158
FXUS63 KABR 101111 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
611 AM CDT Fri Jul 10 2026

.KEY MESSAGES...

- A Marginal Risk (Level 1 of 5) for severe thunderstorms has
  been posted for parts of northeast SD and west central MN
  this afternoon into this evening. Hail of 1 inch in diameter
  will be the main threat.

- A warming trend begins this weekend. High temperatures could
  potentially hit triple digits Sunday through Tuesday. This
  level of heat may cause widespread heat related impacts
  particularly for those without adequate cooling and those
  sensitive to heat.

&&

.UPDATE...
Issued at 607 AM CDT Fri Jul 10 2026

Updated discussion for the 12Z TAFs below.

&&

.DISCUSSION...
Issued at 316 AM CDT Fri Jul 10 2026

Late evening and early morning convection that rolled out of ND into
northeast SD and west central MN has mostly diminished below a
severe threat concern with only light to moderate rain showers with
some embedded thunder left. This activity is expected to continue
tracking southeast and continue to diminish in areal coverage
through the early-mid morning hours.

Water vapor imagery and upper air analysis early this morning depict
broad quasi-zonal flow across the CONUS with two distinct
differences from west to east. Across the Great Lakes and Eastern
CONUS, some troughiness does exist where a nearly stalled out
frontal boundary is leading to showers and thunderstorms through the
Ohio Valley into the Mid-Atlantic. Across the western CONUS and
Intermountain West, upper flow is beginning to show some shortwave
ridging with shortwave troughing working on the downstream side of
this ridging across the Northern and Central Plains and part of the
forcing for our early morning convection. Through the course of
today and into the upcoming weekend, the western CONUS ridging will
become more pronounced as it centers itself over the Four Corners
region. 500mb heights are progged to increase across our region
which should lead to a drier trend as the storm track shifts out of
our area. The building upper ridge will also bring is some of the
warmest temperatures of the season so far to our forecast area.

For today, a sfc frontal boundary will remain draped in a west to
east fashion across our northern zones or in the vicinity of the
ND/SD border. This will be tied in with a lee side low located
across eastern MT/WY and the Black Hills region. Southerly low level
flow on the warm side of this front will maintain a moisture rich
air mass with dew point temperatures warming into the mid 60s to
near 70 degrees the James Valley and points east into western MN.
Daytime heating will push afternoon highs into the upper 80s to mid
90s across the CWA. This will lead to moderate instability of 2500-
3500 J/kg of CAPE across parts of northeast SD and west central MN
this afternoon into this evening. However, deep layer shear isn`t
all the impressive with magnitudes only up to about 25 kts across
our eastern zones. Mid-level lapse rates will range between 6-7 C/km
in those zones. So, despite increasing mid level heights, CAMs are
indicating convective signatures developing late this afternoon into
this evening. The early morning convection the moved through
northeast SD/west central MN may play into when/where the afternoon
activity initiates. Based on the guidance, the most probable areas
would be across our east, mainly along and east of the I-29
corridor. The primary threat will be large hail from the strongest
cells that develop. SPC has continued to highlight parts of
northeast SD and west central MN with a Marginal Risk (Level 1 of 5)
for severe thunderstorms this afternoon into this evening.

Storms are expected to be on the downward trend and exiting the
forecast area by late tonight. That aforementioned frontal boundary
is progged to lift north and through the forecast area on Saturday.
Increasing low level southerly flow will keep humid conditions in
place through the weekend and the upper ridge asserts itself even
more across the Northern Plains. This building heat dome is expected
to deliver daytime temperatures that will range between 10-20
degrees above normal for mid July. 850mb temperatures are progged to
range from +21C to +25C across our eastern zones to +26C to +31C
across our west by the end of the weekend into early next week.
Daytime highs on Saturday look to be solidly in the 90s across the
CWA with parts of central SD approaching 100 degrees. Sunday through
Tuesday will feature even warmer conditions with widespread mid to
upper 90s east to the low 100s from the James Valley and points west
through central SD. Overnight lows won`t provide much relief with
readings in the upper 60s to mid 70s. This will mean that daytime
dew point temperatures will range from the upper 50s to low 60s west
to the mid 60s to near 70 degrees in the east starting Saturday
through at least Monday. Heat indices start to creep up on Saturday
with mid to upper 90s with a couple of isolated spots approaching
100. This does help to push the HeatRisk probabilities of reaching
Level 3 or Major category around 50 percent or higher basically
along and north of US Highway 12. So, this will be something we will
have to watch the trends closely on for a possible heat headline on
Saturday. After Saturday, confidence increases for more widespread
heat building across the forecast area. Heat indices are projected
to reach 100-105 degrees on Sunday and Monday with HeatRisk values
reaching the Major to Extreme category both those days and possibly
on Tuesday as well. Future forecast packages will definitely have to
consider posting headlines for this extreme heat in the next day or
so. Temperatures do look like they will take a step back down by the
middle to latter half of next week, but there remains a 10-15 degree
spread in the NBM 25th to 75th percentile Max and Min T values which
still results in at or above normal temperatures for this time of
year.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 607 AM CDT Fri Jul 10 2026

Terminals KABR,KATY,KPIR,KMBG

VFR cigs are forecast through the end of the TAF period. An
isolated shower or thunderstorm is possible late this afternoon
and evening that could affect the KATY terminal, however, due to
low confidence in areal coverage did not put it in the TAF for
now. Amendments will be made if needed.

&&

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

&&

$$

UPDATE...MMM
DISCUSSION...Vipond
AVIATION...MMM