000 FXUS63 KABR 021832 AFDABR Area Forecast Discussion National Weather Service Aberdeen SD 132 PM CDT Fri Jun 2 2023 .SHORT TERM...(This Evening through Saturday Night) Issued at 130 PM CDT Fri Jun 2 2023 Forecast challenges include: -timing and limited coverage of heat-of-the-day thunderstorms on Saturday -above normal low temperatures tonight and Saturday night and above normal high temperatures Saturday At 1PM CDT, cloud cover was generally increasing over the CWA, from south to north, in response to the approaching mid-level shortwave over Nebraska, as noted in the Water Vapor loop. Temperatures have warmed, for the most part, into the 80s on a south-southeast breeze of 10 to 20 mph with occasionally higher gusts. Mesoanalysis indicates the CWA is sitting in a MLCAPE environment of, at least, 1000-1500J/kg right now, with no CINH and virtually no deep layer or low level shear to speak of. Lightning cast has begun highlighting a couple of areas with low to moderate probabilities of lightning in the next 60 minutes, and have even already detected a few flashes/strikes of lightning thus far. Seeing a few, mainly, showers on radar. Expecting to see a slow steady increase in coverage of showers and thunderstorms over the next few hours. The loss of daytime heating this evening should signal the dissipation of any ongoing showers or thunderstorms by ~midnight CDT. Of course, there will be one more night of decent nocturnal low level jet southerly winds to contend with tonight, so will see whether or not convection behaves itself by late this evening. The models are all in fair agreement on the track of this upper level high pressure system, currently anchored along a line from southern Hudson's Bay Canada down into Michigan and then back toward Arkansas. Over the next 36 hours, that upper high is going to continue to back-build west and north and be centered over southern Canada down into Oklahoma/Texas. In fact, by 18Z Saturday, the upper steering flow may be influenced enough by this upper high, that afternoon-heating-induced isolated/widely scattered convective chances may be a tough sell. Ensemble and deterministic temperature guidance continues to support this ongoing stint of above normal temperatures (normal highs: mid 70s / normal lows: low 50s) with night time lows tonight and Saturday night likely dipping into the 60s, while high temperatures on Saturday rebound back into the 80s to low 90s. .LONG TERM...(Sunday through Friday) Issued at 130 PM CDT Fri Jun 2 2023 By 12Z Sunday the western moving 500mb area of high pressure currently over the Upper Great Lakes will be over southern Manitoba and eastern ND. A ridge of high pressure will be set up at the surface as well, extending from a 1035-1037mb high over Hudson Bay. The potential for diurnal afternoon-evening showers and thunderstorms will remain, with MUCAPE values of 1500-2000J/kg (tall skinny CAPE) over northeastern SD and west central MN and some forecast sounding analogs pointing highlighting similar cases where 1 inch or greater hail occurred. We won't completely be able to rule out the potential for a few storms with hail and lightning. There will be little change in the 500mb pattern across the Northern Plains through Thursday, as we remain dominated by the large area of high pressure. Confidence in temperatures remain higher than normal through Tuesday morning, with little variability in the spread of values from ensemble forecast solutions. This means that highs in the 80s with a few 90 degree readings over central SD, and lows in the mid 50s to low 60s look reasonable. Forecast solutions continue to indicate a weak cold front sinking south-southwest across our eastern forecast area late Monday into Tuesday time frame, as a shortwave rounds the ridge and move through the eastern Great Lakes and New England states. This could be a focus area for additional afternoon-evening shower and thunderstorm activity in our weak shear environment with the large 500mb ridge remaining overhead. Given the changes in the overall pattern and the fact that it's 4 days out, confidence is starting to diminish in specifics, including temperatures. Still, 80s look likely for highs with lows in the mid 50s to mid 60s through Friday. && .AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon) Issued at 1229 PM CDT Fri Jun 2 2023 Terminals KABR,KATY,KPIR,KMBG Outside of convection, VFR conditions are forecast to prevail through the TAF valid period. More unsettled weather, potentially, this afternoon and early evening, as daytime heating showers and thunderstorms are possible. Have either VCSH or VCSH and VCTS in the TAFs for now, and will fine tune timing, etc as the afternoon unfolds. Did refrain from mentioning anything that might be ongoing at/after 00Z this evening. Again, will add some additional detail as confidence increases. Any storms that do develop could produce gusts of 30-50 mph. The shower and thunderstorm potential will diminish quickly during the evening. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ SHORT TERM...Dorn LONG TERM...KF AVIATION...Dorn