Area Forecast Discussion
Issued by NWS Aberdeen, SD
Issued by NWS Aberdeen, SD
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069 FXUS63 KABR 062321 AFDABR Area Forecast Discussion National Weather Service Aberdeen SD 621 PM CDT Mon May 6 2024 .KEY MESSAGES... - Strong to severe thunderstorms are possible across central South Dakota early this evening, where a Severe Thunderstorm Watch is in effect until 8 pm CDT. Another round of showers and non severe thunderstorms will occur across eastern South Dakota and west central Minnesota this evening into the early overnight hours. - Strong winds will translate eastward this morning with gusts to around 50 mph across the entire area through Monday evening. - The weather pattern will remain unsettled through Friday with periods of showers and thunderstorms. Below average temperatures can be expected through at least Friday, with perhaps a warming trend this weekend. && .UPDATE... Issued at 620 PM CDT Mon May 6 2024 The Severe Thunderstorm Watch continues until 01Z Tuesday for much of central South Dakota. We will continue to monitor for the potential isolated strong to severe storms this evening. Strong winds remain, with gusts of 35 to around 50 mph, strongest over central SD. A Wind Advisory remains in effect until 05Z Tuesday. The main severe weather threat is over our central SD counties, but severe weather parameters continue to weaken this evening. Over eastern SD there will be scattered thunderstorms with gusty wind and the potential for small hail, but the main threat will be brief heavy rain. This is where Precipitable Water values are 1 to 1.3". && .SHORT TERM /THIS EVENING THROUGH TUESDAY NIGHT/... Issued at 314 PM CDT Mon May 6 2024 A strong upper level shortwave trough currently just west of the CWA will swing northward tonight, then will spin in place over western North Dakota on Tuesday before weakening as it drops back over South Dakota Tuesday night. At the surface, an elongated low pressure system currently extends from eastern Montana to the Texas panhandle, with the strongest part of the low over northwestern South Dakota. In an area of somewhat clearer skies where instability has been able to increase over western South Dakota, thunderstorms have already developed. This clearing area looks to develop further east into portions of central South Dakota. Models indicate that there will be decent instability in that area (2000-3000 J/kg), as well as shear of about 40 to 45 knots for about a 2 to 3 hour period between 21Z and 00Z. As the surface boundary moves over that area during that time, it will likely become the focus for thunderstorm development, with gusty winds and large hail possible, along with a chance for a tornado or two. As the system swings northeastward this evening, the boundary will continue to be the focus for showers and thunderstorms, mainly along and east of the James River Valley. Instability and shear both weaken when this happens, so do not anticipate any severe weather. The low becomes more west to east oriented across North Dakota on Tuesday, with most of the precipitation coming to an end. Will keep some small POPs in just in case some lingering showers remain. The low broadens out and weakens Tuesday night, reducing precipitation chances even further. Strong southeast winds will continue late this afternoon and this evening, with gusts in excess of 40 mph likely. A Wind Advisory remains in effect for the entire area through midnight. May see a brief respite in the gustiness overnight, then wind speeds will pick up again on Tuesday, especially across central South Dakota. Will reevaluate the situation later tonight for possible additional headlines. Low temperatures tonight will range from the mid 40s along and west of the Missouri River, to the mid 50s across west central Minnesota. High temperatures on Tuesday will range from the lower 50s across north central South Dakota to the mid 60s across west central Minnesota. Lows Tuesday night will be in the upper 30s to the mid 40s. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... Issued at 314 PM CDT Mon May 6 2024 The long term portion of the forecast begins on Wednesday with a surface low pressure system and upper level trough crossing southeastward across the region. The storm system will bring 40 to 50% chance for showers and thunderstorms, mainly Wednesday afternoon through early Thursday morning. After a brief period of dry conditions Thursday afternoon and night, a shortwave crossing eastern SD and MN on Friday will bring a 20-30% chance of showers, mainly along and east of the James River valley. The latest NBM has trended drier west of the James, and slightly higher in northeast SD and western MN. Based on guidance from the grand ensemble, pops could be increased even more to 30-50% Friday afternoon. The weekend still appears mostly dry with seasonal temperatures. Upper level ridging west of the region will produce northwest flow aloft. High temperatures should warm into the mid 60s to the lower 70s Saturday and Sunday. While the NBM and grand ensemble are mostly dry, there are some hints of weak storm systems crossing the region this weekend and into early next week. && .AVIATION /00Z TAFS THROUGH 00Z TUESDAY/... Issued at 620 PM CDT Mon May 6 2024 Terminals KABR,KATY,KPIR,KMBG Winds gusting 35 to 45kts will only slowly diminish to around 30-35kts on Tuesday. Look for improving conditions at PIR with VFR conditions returning after the main area of rain/thunderstorms exits north. Borderline VFR to MVFR ceilings will return 07-18Z Tuesday. Scattered to steady showers and embedded thunderstorms will move into both ABR and ATY. The result will be mainly MVFR ceilings at ATY through 09Z Tuesday. While VFR conditions are currently forecast after 05Z Tuesday at ABR, confidence is low, as the site will be near MVFR ceilings during much of the next 24 hours. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...Wind Advisory until midnight CDT /11 PM MDT/ tonight for SDZ003>011-015>023-033>037-045-048-051. MN...Wind Advisory until midnight CDT tonight for MNZ039-046. && $$ UPDATE...KF SHORT TERM...Parkin LONG TERM...SD AVIATION...KF