textproduct: Wilmington

WHAT HAS CHANGED

There is a chance for showers and storms this evening mainly west of I-75.

KEY MESSAGES

1) Showers and thunderstorms are possible this evening into the overnight.

2) Hot and humid conditions are expected Wednesday and Thursday.

3) A cold front will move through the area on Friday bringing the chance for severe storms on Friday. Cooler, drier air works in for the weekend.

DISCUSSION

KEY MESSAGE 1) A cluster of showers and thunderstorms will remain mainly to the south of the area this afternoon. Skies to the north of this cluster are likely to continue to scatter and allow off and on sun through the rest of the afternoon. Temperatures should rise into the lower 80s.

The forecast becomes a bit more uncertain later. Showers and thunderstorms are possible this evening/early overnight along and west of I-75 as a weak upper level shortwave trough moves in. However, confidence in these storms is fairly low since CAMs show a range of widespread storms to no storms at all.

Later overnight, mesoscale guidance continues to show the forecast area mostly drying out and an axis of heavier rain setting up to the southwest. Given the clustering of guidance keeping the heavier rain out of the area and fairly dry antecedent conditions, the flood watch remains to the south and west. Lows only drop into the lower 70s.

KEY MESSAGE 2) Persistent southerly low level flow stretching to the Gulf remains in place on Wednesday and Thursday. Low level moisture is continuously advected to the Ohio Valley allowing dew points to reach into the lower and middle 70s. Afternoon temperatures are also forecast to top out in the upper 80s both afternoons which supports the heat index reaching into the upper 90s to near 100 across the area. Forecast lows offer little relief only dropping into lower and middle 70s Wednesday and Thursday nights.

There is a chance that some patchy, brief relief from the heat could occur if diurnal thunderstorms develop each afternoon. However, with lack of forcing, storm coverage may remain low.

KEY MESSAGE 3) A surface low forms in Canada on Friday in response to a trough ejecting east out of the northern Plains. A trailing cold front attached to the low progresses through the Ohio Valley on Friday. The timing of frontal passage will be important for our area since showers and storms are likely to form ahead of the front Friday afternoon. Some of the showers and storms could be severe since instability and shear are forecast to be sufficient for storm organization. Currently, it appears that the front may be at least partially through the area by Friday afternoon which supports better severe chances along and southeast of I-71.

Behind the front, shower and storms chances end. Drier and slightly cooler air arrives behind the front for the weekend and into early next week.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

Visible satellite and surface observations depict ceilings lifting and scattering across the area this afternoon north of a cluster of thunderstorms over Kentucky. VFR conditions may persist once ceilings scatter into at least the early evening hours. After 0000z, a shortwave trough moves into the area and could lead to some new showers and thunderstorms at Dayton and the Cincinnati sites this evening. As the overnight progresses, ceilings are likely to lower into the MVFR category with some IFR ceilings possible. Ceilings eventually scatter with diurnal mixing on Wednesday. An isolated shower or storm cannot be ruled out Wednesday afternoon, but probabilities are far too low to include in the TAFs.

Southwesterly winds become weak overnight before strengthening once again Wednesday afternoon.

OUTLOOK... Off and on showers and storms remain in the forecast through Friday.

ILN WATCHES/WARNINGS/ADVISORIES

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