textproduct: Wilmington

WHAT HAS CHANGED

Lowered surface dew points Sunday afternoon with diurnally-enhanced mixing. Increased wind gusts for Monday and Tuesday.

KEY MESSAGES

1) Quiet weather will persist through Monday, with breezy conditions expected both this afternoon and Monday afternoon.

2) A warmer and more active weather pattern will evolve by late Tuesday and beyond, with several rounds of showers and storms expected from midweek into next weekend.

DISCUSSION

KEY MESSAGE 1)

NW flow aloft will be maintained across the OH Vly through Monday, with sfc high pressure drifting to the E, allowing for return/SW sfc flow to become re-established. Temps will trend above normal today through Monday with this steady SW flow across the region. Temps will top out in the lower to mid 60s today before dipping into the lower to mid 50s tonight. Even with increased cloud cover and some spotty SHRA and/or sprinkles late tonight through early Monday, temps will still reach into the lower 70s by late afternoon area-wide. The best coverage of ISO/SCT SHRA late tonight into early Monday is likely to be focused near/SE of the I-71 corridor between midnight and mid morning.

KEY MESSAGE 2)

An active weather pattern will develop by midweek and beyond as persistent SW flow aloft become established from the south-central plains into the OH Vly. This conveyor belt of warmer/moisture-rich air will overspread the area late Tuesday into Wednesday. Even by early Tuesday morning, however, rain will likely develop in a W-E corridor near a tightening warm front across the Great Lakes and nrn OH Vly regions, just north of the immediate local area. A weak sfc wave will translate to the E across the Great Lakes during the day Tuesday, with an attendant cold front draped back to the SW, which will sag into the ILN FA late Tuesday night into Wednesday. Shower and thunderstorm coverage will increase across far NW parts of the ILN FA late Tuesday evening into early Monday morning, with a weakening trend with this activity with SE extent later into the overnight. The better forcing and more-defined S/W will move through very late Wednesday into early Friday, with a LL baroclinic boundary oscillating about the region during this time.

While the placement of the front and associated sfc low at any one particular time from Wednesday through Friday is far from certain, the overall pattern, characterized by PWat anomalies on the order of 200+% of seasonal norms, alongside an oscillating LL front, which will provide a focus for lift, and periodic large-scale ascent courtesy of the stronger S/W and height falls which will overspread the OH Vly by Thursday, will be watched carefully for episodes of both excessive rainfall and severe storm potential. In fact, ensemble guidance supports the front continuing to pivot about the region even through most of this upcoming weekend, suggesting that multiple rounds of showers and storms are likely from midweek through at least Saturday. There is a strong signal from both the ensemble and AI guidance to suggest widespread rainfall on the order of 1-3+" during this time across a large portion of the OH Vly. This pattern, owing to convective influences, may produce isolated higher amounts in some locations by the time drier air finally makes a return in a post-frontal environment perhaps by late Sunday.

The specifics of this pattern are far from certain at this juncture, but it will need to be watched carefully for periodic/episodic heavy rain and severe storm potential. Any prolonged PW anomaly of 200+% with a parade of S/Ws through this moisture-rich environment is cause for at least some concern, especially after a fairly wet March (rainfall 150%-200% of normal) across most of the local area.

As the weather undergoes a pattern change, above normal temps are likely midweek and beyond, with highs in the 70s and lows in the 50s for most of the week from Tuesday onward.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

VFR conditions will continue through the period, with an increase in mid/high clouds during the daytime. Light SE flow early will increase to around 12-15kts out of the SW during the daytime, gusting around 20kts at times for the afternoon. SW LLWS on the order of 40-45kts is likely to develop by 04z across the region before tapering off between 09z-12z.

Some ISO/patchy SHRA will develop between 06z-11z, primarily near KCMH/KLCK. A PROB30 has been added at these sites to account for this potential. Suppose a stray sprinkle or light SHRA will be possible at KILN as well.

OUTLOOK...Gusty winds in excess of 30 knots are likely on Tuesday. Periodic thunderstorms are possible Wednesday through Thursday. Some brief MVFR CIGs may be possible Monday. Additional MVFR conditions are possible Wednesday through Thursday.

ILN WATCHES/WARNINGS/ADVISORIES

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