Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 240517 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 1217 AM CDT TUE MAY 24 2016 .SHORT TERM...(tonight through Thursday) Issued at 322 PM CDT Mon May 23 2016 Forecaster uncertainty remains high as several disturbances drift into the region through the holiday weekend. It is hard to find any 12 hour period that has little to no chance of thunderstorms. Initial wave of weak convection has pushed through the CWA and second wave is beginning to show itself along a very weak low level boundary. A weak shortwave currently over southwest Nebraska will continue to drift northeast and approach the area. A very moist boundary layer in addition to daytime heating has allowed an instability axis to extend across the CWA with MUCAPE around 2000J/KG. Despite weak low level convergence, 40-45kts of deep layer shear could be enough to sustain an isolated severe threat for hail/wind. Also have a report west of our CWA of a brief landspout tornado along this weak boundary. High-res CAMs continue isolated convection along this area of weak convergence and then transition it into an MCS across southeast Nebraska through the evening hours. Much of Tuesday morning looks dry but pops are reintroduced again Tuesday afternoon as a low pressure trough continues to deepen across the central High Plains with continued southwesterly mid level flow over our region. This will send a couple of shortwaves into the area during peak heating where a continued very moist and increasingly unstable airmass resides. Better focus for deeper convection will be across the Nebraska panhandle in association with a stronger shortwave trough. This activity could maintain itself and spread east into Wednesday morning but many uncertainties remain. PW`s remain very high and heavy rain continues to be a threat. .LONG TERM...(Thursday night through Monday) Issued at 322 PM CDT Mon May 23 2016 Forecast uncertainty remains high through the long term period as we move into the holiday weekend. By Thursday night the primary mid level shortwave axis will extend across eastern Colorado and drift northeast across central Nebraska Thursday or Friday with the 12Z operational ECMWF timing a bit slower than the 12z operational GFS. In any case, lee side cyclone will deepen over eastern Colorado with a northeastward extending warm front draping across the CWA Thursday night into Friday. Instability ahead of this wave will be very high and could lead to a fairly good shot for severe wx if timing all works out. Sporadic chances for scattered convection will continue through Memorial Day weekend as several embedded shortwaves move through southwesterly flow into the region. && .AVIATION...(06Z TAFS for KOMA...KLNK...KOFK through 06Z Wednesday) Issued at 1214 AM CDT Tue May 24 2016 Thunderstorms will move east of KOMA and KLNK TAF sites early in the period. Then a period of VFR conditions will occur before MVFR cigs/vsbys overspread KLNK/KOMA...with some brief IFR vsbys in fog possible between 10Z and 15Z. KOFK will likely see IFR vsbys in fog during that time as well. Expect vsbys and cigs to improve to VFR during 15Z to 18Z timeframe. The attention turns to the potential for thunderstorms again Tuesday afternoon or evening. There is some question exactly when storms will fire near TAF sites, with the most likely time after 00Z. && .OAX Watches/Warnings/Advisories... NE...None. IA...None. && $$ SHORT TERM...Kern LONG TERM...Kern AVIATION...Dergan is the U.S. government's official web portal to all federal, state and local government web resources and services.