Area Forecast Discussion
Issued by NWS Wilmington, OH

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810 FXUS61 KILN 210611 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 211 AM EDT Thu Sep 21 2017 .SYNOPSIS...
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A stagnant weather pattern will set up over the next several days, with mid-level ridging over the region. Warm temperatures 10 to 15 degrees above normal will continue through the weekend.
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&& .NEAR TERM /THROUGH TODAY/... A stray shower or two may still pop up over the CWA for the next few hours as a high moisture content airmass continues to interact with a departing upper level shortwave. Any cells that might pop will not be deep enough to support thunderstorm activity and thunder has been removed from the forecast with a weak 20% coverage added to mainly the southeastern quarter of the CWA. Did not change the fog forecast tonight given the unusually moist air over the region. Fog potential is the greatest concern for tonight, with a favorable setup in the wind and pressure pattern (overall light flow with the main axis of the boundary-layer ridging just to the east). Where skies clear out, conditions will be favorable for fog to become locally dense, especially in river valleys or more broadly in the eastern half of the forecast area. && .SHORT TERM /TONIGHT THROUGH 6 PM FRIDAY/... The stagnant weather pattern will essentially remain in place on Thursday, with broad mid-level ridging extending from the Great Lakes into the middle Mississippi Valley, and an elongated surface high centered well northeast of the Ohio Valley region. Thursday appears to set up as another day with light wind flow and some chance of afternoon instability, which has resulted in some inconsistent/weak QPF output across the suite of models. Looking at soundings, there will be some warming of temperatures in the 800mb-750mb layer between Wednesday and Thursday, which will make it less likely for any precipitation to develop. The chance certainly isn`t zero percent, but appears small or isolated enough to not include in the main forecast. Temperatures should be able to rise by a few degrees for both Thursday and Thursday night. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Strong H5 ridge will be the dominant feature for much of the forecast period. The ridge will keep Jose off the East Coast and away from the Ohio Valley, and later on Maria. Meanwhile at the surface, a surface high centered over the St. Lawrence Valley will extend southwest into the fa. The combination of these two features will bring dry condition and above normal temperatures through the weekend and into early next week. High temperatures will be about 10 degrees above normal values through Tuesday as they push into the mid and upper 80s. Morning lows be around 60. By Wednesday a cold front will be moving east up the Ohio Valley. It will bring some scattered convection. The GFS is a little quicker than the ECMWF and Canadian with the front. Have included 20 PoPs in the wrn half of the fa for Wednesday. Highs Wednesday will still be around 80 degrees. && .AVIATION /06Z THURSDAY THROUGH MONDAY/...
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Mid level ridge to build from the Lower MS VLY through the Eastern Great Lakes. Surface high pressure will remain centered just to our east over the Upper Ohio Valley. Subsidence over the area has led to clear skies. The clear skies, light winds and a moist boundary layer is creating favorable conditions for fog development, mainly in river valleys. Have IFR VSBY restrictions at favored KLUK and KILN with mainly MVFR restrictions at remainder of the TAF sites. Moisture is shallow, so the fog will burn off quickly after sunrise. Expect some scattered cu development along with high level clouds from upstream convection. Radiation fog development likely again tonight with IFR restrictions limited to the favored valley location at KLUK. Through 06Z have limited the restriction to the MVFR category. OUTLOOK...No significant weather is expected at this time.
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&& .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Hatzos NEAR TERM...Franks SHORT TERM...Hatzos LONG TERM...Sites AVIATION...AR

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