Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 222042 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 342 PM CDT SUN MAY 22 2016 .SHORT TERM...(tonight through Wednesday) Issued at 330 PM CDT Sun May 22 2016 Latest water vapor imagery indicates a closed low over southern Alberta with an amplified ridge to our east extending along the Mississippi River Valley. In the lower levels...the 850mb moist axis stretched north from western Texas into the western Dakotas and continues to slowly shift east ahead of the main upper low. 18Z subjective surface analysis showed low pressure centered over Colorado with large ridge of high pressure over the Mississippi River valley. Surface dewpoints continue to increase over the area with a broad area of 65+ extending across western/central Kansas and lower 60s across all of central Nebraska. These lower to mid 60`s dewpoints will continue to spread northeast into the CWA by Monday afternoon. In the meantime, a dryline was noted across the High Plains with an additional weak surface boundary extending across western Nebraska into south central South Dakota along which some convection has initiated in north central Nebraska. With some hesitation, will leave our evening forecast dry as any convection to our west should drift northeast. We do introduce pops in the overnight period...primarily after 06Z as vort max associated with trailing upper trough sparks a convective complex over the Black Hills region. This activity will likely be sustained by 40-50kt southwesterly low level jet overhead. Convection will continue to slide southeast along weak frontal boundary through the morning and into the afternoon hours. This activity will most likely leave a mess of outflow boundaries draped across the region where convection could later focus. A continued complex, lower confidence forecast continues Monday night into Tuesday as a series of vort max`s moves through southwesterly flow aloft. A surface warm front is progged to extend east from the eastern Colorado surface low across northern Kansas by Tuesday morning. The advancement of this boundary is still somewhat uncertain but should be the focus for convection into Wednesday. In any event...PW`s are are forecast to be 150-175% of normal so heavy rain is certainly a possibility...especially across our southern counties in closer proximity to the warm front. Our area has been outlooked in the Slight Risk for excessive rainfall in addition to SPC`s Slight Risk outlooks. .LONG TERM...(Wednesday night through Sunday) Issued at 330 PM CDT Sun May 22 2016 At the beginning of the period, modest southwesterly upper level flow will continue over the Central Plains region ahead of an upper low moving just to the south of the Great Basin. This feature is forecast to open as it moves east into the Four Corners providing continued southwest flow to the area. The shortwave trough is progged to move across eastern Nebraska/western Iowa sometime either Friday or Saturday. The 12z ECMWF has slowed this feature down from previous runs. Model uncertainty increases behind the above mentioned trough but overall mid/upper level pattern remains southwesterly with unsettled weather continuing into Memorial Day. && .AVIATION...(18Z TAFS for KOMA...KLNK...KOFK through 18Z Monday) Issued at 1215 PM CDT Sun May 22 2016 Generally still expect VFR conditions into at least the evening. MVFR ceilings possible tonight all three TAF locations...and IFR ceilings possible at KOFK with thunderstorms. IFR visibilities also possible in any thunderstorms. && .OAX Watches/Warnings/Advisories... NE...None. IA...None. && $$ SHORT TERM...Kern LONG TERM...Kern AVIATION...Miller

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