562 FXUS63 KABR 160523 AFDABR Area Forecast Discussion National Weather Service Aberdeen SD 1223 AM CDT Sun Oct 16 2022 .UPDATE... Issued at 822 PM CDT Sat Oct 15 2022 The current forecast through the overnight hours looks good overall. Did reduced winds some as several obs are no longer reporting wind gusts. The winds may still become breezy overnight and into the morning hours on Sunday. UPDATE Issued at 622 PM CDT Sat Oct 15 2022 Updated aviation discussion below. && .SHORT TERM...(This Evening through Sunday Night) Issued at 339 PM CDT Sat Oct 15 2022 A small ribbon of dry air developed this afternoon from north central SD, southeast into the central James River valley, where RH has fallen below 20 percent. Models actually picking up on this fairly well, but of course given the dry air mass and surface soils/vegetation, we're ending up on the lower end of guidance dewpoints. What's interesting is that we're actually advecting in higher moisture near-surface air from the north this afternoon, and many obs have shown a min in RH earlier this afternoon, with rising RH over the past few hours. This is most evident over the eastern CWA. This small band of sub-20% RH seems to be residing a bit longer from around MBG through HON/MHE areas, although model trends do eventually take this south while also moistening things up over the next couple hours. Thought about a Red Flag warning earlier this afternoon, but residence time of the lowest RH band was in question and the areal coverage is somewhat small. Also, some places that were briefly below 20/25% RH have now risen above criteria. There are still some stubborn sites staying below, but for what it's worth this late in the game, will let the SPS for fire danger ride and may end up with a few misses in regards to the RFW. For the overnight hours. HREF cloud cover product shows the current cloud deck across ND moving south and overspreading the CWA. So once again, low temps tonight are rather tricky as we try to determine just how much cloud cover and clearing spots there will be and just how many areas decouple overnight or stay with a northwest breeze. All that said, most areas should range from the mid 20s to mid 30s for lows. Will also be watching cold air advection increasing over the area tonight as cooler air aloft moves in. Weak mid-level forcing also slides south across the area and may bring a few flurries or sprinkles to the eastern CWA, maybe even some legit rain or snow showers. For now, will mention flurries/sprinkles in the forecast and let evening shift make and updates if actual POPs seem warranted. Surface high pressure will build into the region Sunday into Sunday night, with colder temperatures moving in. After pleasant temps in the 50s and 60s today, Sunday's highs will drop back into the 40s to around 50 degrees. As the axis of high pressure settles overhead Sunday night, expect cold temperatures to develop. Not completely confident on the degree of cloudiness/clearing there will be Sunday night based on cloud output, but still anticipating lows in the teens and 20s nonetheless. Blended in a bit of NBM25 for min temps. .LONG TERM...(Monday through Saturday) Issued at 339 PM CDT Sat Oct 15 2022 Much of the long term period, through the middle of the upcoming work-week, will likely be dominated by a nearly unchanged upper- level flow pattern featuring a highly amplified ridge across the western US and a large stacked low across the eastern Great Lakes/Hudson Bay region. This will lead to continued dry conditions, and thus the continued potential for elevated grassland fire danger. At 12z Monday, temperatures should be in the 20s and teens, generally between 10 and 15 degrees below normal. Temperatures will remain relatively cold through the day, with 850mb temperatures by 18z between 0 and -10 C from west to east across the CWA (mean from both the NAEFS and ECMWF ensemble members). Meanwhile, very dry air will advect southward through the day. Mean PW values by 18z CWA- wide range from 0.35" to near 0.15" across the far east. It'll be most anomalously dry across localized portions of central MN ("min of all hours" forecast by the NAEFS), with a tight west/east gradient in percentiles extending into this CWA (10th to 0.5th percentile). Fortunately, the cold temperatures should help limit how low RH values would go. Also, the strongest winds in the atmosphere Monday will be between 700-500mb, and forecast soundings don't have us mixing that high. Still, incoming high pressure may cause enough of a gradient for breezy conditions (northerly gusts 20- 30 mph) along and east of the Prairie Coteau. Sfc high pressure moves overhead Monday night into Tuesday morning, and this should be the coldest night of the week as ideal radiational cooling develops. There's good agreement about this in the models with a narrow range of 25th-75th percentile box and whisker plots for lows across the CWA. Low teens to low 20s are most likely for lows, which is 10 to 20 degrees below normal. Thereafter, a warming trend is expected, and high temperatures Wednesday should be near to slightly above normal for mid-October, as the upper-ridge nudges further east into the Northern Plains. Just how warm it gets through the rest of the week depends on the positioning and amplitude of the upper-level ridge/trough, but uncertainty begins to increase around this time. && .AVIATION...(For the 06Z TAFS through 06Z Sunday Night) Issued at 1212 AM CDT Sun Oct 16 2022 Terminals KABR,KATY,KPIR,KMBG Low end VFR CIGS can be expected for all terminals though the overnight hours, with good VFR conditions with a mostly clear sky by Sunday afternoon. Northwest winds will remain, with a 15 to 25 knot range on Sunday. The winds will diminish around sunset. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...SD SHORT TERM...TMT LONG TERM...Lueck AVIATION...Connelly