Area Forecast Discussion
Issued by NWS Aberdeen, SD
Issued by NWS Aberdeen, SD
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692 FXUS63 KABR 071741 AAB AFDABR Area Forecast Discussion...UPDATED National Weather Service Aberdeen SD 1241 PM CDT Sun Jul 7 2024 .KEY MESSAGES... - There is a 40% chance of precipitation in the form of showers and thunderstorms this afternoon into the early evening hours. Severe weather is not expected at this time, although lightning is expected. - Isolated shower and thunderstorm chances (15-25%) remain in the forecast on both Monday and Tuesday, mainly during the afternoon and evening hours across northeastern SD into west central MN. - Heat and humidity will be on the increase through the week into the weekend. By Friday/Saturday temperatures will be about 5 to 10 degrees above average, with highs in the upper 80s to mid 90s and lows in the upper 60s to near 70 with dewpoints well into the 60s to near 70 degrees. && .UPDATE... Issued at 1233 PM CDT Sun Jul 7 2024 See the updated aviation discussion below. UPDATE Issued at 954 AM CDT Sun Jul 7 2024 As of 930AM, skies were party to mostly sunny across the CWA with winds out of the west to northwest around 5 to 10 mph. Temperatures range from the mid to upper 60s to the lower 70s across the area. Radar indicates a few lingering rain showers over parts of central SD, pushing east. Otherwise dry for the next few hours before showers and thunderstorms form this afternoon and evening with daytime heating. Few of the storms, if strong enough, could produce small hail with the main threat being lightning. Severe weather is not anticipated. Forecast remains on track for the rest of the day. && .SHORT TERM /TODAY THROUGH MONDAY AFTERNOON/... Issued at 333 AM CDT Sun Jul 7 2024 We have yet another day of mainly afternoon and early evening convection, with the chance of precipitation being near 40%. While there will again be another 500mb shortwave moving through this afternoon (currently set up from northern MN through western ND and northwestern SD), west to northwesterly flow has set up at the surface. The surface trough will be in MN by the time we reach daytime heating. Plenty of moisture remains, with dewpoints in the upper 50s to low 60s today, and PW values are around 1". Expect lightning to be the main concern with any stronger storms this afternoon. However, we can`t rule out some small, mainly pea-sized hail. The broad surface high will continue to slowly build a ridge across the Dakotas and western MN Monday, with the 500mb trough focused to our east/across MN and WI. So, while there will again be the potential for afternoon convection, it will become more limited in intensity and coverage. The chance of precipitation Monday afternoon is only 20%, and mainly east of the James River. Confidence remains high in the temperature forecast, with little spread in the probabilities through the short term period. For today that means highs in the upper 70s to near 80 degrees. && .LONG TERM /MONDAY EVENING THROUGH SATURDAY/... Issued at 333 AM CDT Sun Jul 7 2024 Main themes again during the extended are the weakly unstable atmosphere during the afternoons thanks to ample low level humidity and relatively un-anomalous mid level temperatures, and the eventual warmer air aloft and hotter temperatures. Will once again enhance POPs for Tuesday afternoon over the NBM with NAM BUFKIT profiles showing weak instability (skinny CAPE) and a weakly sheared environment, under northwest flow with a subtle upper wave in North Dakota. This is all while the persistent upper trough is finally moving over into the eastern CONUS. Thereafter, we start to see the ridge fold over into the Northern Plains, as a surface high/heat dome shifts into the central Rockies. Mid level temperatures begin to warm, and while not exceptionally fast or anomalously high, enough to stabilize the atmosphere, despite the presence of several subtle waves moving across the top of this upper level high towards the Western Lakes region. We don`t actually begin to see 700mb/850mb thermal anomalies begin to reach a standard deviation above climo until the Friday/Saturday timeframe however. During the course of the extended, NBM box and whiskers for both high and low temperatures show a slow steady increase with a fairly confident range of only 3-5F. Additionally, there is generally a slowly increasing trend in the 25th/75th percentile range of dewpoints, with fewer/weaker transient systems allowing for the ET of recent ample moisture to build up. Forecast heat index values currently reside below advisory criteria, however we are 1) beginning to see low temperatures migrate into the mid/upper 60s to near 70 and 2) the HeatRisk scale increases well into Moderate category with some locations peaking at Major category. Still suspect the NBM dewpoints are underrepresented given the current growth stage of corn and the amount of moisture we have received across the region over the last few weeks. && .AVIATION /18Z TAFS THROUGH 18Z MONDAY/... Issued at 1233 PM CDT Sun Jul 7 2024 Terminals KABR,KATY,KPIR,KMBG VFR conditions will prevail through the period. The only concern will be late afternoon diurnally induced showers and thunderstorms. These will be very limited in coverage and will dissipate with loss of daytime heating. Low predictability in the location of any single pulse storm, so carried VCTS in the TAFs and will amend as necessary. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...Serr SHORT TERM...KF LONG TERM...Connelly AVIATION...Serr