596 FXUS63 KABR 081748 AFDABR Area Forecast Discussion National Weather Service Aberdeen SD 1148 AM CST Wed Nov 8 2023 .UPDATE... Issued at 1147 AM CST Wed Nov 8 2023 The Wind Advisory remains over portions of north central SD this afternoon. Have been impressed with the winds being reported around the Pierre area so far this morning with the initial push of northwest winds. Will continue to monitor the trends this afternoon and adjust the wind forecast. Otherwise, no significant changes are anticipated. && .SHORT TERM...(Today through Thursday Afternoon) Issued at 257 AM CST Wed Nov 8 2023 Key Messages: - Fog to start things off early this morning in the James River valley. - Strong enough post cold-frontal northwest winds to warrant an advisory over, at least, parts of north central South Dakota today. - More 15 to 25 mph northwest winds on Thursday, with gusts perhaps as high as 40 mph. At 2 AM CST, skies are partly cloudy, and patchy fog dots the map across central/north central South Dakota, while more widespread dense fog has developed and taken up residence across the James River valley early this morning. Temperatures, for the most part are running in the upper 20s to upper 30s, while a strong cold front out over the northern high plains (eastern Montana/far western North Dakota) is poised to sweep through the CWA a bit later on today. Again, with visibility down to one quarter mile or less over multiple counties early this morning, went ahead and tossed out a Dense Fog Advisory until 7 AM CST throughout the James River valley. As the period opens, upper level longwave troughiness is being carved out over the northern plains (and eventually into the Great Lakes region). This broad cyclonic longwave troughiness lingers into Thursday; the type of pattern that supports prolonged low level CAA. It's not the strongest cold front to ever sweep through the northern plains, but the front that sweeps through the CWA today should yield enough CAA and pressure rises in its wake during "daytime mixing" to support sustained winds near 30 mph for an hour or two early this afternoon, mainly out over portions of north central South Dakota. Gusts could be running up into the 40 to 50 mph range for a few hours today, as well. The CAA isn't done today, though. More low level CAA will filter into the CWA on Thursday, while 25 to 35 knots of northwesterly mixing layer-capable winds are still hanging around. So, maybe not with quite the same pressure rise "punch" as today, there should still be some 15 to 25 mph winds with gusts to 35-40 mph possible on Thursday. It may just take a little longer to achieve/mix out these breezy/windy conditions. Ensemble S.A. table 850hpa temp anomalies confirm what deterministic solutions are showcasing for mixing layer air temperature today and Thursday; warmer 925hpa and 850hpa air in place to start today eventually being replaced by cooler air, such that today's high temperatures will probably end up being 5 to 10 degrees warmer (highs in the upper 40s to mid 50s) than Thursday's high temperatures (near 40 to upper 40s). .LONG TERM...(Thursday Evening through Tuesday) Issued at 257 AM CST Wed Nov 8 2023 KEY MESSAGES: * Split flow pattern through the weekend with a strengthening omega block pattern next week, keeping the area dry. * Cooler Friday with above average temperatures Sunday into next week where temps are forecasted to be quite a bit above average (especially Mon-Wed where temps could be 15-20 degrees above average). Clusters agree on split flow continuing with the axis of the ridge over Saskatchewan and a trough over southern/southwest U.S. Friday. By Saturday the ridge moves east with a shortwave across the upper Rockies/Northern Plains and the trough/low over the Baja, Ca area. By Sunday, Clusters still agree fairly well of this ridge over Ontario with another ridge moving in over the western Conus and a trough over the Pacific. By early next week this ridge will be over much of central and upper Midwest with the trough still over the Pacific. Towards the middle of the next week, a negative PNA pattern sets up with the trough coming onshore over the western Conus and the ridge over central and eastern Conus. Variations exists between the Clusters on exact placement and intensity of both the ridge/trough but even this far out the ensembles/members agree on the overall pattern. As mentioned above, this shortwave will sweep across the Northern Plains Saturday along with a weak low/sfc trough. EC meteograms hint at 10% chance or less of possible precip at KATY/KPIR/KMBG. However, GFS RH at lower levels remain pretty dry with moisture aloft present in the form of passing clouds. Latest NBM run still keeps the area dry so just something to watch for as confidence remains low at this time. Otherwise, with the ridge overhead into next week this will keep the area in a dry pattern. the Climate Prediction Center indicates a 50-60% chance of below average precipitation for next week. With a high pressure system moving in over the area Friday, this will bring in cooler air as 850mb temps range from -5 to +2C. NBM 25- 75th spread is about 5-6 degrees at each site with the coolest temps in the upper 30s/lower 40s and highest in the mid/upper 40s. A few degrees warmer on Saturday as the high moves east/southeast. The spread still around 5-6 degrees or so for Saturday ranging in the 40s to maybe the lower 50s. We really see the warm up start on Sunday with the incoming ridge with the warmest temps looking to be Monday-Wednesday. There is still a 5-8 degree spread depending on the intensity of this ridge and WAA. Highs look to range well into the mid/upper 50s to the lower/mid 60s and lows in the 30s/lower 40s. Climate Prediction Center indicates between 70-90% above average temps next week. No complaints here! && .AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon) Issued at 1147 AM CST Wed Nov 8 2023 Terminals KABR,KATY,KPIR,KMBG While mainly VFR ceilings and vis are expected to continue over the next 24 hours, the main concern will be strong winds today and tomorrow mainly during the daytime hours. Gusts of 30-40kts will be possible, strongest at MBG this afternoon. Borderline MVFR ceilings continue near MBG and ABR early this afternoon. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...Wind Advisory until 4 PM MST this afternoon for SDZ003-015. MN...None. && $$ UPDATE...KF SHORT TERM...Dorn LONG TERM...MMM AVIATION...KF