306
FXUS63 KABR 301756 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1256 PM CDT Thu Jul 30 2026

.KEY MESSAGES...

- A Slight Risk (level 2 out of 5) for severe weather is in place
over portions of south central SD Thursday. A Marginal Risk (level 1
of 5) for severe weather is in place for the rest of the forecast
area. The main hazard will be wind gusts of 60 to potentially 70 mph
and hail of one inch in diameter.

- Through Friday morning, much of northeastern South Dakota and
western Minnesota may see around 1.5"-2" of rain. Localized areas of
3"-4" may be possible, and Flash Flooding will be possible in places
that see these higher end rainfall totals.

- Temperatures into the upper 90s to low 100s return over parts of
central and north central South Dakota this weekend. Temperatures
are set to cool down to below normal by the middle of next week.

&&

.UPDATE...
Issued at 1238 PM CDT Thu Jul 30 2026

The aviation discussion has been updated for the 18Z TAFS.

UPDATE Issued at 1014 AM CDT Thu Jul 30 2026

Main updates made to the forecast for the remainder of the today
period revolve around precipitation and sky cover trends this
morning. An area of showers and storms continue to develop and
expand across the Pierre area and points south and east into the
I-90 corridor. More isolated showers are developing across parts
of east central SD(southwest of the Watertown area). Evolution
of this activity calls for continued development and expansion
in coverage as the main shortwave trough tracks into the Dakotas
out of WY this afternoon into tonight. Best chances for severe
weather continue to align south of the US Highway 14 corridor
this afternoon and evening. Main threats with any of the
strongest storms will initially be large hail before
transitioning into a damaging wind threat. Any thunderstorms in
the forecast area will have the potential for excessive
rainfall with the best probabilities of this occurring from
west central MN/east central SD south and west into portions of
the James Valley into far south central SD. Rainfall amounts in
those locations could range from 1.5 inches to more than 2
inches of rain once this event comes to an end Friday morning.

&&

.DISCUSSION...
Issued at 251 AM CDT Thu Jul 30 2026

Keeping an eye on some rain showers and weak storms early this
morning as they track east across central South Dakota. Currently
(~07Z) this system is producing 30-40 mile per hour winds.
Environmental parameters, namely DCAPE and low-level lapse rates for
assessing the potential wind threat, have decreased over the past
few hours. At this point there is little concern for severe weather
over the next few hours.

Main forecast focus today will be the storms through the day,
produced by a shortwave aloft embedded within the broad upper-level
ridge dominating the pattern. Storms will remain possible this
morning, but severe chances increase beginning this afternoon and
continuing into the evening. Signal in high-resolution model
guidance is for multiple potential areas of development during the
afternoon - one over northeastern South Dakota and another over
central South Dakota. In both areas, there will once again be under
a low CAPE/Shear environment (roughly 1000-1500 J/kg and 20-30 knots
of shear), so storms will likely have a difficult time producing
severe hail. For that same environmental reason however, collapsing
storms may produce severe winds at times. There are some potential
limitations to those chances however. First, the DCAPE environment
will be less than impressive, and hi-res CAMs show a struggle to
reach 1000 J/kg. Additionally, due to the cloud cover and rain
through the morning, diurnal heating will be somewhat limited over
most of the forecast area. This will keep low-level lapse rates well
below dry adiabatic, providing another potential obstacle for
potential severe winds to overcome. At this time, a Marginal Risk
blankets the forecast area, with the addition of a Slight Risk over
parts of south central South Dakota.

With storms today there is also a Slight Risk for Excessive Rainfall
covering northeast South Dakota and western Minnesota. Over this
area, the latest ensemble guidance is fairly consistent in median 24
hour rainfall totals (ending Friday morning) around 1.5"-2" over
parts of eastern South Dakota and western Minnesota. The one
exception would be the NBM, which pushes median values up over 2".
90th percentile values, a reasonable "worst case scenario", have
rainfall totals around 3-4". One potential saving grace is that
soils over that area (and really the entire forecast area) are
fairly de-saturated. Therefore, the ground should hopefully be able
to take a bit of rain before flooding occurs. The flip side is that
3-4" over 24 hours is the point at which flooding tends to occur
(based on local research), so if these higher end values verify,
flooding is certainly a possibility this evening.

Southerly winds this morning will help push most if not all of the
remaining near-surface smoke out of the area and to the north.
Therefore, expect air quality to remain good this afternoon. Smoke
aloft will also be mostly out of the area today, although with
cloudy skies all day that will be not much of a concern anyway.
However, smoke aloft will likely move over at least part of the
forecast area once again on Friday. Near surface concentrations may
also reach Moderate levels again, and minor visibility reductions
may become possible. Coverage of the highest near-surface
concentrations Friday does not appear to be very broad at this point
in time.

As the shortwave moves out, the upper-level ridge in place will
become more positively tilted, leading to a bit of a temperature
gradient over the CWA over the weekend. Near-normal temperatures
will be in place over the east, but central and north central South
Dakota are once again set to reach the upper 90s to 100s,
particularly on Sunday.

The next chances for rain will come early next week after the dry
weekend. The upper-level pattern will shift as a trough pushes down
over the Pacific Northwest and Northern Plains. With this trough
will come a jet streak aloft, and the potential for storm
development as a result. Given the extended time frame, diving into
the details would be fruitless at this point other than to say that
extended model guidance shows some potential for the equivalent of a
Marginal Risk for severe weather over the area. This pattern shift
will also bring about a cooler airmass over the Northern Plains, and
below normal temperatures will be likely (70-90% chance of highs
below 85 degrees) Tuesday and Wednesday.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1238 PM CDT Thu Jul 30 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are expected to prevail at all TAF sites through
this forecast period outside of times when showers and
thunderstorms will be moving through the 4 aerodromes.
Increasing coverage of showers and thunderstorms are expected
this afternoon into tonight. Low confidence remains on timing
and placement of this activity through the period. Tried to
leverage the timing in the direction of best chances for
SHRAs/TSRAs in prevailing groups while using PROB30 groups for
durations where activity could be more widely scattered. MVFR
cigs/vsbys will be possible in the heavier SHRAs/TSRAs with more
widespread MVFR/IFR cigs/vsbys developing overnight at
KABR/KATY due to low stratus and fog. Southerly winds will
eventually become north to northeast late tonight/early Friday
and become gusty by late in this forecast cycle.

&&

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

&&

$$

UPDATE...Vipond
DISCUSSION...BC
AVIATION...Vipond