Area Forecast Discussion
Issued by NWS Aberdeen, SD
Issued by NWS Aberdeen, SD
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960 FXUS63 KABR 211844 AFDABR Area Forecast Discussion National Weather Service Aberdeen SD 144 PM CDT Tue May 21 2024 .KEY MESSAGES... - Strong north wind gusts of 45-55mph will persist late into this evening before diminishing overnight. - An unsettled weather pattern continues with another shot of moisture possible Thursday into Friday and again Sunday into Monday. - Except for a brief potential warm up on Thursday, temperature guidance remains near to below normal Friday through Monday. - Chance of frost/freeze Friday and Saturday mornings with low temps near freezing. && .SHORT TERM /THIS EVENING THROUGH WEDNESDAY NIGHT/... Issued at 143 PM CDT Tue May 21 2024 At 1 PM CDT, a moderate to heavy rainfall event is ongoing across far northeast South Dakota and west central Minnesota. Temperatures under clouds and rain are holding in the 50s this afternoon. Further west, where cloud cover is less/thinner and there is no rainfall occurring, temperatures have been able to warm into the low to mid 60s. Across the wind advised region of the CWA, north winds have increased, at times, into advisory criteria sustained winds (30mph) and gusts (45mph or greater). The current deformation-zone-forced precipitation occurring over northeast South Dakota will shift off to the northeast, as the upper circulation/lift support pulls away from the region. The ongoing strong winds across the far eastern forecast zones will gradually diminish late this evening into the overnight hours. So, for now, will leave the expiration time at 11 PM CDT. From late tonight through Wednesday night, the forecast goes dry, as surface high pressure settle over the region. Wednesday night, the surface high shifts away from the CWA, and return flow southerly/southeasterly winds develop. There is a low level jet progged to form over the CWA Wednesday night, but right now, it does not appear that sufficient LLM recovers in time to support elevated, nose-of-the-low level jet convection. Low temperatures tonight and Wednesday night should be running close to, or perhaps a little bit below, normal. If the HREF is correct, and there is more sun than clouds on Wednesday, then high temperatures warming into the 60s and 70s seems achievable. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Issued at 143 PM CDT Tue May 21 2024 The long term period will have a couple chances for rain as some lows roll through the region. The first will be Friday morning through possibly Saturday morning. Deterministic models all have the upper level low in approximately the same area of ND/SD. Since the Canadian model has the low a little farther south, it stays in the area a little longer (into early Saturday morning). In general, the low moves northeast and out of the region by 7AM Saturday. The EC and GFS have another low coming into the area late Sunday into Monday. The upper level low passes over western and south central SD. The end of the period shows a large ridge building to our west and moving towards the region. Thursday afternoon, ahead of the Friday system there is a chance (30- 80%) for rain and some storms. At the moment, SPC has the southeastern portion of SD in a marginal (1 of 5) risk for severe storms. While mid level lapse rates look pretty favorable across deterministic models (between 6.8 and 8.4 C/km), CAPE is pretty variable. The EC has anywhere from 100 J/kg of MLCAPE to 1000 J/kg. The Canadian and GFS have the most MLCAPE in the risk area - between 1500 and 2000 J/kg. As for bulk shear, all deterministic models have at least 35 kts, so fairly favorable for storm formation. Threats are hard to nail down right now, but leaning towards hail. General (non-severe) thunderstorms will be possible across the forecast area. Rain chances (30-60%) continue into Friday morning. The next chance of rain looks to be Sunday afternoon through the day Monday (30-50%). It is possible that storms could form but being 5/6 days out, severe potential is hard to determine. Temperatures will be up and down during the period with the lows bringing clouds and rain. The first day of the long term looks to be around average with highs in the mid 70s. Then, for the holiday weekend, temperatures look to be in the 60s to low 70s with those rain chances. For the end of the period, temperatures look to warm back up into the mid to upper 70s. NBM is starting to show a chance for some overnight temperatures close to the freezing mark for Friday morning and Saturday morning. We will be keeping an eye on this, but Saturday morning looks a bit more likely for some frost or a freeze, with around a 30% chance of temperatures at or below 32 degrees for areas of northern SD between Herried and Long Lake. Winds could gust up to 35 mph in Corson and northern Dewey counties Thursday afternoon, and then over the Coteau Friday afternoon. Otherwise, winds stay around normal through the period. && .AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 1230 PM CDT Tue May 21 2024 Terminals KABR,KATY,KPIR,KMBG KATY will be in and out of IFR conditions through late this afternoon before conditions improve to prevailing VFR. But, VFR conditions are forecast at KABR/KPIR and KMBG through the TAF valid period. North winds for KATY have come up and will range from 20 to 30 knots sustained, with gusts ranging from 35 to 45 knots through late this evening, before diminishing overnight. Rain is expected to persist at KABR and KATY this afternoon. But, after 00Z, TAFS for all four terminals should be dry. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...Wind Advisory until 11 PM CDT this evening for SDZ007-008-011- 019>023. MN...Wind Advisory until 11 PM CDT this evening for MNZ039-046. && $$ SHORT TERM...Dorn LONG TERM...KK AVIATION...Dorn