252 FXUS63 KOAX 100301 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 1001 PM CDT Tue Jun 9 2020 ...Updated for Headlines Tonight... .UPDATE... Issued at 939 PM CDT Tue Jun 9 2020 Severe thunderstorms were rotating east of our area late this evening, so have cancelled the tornado watch just a little early. Attention then turns to strong winds and additional rains on back side of system. Wind gusts near or over 60 mph have already been reported in some spots, and expect widespread 50 to 60 mph gusts much of the night as surface low works east through northern Kansas. Moderate to locally heavy rain fell over parts of southeast Nebraska and southwest Iowa with convective storms. Radar estimates showed pockets of 2 to 3 inch amounts. Additional rainfall could add another inch and a half as rain redevelops in deformation zone of upper system. Therefore will continue the flash flood watch for southeast Nebraska and southwest Iowa overnight. && .DISCUSSION... Issued at 330 PM CDT Tue Jun 9 2020 At 330 PM, our region was experiencing a narrow band of warm unstable air sandwiched between a strong upper level trough over northern Kansas and the remnants of what was Tropical Depression Cristobal in eastern Iowa. At the surface temperatures were in the upper 80s in the Omaha and Lincoln Metros. However the winds of change were visible on the western horizon, with temperatures in the 50s and 25 to 35 mph northwest winds ongoing in central Nebraska. The dividing line between these two extremes, was a cold front that stretched from Sioux City to just west of Lincoln. Along the cold front, thunderstorms were widespread. The aforementioned cold front, and strong trough of low pressure will surge through the region tonight, resulting in severe thunderstorms, very strong winds and heavy rainfall. The most immediate threat this evening will be in southeast Nebraska and southwest Iowa, where storms developing along the warm front may produce a couple tornados, and golf ball or larger hail through around 10 PM. Given ample instability and 0-3 km shear in excess of 50 kt, any storms that form will have the potential to rotate and produce tornados rapidly. Due to PW values near 1.5 inches, the potential for several rounds of thunderstorm activity, and rain rates in excess of an inch per hour, there will also be a moderate risk for flash flooding tonight in southeast Nebraska and southern Iowa. Most locations will see between 0.5 and 2 inches of rainfall through 9 AM Wednesday, but localized totals of 2 to 5 inches are possible. This evening is a good night to have the weather radio on and/or a TV tuned to you local news station for updates. Another aspect of this storms system (and by far the one that is most unusual for June) will be the strength of the northwest winds behind the cold front tonight. CAMs are suggesting suggesting a potential for 50 to 65 mph winds gusts tonight. These gusts in the CAMs are supported by 850 mb wind speeds of 50 to 70 kts, that will should offer ample opportunity for winds to mix to the surface (especially in regions of shower activity). Scattered power outages and tree damage are possible with winds of this magnitude. High profile vehicles will also have difficulty traveling along Interstate 80, and it wouldn't be surprising to see a couple big rigs blown over if winds really do reach 65 mph. And now to the better, better, better part of the forecast...the improved weather for the rest of the week! Wednesday will see much cooler weather (highs in the 70s), less humidity and ample sunshine. A great day to get outside right? Well that will depend on your activity of choice, as the winds will be gusty from the northwest (gusts of 30 to 40 mph most of the day). If you are trying to avoid the winds, your best chance will be in the evening. A building ridge of high pressure over the south central U.S. will bring dry weather and a gradual warming trend Thursday through Sunday. Look for temperature to top out in the 80s each day, with lighter winds Thursday and Friday, trending toward more persistent south winds Saturday and Sunday. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 633 PM CDT Tue Jun 9 2020 Scattered storms are popping up behind a surface that is slowly advancing eastward, and will kick off a very busy TAF period. Thunderstorms are expected to continue through 04/05z for KLNK and KOFK respectively and through 07z for KOMA. The ceilings under any storms may deteriorate to around 1500ft AGL and visibilities down to 2SM. The general activity will then transition to rain across all sites, and will be accompanied by very strong wind gusts (over 45 knots) out of the northwest. With the strong surface winds, very strong winds above the surface may reach near 60 knots at 1500 ft AGL, introducing wind shear into the mix as well. Eventually, rain will taper off and leave the TAF sites dry after 12z for KOFK and KLNK, and 13z for KOMA. In its wake, we will still be dealing with winds 33-36 knots out of the northwest and VFR conditions. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...Wind Advisory until 7 AM CDT Wednesday for NEZ015-091-093. High Wind Warning until 7 AM CDT Wednesday for NEZ034-045-052- 053-067-068-089-090-092. Flash Flood Watch until 7 AM CDT Wednesday for NEZ051>053- 065>068-078-088>093. High Wind Warning until 4 AM CDT Wednesday for NEZ030>033- 042>044-050-051-065-066-078-088. Wind Advisory until 4 AM CDT Wednesday for NEZ011-012-016>018. IA...Wind Advisory until 7 AM CDT Wednesday for IAZ043-055-056-069- 079-080-090-091. Flash Flood Watch until 7 AM CDT Wednesday for IAZ069-079-080- 090-091. && $$ UPDATE...Dergan DISCUSSION...Albright AVIATION...Petersen