FXUS63 KABR 051511 AAB AFDABR Area Forecast Discussion...UPDATED National Weather Service Aberdeen SD 1011 AM CDT Sun May 5 2024 .KEY MESSAGES... - Southeasterly winds increase this afternoon ahead of an approaching low. Highest gusts of 45 to 50 mph expected west river. A Wind Advisory is in effect this afternoon and evening west of the Missouri River. Strong, gusty winds spread east on Monday. - Strong low pressure will move into the Dakotas late tonight through Tuesday morning with showers and thunderstorms. Strong to severe storms are possible late Monday afternoon through Monday evening. - An unsettled and at times wet pattern looks to persist through Thursday. Temperatures will begin to turn cooler Tuesday with daily readings near to slightly below normal. && .UPDATE... Issued at 1009 AM CDT Sun May 5 2024 Current forecast is on track. Still looking for winds to increase by midday or so, especially across central South Dakota where gusts of 40 to 50 mph still look possible. No changes made to wind headlines at this time. No changes made to temperatures. && .SHORT TERM /TODAY THROUGH MONDAY AFTERNOON/... Issued at 519 AM CDT Sun May 5 2024 Sfc high pressure slides east today leaving South Dakota squeezed between the exiting high and an approaching Rocky Mountains low. Southeast winds will increase as a result. The wind advisory remains in effect for west river counties this afternoon as winds gust to 45 to 50 mph. As the low pushes into the Dakotas on Monday, strong winds will spread east across the region. Upper ridging and good mixing will help push highs into the 70s today across much of the area. A strong 979mb low then dominates the story for Monday. It's well-stacked with a deep accompanying upper trough and strong 45 to 55kt llj by Monday. Showers and thunderstorms will spread from west to east on Monday. As the system pivots through western South Dakota from 21z Monday through 3z Tuesday, chances for strong to severe storms may increase. SPC has yet to expand the marginal risk out of Lyman and Buffalo county, but models are starting to key into a more expansive risk for low-topped supercells ahead of the low in the warm sector. Can't rule out any types of severe weather at this time, as the tornado composite is even up to 1 on the border of Stanley, Hughes, and Lyman counties at 21z (at the boundary of the warm sector/dry slot in very strong turning and shear). However, the main concern is for amplification of already strong environmental winds and resulting gusts well over 60 mph. CAPE will be the one limiting factor, as there's only a very narrow, quickly moving corridor. 0-1km CAPE maxes out at 21z Monday around 700 to 1000 J/kg over Stanley county then arcs north and east through 3z, falling as it goes through the evening. Bulk shear ranges from 45 to 65 kts at this time. && .LONG TERM /MONDAY EVENING THROUGH SATURDAY/... Issued at 519 AM CDT Sun May 5 2024 Monday evening, we continue to see an upper level trough over the region. This is expected to continue to circulate over the area for a few days before moving east to park over the Great Lakes region. While circulating over MT/ND/SD, models show the low sending out multiple bands of shortwave energy. These will drive several rounds of rainfall during the first half of the forecast. Once the low moves east, we move to more of the upwind side of the trough with some shortwave energy still remaining in the area. By Saturday evening the low has moved far enough east that the upper level pattern can transition for more of a northwest flow and we no longer have shortwave energy over the region. Monday evening has significant chances for rain (50-75% decreasing after midnight) and there is a chance of some possibly strong storms, although CAPE values are low. NBM shows a consistent low level chance for some rain Tuesday through Thursday morning, with some localized increases for heavier showers. As for QPF probabilities, Monday evening to Tuesday evening areas east of a line from Hecla to Watertown have a 50 to 65% chance of more than 0.25 inches, as does western Corson county. The rest of the forecast area has less than 50% chance of more than 0.25 inches. The rest of the period remains at around or less than a 20% chance of 0.25 inches in 24 hours. Although we still have that shortwave energy in the region through Saturday, there is not much moisture for it to bring rain chances, so Friday and Saturday looks pretty dry. Temperatures through the week look to remain 5 to 10 degrees below average. However, things start to warm back up towards normal for the weekend. Winds are still expected to be strong on Tuesday, especially along the ND/SD border and in north central SD. Winds are expected to die down after sunset and stay down for the rest of the period. && .AVIATION /12Z TAFS THROUGH 12Z MONDAY/... Issued at 617 AM CDT Sun May 5 2024 Terminals KABR,KATY,KPIR,KMBG VFR conditions are expected through tonight. Southeast winds will increase with gusts up to 25 to 35 kts today. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...Wind Advisory until midnight CDT /11 PM MDT/ tonight for SDZ003- 015-033-045-048. MN...None. && $$ UPDATE...Parkin SHORT TERM...Wise LONG TERM...KK AVIATION...Wise