Area Forecast Discussion
Issued by NWS Aberdeen, SD
Issued by NWS Aberdeen, SD
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429 FXUS63 KABR 111733 AAC AFDABR Area Forecast Discussion...UPDATED National Weather Service Aberdeen SD 1233 PM CDT Thu Jul 11 2024 .KEY MESSAGES... - While mainly dry weather will continue, isolated late evening and overnight showers and thunderstorms will be possible through at least the weekend due to weak disturbances moving through the region. Chances of precipitation are less than 30 percent not only through the weekend, but through the middle of next week. - High confidence in hot and muggy conditions Friday through Sunday. High temperatures will be in the 90s (5-10 degrees above average) with dewpoints in the mid to upper 60s. This will result in heat index values in the mid and upper 90s with a few spots to 100 degrees during the afternoon hours. - Temperatures will moderate with lower humidity for the first half of next week. && .UPDATE... Issued at 1231 PM CDT Thu Jul 11 2024 Aviation discussion updated below for the 18Z TAFs. UPDATE Issued at 1021 AM CDT Thu Jul 11 2024 Current forecast has things handled well through 00Z, so no big updated planned. Skies will remain mostly sunny with southerly breezes as highs rise into the 80s to around 90 degrees. && .SHORT TERM /TODAY THROUGH FRIDAY AFTERNOON/... Issued at 254 AM CDT Thu Jul 11 2024 At 07Z the surface high stretched from north central NE through southeastern SD and through Lake Superior. At 500mb the northerly flow continued with the ridge stretching from the southwestern U.S. through MT and the western Dakotas. We`ll continue to see this ridge slowly inch our direction. The main result will be increasing temperatures and dewpoints. The changes will be limited today, with temperatures at most locations 1-5 degrees higher than what was realized Wednesday. While dry weather is expected today, we won`t be able to completely rule out showers and a few thunderstorms, with a 15-25% chance of precipitation overnight tonight over mainly central SD. There will be a 30-35kt low level jet developing overnight and a weak 500mb wave rotating through central SD, helping to support the development of showers and storms. We will need to monitor the latest model trends as some solutions like the 00Z run of the FV3 are more robust than others with a scattered line of storms over western SD by 00Z Friday. At this point the consensus is to keep dry conditions going along and east of the James River Valley. Will highlight the potential for thunderstorms across central SD in the HWO. Surface dewpoints will increase during the day Friday, getting into the upper 60s. Temperatures again, an average of about 5F, topping out in the 90s with a few mid 80s east the the James River Valley. && .LONG TERM /FRIDAY EVENING THROUGH WEDNESDAY/... Issued at 254 AM CDT Thu Jul 11 2024 The very summertime-like pattern continues as advertised for the extended with an upper high over the Four Corners region, and zonal flow with weak embedded waves for the northern tier of the country. Guidance still has the warmest mid level temperatures for the weekend, although it should be noted there has been a slight increase in POPs/cloud cover associated with these ridge-riding systems. A Sunday morning system actually has cause some of that peak heat to shift away from the northeast of the state as convection is likely to produce or form along a backdoor cold front which all the major deterministic models are portraying. NBM probabilities for seeing 100F are mainly limited to the Pierre area regardless, with less than 10-20% probability for north central SD into the James valley. Current NBM dewpoints approaching 70F are also appropriate as we are seeing CAMS come in with low 70s under the southeast low level flow regime during the later portion of the short term. I`m sure they will need a slight nudge upwards due to evapotranspiration, but generally current NBM values are close enough at this point. As such, NBM is generating widespread heat index values in the upper 90s, with a few spots up around 100F. After the weekend, we continue to see a drop in 850mb temperatures as northwest flow over the western lakes region intensifies drawing Canadian air into the region. This will also reduce dewpoints down to closer to what we`ve seen over the previous few days this week here. The Four Corners high weakens, so these fairly seasonal temperatures/modest humidity should dominate for several days to come. && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... Issued at 1231 PM CDT Thu Jul 11 2024 Terminals KABR,KATY,KPIR,KMBG VFR conditions are forecast through the TAF period. A stray shower or two are possible across central SD late tonight, so have included a VCSH mention at KPIR. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...TMT SHORT TERM...KF LONG TERM...Connelly AVIATION...TMT