Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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093 FXUS63 KOAX 261220 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 720 AM CDT THU MAY 26 2016 .SHORT TERM...(today through Saturday) Issued at 431 AM CDT Thu May 26 2016 ...enhanced risk of severe storms today and tonight... rather complex forecast setting up for today and tonight with a substantial risk of severe weather. Apologize for the delay of the discussion, but got a late start on the forecast due to severe earlier convection that produced large hail and wind gusts up to 58 mph. These initial storms have pushed east of the area as the weak upper level impulse moves into the Mississippi river valley. A weak surface trough made a push into the forecast area, and it may still remain across western portions of MN into northeast NE, but really this feature will probably become very diffuse in our area today. Meanwhile, an 08z subjective analysis indicated the surface low remained across the OK panhandle, with a stationary/pseudo warm front extending east northeast into northeast KS and northern MO. Convection continues to bubble up along the eastern edge of the boundary taking advantage of the southern end of the aforementioned upper wave. it`s important to say that the various high-res CAMs all offer varying solutions today of the eventual placement of any severe clusters, which makes the forecast even more difficult. There is one weak upper wave moving through western NE early this morning. This is generating mostly showers, although there is a lightning strike showing up in the most recent imagery. This may bring a slight chance of thundershowers along/north of I80 this morning, but these would not be severe. The CAMs do suggest that convection could develop by 13-14z along the boundary to our south, which then begin to lift north through mid morning. There is a risk that some of these could bubble up enough to produce some hail in southeast NE 14-16z, and could become stronger and potentially severe by 16-18z taking advantage of the building instability with daytime heating. surface dewpoints were in the mid 50s to lower 60s, but should recover into the mid to upper 60s, which will couple with h85 dewpoints of 12 to 14 degrees. if this earlier convection develops as forecast, then it could have an impact on later convection in the area as well, and could delay an onset of the second round until later in the evening. although, the gfs allows the warm front to move a little further north, which develops additional convection in the platte river valley during the afternoon, again making the forecast very challenging pinpoint the details. SPC has placed the southern 2/3 of the forecast area in an enhanced risk of severe storms, with all modes of weather possible, including a 15% probability of damaging winds, a 30% probability of very large hail, and a 10% probability of tornadoes. This is generally along and south of a line from Albion, NE to Harlan, IA. Given the proximity of the warm front with developing storms potentially along it, and environmental parameters of bulk shear of 40-50 knots, ample moisture, and very high instability, have no doubt we`ll eventually have a severe threat later today. As the front continues to lift northward overnight, will have a continued likely chance of storms moving through the area, but we may see a decreasing trend after midnight. Storm chances continue Friday into Saturday as the upper low slowly transitions through the region. Still a marginal risk of severe weather on Friday, but that threat shifts generally shifts east of the area by Saturday. .LONG TERM...(Saturday night through Wednesday) Issued at 431 AM CDT Thu May 26 2016 Opted for a dry Saturday night as I believe we could be in between systems. Rain chances increase again by Sunday and continue on and off through the end of the period. && .AVIATION...(12Z TAFS for KOMA...KLNK...KOFK through 12Z Friday) Issued at 708 AM CDT Thu May 26 2016 VFR conditions are forecast at KOMA...KOFK...and KLNK through 21-24Z. After this time frame, thunderstorm activity is expected to increase across eastern Nebraska, where there could be MVFR conditions in precipitation areas. After 27/09Z ceilings may become MVFR due to low clouds. Note:There is some uncertainty in the timing of thunderstorm activity and there is a possibility some storms may develop prior to the 21-24Z time frame. && .OAX Watches/Warnings/Advisories... NE...None. IA...None. && $$ SHORT TERM...dewald LONG TERM...dewald AVIATION...Smith

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