textproduct: Wilmington

WHAT HAS CHANGED

Increased wind gusts for Tuesday, with very breezy conditions expected through the daytime.

KEY MESSAGES

1) Very breezy conditions are expected on Tuesday, particularly during the afternoon. Gusts of 40 to 45 MPH are likely near and north of the I-71 corridor. Secure loose outdoors items.

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

DISCUSSION

KEY MESSAGE 1)

WNW flow aloft will be maintained across the region today, with a chance for a few spotty showers or sprinkles this morning into early afternoon across SE and NE parts of the ILN FA. Most areas will remain dry, but some low-end PoPs will be maintained for the potential for some ISO showers in parts of the area through today. Highs will top out a few degrees either side of the 70-degree mark, even with fairly expansive cloud cover through most of the day.

Flow will become more zonal tonight into Tuesday as a weak S/W pivots E through the nrn OH Vly into the Great Lakes region, with a sfc wave ejecting E through these areas during the afternoon. This will place the ILN FA squarely in an expanding warm sector, with a tight pressure gradient on the SE flank. This will lead to very breezy conditions amidst diurnally-enhanced mixing Tuesday afternoon. An H8 LLJ on the order of about 40kts will develop from SW to NE through the OH Vly during the day Tuesday, particularly from IL/IN into nrn OH. Although the vertical mixing won't be particularly deep, we should be able to mix down 30-35kt winds near/NW of the I-71 corridor Tuesday afternoon. Although max gusts may get close to advisory-level (40kts) in a very isolated fashion, do think that the setup will stay mainly sub-advisory for most of the ILN FA. Nevertheless, gusts of 30-35kts are expected across a large portion of the local area Tuesday afternoon, with mainly dry conditions persisting through the daytime.

KEY MESSAGE 2)

An active weather pattern will develop by midweek and beyond as persistent SW flow aloft becomes 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 region, 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 Wednesday morning, with a weakening trend with this activity with SE extent later into the overnight. This will occur with an increasingly-stable environment entrenched across the area late Tuesday night, with the primary focus for lift near the sagging front. Most areas near/SE of I-71 may stay dry into early Wednesday morning, with decreasing disorganized convection lingering in the NW third of the local area by daybreak Wednesday.

By Wednesday afternoon/evening, digging S/W energy into the central plains will promote height rises downstream into the OH/TN Vlys. This will allow the LL front to stall, or even pivot back to the N, during the daytime Wednesday. Although there will be some LL convergence along the front (which may be draped squarely across the heart of the local area by midday), the focus for lift will be fairly weak, with only spotty ISO/SCT showers/storms between the OH Rvr and I-70 during the daytime. Pcpn chances/amounts will be highest in the N/NW third of the ILN FA from Tuesday evening through Wednesday night, even with some ISO/SCT showers/storms during the day Wednesday across central/southern parts of the local area.

The more-amplified S/W will pivot into the OH Vly Thursday night into early Friday, with downstream ridging expanding in response to the approach of this feature. Shower/storm activity will likely increase into the local area Thursday night into early Friday, with the system gradually flattening with eastward extent. This suggests that the forcing should decrease a bit later into the night, so there are uncertainties regarding the maintenance of convective coverage further E into the local area into Friday morning.

Another (stronger) system will impact the region Saturday into Saturday night before drier conditions return by Sunday. At this juncture, it seems the best potential for widespread 1-3" of rain from late Tuesday through this weekend will be centered across NW parts of the local area, but there are still quite a few details to be determined regarding the evolution of the several rounds of convection during this stretch.

Although the specifics of this pattern Saturday evening/night are far from certain at this juncture, it will need to be watched carefully for severe storm potential. Additionally, 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. So certainly some flooding potential may evolve as well late week into this weekend , owing to the repeated rounds of showers/storms (even with the relatively-progressive nature of the individual systems).

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. Some 80s are possible Tuesday, Thursday, Friday, and Saturday.

AVIATION /06Z MONDAY THROUGH FRIDAY/

VFR conditions are likely for the start of the period, although some borderline MVFR/VFR CIGs should develop around daybreak and persist into early afternoon. Confidence on persistence of the MVFR CIGs into early afternoon is still somewhat low, but certainly this cannot be ruled out, particularly at KDAY/KILN/KCMH/KLCK. Some ISO/spotty SHRA cannot be ruled out between about 08z-14z, but do think that coverage should be relatively low, with minimal impacts to CIGs or VSBY.

Increasing SW flow will lead to SW LLWS on the order of 40-45kts through the predawn hours. At the sfc, SW winds around 10-12kts will continue through mid morning before increasing to 15-18kts, with gusts around 25kts, for the afternoon.

OUTLOOK...Gusty winds in excess of 30 knots are likely on Tuesday. Periodic thunderstorms are possible Wednesday through Friday. MVFR conditions are possible at times Wednesday through Friday.

ILN WATCHES/WARNINGS/ADVISORIES

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