651
FXUS63 KABR 121937
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
237 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).

&&

.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 tonights
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 /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1159 AM CDT Sun May 12 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions for all terminals. Cant rule out smoke lowering
VISBY down to MVFR but probability is too low and at this time
only expected to fall to 4-5 miles at worst according to upstream
obs.


&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&

$$

SHORT TERM...Connelly
LONG TERM...MMM
AVIATION...Connelly