textproduct: Wilmington

WHAT HAS CHANGED

In collaboration with surrounding offices and WPC, high temperatures for Saturday through Tuesday continue to be adjusted down from the NBM.

KEY MESSAGES

1) Unsettled weather is expected this weekend with showers and thunderstorms occurring across the region. A warm front shifts north on Sunday providing drier conditions on Monday. The next cold front approaches the region Tuesday.

2) Above normal temperatures are forecast Sunday through Tuesday before a cold front moves Wednesday or Wednesday night.

DISCUSSION

KEY MESSAGE 1)

Westerly flow aloft with favorable moisture advection and WAA ahead of an approaching trough due to a southerly low level jet. This will lead to shower and thunderstorm development this morning. Forecast soundings show that this convection will be elevated with a good low level inversion in place. Moderate instability and favorable elevated lapse rates >7 deg C/KM may lead to some strong to severe storms. Analogs point to this potential for hail.

Confidence continues to be high for higher chances for rain, but more uncertainty develops as we head into this afternoon and evening. A weak disturbance in the mid- level flow could provide better forcing for portions of northern Kentucky and southwest/southern Ohio during the late morning and early afternoon hours. Model solutions showing moderate CAPE with effective shear of 25-30 kts. The exact placement of this second round of storms is still uncertain but the most favored region looks to be along and south of the Ohio River. Strong to damaging winds and large hail will be the main threats. Trends will be closely monitored during the late afternoon and early evening for the placement of this second round of thunderstorms. Also, PWATs increase to 1.3 to 1.5 inches with the highest axis along and south of the Ohio River. HREF localized probability matched mean indicating that some swaths of 2 to 3 inches of rainfall are possible if training occurs. The most favored location for this locally heavy rain is across northern Kentucky.

The warm front will be the focus for any lingering showers and thunderstorms into the day on Sunday. After that, the warm front lifting north will provide a break in the rainfall for Monday ahead of the next cold front system. Can not rule out isold late afternoon and evening hours on Monday due to the heat and moisture in the region.

Confidence is increasing across the models solution with a cold frontal passage Wednesday.

KEY MESSAGE 2) Temperature

A period of well above normal temperatures will persist until a cold front approaches moves thru the region Wednesday. Sunday through Tuesday, temperatures range from the mid to upper 80s and into the lower 90s, especially on Monday. With a slower frontal passage Tuesday could also remain quite warm. The temperatures on Wednesday are mitigated by the presence of the front, along with any showers and thunderstorms.

Cooler temperatures are then forecast Thursday and Friday in the wake of the front.

AVIATION /10Z SATURDAY THROUGH WEDNESDAY/

Scattered showers and thunderstorms will move across the TAF sites with the first wave of convection between 14Z and 18Z. Have prevailing showers with tempo or prob30 for TSRA at times where probability of thunderstorms is a little higher. Additional shower and thunderstorm activity is expected to develop this aftn into this evening but more uncertainty exists regarding specific location. The most favored location for this second round looks to be across the southern TAF sites where a mention of thunder continues in the forecast until 03Z.

Clouds look to remain prevailing VFR with brief periods of MVFR possible during storms thru the day. There is a signal for lower ceilings developing across the north tonight. Confidence is moderate with MVFR ceilings developing at KCMH and KLCK tonight. Have included a period of MVFR ceilings thru 08Z.

Southwest winds will gust to around 25 kts through the day today and then drop to 10 kts or less tonight.

OUTLOOK...Thunderstorm on Tuesday and Wednesday.

ILN WATCHES/WARNINGS/ADVISORIES

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