####018006748#### FXUS63 KFSD 241659 AFDFSD Area Forecast Discussion National Weather Service Sioux Falls SD 1159 AM CDT Wed Apr 24 2024 .KEY MESSAGES... - Chances for rain and storms return late Thursday and persist through the weekend. Strong to severe storms are possible on Friday. - Beneficial rainfall is possible Thursday night, with a 50-80% chance for exceeding a half an inch of rain. && .DISCUSSION... Issued at 342 AM CDT Wed Apr 24 2024 Today will be a quiet day across the area as a surface ridge slowly pushes through the Northern Plains and into the Upper Midwest. Light winds will begin the day out of the east and slowly turn southeasterly throughout the day. Soundings do show a small moist layer between 700-600 mb which is expected to result in some mid level clouds. This mid level cloud deck will develop over south central South Dakota and push eastwards throughout the day. With dry low levels beneath the cloud deck, do not expect any rain to reach the surface. This mid level cloud deck will keep high temperatures just a touch cooler with highs warming to the 60s this afternoon. The near seasonal temperatures and light winds will make for a solid day for outdoor activities. Get out there any enjoy it if you can! Elevated southeasterly winds will persist through the night and keep low temperatures on the mild side, only falling down to the 40s to perhaps 50 degrees F. A strong upper level wave will begin to eject into the Plains states on Thursday. The best lift with the wave looks to stay south and west of the area during the daylight hours, keeping conditions mostly dry. High temperatures will remain in the 60s but dew points will slowly moisten to the 40s. Southeasterly winds will remain gusty with gusts as high as 30-40 mph. As the wave begins to encroach on the Northern Plains, warm air advection (WAA) will strengthen in response to an intensifying low level jet (LLJ). This will set the stage for increasing precipitation chances Thursday evening and night. The WAA will encounter an elevated warm front around 850 mb which should allow for weak elevated convection to develop. Strong to severe storm chances Thursday night looks low (<30% chance) as instability will be lacking with only a few hundred J/kg of CAPE. The other aspect to Thursday night is that 850 mb moisture transport will increase due to the strong LLJ in place, which will set the stage for beneficial rainfall. Ensembles have slightly increased their probabilities, now up to a 50-80% chance for exceeding a half an inch of rain Thursday night. The upper level wave pushes into the Northern Plains on Friday, bringing the potential for strong to severe storms with it. Questions still remain regarding the severe storm potential as overnight storms could limit diurnal destabilization during the afternoon hours via storm outflow cooling the low levels and cloud cover. Along with potential destabilization issues, medium range guidance continues to vary how far north the surface warm front gets. If the warm front is able to push into the Missouri River Valley, then severe storms may be possible. If not, perhaps elevated storms will be possible. The deterministic Euro, GFS, and NAM are generally in support of stable low levels and thus the potential for elevated convection. However, cluster analysis reveals that the most favored cluster has the warm front getting into the Missouri River Valley and about 1,000 J/kg of CAPE and minimal convective inhibition (CIN). Latest hi-res ensemble does show convection firing along the warm front as well. Despite some CIN in place, think that the ensemble develops convection due to strong positive vorticity advection (PVA) from the wave finally pushing into the forecast area. On top of the PVA, an upper level jet streak will reside over the surface warm front which could result in a coupling of the frontal circulation and the jets indirect thermal circulation via the lift in the left exit region. Will continue to monitor severe storm trends. Aside from storm chances, Friday will continue the trend of near seasonal high temperatures in the 60s and perhaps 70s, again depending on cloud cover. Dew points will moisten into the 50s which will make for the first humid day across the area this Spring. With the previously mentioned LLJ remaining strong throughout the day, gusty southeasterly winds will continue with gusts up to 30-40 mph. Low temperatures will only fall to the 40s and 50s overnight. Another upper wave will eject into the Plains on Saturday brining renewed chances for rain and storms. This chance for storms will depend on where the surface front sets up. As of now, ensembles keep the front southeast of the forecast area. This can still change so trends will be monitored but the fronts position suggest a minimal chance for severe storms on Saturday. Sunday will be a similar day as the base of the upper level trough will push through the region. Severe storm chances will again depend on the waves evolution and surface front location. Ensembles do show nearly a 100% chance for exceeding a tenth of an inch of liquid QPF over the weekend, but with details uncertain, have stuck with model blended PoPs. High temperatures look to remain in the 50s and 60s for the weekend. Dry conditions look to return on Monday as the wave lifts north and subsidence prevails on the wave's backside. The dry conditions look to persist into the middle of next week along with warmer high temperatures, potentially into the 70s as supported by the ensembles. && .AVIATION /18Z TAFS THROUGH 18Z THURSDAY/... Issued at 1159 AM CDT Wed Apr 24 2024 VFR conditions are forecast to prevail this TAF cycle. Should see south/southeasterly winds continue through the afternoon, with direction becoming more predominantly southeasterly after sunset. Will then see winds gradually strengthen through the overnight period with gusts between 20 to 25 MPH possible by daybreak. Winds strengthen even more Thursday, especially along and west of I-29, with gusts forecast to range between 25 to 35 MPH. Otherwise, expect scattered showers to develop by the end of the period, though confidence in any one location remains low at this time - thus, have opted to exclude mention for the time being. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && $$ DISCUSSION...Meyers AVIATION...SST