BGP Severe Weather Alert Day 7/9/24

**nWo** · July 9, 2024

Today, Beryl's remains will traverse the mid-Mississippi and lower Ohio Valleys. Surface dewpoint temperatures will be in the lower to mid-70s Fahrenheit ahead of the corresponding surface low. By afternoon, pockets of moderate instability are predicted to form south of a warm front that is expected to pass parts of Kentucky in reaction to surface heating. A broken line of storms is expected to develop and proceed across the lower Ohio Valley in an east-northeast direction, according to most model forecasts.

It is probable that the storms will be situated on this feature's northeastern border. Prediction soundings from Paducah to Louisville in the early to mid-afternoon are expected to rise. It will be advantageous for tornadoes with rotating cells to form in Beryl's residual rainband, particularly when the storms interact with a warm front close to the Ohio River. The hours between 2 p.m. to 8 p.m. EDT are predicted to be the most dangerous for tornadoes. The low-level jet for today is a little weaker and farther to the west than where convective development is predicted by the models compared to yesterday. This raises questions about how big the tornado potential is today.

The area that is most favorable for possible tornado development has been extended northeastward to include portions of the Cincinnati/NKY area. With the increased severe threat the Storm Prediction Center has issued a level 2 Slight Risk area for portions of Kentucky.

**nWo** · July 9, 2024

I just received an email from the NWS-Louisville office.

Quote

Good morning,

The remnants of Hurricane Beryl will move across the Ohio Valley today into tonight. This afternoon and evening, strong to severe thunderstorms will develop over western Kentucky, moving toward the I-65 corridor during the early-to-mid evening hours.

The Storm Prediction Center has continued with a Level 2 out of 5 risk for severe weather across all of southern Indiana and portions of Kentucky along and west of I-65 (map included below). Damaging winds and brief tornadoes will be the primary severe threats, and localized flooding will be possible where the heaviest rain rates occur. The severe threat should subside by around midnight tonight.

As always, feel free to reach out to us if you have any questions.

Regards,
-NWS Louisville

**nWo** · July 9, 2024

The Storm Prediction Center has upgraded the threat to level 3 Enhanced Risk for sections of Kentucky and southern Indiana. Cities included in Indiana, Evansville, New Albany, and Jeffersonville. Owensboro is the only major city, but Louisville should be included, in my opinion.

Despite considerable cloud cover this morning, significant cloud breaks south of the warm front, and pockets of heating will destabilize the airmass from the mid-MS Valley to the OH Valley.

Today, Beryl's remains will traverse the mid-Mississippi and lower Ohio Valleys. Morning surface study leads to a reservoir of lower 70s deg F dewpoints from the IN/OH/KY tri-state south/southwest into the Mid South ahead of the related surface low. A warm frontal zone may be seen stretching east-northeast from the low-surface streamlines. By mid-afternoon, the warm front will have moved north to a location close to the OH River, where it will likely concentrate into a severe thunderstorm potential.

This morning's water-vapor picture reveals a developing mid-level shed. The airmass from the mid-MS Valley to the OH Valley will become unstable due to pockets of warmth and major cloud breaches south of the warm front, even if there is a lot of cloud cover this morning. In the area of the warm front and to its south, over portions of KY and TN, moderate buoyancy is expected to develop. A few convective bands are predicted to preferentially favor storm development today, a theory that is corroborated by morning observational patterns. It is predicted that a moderately unstable airmass ) will give rise to widely dispersed to scattered thunderstorms. One or more bands of quasi-discrete supercells are forecast with tornado potential greatest in a southwest to northeast corridor paralleling the Ohio River this afternoon into the evening.

**nWo** · July 9, 2024

There's a conference call this morning at 11:30.

**nWo** · July 9, 2024

From the conference call:

The main reason the threat level was raised was because of the tornado threat. The thinking is that there could be several tornadoes this afternoon. They could be fast-moving, similar to those on July 4, meaning there could be little or no warning. So everyone should be weather-aware this afternoon. Also for heavy rains and flash flooding. The best time for a severe threat is between 3 and 11 pm EDT.