Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 241116 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 616 AM CDT Sat Jun 24 2017 .SHORT TERM...(Today through Monday) Issued at 321 AM CDT Sat Jun 24 2017 A dry and mild weekend will remain in the forecast, with rain chances returning later Sunday night and Monday. Northwest flow aloft will continue in the Plains until Monday as mean trough position lingers in the Great Lakes area. A couple of shortwaves are forecast to drop through that flow. The first will dive southeast across Minnesota and Wisconsin today, triggering scattered afternoon showers as far southeast as central Iowa. Affects here should be limited to afternoon cumulus and gusty northwest winds in our north and east, then a reinforcement of cooler airmass as cool advection follows shortwave for later tonight and Sunday. Thus highs today may be a few degrees higher than Sunday, but still looking at max temps in the 70s for the most part each day. The second shortwave of note is forecast to spread vorticity channel under 90-100kt upper level jet into eastern Nebraska late Sunday night into Monday morning. Moisture will remain somewhat limited before this time, but a modest increase is forecast by GFS and Canadian models in the 850 to 700mb layer. Increasing forcing under jet combined with increasing moisture suggests at least a few showers will develop after midnight Sunday night and continue into Monday evening before jet tracks to the east. GFS is a bit more aggressive with moisture return and thus instability. Have sided more with Canadian in regards to instability, so expect only isolated areas of thunder potential. .LONG TERM...(Monday night through Friday) Issued at 321 AM CDT Sat Jun 24 2017 Things get a little more interesting next week with mid level ridging briefly building into the Plains before more zonal configuration sets in Wednesday and Thursday. By Friday, flow begins to buckle somewhat as upper low settles southeast into the southern Canadian Plains, suggesting at least shallow troughing in our part of the CONUS. The first chance for convection in this scenario will be Tuesday as warm/moist advection occurs under building ridge. This should affect areas mainly to our west, but there is a chance storms could skirt western and northern sections of eastern Nebraska. Mid level shortwave quickly moves into the Plains Tuesday night, effectively breaking down short-lived ridging, and likely triggering convection over much of our area as robust theta-e advection occurs on increasing low level jet. A weak frontal boundary will follow shortwave and settle across eastern Nebraska and western Iowa, then remain in our area through Thursday and offering low level focus for convection those days. While the exact configuration of frontal boundaries and thus instability maxima will have to be determined as we get closer to mid week, a good majority of longer-term model solutions show 2000-3500 J/kg of MLCAPE and strong shear, with Thursday offering the highest numbers on both parameters, and thus the greatest threat of severe convection. By Friday, it appears surface front will be south of our area, but potentially close enough to keep thunder chances in our south. && .AVIATION...(For the 12Z TAFS through 12Z Sunday morning) Issued at 610 AM CDT Sat Jun 24 2017 VFR conditions will prevail thru the fcst pd. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ SHORT TERM...Dergan LONG TERM...Dergan AVIATION...DEE

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