271 FXUS63 KFSD 031648 AFDFSD AREA FORECAST DISCUSSION National Weather Service Sioux Falls SD 1148 AM CDT Sat Aug 3 2019 .SHORT TERM...(Today and Tonight) Issued at 407 AM CDT Sat Aug 3 2019 A band of heavy rain has developed overnight extending from Yankton county northward into Hutchinson county, with radar estimates of 2- 4 inches of rainfall around the Yankton area. With strong moisture transport into the western portion of our CWA, low level convergence, and model soundings continuing to indicate a deep warm cloud layer, any convection that develops will have the potential to produce heavy rainfall through at least mid to late morning, with the greatest threat remaining over the lower James River Valley/central MO River Valley. Hi-res CAMs have been playing catch up through most of the night, generally having QPF output too far west in comparison to reality, though all continue to point to a threat of scattered convection even into the afternoon for areas mainly west of Interstate 29. There will continue to be decent forcing through the early part of the day as the mid level shortwave continues to drift to the east, and upper level divergence is supplied by a jet max streaming from southwestern SD into eastern NE. By afternoon, forcing begins to weaken, so shower/isolated thunderstorm activity is expected to wane. Presently forecasting high temperatures in the upper 70s to lower 80s, though if cloud cover is more persistent than anticipated it will be a little cooler than that. Most models indicate drying by tonight, although some of the CAMs and the NAM would leave a threat of isolated convection lingering even into part of the overnight period. At this point, kept the forecast dry with forcing drifting away, but it may be something that will have to be updated in future forecasts. Lows tonight will again be in the 60s. .LONG TERM...(Sunday through Friday) Issued at 407 AM CDT Sat Aug 3 2019 Sunday looks to be a better day as upper level ridging in the western CONUS nudges a bit eastward. With a southeasterly low level flow taking on a more south/southwesterly direction, temperatures should warm into the mid and upper 80s. The quiet weather will be short-lived however, as a cold front dropping through the region will bring a return of thunderstorm chances on Monday. Depending on the timing of the frontal passage, convective parameters would support the threat for a few severe storms on Monday afternoon and evening. The remainder of next week looks to have temperatures at or just below normal in a northwesterly upper level flow across the region. Hard to pin down timing for convective chances, with no significant systems expected, though there could be a periodic low chance of thunderstorms through the week. && .AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon) Issued at 1139 AM CDT Sat Aug 3 2019 Morning rain has diminished although isolated to scattered showers will likely continue into the evening hours. At this time, the better chances for this activity look to be west of KFSD/KSUX and south of KHON although can't rule out some of this precipitation making its way into the terminals at times. MVFR ceilings will also continue for areas west of I-29 into the afternoon. Some uncertainty exists overnight with how much lingering precipitation will be around. This will be important as a moist boundary layer and lighter winds could lead to some lower ceilings or fog potential late tonight into early Sunday if enough clearing develops, with areas near/west of the James River the highest threat area. Will leave mention minimal at this time given uncertainty. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...JM LONG TERM...JM AVIATION...Kalin