Area Forecast Discussion
Issued by NWS Aberdeen, SD
Issued by NWS Aberdeen, SD
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338 FXUS63 KABR 250540 AAC AFDABR Area Forecast Discussion...UPDATED National Weather Service Aberdeen SD 1240 AM CDT Sat May 25 2024 .KEY MESSAGES... - The unsettled weather pattern continues with chances of showers and thunderstorms Saturday afternoon into Sunday (35-80% chance) and Monday 25-35% chance) before things dry out for much of the rest of the forecast. && .UPDATE... Issued at 1233 AM CDT Sat May 25 2024 The aviation discussion has been updated below for the 06Z TAFs. UPDATE Issued at 901 PM CDT Fri May 24 2024 Weak vort/disturbance noted on water vapor across eastern MT into western ND, responsible for scattered showers over said region. Upstream KBIS radar showing activity moving eastward along the southern portion of ND, with trajectory perhaps taking it into the far northern CWA over the next few hours. Latest HRRR runs, along with various hi-res output does show potential for isolated or widely scattered light showers moving eastward along the ND/SD state line over the next several hours. Added slight chance PoPs to account for this. Some of this cloud cover may keep lows up just a couple degrees from previous forecast lows. That said, still a cool night in store with lows in the upper 30s to low/mid 40s. && .SHORT TERM /THIS EVENING THROUGH SATURDAY NIGHT/... Issued at 304 PM CDT Fri May 24 2024 Occluded low pressure will exit the region this evening. Strong northwest winds associated with the cold air advection in the upper low will diminish as well this evening. Some areas along the ND/SD border did receive a mix of rain and snow as temperatures fell into the 30s. That`s leaving a big question mark for overnight lows as clouds clear out. Dewpoints are in the upper 30s and 40s this afternoon, so don`t have lows falling below 37 degrees right now, but that`s dependent on places like McPherson county seeing some rebound after the last of the precip exits over the next couple of hours. If there`s no recovery, a frost advisory may be warranted. Heights rise on Saturday and winds shift to the south and east on the northeast side of another Colorado low. Shortwave energy moving through the upper flow may generate some showers and thunderstorms as early as 11am across south central SD before more thunderstorms develop in increasing instability in the afternoon. Expecting just general thunder due to limited moisture and temperatures, but 30 to 80% chances for convective showers push east and north on the shortwaves through the afternoon as a weak sfc trough/boundary develops. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Issued at 304 PM CDT Fri May 24 2024 Sunday morning starts the long term with a shortwave moving across the area. Deterministic models show this lasting through at least the first part of Monday afternoon. Monday evening, a ridge starts to build into the region and looks to last through mid week. We are starting to see a shortwave ride that ridge across the area on Thursday. By Friday evening we are on the upwind side of the ridge and a low reaching down from southern Canada starts to move into the region. Sunday will have some chances (25-65%) for rain with that shortwave. While some storms could form, it is unlikely they will become severe. Wednesday evening, rain chances (15-25%) return for the rest of the term as the Thursday (20-40%) shortwave rolls through followed by the incoming trough on Friday (30-40%). With mid level lapse rates between 6.5 and 8.5 C/km and MLCAPE values around 1000 to 2000 J/kg (depending on model), some storms have the potential to become severe Thursday afternoon and evening and potentially again Friday evening. This is still 6 to 7 days out so things could change. Temperatures for the first part of the long term will be rising back up to around normal with highs in the high 70s to low 80s expected Wednesday and Thursday. With the increased rain chances Friday, highs look to be closer to the mid 70s. At the moment, winds look to remain around normal for the entire period. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 1233 AM CDT Sat May 25 2024 Terminals KABR,KATY,KPIR,KMBG VFR conditions are expected through the TAF period. LLWS (low-level wind shear) is forecast at KATY Saturday morning. Also, guidance suggests a few scattered -SHRA/-TSRA are possible near and south of KPIR around 22Z or after. For now, have a VCSH mention as confidence on areal coverage and placement of any precipitation is low. As for KPIR`s wind forecast, some uncertainty here too as a surface frontal boundary looks to be splayed out over the region during the afternoon hours, with NE winds north of the front, and SE winds south of the front. This front may hang out in the KPIR region during the afternoon, with potential for winds to waffle from SE to NE at times. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...TMT SHORT TERM...Wise LONG TERM...KK AVIATION...Vipond