Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 191733 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 133 PM EDT Wed Sep 19 2018 .SYNOPSIS... A weak front will bisect the region today and then lift back north tonight. A stronger cold front will cross the area Friday afternoon and evening. High pressure will build across the Great Lakes over the weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A few stray/spotty showers continue to weaken across south- central Ohio this morning with the associated band of mid clouds slowly progressing southeast. In its wake, mainly clear skies will overspread the local area through the late morning and early afternoon hours, including in the far northwest ILN FA where some low clouds continue to erode. Some diurnally-driven Cu development will occur near and after the noontime hour, with a very stray popup shower or storm possible during the middle and late afternoon across the central ILN FA. The coverage of this will remain extremely isolated even at its best, but felt it was prudent to maintain the slight chance PoP near and just north of the Ohio River during peak heating hours. With a gradual increase in sunshine through the late morning hours, temperatures will warm quite quickly through early afternoon. Temperatures near 90 degrees will be common once again this afternoon south of the I-70 corridor, especially in the absence of any widespread cloud of precipitation coverage. Near and north of I-70, temps will top out in the mid and upper 80s near and behind (north of) the weak surface boundary. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... Weak boundary across the area will lift north late tonight into Thursday morning. Cannot rule out a few showers and thunderstorms near this retreating front in the northwest counties. A weak disturbance riding along the periphery of a building mid level ridge could result in a few more storms later in the day. Given subtle forcing, confidence is low on precipitation occurring. Very warm temperatures will continue with lows tonight and highs Thursday being 10 to 15 degrees above normal. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Global models in generally good agreement with a deamplifying mid level ridge and broad shortwave across the upper great lakes bringing an intensifying shortwave and associated frontal boundary through the region by Friday evening. While overall bulk shear favorable for some storms containing damaging winds, instability will be somewhat marginal. Will continue to include mention of strong to isolated severe storms Friday afternoon through early evening. Increasing clouds and precipitation will bring the above normal temperatures back down to closer to seasonable values, and then seasonable lows in the mid 50s to low 60s with the passage of the frontal boundary Friday night. Both the deterministic GFS and ECMWF hanging up the frontal boundary in the Tennessee valley through the day on Saturday. There are still several members of the GEFS which linger the precipitation further north. Previous runs had been more consistent with lingering precipitation further north and affecting the far southern forecast area, but the trend with each run has been slightly south. Lingering frontal boundary and associated precipitation may more likely remain in central KY given the deterministic trends, but keeping slight chances for precipitation through Saturday very close to and south of the Ohio River. Seasonable temperatures with just the southern forecast area at risk for scattered to isolated showers and storms through the day on Sunday as a more zonal flow pattern sets up over the upper CONUS while the washed out frontal boundary lingers over the TN/southern OH valley. For Monday into Tuesday, a deepening trough over the upper plains combines with the lingering/flattened ridge over the SE CONUS to allow for a prolonged period of southwesterly flow and increased moisture into the forecast area. Differences between the ECMWF/GFS/GEFS with just how active the early part of next week will be. ECMWF more generous with the precipitation potential, whereas the GFS is more scattered. Given the favorable upper level pattern to a more prolonged period of precipitation potential with a slow moving trough and the lingering ridge in the SE CONUS, have raised chances for precipitation Monday into Tuesday. Near normal temperatures during this period in the upper 70s for highs and 50s/low 60s for lows with ample cloud cover and rainfall potential. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... Early morning VSBY restrictions and spotty -SHRA coverage has ended, yielding VFR and dry conditions for the local terminals. Although a very spotty afternoon/early evening -SHRA cannot be completely ruled out, particularly for KCVG, KLUK, and KILN, coverage will be sparse enough as to not include a VC at this time. FEW to SCT VFR Cu/stratocu will slowly be on the increase from the south/southwest after 06z, but should any CIGs develop, they are expected to remain VFR. With the skies not expected to be completely clear overnight, BR/FG development may end up being a bit more limited than would otherwise occur under clearer skies. However, still expect that KLUK could see IFR or lower VSBYs briefly in the several hour period around sunrise. Some brief MVFR VSBY restrictions may also occur at KLCK. Light and variable winds will transition to a steadier (albeit still light) easterly and eventually southeasterly surface flow late tonight into the early morning hours of Thursday. Southerly winds of around 5-8kts will develop towards the end of the period. OUTLOOK...Thunderstorms possible Friday afternoon into Friday night. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS... NEAR TERM...KC SHORT TERM... LONG TERM...JDR AVIATION...KC

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