textproduct: Wilmington

WHAT HAS CHANGED

No significant changes.

KEY MESSAGES

1) Cooler temperatures through Tuesday.

2) A series of low pressure systems moving across the Great Lakes will bring chances for showers and thunderstorms Tuesday night and then again Wednesday night into Thursday.

DISCUSSION

KEY MESSAGE 1)

High pressure moves across the region today and tonight bringing fair weather and below average temperatures. The surface high moves off to the southeast by Tuesday morning. Southerly flow redevelops on the back side of the high leading to warmer temperatures later on Tuesday.

KEY MESSAGE 2)

Two low pressure systems bring chances for showers and storms across the Ohio Valley for the middle of this week. The first low forms on Tuesday in response to an upper level shortwave trough. A weak, trailing cold front south of the first low moves into the Ohio Valley Tuesday afternoon and evening. Showers and storms are possible east of the boundary. The best chance for greater storm coverage and stronger storms is northwest of I-71 Tuesday afternoon and evening in response to better forcing and and stronger shear. Strong straight line winds are the main threat with these storms.

A second low pressure system moves through the Great Lakes on Wednesday and Thursday. Medium range guidance continues to depict this low being anomalously deep for mid June along with strong upper level support. This strong low has the potential to lead to impactful weather across the Ohio Valley in the form of severe weather, localized flash flooding, and gusty winds.

On Wednesday afternoon/evening, the deepening low enters the Great Lakes region and lifts a warm front into the Ohio Valley. Very strong shear and strung out hodographs are forecast to be in place while destabilization occurs during the afternoon and evening hours. If storms do end up forming along the warm front and in the warm sector Wednesday afternoon and into Wednesday night, any mode of severe weather is possible. Additionally, localized flash flooding could occur as PWATs in excess of 2+ inches are likely by Wednesday night. The storm threat persists through the overnight hours in the warm sector. At this time, it is not clear yet if storms will occur and take advantage of the forecast environment. This leans towards the severe threat being conditional on storm occurrence.

Late Wednesday night or some point on Thursday, a cold front on the back side of the strong low pushes south through the Ohio Valley. Showers and storms are possible ahead of this front although details remain uncertain. Some models continue to show sufficient shear, instability, and PWATs in place to support a severe and flooding risk until FROPA occurs. However, this is all contingent on track of the low, positions of frontal boundaries, and antecedent convection. Regardless of the exact details that need to be worked out, gusty winds can be expected on Thursday in the pressure gradient around the deep low.

AVIATION /00Z TUESDAY THROUGH SATURDAY/

VFR conditions are expected through the TAF period. Some river valley fog will be possible at KLUK.

On Tuesday, southwest winds will increase to around 10 knots, with some 15-20 knot gusts possible. Late in the day some showers and thunderstorms will be possible as well, but confidence in coverage is low, so will only include a PROB30 for showers at KDAY (prior to 00Z) and at KCVG (after 00Z) for now.

OUTLOOK...Showers and thunderstorms are possible Tuesday evening. Thunderstorms and gusty winds are expected at times Wednesday afternoon through Thursday afternoon.

ILN WATCHES/WARNINGS/ADVISORIES

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