textproduct: Wilmington

WHAT HAS CHANGED

No significant changes.

KEY MESSAGES

1) A deep low pressure system brings the chance for severe thunderstorms, isolated flooding, and gusty winds this afternoon into Thursday. The most widespread severe storm risk will be tonight.

DISCUSSION

KEY MESSAGE 1)

Mid level short wave energy moving through the Great Lakes will lead to a developing surface low over the upper Mississippi Valley this morning. The low will then deepen through tonight as it pivots through the Great Lakes region overnight into early Thursday. A trailing cold front will push southeast across our area later tonight into Thursday morning. Ahead of the low, a 70 knot 850 mb jet will shift eastward across our area tonight, with good moisture advection up into the region and PWs increasing to around 2 inches or so.

Shower activity currently back across northern Iowa/southern Minnesota is forecast to continue to move southeast this morning and increase in coverage and intensity through early afternoon as the airmass destabilizes ahead of it. There are some model differences on just how far southeast this pcpn will make it through mid to late afternoon, with several of the CAMs trying to bring at least some of this pcpn into our northwest areas through late afternoon. Depending on how this plays out, this could affect the degree of instability present across our area later this afternoon into early evening. Nonetheless, the general trend is to allow for instabilities to nudge back up through this evening in developing low level theta e advection into our area. This should allow for more widespread showers and thunderstorms back to our northwest to push southeast across our area through the overnight hours. While damaging wind will be the main severe weather threat given the strong wind fields, impressive low level shear/hodographs will support a secondary threat for possible tornadoes and perhaps large hail. The highest severe threat will be along and northwest of the I-71 corridor, where the better instability/stronger forcing will exist.

The other concern will be locally heavy rainfall and the potential for flash flooding. As the storms congeal into more of a line of overnight, they should be somewhat progressive as they move through our area. However, given the high PWs, some localized rainfall amounts in excess of 2-3 inches will be possible with any training storms. There appears to be some signal in the HREF that the best chance for this would be across our far western/southwestern areas overnight.

Meanwhile, given the strengthening pressure gradient, gusty winds of 30-40 mph will also be possible outside of the storms tonight into Thursday.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/

High level clouds will be on the increase through late morning and into this afternoon as a thunderstorm complex currently over Iowa drops southeast toward our region through the day. Most of the model guidance has this feature weakening as it approaches from the northwest, but some remnant shower/thunderstorm activity may reach the TAF sites by late afternoon. The best chance for this will be at KDAY. Otherwise, additional showers and thunderstorms will develop off to our northwest this evening and then drop southeast across the area overnight ahead of an approaching cold front. Gusty winds, locally heavy rainfall and reduced visibilities will be likely with these storms as they move through overnight. Pcpn will taper off from the northwest later tonight into Thursday morning. There could be some brief periods of MVFR cigs once the front moves through late in the TAF period, but generally expect VFR cigs to prevail.

A tightening pressure gradient and strong low level jet will lead to gusty winds developing. Southwest winds will gust in the 25 to 35 knot range through tonight. Winds will become more westerly and remain gusty late tonight into Thursday as the front moves through. LLWS will also be possible tonight as a strong low level jet develops over the region.

OUTLOOK...Winds gusts at or above 30 kts possible Thursday.

ILN WATCHES/WARNINGS/ADVISORIES

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