Area Forecast Discussion
Issued by NWS Hastings, NE
Issued by NWS Hastings, NE
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203 FXUS63 KGID 230942 AFDGID Area Forecast Discussion National Weather Service Hastings NE 442 AM CDT Thu May 23 2024 .KEY MESSAGES... - "ENHANCED RISK" for severe weather this evening into tonight for most of the area. Primary threat will be severe winds to 75 mph, but large hail to the size of golf balls and a few tornadoes are also possible. Greatest severe threat (10PM-3AM) - Cooler (67-74F) and dry behind the cold front on Friday. - Next upper level storm system will bring another chance for severe storms Saturday afternoon into Saturday night with a SPC Day 3 "SLIGHT" risk area. - Rain chances will continue into Sunday (30-50%), but then decrease for Monday (10-20%). Good confidence in cooler highs in the upper 60s to around 70 on Sunday and then mainly 70s for memorial day. && .DISCUSSION... Issued at 339 AM CDT Thu May 23 2024 Today/Tonight (Severe Thunderstorms)... We have some early morning showers with perhaps just a few lightning strikes tracking east near and south of the Kansas border early this morning. This area of showers should quickly diminish with remnants sliding east of our area by 6-8 AM. The rest of the morning and at least early afternoon should then be dry. Most areas including the Tri-Cities should be dry today through at least 8 PM. We will see a slight chance (20%) for isolated thunderstorm development within the warm sector out ahead of the cold front. The most likely location for any earlier development in the 4-8 PM window will be across our far western zones. We do have a few models like the 00Z and 06Z NAM NEST that try to develop these isolated supercells during day time hours out ahead of the cold front. However, a strong cap over the warm sector will make it difficult for thunderstorms to develop except for right along the cold front. Other models like the 06Z NAM and 06Z HRRR keep thunderstorms out of our area until a line of storms track from west to east across the forecast area with the front tonight between 10 AM and 3 PM. Strong to severe thunderstorms are likely (70-90%) across the area tonight as that cold front swings through with the highest likelihood across our Nebraska counties. How far south into Kansas and how quickly thunderstorms develop along the front remains a bit in question. A QLCS with bowing line segments is the main forecast concern tonight as thunderstorms along the cold front are fed by a strong moist 50 kt 850 mb low level jet, which with high confidence (70-90%) will keep that line of storms going through much of the night right through our CWA. The primary severe weather threat during the late night hours with this QLCS will be severe winds including the potential for a few high end severe wind reports of over 75 mph. The larger golf ball hail threat will primarily be with any isolated storms that can form earlier or during the earlier portion of the lines development. There will be a tornado threat with any discreet supercells that can develop out ahead of the line, but again this is a small probability of seeing discreet supercells (20%). There will also be a chance for rain wrapped QLCS tornadoes embedded within the bowing line segments late this evening as the low level shear ramps up. The 06Z NAM indicates 40kts of 0-1km shear ahead of the line tonight with 0-3 km helicity values to over 500 m2/s2 Friday (Cooler and Dry)... Cooler (67-74F) and dry behind the cold front on Friday with breezy northwest winds at 15-20 mph gusting 25-30 mph. Saturday/Saturday Night (Next Chance For Severe Thunderstorms)... The best chance (40-60%) for thunderstorms will be ahead of a quick moving upper trough late Saturday evening into Saturday night. However, we could see thunderstorms develop as early as late Saturday afternoon, mainly after 4 PM, but with lower probability (20-30%) for these earlier thunderstorms. This upper trough should be a quick mover and we don`t get much time for return moisture to flow back into the region after the moisture vacates the area on Friday behind the cold front. Therefore, the better chance for strong to severe storms will be south of our forecast area Saturday evening/night where there will be better moisture/instability. Sunday through Memorial Day... We could see some lingering mainly showers on Sunday, but can`t rule out a few thunderstorms. Our NBM rain chances are probably a bit on the high side and may need to be lowered with future forecast updates as the upper pattern becomes less favorable for precipitation. The NBM low 20% rain chances on Memorial day may also be a bit on the high side and most areas will likely see a dry Memorial Day. However, temperatures will not be all that warm with mainly 60s on Sunday and then lower to middle 70s for Memorial Day. Tuesday and Wednesday... Mainly dry weather expected and warming back up into the upper 70s and lower 80s. && .AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 1254 AM CDT Thu May 23 2024 VFR ceilings will prevail with only passing high clouds tonight and a scattered low- VFR deck Thursday daytime. It should be dry until after 7 PM and then there will be increasing chances for thunderstorms the later we get into the evening when the cold front comes through, most likely after 10 PM. Some of these thunderstorms could be severe late Thursday evening with large hail and damaging winds possible. In the short term we expect increasing southerly winds will be the primary aviation issue through the morning. Do not think that low level wind shear will meet thresholds for inclusion in the TAF through the period, but it could be close just ahead of the front this evening. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ DISCUSSION...Wesely AVIATION...Wesely