Area Forecast Discussion

WHAT HAS CHANGED

No significant changes.

KEY MESSAGES

1) Showers and thunderstorms will be possible this afternoon and evening. Some storms could have strong to damaging winds.

2) Additional rounds of showers and thunderstorms will occur through Sunday night with a potential for heavy rain.

3) Cooler and showery weather will occur for the first half of the week.

DISCUSSION

KEY MESSAGE 1)

Low level clouds are breaking up from the southwest as low level flow veers southerly and favorable theta-e advection develops. This return flow of moisture will provide an axis of lower 70 dewpoints and moderate instability. An outflow boundary tracking across east Indiana will be the focus for convective development this afternoon. Effective shear is limited to around 20 kts so do not expect great organization to storms. DCAPE values around 1000 J/KG point to the potential for strong to isolated damaging winds. Machine learning guidance continues to be focused on the Tri-State region for strong to damaging winds. PWAT values approach 2 inches, so heavy rain could produce heavy rain, but storms should be progressive enough to keep any flooding localized. Will continue to message these threats with the timing between 3 pm over our west to 7 pm across the southeast.

KEY MESSAGE 2)

Active westerly zonal flow will remain across the region through the rest of the weekend. The primary activity tonight looks to be across northern Indiana and northern Ohio, but the southern periphery of this convective activity may affect our northern counties. In the moist airmass with efficient warm rain processes, heavy rain will be possible but the progressive nature of the storms looks to limit the flood potential.

Weak surface low pressure and a cold front moves across the ILN/s area Sunday afternoon and evening. Another round of showers and thunderstorms will occur along and north of the front. PWATs up to 2 inches and warm cloud depth will keep the threat for heavy rain the forecast. Greatest potential for heavy rain looks to be across the I-70 corridor Sunday night with HREF showing a signal for potential 3 hour totals exceeding 3 inches.

KEY MESSAGE 3)

In the wake of the front, a cooler airmass will prevail over the area next week. A mid level low closes off and slowly works its way east across the region through mid week. This will result in periods of showers and maybe some embedded thunderstorms. High temperatures for the period Tuesday thru Friday look to be mainly in the lower 70s.

AVIATION /18Z SATURDAY THROUGH THURSDAY/

Low level clouds are breaking up from the southwest as low level flow veers southerly and favorable theta-e advection develops. This return flow of moisture will provide moderate instability which interacts with an outflow boundary to bring a period of showers and thunderstorms to the TAF sites this afternoon into very early evening. These storms will move across the area thru 00Z. After the storms, mid and high level clouds will linger. Another disturbance passing north of the area could bring some showers to the the central Ohio TAF sites overnight. Have limited this mention to a PROB30 of showers.

As low pressure and a cold front tracks thru the area additional showers and thunderstorms are expected Sunday afternoon. Have a mention at the end of the 30 hour KCVG TAF.

OUTLOOK...Thunderstorms possible Sunday afternoon and evening. MVFR to IFR ceilings and visibilities possible Sunday night through Tuesday.

ILN WATCHES / WARNINGS / ADVISORIES

OH...None. KY...None. IN...None.