Forecast Courtesy of: Chloe
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Tuesday, May 7th
Current guidance have downtrended slightly since earlier model trends, which produces some uncertainty on placement and timing. However, the trough ejection will make potential disturbances that may increase severe weather potential, with one area being over the ArkLaTex, and another one into the Ohio and Tennessee Valleys. Current ensemble guidance suggests that the potential is there for some widespread severe weather, spanning from northeast Texas to the lower/middle Ohio Valley on Tuesday into Tuesday night. This will still provide ample moisture, with dewpoints in the mid/upper 60s to lower/middle 70s.
However, 12z and 18z runs of the GFS suggested a trough ejection over Missouri/Illinois, which may bring potential severe weather across the Midwest and Ohio Valley, with another shortwave embedded into this trough on Tuesday, producing potentially a bimodal severe threat (1. ArkLaTex, 2. Ohio Valley/Midwest). Strong instability and strong shear combinations are evident across much of the Midwest and Ohio Valley, which may enhance the severe potential a tad bit. There still remains uncertainty with timing and placement of greater severe potential, so will have to monitor closely. There still remains some pretty widespread severe weather, with some significant severe weather in some places, but uncertainty remains on where this will occur at this time.
Wednesday, May 8th
Over the last day or two, model guidance have since corrected itself with Wednesday, and it provides another general reload of troughing, providing ample moisture, with dewpoints in the upper 60s to middle 70s degrees F. Strong instability and strong shear will also be present during this timeframe. Recent deterministic model guidance suggested strong instability with 2500-4000 J/kg being present across much of the Midwest and Ohio Valley, with even higher instability values (4000-6000 J/kg in the south [Texas/southern Plains]). The strongest shear will be near a low, that may form from OK/TX and move into MO/IL, providing a strong low-level jet that may develop sometime Wednesday afternoon/evening across the lower Ohio Valley. Strong shear may also be across the Midwest and Ohio Valleys aswell, given the low pressure system on newer model guidance.
The greatest confidence of any severe weather potential is over the Midwest and Ohio/Tennessee Valleys, with even the potential for a all-hazard severe weather event. Across Texas and southern Plains, all hazards will be possible, with hail the primary hazard across that region. There is somewhat increased confidence that Wednesday may be a big day across the Ohio Valley and Midwest, but we will have to monitor that over the next couple of days, pending short-range and medium-range models. The Storm Prediction Center may even expand the 15% originally added earlier (5/3/2024 at 4AM outlook), to include much of the Ohio and Tennessee Valleys due to increased confidence of severe thunderstorms. Will update this as we get much closer to Wednesday.