Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 172104 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 304 PM CST Tue Jan 17 2017 .SHORT TERM...(tonight through Friday) Issued at 302 PM CST Tue Jan 17 2017 Stratus deck is creeping eastward thorugh the day, with sunny skies behind it. Subjective 12Z upper-air analysis indicates upper-level trough responsible for the weekend weather now over ON/northern WI/MN, with trough axis extending back through NE/KS/CO/NM toward the Baja. Unusually warm 850mb temperatures continue across the central US, with most of the region outside of the northern Great Lakes above 0C, along with a finger of sub-0C temperatures from the TX panhandle west/northwestward. In fact, temperatures were as warm as nearly 12C in AB and 6C in MT. Surface ridge at 20Z was centered over the MO river near NE/IA and into eastern KS. Main forecast concern for the next few days is temperatures. Temperatures at 850mb will be around 5-10C on Wednesday, with the higher temperatures in the northwest CWA and lower in the southeast. Other than some melting that will still need to occur in both northeast NE and southeast NE, southwesterly low-level winds should aid mixing and allow temperatures to pop well into the 40s and possibly near 50. Continued low-level warm/moist air advection will bring enough moisture by Wednesday night to increase cloud cover, which then should dampen the diurnal swings through Friday; in fact, I suspect I have not quashed the diurnal swing quite enough yet. Models and model runs are hit and miss on having enough moisture on Thursday for drizzle, but they are rather consistent by Friday, and have kept slight change pops with drizzle mention for Thursday night and Friday. .LONG TERM...(Friday night through Tuesday) Issued at 302 PM CST Tue Jan 17 2017 A shortwave trough should eject across the central Plains on Friday night/Saturday, bringing higher precipitation chances in the form of rain, as temperatures remain warm with the system. A second and stronger upper-level low is then progged to kick across the southern Plains on Sunday. Its northward extend and impacts on this area are still in question, but if it does graze us, it is likely to also be in the form of a colder rain, as the moisture precedes the cold front coming through on Sunday night. Temperatures should return to near- to slightly above-normal readings in the upper 30s to lower 40s for the rest of the forecast period. GFS/ECMWF solutions are consistently indicating some kind of upper-level low and associated surface low moving across the central Plains on Tuesday night/Wednesday, bringing a swath of precipitation to the region that is most likely to be rain in the warm sector ahead of the low and snow and some wind behind it. Details are still very fuzzy for this time range, but it is a system that bears watching as it approaches. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon) Issued at 1116 AM CST Tue Jan 17 2017 An MVFR cloud deck at KOMA should scatter out by 19-20z. Otherwise VFR conditions until later in the night when some patchy fog could develop by 02-07z. Not confident enough to drop any location into to MVFR, but will go down to 6sm and see how this eventually develops. && .CLIMATE... Issued at 302 PM CST Tue Jan 17 2017 Something of a snow drought is in place across the area, despite above-normal precipitation. The total snowfall of 3.8 inches at Omaha Eppley is the 16th lowest year-to-date (since 1886). The total of 3.7 inches at Lincoln is the 6th lowest year-to-date (since 1948). The total of 8.4 inches at Norfolk is the 28th lowest (since 1921). All of these are for years with no missing data. The Accumulated Winter Season Severity Index (AWSSI) year-to-date is in the mild category at 193. This is the 8th lowest to date. Of the years ranked ahead of it, two went on to be ranked near average, and the other five are among the 10 mildest winters on record (since 1950-51). AWSSI information can be followed at http://mrcc.isws.illinois.edu/research/awssi/indexAwssi.jsp (case sensitive). && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ SHORT TERM...Mayes LONG TERM...Mayes AVIATION...DeWald CLIMATE...Mayes

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