Area Forecast Discussion
Issued by NWS Aberdeen, SD
Issued by NWS Aberdeen, SD
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196 FXUS63 KABR 300909 AFDABR Area Forecast Discussion National Weather Service Aberdeen SD 409 AM CDT Thu May 30 2024 .KEY MESSAGES... - A storm system moving through the region today will lead to a 40-80 percent chance for showers and thunderstorms. Although severe storms are not expected, there could be a few stronger storms that develop by afternoon across northeast SD and west central MN as a cold front moves into the area. - There is a 50-70+% chance for showers and thunderstorms between Sunday afternoon and late Sunday evening. Other mentionable potential periods of precipitation include Saturday night (20-45% chance) and Tuesday afternoon/evening (20-40% chance). - Temperatures are forecast to rise above normal over the weekend and into next week (highs in the 80s). && .SHORT TERM /TODAY THROUGH FRIDAY AFTERNOON/... Issued at 407 AM CDT Thu May 30 2024 The overall theme in this forecast period will continue to reflect an active weather pattern at times across our forecast area through the end of the week. A sfc low pressure system, currently located across portions of northern ND early this morning, with a trailing occluded frontal boundary extending southward into parts of western and central SD is in part responsible for the ongoing scattered showers and thunderstorms across the western and central Dakotas. Most of this activity has remained rather benign so far as ingredients remain rather lacking for any strong to severe storms. Things may change and evolve into more of a active situation, convectively speaking, as we get into the daytime hours today. A pretty stout low level jet has set up early this morning, especially across our eastern zones. KABR VAD Wind Profile indicates 50kts observed just off the deck. Some CAM solutions generate scattered convection developing closer to daybreak in the James Valley, perhaps on the nose of this low level jet that begins to impinge on portions of northeast SD. Perusing the convective parameter progs going through the morning hours today, we do see instability remaining fairly low and deep layer shear unimpressive. By midday into the afternoon, a narrow ribbon of some higher instability builds across our eastern zones(I-29 corridor and east). Now, this instability is far from mentionable with MLCAPE values up around 1000-1200 J/kg. 0-6 km bulk shear values are lacking ahead of the sfc boundary on the order of about 20-25kts. However, low level lapse rates are expected to be steep around 7 C/km for a short time this afternoon in our eastern zones. All this to say is we`ll likely get convection to develop along and out ahead of the advancing sfc frontal boundary, but most storms should remain sub-severe. CAMs depict a scattered line of thunderstorms setting up across the James Valley closer to midday and shifting east with time through the late afternoon hours. Wouldn`t be surprised if a couple storms get strong enough for some small hail and localized gusty winds, but ingredients are a better for more organized severe weather just to our south in southeast SD and eastern NE this afternoon. Breezy southeast sfc winds ahead of the aforementioned boundary in the east will be persist through the late morning, while winds turn west to northwest behind the front across central SD by mid morning. Stronger northwest wind gusts will be possible through the afternoon across north central SD with speeds reaching 25-35mph. The sfc frontal boundary will get shunted eastward as the upper level trough currently across the Northern High Plains shifts eastward across the US/Canadian border region. Rain chances will end from west to east through the morning into the afternoon, lingering the longest across our eastern zones through late this afternoon into the evening. Sfc high pressure briefly tries to build into the area tonight into Friday. However, with the sfc front stalling out south of our area and perhaps some lingering s/w energy working through the mid level flow across southern SD on Friday, we could see some showers returning to parts of the area by by midday and the afternoon. && .LONG TERM /FRIDAY EVENING THROUGH WEDNESDAY/... Issued at 407 AM CDT Thu May 30 2024 Clusters analysis continues to support a semi-progressive upper flow pattern with the best precipitation chances attached to mid/upper level systems progged for Sunday and Tuesday. Still a lot of time to conjecture over whether or not there is a severe weather threat attached to either of these systems. But, timing-wise, right now, models are still working frontal boundaries through the CWA Sunday and Tuesday during peak-heating. So, there`s that. Beyond Tuesday, it still looks like an upper level ridge will be trying to establish across the western two-thirds of the CONUS, including over this CWA, while a longwave upper trof hangs out over the east coast of the CONUS. Also, regarding precipitation chances, will have to see what happens Saturday night, when a low level jet is forecast to develop down near the Nebraska/South Dakota border and spread north overnight. Other things needed for convection include low/mid-level WAA and a good low level moisture feed. And, some upper level jet support (lift) would be helpful. Will have to see if all these ingredients can come together to promote nocturnal convective development late Saturday night/early Sunday morning. Otherwise, the temperature forecast remains a toasty one in the out periods. The probability of seeing the temperature warm to 90 degrees or higher has increased now, for Sunday, to 40 to 55% across portions of the southwestern forecast zones. Seems like high temperatures climbing into the 80s is a good bet for much of the CWA for much of the out periods. && .AVIATION /06Z TAFS THROUGH 06Z THURSDAY/... Issued at 1240 AM CDT Thu May 30 2024 Terminals KABR,KATY,KPIR,KMBG There will be a mix of VFR to MVFR conditions through at least the first half of this TAF valid period. Scattered showers and thunderstorms across central SD early this morning will mainly affect the KPIR and KMBG terminals through at least the next 6-9 hours or so. This activity will shift east into northeast SD closer to daybreak and affect KABR and KATY terminals during the mid morning through mid to late afternoon hours. Occasional MVFR cigs will be possible at KMBG during the overnight hours this morning. It appears more likely that MVFR cigs will be possible at KABR and KATY by mid morning through late afternoon. Southeasterly winds this morning will switch to the west-northwest as a cold front slowly shifts west to east across the TAF sites today. There will be some LLWS possible at any terminal, especially in the east overnight as a low level jet sets up. VFR conditions will return to all terminals by the end of this forecast period. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ SHORT TERM...Vipond LONG TERM...Dorn AVIATION...Vipond