Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS63 KOAX 171738 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 1138 AM CST Fri Nov 17 2017 .SHORT TERM...(Today through Sunday) Issued at 315 AM CST Fri Nov 17 2017 Fairly complex forecast with temperatures today and precipitation tonight the main concerns. Modest west/southwest mid level flow was in place from the nations mid section back to the western United States. Main area of height falls at 00Z extended from southern Saskatchewan down into MT then back toward ID and OR. There were a couple of jet segments noted in the 300 mb flow, one over MT and another over central CA. At 850 mb, a thermal ridge extended from Mexico up into CO, WY and then to along the MT/ND border. Decent moisture at 850 mb (dewpoints 2 degrees C or higher) was lifting north from TX, OK and parts of KS. That moisture had moved up into parts of southeast NE and southwest IA based on recent RAP model initializations and recent observations. Today, just how warm it will get as warm is a challenge since there is not a clear signal as to how deep we will mix. Forecast will have highs mainly in the 50s north and in the 60s for about the southern 1/2 to 1/3 of the forecast area. Some light rain or drizzle is expected, mainly this morning, when low level cloud thickness will be deepest. Winds should shift to the north or northwest across all of the area by mid to late afternoon with the low levels drying temporarily. Short range models are in fairly good agreement that forcing for ascent will be stronger tonight. Lift will be mostly at and above 700 mb, and this will shift southeast through the area with time. The airmass becomes cold enough for a light rain/light snow mix in parts of northeast NE late tonight, but it appears that the precipitation will be ending about the time or shortly after the changeover occurs. For that reason, expect little or no snow accumulation. Some light rain could linger in parts of southeast NE and southwest IA into mid morning Saturday, until the mid level trough moves east of the area, then the rest of the weekend should be dry. .LONG TERM...(Sunday night through Thursday) Issued at 315 AM CST Fri Nov 17 2017 Fast westerly flow aloft should become northwest by Monday night then turn to the north by mid week as a 500 mb ridge amplifies from northern Baja toward Saskatchewan and Manitoba. Model agreement falls off later in the week, but it does look like the pattern should be dry. Highs will be mostly in the 50s Monday, in the 40s Tuesday and Wednesday, then back to the lower and mid 50s for Thursday into Friday. && .AVIATION...
-- Changed Discussion --
(For the 18Z TAFS through 18Z Saturday afternoon) Issued at 1136 AM CST Fri Nov 17 2017 Lingering MVFR ceilings may lift for a few hours this afternoon but will deteriorate again this evening if they do. Winds will shift to northwesterly and increase to around 10-15kt through the afternoon/evening. Behind that cold front, rain could affect all sites tonight. Later tonight, there is some potential for rain to mix with snow. For now, have included this mention as tempo only at KOFK, but the potential at KOMA/KLNK bears watching.
-- End Changed Discussion --
&& .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ SHORT TERM...Miller LONG TERM...Miller AVIATION...Mayes

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.