Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 261946 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 246 PM CDT Fri May 26 2017 .SHORT TERM...(Tonight through Monday) Issued at 245 PM CDT Fri May 26 2017 The main forecast problems are in regards to thunderstorm chances from late tonight through Saturday evening, along with potential for severe storms. Water vapor satellite imagery showed the weak feature that moved through the area last night and early this morning was moving into northern Illinois early this afternoon. Meanwhile, of more concern is a closed low over eastern Idaho, which is embedded in a trough that extended from Saskatchewan and Manitoba down into Nevada. That low should become more of an open wave overnight, then that will move eastward through the local area Saturday night. Forcing is expected to be strongest in our area during the day Saturday. Storms that initially develop out over the High Plains this afternoon will move eastward overnight. Latest consensus from the convection allowing models (CAMs) is that precipitation will stay west of our area through 1 am cdt tonight, but may start to approach Highway 81 by 4 am cdt, and may affect the western half of the forecast area by 7-8 am cdt. Focus of the low level jet stays well to the west, so the chance of severe storms overnight looks low. Severe threat on Saturday will be higher to our south/southeast across Missouri, but we could see some strong to severe storms in southeast Nebraska and parts of southwest Iowa. 0-6 km bulk shear values are 30-50 knots and MU CAPE values are 2000-3500 J/KG much of the afternoon. Will mention some severe storms possible in the HWO. It looks like some showers/weaker thunderstorms may linger into the mid or possibly late evening, then end by midnight. That then sets us up for a mainly dry forecast (at least for now) for the Sunday and Monday periods. Temperatures should be cooler on Saturday, compared to today, ranging from mid to upper 60s in northeast Nebraska to mid and upper 70s near the Missouri and Kansas borders. Highs Sunday and Monday should reach the 70s. .LONG TERM...(Monday night through Friday) Issued at 245 PM CDT Fri May 26 2017 The 500 mb pattern will be quite amplified at the start of the period, with a ridge over the western parts of the CONUS and Canada. A closed low will be over or just north of Lake Superior and our area should be in modest to strong northwest flow. This should dampen out during the week, while a closed low tracks from the Pacific into the four corners region. Rain chances in our area look highest from Wednesday night into Thursday, but confidence on timing of showers and storms next week is only moderate. Highs will be mostly in the 70s, with lows from the upper 40s to upper 50s. && .AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon) Issued at 1236 PM CDT Fri May 26 2017 VFR conditions will prevail through much of the period. Convection is expected to develop again over the western High Plains region after 21Z as upper trough approaches the central Rockies. This complex will then spread east through 12Z with periods of MVFR cigs and vsbys in showers and storms possible from 12Z to 18Z at TAF sites. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ SHORT TERM...Miller LONG TERM...Miller AVIATION...Fobert

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