textproduct: Wilmington

WHAT HAS CHANGED

Severe threat increased on Saturday afternoon and evening.

KEY MESSAGES

1) Warm, humid, and breezy conditions with scattered showers and some thunderstorms through Saturday. Severe storm threat has increased

2) Cold front crosses Saturday night and changes wx pattern to cool and dry through the remainder of the forecast, with frost possible Sunday, Monday, and Tuesday nights.

DISCUSSION

KEY MESSAGE 1) Weakening disturbance will shift through the Ohio Valley early this morning. With the presence of a low level jet, a few wind gusts of 30-40 mph could mix down in the showers. However, the predominant wind will be southerly at 10-15 mph.

Another shortwave will lay out across the CWA through this afternoon. With some heating and persistent moisture, scattered showers and storms will develop throughout the day... especially during the afternoon.

The main mid-level trough will lift from the northern plains into the Upper Midwest on Saturday. Ahead of the wave, our area will be entirely warm sectored. At this juncture, it appears poor mid-level lapse rates (4.9 C/km 700-500mb on the 00Z HRRR) will limit instability to around 1000J. However, with effective bulk shear of nearly 40 knots and decent forcing along and ahead of the cold front, storms will likely become organized with severe storms possible Saturday afternoon into the evening.

KEY MESSAGE 2) Much cooler air pushes in behind the cold front from Sunday into the middle of next week. Frost potential Sunday, Monday, and Tuesday nights will be largely dependent on both surface winds and sky cover each night. Overall, the cold night of the period will likely be Tuesday night with the center of surface high pressure shifting across the Great Lakes.

AVIATION /12Z FRIDAY THROUGH TUESDAY/

Scattered showers and a few thunderstorms will develop this morning across ILN and the Cincinnati terminals, then slowly shift to the north across DAY and the Columbus terminals this afternoon. Southwesterly winds will continue to occasionally gust to 20-25 knots through much of the day before slacking off a bit this evening. Next disturbance will approach from the west on Saturday, bringing another round of LLWS to close the CVG extended TAF period.

OUTLOOK...Periodic showers with MVFR conditions are likely Saturday night behind a line of thunderstorms coincident with a frontal passage.

ILN WATCHES/WARNINGS/ADVISORIES

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