Area Forecast Discussion
Issued by NWS Aberdeen, SD
Issued by NWS Aberdeen, SD
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777 FXUS63 KABR 251521 AAB AFDABR Area Forecast Discussion...UPDATED National Weather Service Aberdeen SD 1021 AM CDT Tue Jun 25 2024 .KEY MESSAGES... - Periodic chances(20-40%) for showers and thunderstorms this morning and tonight with dry periods in between, especially this afternoon and on Wednesday. A couple of storms will be capable of becoming strong to severe. - Two rounds of moisture for late in the week. Showers and weak storms for Wednesday night/Thursday (30-70%) and then again early Friday (30-80%). - Very cool temperatures for the upcoming weekend (5-15 degrees below normal) with lows down into the upper 40s possible Sunday morning. && .UPDATE... Issued at 1017 AM CDT Tue Jun 25 2024 No changes planned to the today period forecast at this time. Going gridded database is doing okay right now. && .SHORT TERM /TODAY THROUGH WEDNESDAY AFTERNOON/... Issued at 414 AM CDT Tue Jun 25 2024 This period will be marked by on again/off again chances for showers and thunderstorms, especially this morning and tonight. Dry conditions should eventually take hold during the day on Wednesday as sfc high pressure gradually builds in from the northwest. Returns on radar early this morning evidence of a bit of a continued agitated upper flow pattern. Showers and some thunderstorms have been moving across parts of central SD since late last evening and now some activity has started shifting east into western James Valley. Weak embedded mid level shortwave energy is working across SD in the fast westerly flow aloft. A weak sfc boundary is draped northeast into our area from sfc low pressure situated across western SD/eastern WY. This disturbance will in part allow for the persistence of this precipitation across the forecast area the remainder of the pre-dawn hours and through about mid/late morning. It will stay scattered that not everyone sees rainfall with PoPs remaining about 20-40 percent at best. Several hours of dry conditions are anticipated from around midday through at least late this afternoon. Temperatures will be cooler but still quite warm and humidity levels will be lower but remain still somewhat humid to versus what we experienced on Monday. High temperatures should top out in the 80s for most locations to around 90 degrees in a few other spots. This daytime heating will lead to increasing instability through the afternoon ahead of a weak cold front that is progged to shift south and east out of ND later today and into tonight. MLCAPE values of 1500-2500 J/kg and 0-6 km bulk shear values >40kts should be sufficient ingredients to work with to kick off some convection as the aforementioned fropa comes through and a s/w upper trough axis works southeast across the Dakotas into MN tonight into early Wednesday. The strongest of any storms that do get going would be capable of producing large hail and localized strong wind gusts. Have painted mainly our northwest zones into central and eastern zones with some low end PoPs for this anticipated activity late this afternoon into the early overnight hours. That activity should be clear of our forecast area by daybreak Wednesday morning. Sfc high pressure will gradually build in from the northwest during the day. Cooler temperatures, but still seasonal values for late June and less humid conditions can be expected for the end of this period. && .LONG TERM /WEDNESDAY EVENING THROUGH MONDAY/... Issued at 414 AM CDT Tue Jun 25 2024 Plume of monsoon moisture drifts up from the 4-corners region to link up with a wave embedded within a weak ridge that traverses the region early Thursday. NAM BUFKIT profiles point to a moist adiabatic profile with PWATS of about an inch and a half. Mid-level warm advection associated with this feature brings 700mb temperatures up to around +13C, so convection will likely be elevated. Probability of a quarter inch is still only 20-40% though the highest probability has now shifted towards the Pierre area. This is ahead of a stronger shortwave that traverses eastern Montana into North Dakota, with the surface reflection being a cold front that passes through the CWA late Thursday night/early Friday. NBM CWASP has shifted east in comparison to 24 hours ago, and is in line with the latest deterministic guidance having the front along the eastern CWA border by 18Z with low level westerly/cold advection stabilizing the low levels. High pressure follows, with an anomalously cool airmass. NBM box and whiskers for Sunday morning are consistent with about a 3-6 degree range in lows with the deterministic value right around 50 (and even upper 40s). && .AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/... Issued at 614 AM CDT Tue Jun 25 2024 Terminals KABR,KATY,KPIR,KMBG VFR conditions for all terminals. Low probability for thunderstorms at any terminal through the day and overnight for KABR/KATY. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...Dorn SHORT TERM...Vipond LONG TERM...Connelly AVIATION...Connelly