047 FXUS63 KABR 262029 AFDABR Area Forecast Discussion National Weather Service Aberdeen SD 229 PM CST Tue Dec 26 2023 .KEY MESSAGES... - A couple changes to the forecast to highlight where freezing rain/snow accumulations have shifted. - Looks to be mostly dry through the period, with the exception of a potential shortwave dropping south across the region Saturday night into Sunday bringing minimal (~10% or less) chances for precipitation. - Near to above normal temperatures through the period, with a shot of colder (not arctic cold) air on Sunday with the aforementioned shortwave potential. && .SHORT TERM /THIS EVENING THROUGH WEDNESDAY NIGHT/... Issued at 229 PM CST Tue Dec 26 2023 At 2 PM CST, skies are cloudy and temperatures are holding in the low to mid 30s. Within the deformation zone-turning-TROWAL of this system spinning over the borders region of NE/KS/IA and MO, mostly light precipitation continues across central and north central South Dakota, while slowly coming to an end from east to west over northeast South Dakota and west central Minnesota as the leading edge of a dry slot moves in. The precipitation falling over central/south central South Dakota is snow and should remain snow until the dry slot extends over to that area later this evening. Over north central South Dakota, the precipitation has been falling as either snow/sleet or sleet/freezing rain or a mixture of all of the above, while precipitation over northeast South Dakota has been transitioning over to snow (the northern half of Roberts County is still in the form of rain). Also, wind gusts continue to slowly subside, but there remains some gustiness in the 20 to 35 mph range out across and west of the Missouri River valley. Once the dry slot takes over, precipitation should terminate, being replaced with either drizzle or freezing drizzle intermittently. Not expecting a long-lived period of drizzle. But, "periods of" drizzle certainly seems appropriate, with this BUFKIT soundings-modeled deep layer of supercooled stratus hanging around overnight under the dry slot. It's possible that the dry slot ends up not making it all the way to north central South Dakota overnight, in which case, the potential for freezing rain/ice accumulation will last for much of the tonight period, with up to a quarter inch of ice (or more) possible, on top of what has already fallen/accumulated out there. With the freezing rain/icing cross-hairs centered over north central South Dakota (where the warm tongue is forecast to advect to), the Ice Storm Warning goes to midnight tonight. Portions of central/south central South Dakota are still set to their current expiration time of 6 PM CST. At that time, the warning will be replaced with a winter weather advisory until the wind diminishes enough that hazardous travel/visibility issues are not a concern. Beyond 6 PM CST, the only area of the CWA that is expected to accumulate "significant" precipitation looks to be north central South Dakota where the freezing rain/icing threat looks to persist for several more hours into the tonight period. As the upper circulation well off to the south-southeast of the CWA begins to pull away from the region, any remnant TROWAL forcing and associated light precipitation will quickly shift south and east through the CWA on Wednesday. While this is happening, surface high pressure is building across the region and will inhabit the northern plains and northern high plains into Wednesday night. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Issued at 229 PM CST Tue Dec 26 2023 Thursday starts off with surface high pressure over the region. As this high moves off to the south Thursday night, upper level ridging tries to build in from the north, leading to somewhat mild temperatures for Friday - although perhaps tempered a bit from forecast numbers due to the current snowpack across the region. There is a potential shortwave that drops south over the area Saturday night and Sunday, with a shot of colder air behind it as highs look to drop back into the 20s Sunday and Monday. Cluster analysis does not lead to very high confidence on the overall strength and evolution of the shortwave. As for precipitation, things look mostly dry though the period. Only exception could be this potential shortwave Saturday night and Sunday. Current NBM PoPs are around 10% or less at this time. Looking at EC/GEFS ensembles, and probabilities for 24-hour QPF greater than .01 ending at 18z Sunday is generally less than 50%. CMC camp is a bit more bullish with chances greater than 70%. These numbers are all for the eastern CWA, where any "better" chances for precip reside. Will watch NBM trends over the coming days to see if PoPs increase over the coming days. && .AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 1126 AM CST Tue Dec 26 2023 Terminals KABR,KATY,KPIR,KMBG IFR conditions are forecast at KATY for the entire TAF valid period. Expect precipitation to have ended at KATY at the start of the period; replaced by a light to moderate mist (drizzle?) and some fog/low clouds. This should persist at KATY until around mid-day on Wednesday, when light precipitation in the form of snow or snow/freezing rain will befall the KATY terminal for a few hours. IFR conditions are forecast at KABR for the entire TAF valid period. Expect precipitation in the form of rain to persist into the afternoon. By 6 PM CST, rain could be mixing with or changing to snow for a few hours before ending. By mid-morning Wednesday, light precipitation in the form of snow or snow/freezing rain will befall the KABR terminal for a few hours. IFR conditions are forecast at KPIR for the entire TAF valid period. Expect precipitation in the form of snow to persist into the evening. There could be a several hour break in the precipitation at KPIR. But, by early morning on Wednesday, light precipitation in the form of snow or snow/freezing rain will befall the KPIR terminal for a few hours. IFR conditions are forecast at KMBG for the entire TAF valid period. Expect precipitation in the form of snow or snow/freezing rain to persist through the afternoon. After 6 PM CST, precipitation should be changing to freezing rain or freezing rain/sleet and persisting throughout tonight before coming to an end during the morning hours on Wednesday. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...Ice Storm Warning until midnight CST /11 PM MST/ tonight for SDZ003>005-009-015. Winter Weather Advisory until midnight CST tonight for SDZ010- 016-017-034>037-051. Blizzard Warning until 6 PM CST /5 PM MST/ this evening for SDZ033-045-048. Winter Weather Advisory from 6 PM CST /5 PM MST/ this evening to midnight CST /11 PM MST/ tonight for SDZ033-045-048. MN...None. && $$ SHORT TERM...Dorn LONG TERM...TMT AVIATION...Dorn