Area Forecast Discussion
Issued by NWS Aberdeen, SD
Issued by NWS Aberdeen, SD
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255 FXUS63 KABR 122334 AAA AFDABR Area Forecast Discussion...UPDATED National Weather Service Aberdeen SD 634 PM CDT Sun May 12 2024 .KEY MESSAGES... - Northerly winds with smoke coming out of Canada. Worst air quality is current, with slow improvement tonight/Monday. - Near normal temperatures next several days. - Precipitation chances return to the area Tuesday through Wednesday evening (30-75% chance). && .UPDATE... Issued at 629 PM CDT Sun May 12 2024 See below for an aviation forecast discussion for the 00Z TAFs. && .SHORT TERM /THIS EVENING THROUGH MONDAY NIGHT/... Issued at 236 PM CDT Sun May 12 2024 Low pressure in eastern Canada, and high pressure in its wake, is feeding smoke out of central Canada, though the highest concentration of smoke is currently overhead and HRRR smoke products show a slow diminishment tonight/Monday with it lingering in the northeast of the state and western Minnesota though much of Monday morning. There is also a weak shortwave embedded in a northwest flow regime over the western Dakotas and eastern Montana. This feature will drift slowly southeast, overrunning the high pressure at the surface. Thus, looking at mainly high based/weak showers with little actual QPF. High pressure and upper ridging dominate Monday till we begin to see diffluent flow associated with the next wave coming in from the west for early Tuesday. A front along the gulf will block any moisture return and as such looking at mainly light QPF though with more coverage in comparison to tonight`s system. && .LONG TERM /TUESDAY THROUGH SUNDAY/... Issued at 236 PM CDT Sun May 12 2024 Clusters are in agreement with a slightly positive tilted shortwave over the Northern Rockies at 12Z Tuesday. The axis extends from southwestern MT into ID, leaving zonal flow across the area. They also indicate a separate weak shortwave pushing east across Saskatchewan into Manitoba/ND as well. The 850mb low will be over western MT/ND as this system occludes and a secondary surface low forms over ~western SD Tuesday. Through the day, this low and warm front will push east/northeast across the CWA. By Tuesday evening, both of the waves will continue to push east/northeast (and merge together) along with the surface low as models indicate the cold frontal passage early Wednesday morning across central SD and more Wednesday midday/afternoon across eastern SD into western MN as winds shift to the northwest. By the end of the week, another wave will push northwest to southeast and over the Northern Plains along with a broad mid level low in Canada. Clusters start to diverge at this point on timing and intensity of our next system. Ensembles agree well on precipitation in the form of rain moving in from the northwest and into our northwestern and central CWA by Tuesday morning. EC seems to be the quickest on the progression of this precipitation as it pushes eastward across the CWA and GEPS being the slowest so time may vary a bit. Rain will become widespread over the CWA by Tuesday evening/night. NBM shows this pattern well with our highest pops between Tuesday afternoon across central and western CWA (30-75%) and pops ranging from 40-60% Tuesday night into early Wed morning. As this low continues east, rain will end west to east Wednesday evening. Prob of QPF>0.25" from Tuesday morning through Wednesday through evening from the ensembles range from 25 to 70%, highest over our western CWA. NBM pops indicate this well with QPF up to 0.35" or so in this area. Prob of CAPE>500 j/kg per GEFS ranges from 30-50% across south central SD with 20-30kt shear out of the west Tuesday afternoon and evening in the warm sector of the low and dp`s in this area reaching the lower 50s. This could lead to some general thunderstorms with severe weather remaining low at this point. Additional slight pop chances are noted by NBM (15-30%) for the end of week with the next system, however low confidence exists. Temps will range in the lower to mid 70s Tuesday and cooler on Wednesday behind the front, with highs in the upper 60s to the lower 70s. Temps will rebound and gradually warm for the end of the week back into the mid to upper 70s/lower 80s by Friday. && .AVIATION /00Z TAFS THROUGH 00Z MONDAY/... Issued at 629 PM CDT Sun May 12 2024 Terminals KABR,KATY,KPIR,KMBG Except for the periods of time when near surface smoke concentrations are high enough to reduce visby (4-5sm FU), VFR conditions are forecast for all terminals through the TAF period. Out of any of the terminals, the highest smoke concentrations are supposed to reside over far northeast South Dakota (KATY?) through Monday evening. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...Dorn SHORT TERM...Connelly LONG TERM...MMM AVIATION...Dorn