textproduct: Wilmington

WHAT HAS CHANGED

No significant changes.

KEY MESSAGES

1) Showers and thunderstorms will occur later this evening into the overnight ahead of a cold front. A few strong to severe storms will be possible late this evening and into the overnight hours.

2) A low pressure system will move through the Ohio Valley Tuesday night, bringing additional showers and thunderstorms. A drier and cooler airmass will then settle into the region for the rest of the week.

DISCUSSION

KEY MESSAGE 1) Ongoing periods of showers and thunderstorms are expected west of the area throughout the day today ahead of an approaching shortwave. Ahead of this activity, deep-layer moisture is still quite limited across the local area, inhibiting the potential for rainfall until later this evening. There remain model differences on the exact timing of the rainfall, with some CAM solutions attempting to bring remnant periods of rainfall from weakening thunderstorms which developed overnight. Therefore, some low PoPs are present in the forecast as early as 4 to 5 pm. However, confidence is high that the main push of moderate rain and thunderstorms would be later in the evening after the new afternoon development across Illinois and Indiana moves east.

The severe threat for this event continues to be uncertain, as boundary layer temperatures and moisture are not supportive of high values of instability. Instead, organized thunderstorm line segment present within strong wind shear may support a threat of damaging winds. The highest threat is still confined to the portions of Indiana, southwest Ohio, and northern Kentucky. As of now, the arrival time of this threat across the area would be in the 11 PM to 3 AM time frame. As a reminder, some rain may arrive before 11 PM.

A locally heavy rainfall threat is expected west of the area, with effective moisture transport occurring into the late evening hours. If multiple bands of heavier thunderstorm (even if non-severe) rainfall rates can be maintained into the Ohio/Indiana border area, some localized flooding would be possible. For now, it appears the necessary rainfall rates would not persist long enough over the local area to cause a concern similar to locations to the west.

KEY MESSAGE 2) Tuesday morning appears to be mostly rain free as the bulk of the rain and thunderstorms will have dissipated or shifted east overnight. The cold front will then stall out across our area Tuesday afternoon, with some showers and a few thunderstorms developing along it. The lack of a stronger forcing mechanism likely keeps the coverage quite isolated. With the latest update from the SPC, the severe threat is trending lower for Tuesday afternoon.

Additional mid level energy will move into the lower Ohio Valley Tuesday evening, helping for a surface wave/low to develop along the frontal boundary. More widespread showers and thunderstorms will overspread the area Tuesday night into Wednesday morning in association with this feature.

Behind this system, drier and cooler air will move into the region for the second half of the week.

AVIATION /12Z MONDAY THROUGH FRIDAY/

Prevailing VFR through 04Z Tuesday. Light southeasterly flow will increase this afternoon with gusts between 20 and 25 knots.

Thunderstorm activity to the west moves toward the local TAF sites late this evening, primarily after 02Z. Weakening thunderstorms decreases the potential for thunderstorm activity, but some thunder mention may be needed depending on the eventual coverage. Even if thunderstorms do not directly impact the sites, embedded thunder is expected north of the primary thunderstorm activity. The persistent rain will help to produce MVFR CIGs, and IFR CIGs will be possible. For now, will maintain the mention of lower VIS due to stratiform rain shields and IFR CIGs to Prob30.

The shield or bands of stratiform rain quickly move through from west to east between 05Z-10Z. A cold front is still off to the west to start the day on Tuesday. The cold front slowly moves through the area with southerly and eventually southwesterly flow forecast Tuesday morning and afternoon. Some widely scattered showers are possible, but coverage is too low to include in the extended CVG TAF.

OUTLOOK....Additional thunderstorms are possible Tuesday night through Wednesday morning. MVFR ceilings are possible at times Tuesday into Wednesday.

ILN WATCHES/WARNINGS/ADVISORIES

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