Area Forecast Discussion
Issued by NWS Aberdeen, SD
Issued by NWS Aberdeen, SD
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256 FXUS63 KABR 110438 AFDABR Area Forecast Discussion National Weather Service Aberdeen SD 1138 PM CDT Fri May 10 2024 .KEY MESSAGES... - Above normal temperatures (about 10-15 degrees Saturday/5-10 degrees Sunday) with dry conditions through the weekend. - Precipitation chances return to the area Tuesday with the highest probability of rainfall occurring Tuesday afternoon through Wednesday morning (30-60%). && .UPDATE... Issued at 602 PM CDT Fri May 10 2024 The afternoon cumulus clouds will continue to diminish over the next couple of hours, leading to a mostly clear sky overnight. Few changes were needed to the ongoing forecast. && .SHORT TERM /THIS EVENING THROUGH SATURDAY NIGHT/... Issued at 205 PM CDT Fri May 10 2024 Passage of weak cold front has resulted in gusty north/northwest winds with a few spots in excess of 40mph, but aside from an exception or two, below wind advisory criteria. These winds will subside this evening with loss of daytime heating, a surface ridge moves overhead and gradient weakens. Aloft, its a northwest flow regime as an upper trough moves out of the eastern Dakotas/Minnesota, with dry air aloft spilling over a northwest Pacific/western Canada ridge. This will provide ideal conditions for auroral viewing tonight. As the ridge heads east for Saturday, low level flow becomes westerly, which will enhance mixing under 850mb warm advection. Will lean towards the NBM 75th percentile for highs/temperatures and anticipate better mixing out of dewpoints in the afternoon. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Issued at 205 PM CDT Fri May 10 2024 Clusters agree on continuing split flow for the start of the long term as the ridge axis will be over western Canada and pushing eastward through the evening. Through the day Monday, this ridge becomes more positive tilted as it moves overhead. There is a difference on how amplified the ridge will be by Monday evening as Clusters 1 and 3 (made up of mostly EC) keep it more amplified than Clusters 2/4 (made up of majority GEFS/GEPS). Following this ridge will be our next system as a trough sets up over the northwestern U.S into western Canada and pushes east over the Northern Plains Tuesday night into Wednesday, along with its surface low. The Clusters made up of mostly EC seem to show a little faster movement into the Northern Plains than GEFS/GEPS, with GEFS/GEPS indicating this trough being a bit deeper and positive tilted. Through the day Wednesday we really see differences in the Clusters with overall timing and intensity as this wave pushes east. Day 7 and onward is split 50/50 on either a ridge over the western CONUS or zonal/another trough moving in. With this setup, a surface trough/weak cold front will pass over the CWA, associated with a low moving east over Ontario/Hudson Bay area on Sunday. Main indicator will be a wind shift behind it out of the northeast as low levels remain dry. However, some shortwave energy riding down the ridge could support very isolated chances of rain showers. GEFS seems to be more aggressive on this shortwave energy than EC/GEPS. Latest NBM indicates a 14% chance or less Sunday late afternoon and evening. 15-20% pops are in the grids over the Coteau for this time. With this next low moving in Monday night, ensembles show moisture increasing from northwest to southeast over the CWA through Tuesday morning (20-40%), becoming widespread with our highest chances of rains Tuesday afternoon and evening (40-60% pops). Rain chances continue Wed as the front pushes east (20-40%), highest over our eastern CWA. No organized severe weather is expected but there is enough CAPE and some shear for some thunder chances during the afternoon through even hours on Tuesday. Highs will remain above average for Sunday ranging in the mid to upper 70s to the lower 80s. Slightly cooler air moves in Monday with highs in the 60s to lower 70s with a bit of a rebound on Tuesday. Temps look to cool again midweek. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 1138 PM CDT Fri May 10 2024 Terminals KABR,KATY,KPIR,KMBG VFR ceilings and visibility will continue over the next 24 hours. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...KF SHORT TERM...Connelly LONG TERM...MMM AVIATION...KF