Issued: 8pm on Sunday, June 29th 2025
Technical Forecast Discussion
Short-Term Forecast (Sunday 06/29/2025 through Tuesday 07/01/2025):
The short-term period will be dominated by the gradual eastward progression of an upper-level ridge currently centered over the Central Plains. This ridge will expand across the Ohio Valley, promoting a generally subsident and stable environment through the end of the week. At the surface, high pressure over the southeastern U.S. will maintain a persistent southwesterly flow, allowing warm and moist air to remain in place across the region. With little synoptic lift and a warming column aloft, convective development will be largely suppressed Thursday and Friday, though weak diurnal instability and residual surface moisture may be sufficient for isolated pulse-type storms, especially along terrain-induced boundaries or differential heating zones. By Saturday, subtle height falls associated with a northern stream shortwave traversing the Great Lakes may begin to erode the ridge slightly, allowing a weak frontal boundary to approach from the northwest. While the core of this feature will remain displaced to the north, its presence may lead to a slight uptick in afternoon convective potential. However, deep-layer shear will remain minimal, suggesting that any storms that do develop will remain disorganized and short-lived. Overall, the pattern will continue to support hot and humid conditions, with limited relief due to weak nocturnal mixing and high overnight dewpoints.
Long-Term Forecast (Wednesday 07/02/2025 through Saturday 07/05/2025):
The long-term pattern shows signs of more active weather as a series of northern stream disturbances begin to undercut the weakening ridge and enhance mid-level flow across the Ohio Valley. Ensemble guidance indicates the potential for a more defined trough axis to push into the eastern Great Lakes and Upper Ohio Valley Sunday into Monday, bringing with it an attendant cold front. This feature may bring scattered showers and thunderstorms to the area, particularly Sunday afternoon and evening, with better organized convection possible given increased shear and moisture convergence along the boundary. By Tuesday, surface high pressure looks to build back in from the northwest in the wake of the front, promoting a period of drier and slightly cooler conditions. Upper-level heights will rebound briefly, but not to the extent seen earlier in the period, suggesting a more zonal flow pattern taking hold. Wednesday should feature mostly sunny skies and more seasonable humidity levels as the cooler airmass settles in. Confidence is moderate in this transition, but timing and strength of the frontal passage will need to be monitored for potential adjustment in storm coverage and temperature trends early in the period.
