865 FXUS63 KABR 161738 AAC AFDABR Area Forecast Discussion...UPDATED National Weather Service Aberdeen SD 1238 PM CDT Thu May 16 2024 .KEY MESSAGES... - A weak disturbance will bring a 20 to 30 percent chance for showers and thunderstorms to areas along the North Dakota/South Dakota border this afternoon and evening. - Above average temperatures can be expected on Friday with highs in the 80s. A few locations may exceed 90 degrees. - A frontal boundary crossing the area late Friday afternoon and Friday night will be the focus for a 30 to 60 percent chance for thunderstorms. Some may be severe across parts of central South Dakota. - Westerly winds with gusts of 35 to 45 mph will be possible Saturday afternoon. The highest wind gusts should occur over north central South Dakota. && .UPDATE... Issued at 1233 PM CDT Thu May 16 2024 Aviation discussion updated below for the 18Z TAFs. UPDATE Issued at 946 AM CDT Thu May 16 2024 Made some minor adjustments to sky cover based on current satellite trends. Otherwise, much of the forecast appears on track for today. Still expect widely scattered showers and thunderstorms across ND into parts of northern SD late this afternoon through this evening and will maintain small chances (20-30%) PoPs for this. && .SHORT TERM /TODAY THROUGH FRIDAY AFTERNOON/... Issued at 318 AM CDT Thu May 16 2024 An upper level trough currently over the region will gradually track off to the east today, with a more zonal flow setting up tonight. Weak ridging then develops on Friday ahead of another approaching shortwave trough. At the surface, weak high pressure will remain over the area today, with dry conditions expected most of the day. A warm front associated with low pressure over Montana will set up along the North Dakota/South Dakota border late this afternoon into the evening, and may be the focus for some shower and thunderstorm development. The better instability (MUCAPE of 1000-1500 J/kg) looks to be a bit south of the boundary, so just looking at a small chance (15 to 25 percent) for showers and non-severe thunderstorms across the northern CWA. The overnight hours into the morning hours on Friday will be dry, then the stronger cold front associated with the low will approach, reaching the far western CWA by early Friday evening. Very warm air will be ushered into the region ahead of the front, which will result in some decent instability (MUCAPE of 1500- 2500 J/kg) developing over much of the CWA. Fairly strong shear (bulk shear values of 40 to 60 knots) will occur along the front, which looks to be the focus for thunderstorms (30 to 45 percent chance) late Friday afternoon/early Friday evening across parts of north central South Dakota. SPC has highlighted this area with a Marginal Risk for severe weather, with strong winds gusts being the main threat. High temperatures today will be in the 70s. Low temperatures tonight will be in the lower to mid 50s. Highs on Friday will be in the 80s. && .LONG TERM /FRIDAY EVENING THROUGH WEDNESDAY/... Issued at 318 AM CDT Thu May 16 2024 The long term portion of the forecast begins on Friday night with a frontal boundary pushing eastward across the region. Models have trended drier across this CWA, with pcpn best along the frontal boundary over North Dakota. Warm 700 mb temps (above the 90th percentile) may cap convection over the southern, and perhaps the eastern portion of the CWA. The convection should exit the CWA by 12Z Saturday with dry conditions and cooler temperatures moving into the region. With the mid level trough near the CWA, along with a tight pressure gradient, Saturday will feature westerly winds with gusts exceeding 35 to 45 mph at times. ECMWF ensemble data suggests there is a 60 percent chance wind gusts at KABR will be 35 mph or stronger Saturday afternoon. The probability is higher further west, especially over north central SD. If model trends continue, a wind headline may be needed on Saturday. Another low pressure system and upper level tough should cross the region Sunday through Monday, bringing a round of showers and thunderstorms. The pcpn potential is best, 30-50% Sunday night. Some deterministic models are showing drier condition Monday into Tuesday. However, with the region under the influence of an upper level trough, isolated to scattered showers and thunderstorms may be possible at times. && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... Issued at 1233 PM CDT Thu May 16 2024 Terminals KABR,KATY,KPIR,KMBG VFR conditions are forecast to prevail through the TAF period. Late this afternoon and through the evening, a few widely scattered -SHRA/-TSRA are possible along the ND/SD border. Confidence is very low as to whether or not any of this activity makes it as far south as KMBG/KABR, so won't even include a vicinity (VC) mention at this time, but may consider for the 00Z TAFs once activity becomes more apparent. Any storms that develop would likely remain VFR CIGs, but could contain MVFR VSBY and brief gusty surface winds over 35 knots. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...TMT SHORT TERM...Parkin LONG TERM...SD AVIATION...TMT