333 FXUS63 KGID 141804 AFDGID Area Forecast Discussion National Weather Service Hastings NE 104 PM CDT Tue May 14 2019 ...AVIATION UPDATE... .SHORT TERM...(Today and tonight) Issued at 311 AM CDT Tue May 14 2019 The few showers and thunderstorms we have around early this morning will quickly slide east of our area by around sunrise with a dry day expected until later this evening/tonight. An upper level ridge axis centered over Arizona this morning will slowly slide east and is expected to be centered over eastern New Mexico/west Texas by late tonight. This upper ridge will bring with it even warmer temperatures to the plains today and highs in the lower to middle 80s across our forecast area. We are on the northern periphery of the upper ridge and may catch a weak vort max induced thunderstorm late tonight with Nebraska zones being slightly more favored. If storms form they could be strong to severe given elevated MUCAPE values of over 3000 J/KG and at least marginal 0-6 km wind shear values of 30 to 35 kts. The 00Z GFS and 06Z NAM are pretty bullish with bringing at least isolated convection through our forecast area tonight, while the 00Z ECMWF and some of the WRF models don't give us much tonight. Will carry at least low end pops for threat of isolated thunderstorms tonight. .LONG TERM...(Wednesday through Monday) Issued at 311 AM CDT Tue May 14 2019 The upper level ridge will gradually slide east and a large upper trough will dig across the western United States. This upper trough is expected to move into the plains by Friday afternoon and Saturday brining our best chance for more widespread strong to severe thunderstorms with possibly heavy rainfall. Until then it will be rather warm with either dry conditions or just a few isolated thunderstorms associated with ridge running vort maxes. The first big trough will likely exit to our northeast on Sunday but we could quickly reload with another storm system taking shape over the Rockies by Monday. Wednesday and Thursday... We could see a few lingering thunderstorms Wednesday morning from the Tuesday night upper ridge running system. Also can't rule out isolated thunderstorms across our east Wednesday evening, which is indicated in the blend. However, most areas should be dry through Thursday night after we get rid of any Wednesday morning thunderstorms. Friday through Saturday... The 00Z GFS is now more in line with the 00Z ECMWF than we saw last night with the large upper trough located over the Rockies on Friday and then the upper low ejecting into Oklahoma/Kansas Saturday into Saturday night. Friday will be very warm to hot out ahead of the system with high instability and increasing shear as the trough approaches. At least scattered thunderstorms could begin to form by late afternoon/evening off to our west and then move into our area as we head through Friday evening. This is a classic severe weather set up and if this pattern unfolds as currently modeled we will probably see some severe thunderstorms Friday evening either over our forecast area or at the very least just off to our west. The more southerly track of the upper low on Saturday would bring us thunderstorms with heavy rainfall and perhaps additional severe thunderstorms, but the best bet for severe thunderstorms on Saturday may be just south and southeast of our forecast area. Sunday... We could see some lingering showers and thunderstorms Sunday morning, but overall this will be a break day between systems Monday... It currently appears as through the upper trough will remain across the western United States and reload after the first wave ejects northeast of us on Sunday. The second system could send strong to severe thunderstorms our way again by Monday afternoon or evening. We are getting into a very active severe weather pattern. && .AVIATION...(For the 18Z KGRI/KEAR TAFS through 18Z Wednesday) Issued at 1250 PM CDT Tue May 14 2019 VRF conditions expected to continue through the end of the TAF period. Winds will continue to be light and can be rather variable at times, but the overall trend is winds are shifting from N to E by this evening. Then shifting to ESE and SE tomorrow morning along with increasing wind speeds. There is a small chance that some storms could develop late tonight during the overnight hours, but the environment doesn't look to be supportive of severe conditions. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ SHORT TERM...Wesely LONG TERM...Wesely AVIATION...Shawkey