. This threat will diminish through this evening as the low pressure system weakens and the shear decreases.
Day 2: The SPC has issued no risks for organized severe weather on Tuesday. At this time, the low pressure system in the deep south is expected to diminish, though a second, independent low is expected to form farther north. Model guidance suggests that several upper-level shortwaves will combine into one deeper trough that will encompass the middle third of the country. However, there is some divergence in model output with regards to timing and location of this feature. The probability of severe storms is limited.
Day 3: The SPC has issued a Marginal Risk for the area surrounding the West Virginia and Ohio border. As the trough forms, a strong jetstreak (100 kts) will quickly move through this area. As it does, it will pass through an area of stronger diurnal heating, adequate moisture and 30-40 kt deep-layer shear already in place. This will make severe storms possible. The largest threat is from wind damage and severe wind gusts.
Day 4-8: There is a mix of “Potential Too Low” days and “Predictability Too Low” days during this time period. There is a lot of model divergence associated with the upper-level trough, and so its location and placement will determine the severe threats.
Overall, I think the best potential for storms this week will be winding down this evening, though a few convective bands of severe, or near-severe-limit storms are possible on Wednesday.
Thank you for reading this post.
All data and images are from the Storm Prediction Center Website.