Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 221744 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 144 PM EDT Sat Apr 22 2017 .SYNOPSIS... As an area of upper level low pressure moves into the southeastern states, cool conditions are expected over the Ohio Valley today, warming slightly on Sunday. A continued warming trend is expected going into the new week, with drier and sunnier conditions on Monday and Tuesday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... An initial wave of pcpn is affecting primarily our far southern areas this morning. This will continue to shift off to the east through late morning, leading to a break in the pcpn across our south. However, another wave of pcpn is pushing quickly east across southern Illinois and southern Indiana attm and this is forecast to move back into across our southern areas for later this morning and into this afternoon. The latest HRRR may be struggling somewhat with how to handle this second wave though. Some light returns are showing up quite a bit farther north across central Illinois and into central Indiana than what is being forecast. A lot of this is probably not reaching the ground but suppose a few sprinkles cannot be ruled out. As a result, will allow for chance pops to spread back into our southern areas and linger a 20 pop a little farther north to account for some of these weaker returns. Temperatures will likely only rebound a few degrees today in continued cool northeasterly low level flow. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... Elongated surface high pressure is expected to position itself from Iowa to Lake Erie tonight, as surface low pressure begins to develop in the deep south. A gradient will thus exist between very different air masses -- warmer and wetter in the southern Appalachians, and cool and dry in the northern Ohio Valley and southern Great Lakes. Outside of the chance of a few light showers in the far southern ILN CWA, most of the forecast area should be well within the drier air mass, with clearing skies tonight. Persistent NE flow will keep radiational cooling conditions from becoming ideal, limiting the chances for frost, even as temperatures may get close to 40 degrees by Sunday morning. This pattern will change very little on Sunday, as the main driver of the scenario -- the mid-level low in the southeastern states -- will not be moving very fast. By Sunday afternoon, there may be just enough 850mb-700mb moisture wrapping NW/W into the forecast area to allow for a few showers in the southeastern third of the CWA. That will present another day with an unusual temperature gradient, as temperatures will likely be warmest in the NW CWA, where mostly clear conditions are expected. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Upper level low will slowly move southeast from the Tennessee River Valley to the southeast United States coastline Sunday night into Monday. As this occurs, the threat for showers will end across the southeast CWFA while clearing takes place there as well. More sunshine and airmass modification will boost temperatures into the upper 60s to the lower 70s on Monday, which isn`t too far from normal. For the period Monday night into Tuesday, upper level low will push northeast near the coastline of the Carolinas. We will see weak high pressure across our region. With another day of airmass modification and developing southerly flow, highs will warm into the mid and upper 70s. For the period Tuesday night into Wednesday night, weak ridging shifts east, along a frontal system to push east/southeast through the region. This will bring the next chance of showers and thunderstorms. Thursday may end up being dry in the wake of the front. However, the frontal boundary is expected to lift north as a warm front Thursday night into Friday as upper level flow begins to amplify. This will bring another chance of showers and thunderstorms, particularly for western locations. Discrepancies occur in the long range models as we head into Friday. The ECMWF wants to push another frontal system into the region while the GFS dries the Ohio Valley out in the wake of the warm front. It does not bring the next frontal system into the region until next Saturday. Have decided to keep forecast dry given stark differences. Temperatures will be warm by the end of the week with lower to mid 80s forecast. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/...
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The second wave of pcpn is continuing to overspread southern portions of our fa but much of it does not seem to be reaching the ground. As a result, will continue with just some VCSH coverage in the first few hours of the TAFS for KLUK/KCVG. Cigs are primarily VFR although we have seen some brief periods of MVFR from time to time and this will continue to be possible through at least mid afternoon. Otherwise, the models continue to trend farther south with additional pcpn later tonight and into the day on Sunday. Will keep the TAFs dry through the remainder of the period with VFR conditions expected. OUTLOOK...No significant weather expected.
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&& .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Hatzos NEAR TERM...JGL SHORT TERM...Hatzos LONG TERM...Hickman AVIATION...JGL

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