textproduct: Wilmington

WHAT HAS CHANGED

Issued a Flood Watch for late tonight through Wednesday evening for most of the area.

KEY MESSAGES

1) Several rounds of showers and embedded thunderstorms are expected through Wednesday. Locally heavy rainfall will be possible later tonight and Wednesday.

2) Near normal temperatures expected into the weekend.

DISCUSSION

KEY MESSAGE 1) A warm front currently situated across the Tennessee Valley will lift north into our area later tonight and into the day on Wednesday. Waves of weak low pressure riding east along the front will lead to several rounds of showers and embedded thunderstorms.

The initial round of showers is lifting slowly north across southern portions of our area attm. These showers will continue to push slowly north through mid afternoon before weakening/dissipating heading into this evening.

A strengthening 20-40 knot low level jet will shift north toward the Ohio River through tonight before shunting off to our east through Wednesday morning. This will allow for increasing moisture transport up into our area through tonight with PWs pushing up into the 1.8 to possibly 2 inch range. Models are suggesting scattered to numerous showers and thunderstorms developing in the baroclinic zone to the north of the front later tonight into early Wednesday morning. Most of the models are focusing in on the I-70 corridor with this axis, although a couple of the hi-res models are a bit farther south toward the Ohio River. Where this axis of pcpn sets up, locally heavy rainfall will be possible given the high PWs and deeper warm layer cloud depths. With the ground moisture already running high, the potential for localized flash flooding will exist along this axis.

We will likely get into a lull in the pcpn from mid to late morning before the next wave brings another round of showers and thunderstorms for the afternoon into early evening hours. There is more of a spread between the models with where this will line up, ranging from anywhere along/just south of the I-70 corridor to down to along/south of the Ohio River. In the continued moist environment, locally heavy rainfall/flash flooding will again be possible with some of these storms.

While a lot of areas may receive an inch or less of rain from this event, there will exist at least a low end potential for some areas to receive localized amounts of several inches. Think the best chance for these higher amounts will be for areas between the I-70 corridor and the Ohio River. Farther south, there is more uncertainty with the overall Flash Flood threat, but given that soil moistures are already running high, decided to play it safe and include most of the rest of our area in the Flood Watch.

KEY MESSAGE 2) Surface high pressure will build south across the Great Lakes later this week and remain in place through the weekend. This will provide for dry and seasonable conditions.

AVIATION /00Z WEDNESDAY THROUGH SUNDAY/

A frontal boundary lifting north into the area overnight combined with a 25-30kt low level jet will lead to the development of showers and a few thunderstorms. This favored axis of precipitation will spread from south to north across the area late tonight into Wednesday morning.

As the airmass moistens up, MVFR to IFR cigs and vsbys will develop. The heaviest rain late tonight/early Wednesday is expected to affect the TAFs along the I-70 corridor, where the favored theta-e advection develops. There will be a decreasing trend in pcpn from mid to late morning but additional scattered showers and thunderstorms are expected to redevelop across the area during the afternoon. This pcpn will then end from northwest to southeast late in the day. MVFR to IFR cigs and MVFR vsbys will improve to VFR late in the TAF period.

OUTLOOK...No significant weather expected.

ILN WATCHES/WARNINGS/ADVISORIES

OH...Flood Watch from 2 AM EDT Wednesday through late Wednesday night for OHZ042>046-051>056-060>065-070>074-077>082-088. KY...Flood Watch from 2 AM EDT Wednesday through late Wednesday night for KYZ089>100. IN...Flood Watch from 2 AM EDT Wednesday through late Wednesday night for INZ050-058-059-066-073>075-080.