textproduct: Wilmington

WHAT HAS CHANGED

No significant changes. Slight increase to rainfall north of I-70.

KEY MESSAGES

1) Near record warming today. Colder Friday and Saturday after cold frontal passage.

2) Thunderstorms associated with a cold front passage impact the area tonight. The potential exists for storms to become strong to severe exists. Also, a localized flood threat will exist, especially north of I-70.

DISCUSSION

KEY MESSAGE 1)

An initial round of showers and embedded thunderstorms that affected mainly southern portions of the area moved off to the southeast by mid morning.

In the warm sector most of ILN/s area stays dry until surface cold front slips into the north this evening. Southwesterly flow has increased with gusts up to 35 mph. Also, satellite imagery shows that clouds have given way to abundant sunshine. This combination will allow temperatures to approach or possibly exceed record highs.

The records for Thursday 3/26 CVG 82 set in 1907 DAY 81 set in 1907 CMH 80 set in 1907

The cold front exits the area early Friday with lingering rain showers ending through late morning. Much cooler temperatures settle into the area with highs on Friday are expected to range from the lower 40s north to the lower 50s south.

KEY MESSAGE 2)

Forecast soundings and satellite imagery show that ILN/s forecast area is currently capped in the warm sector. ILN will be putting up a special 20Z balloon release to sample boundary layer moisture.

Strong mid level westerly winds exist thru the Midwest and Great Lakes region. A mid level short wave will track quickly east- southeast offering high falls across the Great Lakes/Ohio Valley overnight.

A strong surface cold front will push south into ILN/s northern counties late this evening and then south of the area overnight. Model solutions continue to show this capping warm layer between 8H and 7H which will inhibit convective development in the warm sector for much of the daytime hours.

Therefore, expect convective activity to hold off until the strong low-level forcing arrives with the frontal boundary. ML guidance and analogs continue to point to the potential for severe weather with the storms tonight. Higher resolution models continue to show a weak surface wave tracking along the east-west boundary during the early evening (most likely just north of ILN/s FA). The best threat for potential tornadoes looks to occur across ILN/s northern counties early in the evening ahead of this wave - if convection were to develop a little south into the area.

Steep mid level lapse rates will be in place over the region, and this will aid destabilization, with moderate instability expected. Given the strong deep-layer flow, hodographs also are elongated/straight. Supercells producing large hail are possible, even with elevated convection to the cool side of the boundary. As we head into the later evening hours and overnight, the favored convective mode looks to evolve to line segments. Damaging winds will continue to be a threat. The storms weaken and severe threat diminishes as the storms and front shift south during the nighttime hours and approach the Ohio River.

PWAT values look to be in excess of 300 percent of normal tonight. Although the system is progressive and the front looks to sink south quickly, with the anomalously high PWATs, and mean flow parallel to the front, the potential exists for localized stripes of 2-3 inches of rainfall. HREF LPMM also backs this potential for 2 to 3 inch rainfall stripes, with the favored region north of I-70. Will continue to highlight this localized flood threat in the HWO.

AVIATION /00Z FRIDAY THROUGH TUESDAY/

Thunderstorms, likely severe, were progressing southeast into the forecast area at the start of the period. Most location were still waiting for the precipitation to arrive and were VFR, but with southwest winds gusting 25-30 kts. IFR or worse conditions were occurring in the storms, along with hail and likely high winds in the strongest storms. The precipitation will continue to spread south and east during the night. The storms are expected to weaken as they push farther south and approach the Ohio River overnight. Low end MVFR or IFR conditions are forecast to linger behind a cold front after the initial storms move through. Winds will shift to the north with frontal passage, but remain gusty.

Improvement back to VFR conditions is expected during the late morning and afternoon and Friday, with the gustiness of the winds also easing.

OUTLOOK...The next threat of inclement weather is on Monday and lasting into the week, with showers and thunderstorms possible at times.

ILN WATCHES/WARNINGS/ADVISORIES

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