Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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292 FXUS63 KOAX 241715 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 1215 PM CDT WED AUG 24 2016 .SHORT TERM...(today through Friday) Issued at 345 AM CDT WED AUG 24 2016 Forecast concerns for the short term will be chances of thunderstorms through Friday and heavy rain potential later this afternoon and tonight. This first round of thunderstorms had pushed through the area and drier air is making it into the northwest part of the county warning area. For details on the rain overnight and hydrologic concerns, see below. A few showers may try to re-develop in parts of western Iowa. Water vapor satellite imagery and upper air analysis shows the complicated weather pattern with a closed h5 low over saskatchewan and leading shortwave troughs from Minnesota into southwest Iowa and another area of low pressure over Colorado into Arizona. The h3 jet streak over the Dakotas is forecast strengthen and drop southward with time as it pushes across the northern U.S. Meanwhile...there is another jet segment from New Mexico into Kansas and this strengthens and merges with the northern stream jet by Thursday. The resulting h5 pattern calls for the h5 low to track into Manitoba today as the trough deepens over the plains and then becomes more westerly as the trough heads into the Great Lakes Thursday night. Another h5 develops over the Rockies Friday deepening over the Western High Plains Friday night The 45kt low level jet has veered and is now feeding into the storms across Kansas...Missouri...Iowa. From 12-00z...this low level jet weakens to 25kts and begins to increase again after 00z across eastern Kansas and northern Missouri. Typically, this would favor thunderstorms south of our area and this is again the case. The surface front will be in southeast Nebraska and southwest Iowa. The H85 front is complicated with the rich h85 dewpoints south of the forecast area...however sufficient dewpoints for storms linger south of I80 and gradually push south through Thursday...then return northward Thursday night and Friday. Favorable upper level divergence...and the approach of the shortwave over Colorado combined with heating and residual moisture lead to a chance for thunderstorm re-development south of I80. The forcing is not as strong as last nights and the theta-e axis is south of the forecast area, however will include thunderstorm chances this area...with the highest pops closer to the front. There is a 0-3km 35kt speed max into southeast Nebraska at 00z and a 45kt max in northeast Kansas at 06z...so will need to keep an eye on storms that form near the border for strong winds. Although not as favorable...do maintain shower/thunderstorm chances for through Thursday with that lingering moisture and upper level support although we are on the cool side of the front. Better shower and thunderstorm chances return Friday with decent warm air advection and return of rich moisture ahead of the next shortwave trough. Highs today will be in the 80s with 70s for Thursday through Friday. .LONG TERM...(Friday night through Tuesday) Issued at 345 AM CDT WED AUG 24 2016 Active pattern continues Friday night through Saturday night with the passage of the mid tropospheric trough. Beyond Saturday night thunderstorm chances will be more spotty. Highs Saturday through Tuesday will range from the upper 70s to the mid 80s. && .AVIATION...
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(18Z TAFS for KOFK...KLNK and KOMA.) Issued at 1211 PM CDT WED AUG 24 2016 Generally VFR conditions are forecast through Thursday morning. An area of showers and thunderstorms will move and develop northeast from north central Kansas into southeast Nebraska. Some of this activity could reach as far north as the Interstate 80 corridor, affecting KLNK and KOMA for a few hours between 22Z and 02Z. Attendant MVFR/IFR vsbys/cigs in storms will be possible. Otherwise expect north or northeast winds and broken mid level clouds through the TAF period.
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&& .HYDROLOGY...
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Issued at 345 AM CDT WED AUG 24 2016 Rainfall amounts over the last day per dual-pol estimates were from 5 to 8 inches near Blair. A public report of 5 inches was received near Blair before 10pm and it was still raining in the area. A large area of 1 inch to 4 inches was noted from east central Nebraska into southwest Iowa. 4.79 inches fell at the Kennard ALERT river gauge and 3.56 inches at the Chalco gauge. Gretna had 3.19 inches. Omaha Eppley reported 1.2 inches and Lincoln 0.17. Here are the NWS office we had 2.81 inches. The ALERT gauge did not reach flood stage at Kennard, however it did at Fort Street on the Big Papillion. Most of the local gauges have dropped from their earlier rises. With the band of storms in the morning in northeast Nebraska .5 to 2.5 inches was likely and Norfolk received 1.15 inches. Concerns for later today and tonight should be focused farther south...however with storms forecast for southeast Nebraska and southwest Iowa...and parts of these areas had rains last night, included them in the Flash flood watch per coordination with DMX/EAX/TOP.
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&& .OAX Watches/Warnings/Advisories... NE...Flash Flood Watch from 6 PM CDT this evening through Thursday morning for NEZ091>093. IA...Flash Flood Watch from 6 PM CDT this evening through Thursday morning for IAZ090-091. && $$ SHORT TERM...Zapotocny LONG TERM...Zapotocny AVIATION...Dergan HYDROLOGY...Zapotocny

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