Area Forecast Discussion
Issued by NWS Aberdeen, SD
Issued by NWS Aberdeen, SD
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215 FXUS63 KABR 011511 AAB AFDABR Area Forecast Discussion...UPDATED National Weather Service Aberdeen SD 1011 AM CDT Sat Jun 1 2024 .KEY MESSAGES... - There is around a 30% chance of showers and storms this afternoon and evening across south central South Dakota. While an isolated severe storm is possible, the threat is low (marginal risk for severe weather, or 1 on a scale of 5). - A slight risk of severe weather (level 2 on a scale of 5) will develop Sunday afternoon and evening as cold front sweeps across the area. All severe weather hazards are possible, including large hail, damaging winds, and tornadoes. - Temperatures are forecast to rise above normal this weekend and return to normal for the work week. && .UPDATE... Issued at 1010 AM CDT Sat Jun 1 2024 The forecast remains on track this morning. No major changes are planned. && .SHORT TERM /TODAY THROUGH SUNDAY AFTERNOON/... Issued at 336 AM CDT Sat Jun 1 2024 The current surface weather map shows a broad ridge of high pressure stretching from MT through SD and southern MN. While satellite imagery indicates lower clouds and fog over far southeastern SD early this morning, our forecast area has been cloud free. This will change through the day today as the surface ridge slowly focuses on eastern SD by 18Z and shifts across MN this evening in response to an elongated area of low pressure beginning to organize to our west. Showers and a few thunderstorms mainly this afternoon will reside over south central SD. The SPC Convective outlook is marginal for that area (or at a level 1 of 5). At this point, it looks like much of the thunderstorm activity will remain south of our forecast area until this evening. Still, a few showers or storms will remain possible over our southwestern counties/closer to the nearing surface trough as MLCAPE values rise above 400 J/kg and 0-3km bulk shear magnitude values briefly increase to 35-45 kts. There is less confidence on if the storms will remain through the overnight hours, but the moderate low level jet of 30-35kts should help. The surface low looks to move into far western SD after 12Z Sunday, and reside over western SD through 18Z, allowing warm and moist air to advect across the forecast area. Dewpoints will rise into the low to mid 60s as temperatures rise into the 80s for much of the area. We`ll be monitoring the eastward progression of the surface low and associated cold front that will be the focus for strong to severe storms during the afternoon and evening hours. MLCAPE values near this boundary will rise above 2500 J/kg and 0-3 and 0-6km Bulk Shear magnitude values of 25-35kts. LCL heights generally stay below 1km through the period. We`ll be monitoring for the potential for all severe weather hazards, including damaging winds, large hail, and tornadoes (along with frequent lightning and heavy rain). The main time of concern remains highest between 22Z Sunday to 04Z Monday and east of the Missouri River. A slight risk of severe weather remains in place for Sunday (level 2 on a scale of 5). && .LONG TERM /SUNDAY EVENING THROUGH FRIDAY/... Issued at 336 AM CDT Sat Jun 1 2024 Sunday evening we are still expecting some storms in the area. These should start to diminish within a few hours of sunset. Monday, the upper level flow pattern is generally from the west southwest and becomes more southwesterly through the day. By Tuesday morning the downwind side of the low is over the region with its deep moisture layer bringing the next chance for rain. Deterministic models seem to be a bit more in agreement this run with very similar tracks and timing across all 3 major models. The Canadian model does show a slightly weaker low and with that, the shortwave energy doesn`t reach as far back as the EC or GFS. Once the low moves off, the models start to differ. The EC shows a second low coming in on the trough of the first, moving southeast to miss us, but pushing the trough south and bringing a wave of shortwave energy north to south across the area. The GFS and Canadian show us staying either on the downwind side of a trough or in northwest flow through the end of the period. As mentioned above, storms are still possible into Sunday evening, probably ending before 10 PM. These storms have a chance to be strong/severe with large hail and strong winds being the main threats. The next chance for rain/storms looks to be Tuesday as the low starts to move into the region. Areas east of the Missouri River will be the most likely area for storms to form as the cold front moves west to east across SD. Lapse rates are around 6.5 to 7.25 C/km and MLCAPE values are around 1500 to 2000 J/kg especially around and east of the James River valley. With lapse rates a little on the low side, confidence is low on severe potential. The rest of the period looks to be dry. Monday looks to be as much as 10 degrees above average with highs in the low to mid 80s possible mainly west river. Overnight temps are also expected to be around 10 degrees above average with lows only getting down into the low 60s. Starting Tuesday, high and low temperatures will be around average through the period. We have some strong CAA moving through the region Wednesday that will cause some strong wind gusts particularly west river where gusts could exceed 40 mph. Gusts of 30-35 mph are possible east of the Missouri. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 634 AM CDT Sat Jun 1 2024 Terminals KABR,KATY,KPIR,KMBG VFR conditions remain at all TAF locations. There is a 10-20% chance of showers and potentially thunderstorms at PIR after 19Z today, and at the remainder of the TAF sites after 06Z Sunday. Given the low potential, no mention was included at this time. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...Wise SHORT TERM...KF LONG TERM...KK AVIATION...KF