Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 240519 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 1219 AM CDT Fri Mar 24 2017 .SHORT TERM...(tonight through Sunday) Issued at 320 PM CDT Thu Mar 23 2017 Forecast concerns in the short term will be shower and thunderstorms through Saturday with the slow moving storm system. Where the best potential for severe weather is and what kind of rainfall amounts may occur. The KTOP/KOAX 12Z soundings from this morning showed moist conditions through h7 with around 1 inch of pwat and steep 3-6km lapse rates around 8 deg C/km. H9 winds increased to around 45kts during the morning and a pocket of strong 0-3km bulk shear across northeast NE between 15Z and 18Z...and the lift ahead of the elevated warm front likely helped spark the TSRA with hail that quickly moved into SD. This initial wave of H7 warm air advection continues to move into MN and IA this afternoon. This afternoon...the latest subjective surface analysis has the warm front lifting across the forecast area with showers and thunderstorms ahead of it. There has been a lot of lightning with the storms and even some grass fires, however not a lot of precipitation. Temperatures south of the warm front have warmed into the mid and upper 60s with dewpoints in the 50s. The large mid-tropospheric trough over NV/CA is forecast to shift toward the four-corners area then deepen over CO/wrn KS overnight into a closed low...slowly tracking across Kansas. Broad surface low pressure over eastern Colorado further deepens tonight with a cold front extending into central and northeast Nebraska. The day1 severe weather outlook tornado probabilities extend from central Nebraska into western Kansas south through the OK Panhandle and the TX panhandle with an area of hail/wind outlook in this similar area where thunderstorms will be more focused. Broad upper level divergence and warm air advection along with PWATs around an inch to 1.25" are progged. The combination of the the approach of the upper level trough/broad upper level divergence/waa/mid-level frontogenesis have isolated to scattered storms this afternoon...becoming more focused from western Kansas into western and central Nebraska into northeast Nebraska this evening and tonight where CAPES of 1000-2500 J/kg will be more prevalent and 0-6km bulk shear is forecast to exceed 60kts. The RAP/HRRR did not have a good handle on the morning convection and started to pick up on the afternoon convection with the 16Z HRRR The general trend is to increase precipitation coverage from central Nebraska into northeast Nebraska this evening and overnight. Will maintain highest pops in northeast Nebraska through tonight and Friday morning. Another area of showers and thunderstorms ahead of the dry slot develops from eastern Oklahoma into eastern Kansas and western Missouri and should make it into southern Iowa friday. In between, scattered showers/thunderstorms will be possible. The day2 SPC outlook brings the marginal risk toward FNB...however keeps the slight risk generally from southeast KS into southwest MO. Rain/showers will continue on the northwest side of the storm system across the outlook area Friday night and Saturday with the slow-moving system. Related to the rainfall expected...trimmed back amounts somewhat with general amounts of a tenth to 0.50 inch. Still have higher amounts from .75 to 1.75 for parts of northeast Nebraska. .LONG TERM...(Sunday night through Thursday) Issued at 320 PM CDT Thu Mar 23 2017 Unsettled weather continues with more showers Sunday night...Tuesday night-Thursday. Highs mostly in the 50s and 60s. && .AVIATION...(For the 06Z TAFS through 06Z Friday night) Issued at 1213 AM CDT Fri Mar 24 2017 The cold front is through KOFK and MVFR and IFR ceilings will start to impact the terminal by 10Z this morning, and should continue through the end of the period. The cold front will move through KOMA/KLNK by 18-20Z with the MVFR/IFR cigs to follow by late afternoon. We will also see period of rain overnight and through the day at KOFK. Although isolated showers are possible overnight tonight at KOMA/KLNK, more steady rainfall will not develop in these area until late Friday afternoon into Friday evening. Although some thunder is possible Friday afternoon at KOMA/KLNK, it appears that the chances are to low to currently include in the TAFs. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ SHORT TERM...Zapotocny LONG TERM...Zapotocny AVIATION...Boustead

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