Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 291814 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 214 PM EDT SUN MAY 29 2016 .SYNOPSIS... A weak cold front will move through the region tonight, providing a chance of showers and thunderstorms. High pressure will move in on Monday, with drier conditions expected through the middle of the week. Another cold front will approach the region on Thursday, bringing the next chance for precipitation. && .NEAR TERM /UNTIL 10 PM THIS EVENING/... With only some light showers remaining in the eastern sections of the forecast area, attention will turn to the approaching cold front just to the west. The front appears roughly coincident with a wide band of enhanced cumulus on visible satellite imagery. Current surface observations indicate that the front currently extends from around Lansing MI to Bloomington IN. There is a very slight wind shift (210-220 degrees to 240-250 degrees) and a notable change in dewpoints (upper 60s to lower 60s), but temperatures are virtually identical on either side of the boundary. With these parameters in mind, and knowing that the front is not moving quickly, it is apparent that frontal forcing is not going to be especially strong. Nonetheless, the first convective cells have begun to develop, and this activity is expected to grow during the next few hours. High-resolution computer model forecasts have, across-the-board, been too fast in generating convection today. This suggests their instability forecasts may have been aggressive. A modified 12Z KILN sounding with current conditions produces MLCAPE of around 1500 J/kg, which is close to current LAPS analysis values (with higher values approaching 2000 J/Kg just ahead of the front in eastern Indiana). Surface-based parcels may be able to add another 500 J/kg on top of that, and perhaps more importantly, SPC mesoanalysis and the aforementioned modified sounding both support values of DCAPE of 600-1000 J/kg. This means that where convection does develop and become mature, it will likely be deep, and will have the potential for strong to possibly severe winds. However, weak forcing and shear (0-6km bulk shear of only around 20 knots) will make it very difficult for storms to become organized. Thus, any severe threat will likely be more pulse-type than based on updraft longevity, but a marginal risk of severe winds and hail still appears a possibility. Storm chances will be highest in the western half of the CWA between 18Z-21Z, and will then move to the east between 21Z-01Z, gradually diminishing after peak heating has been passed. Dry and mostly clear conditions are expected for the entire forecast area after 03Z, as the slightly drier air mass behind the front advects into the area. With less moisture in the boundary layer, min temps will get to around 60 degrees in the northwestern CWA, with lower 60s elsewhere. && .SHORT TERM /10 PM THIS EVENING THROUGH TUESDAY/... The short term forecast discussion will be updated soon. Previous Discussion > High pressure will build into the region during this time frame. Dew points will lower slightly. And this will allow for somewhat cooler night time temperatures. But highs will still be in the lower to mid 80s with readings a bit warmer Tuesday compared to Monday. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... The long term forecast discussion will be updated soon. Previous Discussion > High pressure east of the region at the beginning of the period should still keep dry and warm conditions in place. A cold front will move in from the west on Thursday bringing the next chance of showers and thunderstorms. 00Z guidance in reasonable agreement that this front will move east of the area Thursday night. Meanwhile upper low will close off along the Texas coast. So the threat of precipitation being drawn back into the southeast counties has diminished. Temperatures will fall slightly below normal late in the week as high pressure builds in. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... Shower development is expected to coalesce into a line of thunderstorms ahead of the passage of a cold front this evening. H5 trough in the Upper Midwest will pivot northeastward into the Great Lakes early this afternoon. Showers that develop in the warm sector ahead of the cold frontal passage will deepen with the heating of the day, and as the front approaches later today there may be enough low level shear available for a line of storms to develop and propagate eastward in the late day and early evening. skies will be VFR until storms roll through. Gusty winds and mvfr vsbys are expected in thunderstorms but timing cannot be gleaned at this moment. Will have to wait until the expected line develops and extrapolate positioning and timing with any amendments this afternoon. Sky cover will rapidly improve this evening in favor of generally clear skies overnight. Some fair wx cu may sprout in the drier if not cooler air behind the front tomorrow. OUTLOOK...Showers and thunderstorms are possible Thursday. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Hatzos NEAR TERM...Hatzos SHORT TERM... LONG TERM... AVIATION...Franks/Novak is the U.S. government's official web portal to all federal, state and local government web resources and services.