132
FXUS63 KABR 061748 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1248 PM CDT Sat Jul 6 2024

.KEY MESSAGES...

- Showers and thunderstorms will track east from central SD to
eastern SD by mid morning, with more afternoon and evening showers
and thunderstorms across the area. A few of these storms could
become strong to potentially severe with winds around 60 mph and
hail around 1" in diameter this afternoon and evening from south
central to far northeastern SD and west central MN.

- Isolated shower and thunderstorm chances remain in the forecast on
both Sunday and Monday, mainly during the afternoon and evening
hours. However, a pattern change seems likely thereafter.

- Expect a gradual warming trend through the work week. By the end
of the week we should be seeing temperatures 5 to 10 degrees above
average (highs in the upper 80s-90s).

&&

.UPDATE...
Issued at 1236 PM CDT Sat Jul 6 2024

See updated aviation discussion below.

UPDATE Issued at 1029 AM CDT Sat Jul 6 2024

The weak system continues to track from west to east across the
region. Radar trends show a decrease in the initial shower and
thunderstorm activity which aligns well with hi-res model
depictions. Likewise, hi-res models show a redevelopment of
showers and thunderstorms this afternoon fueled by daytime
heating. The overall forecast captures everything well, no major
changes made.

&&

.SHORT TERM /TODAY THROUGH SUNDAY AFTERNOON/...
Issued at 358 AM CDT Sat Jul 6 2024

The early morning surface weather map showed low pressure over
north central CO and high pressure over WY and western SD. At 500mb
we have a broad trough across much of the U.S., excluding the
southeast and southwestern states where very hot conditions have set
up. A shortwave in the larger trough over far eastern MT and and
northwestern SD is helping to bring the shower and thunderstorm
activity to central SD this morning. Some of these have produced
winds to around 35 mph and show the potential for pea sized hail.
The trough will continue to sink southeast to central SD by 18Z, at
the same time that a weak surface trough sets up around the same
location, while the stronger surface low shifts to far northeastern
CO/western NE/western KS and eventually eastern NE by 00Z Sunday.
While the risk for stronger storms will mainly stay across eastern
NE this afternoon, there is a chance for a few stronger storms south
of a line from Lyman through Grant and Big Stone Counties. This is
where there is a Marginal Risk for severe weather this afternoon,
into early this evening for our far eastern counties. CAPE values
again top out around 1000 J/kg. However, the best shear and lifted
indicies remain south of our counties. Still, the weak surface
through may help keep a couple of storms going to near severe levels
this afternoon.

After some drying this evening, another chance of showers and
thunderstorms (around 20% chance) will push into central SD
overnight, confidence is low on their occurrence and our
precipitation forecast lines up with this thinking. While
thunderstorms will again be possible Sunday afternoon, their
coverage and intensity is expected to be less than Saturday, as the
broad surface trough will be across MN by that time.

&&

.LONG TERM /SUNDAY EVENING THROUGH FRIDAY/...
Issued at 358 AM CDT Sat Jul 6 2024

Will continue to see off-on chances for mainly diabatically driven
convection Monday and Tuesday afternoons with unstable conditions
thanks to mid level temperatures that are still relatively cool for
this time of year (700mb temperatures between +3 and +5C). Not much
overall shear however, limiting any severe weather potential. This
is under the presence of this persistent upper level trough, though
it should also be noted that the surface pressure pattern is rather
anemic both days. Did add on to the low POPs for Tuesday to get the
mention of thunder in for the afternoon (NBM POPs only in the
single digits-low teens) along with a slight uptick in cloud cover
to better represent convection.

The western CONUS heatdome breaks down and spills over into our
region late in the week. We will begin to see some 850mb thermal
anomalies at that point, and NBM shows this persistent steady trend
in warming the high/low 25th/75th percentiles. NBM dewpoint ranges
are not anything to outside the norm however, with a lower/higher
range of low 60s to upper 60s respectively, though given ample
moisture recently and rapid corn growth this time of year, would
expect these numbers to be somewhat underdone. At the same time,
with increased heights and warm air aloft for the latter half of the
work week, the probabilities for moisture trend significantly lower.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1236 PM CDT Sat Jul 6 2024

Terminals KABR,KATY,KPIR,KMBG

Isolated showers and thunderstorms will increase in areal
coverage by 20Z, especially over parts of northeast South Dakota.
The strongest storms may produce large hail, gusty winds and
brief heavy rain, as well as VFR CIGS/VSBYS. Due to the scattered
convective nature of storms will amend TAFs as necessary to
capture this impact.

&&

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

$$

UPDATE...Serr
SHORT TERM...KF
LONG TERM...Connelly
AVIATION...Serr