textproduct: Wilmington

WHAT HAS CHANGED

Discussed the signal for a hot and humid pattern next week.

KEY MESSAGES

1) A chance for showers and thunderstorms will return late Friday night and continue through the weekend.

2) Hot and humid air mass settles in next week, which may result in episodic showers and storms.

DISCUSSION

KEY MESSAGE 1) Several CAMs show a decaying line of convection moving in from the northwest Friday night. The trends appear to favor a later onset of any residual pcpn, which may arrive in our counties a couple hours before daybreak Saturday. Limited (if any) thunderstorm activity expected with this weakening complex. Best chances for thunder will be NW of I-71 corridor.

The early morning showers/storms may play a role in the severe risk Saturday afternoon/evening, but that will be dependent upon coverage and overall intensity of early morning convection. Several models are still showing a good rebound in atmospheric instability given the influx of higher dewpoints. SBCAPE values could certainly increase above 1000 J/kg. However, wind shear still remains a limiting factor, minimizing overall storm organization and likely keeping severe potential isolated based on latest guidance. Damaging straight-line winds and large hail would be the primary severe threats.

Cold front will continue to sink southward Saturday night, which will keep showers/storms in the forecast. In fact, guidance suggests this boundary may stall out just south of the Ohio River on Sunday, which would keep PoPs in the forecast for portions of southern Ohio into Kentucky.

KEY MESSAGE 2) The synoptic pattern next week is quite chaotic with meridional flow over the CONUS. Global models continue to develop an H5 ridge over the Ohio Valley early next week. Previous model runs kept this ridge fairly broad/expansive across the eastern CONUS, but latest trends suggest this ridge will be a lot more narrow. Given the modification of this ridge, a negatively tilted trough will be on the western periphery of our CWA. The H5 ridge will allow for a tropical-like air mass to build in, resulting in hot and humid conditions. The nearby trough will provide upper level support for development of showers and storms given the unstable air mass. While not every day is expected to be a washout, several days may have at least of chance for pcpn if this pattern holds. Ultimately, the extent of the ridge and proximity of the trough will be the driving force of our weather through at least the middle of next week.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

VFR conditions persist. Only exception is at KLUK as the air mass turns more humid and winds will be nearly calm overnight, which could promote some patchy valley fog. Maintained just an MVFR vsby reduction there based on latest guidance.

Surface winds increase after daybreak Friday, with sustained southwesterly winds of 10-15 kts and gusts up to 20-25 kts. Expecting more cu development as well on Friday.

OUTLOOK...Thunderstorms possible both Saturday and Sunday.

ILN WATCHES/WARNINGS/ADVISORIES

OH...Air Quality Alert until midnight EDT tonight for OHZ042-043-051-053- 060>062-070-071-077-078. KY...Air Quality Alert until midnight EDT tonight for KYZ091>093. IN...Air Quality Alert until midnight EDT tonight for INZ050-058-059-066- 073>075-080.