752
FXUS63 KABR 131114 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
614 AM CDT Sun Jul 13 2025

.KEY MESSAGES...

- There is a Marginal Risk (level 1 out of 5) of severe weather for
the afternoon and evening hours Monday and Tuesday. Main threats
include hail up to the size of quarters and 60 mph wind gusts.

- Heavy rain is possible along and east of the James River into west
central MN Tuesday.

- There will be a noticeable cool-down on Wednesday and Thursday,
with highs potentially 10 to 15 degrees below normal.

&&

.SHORT TERM /TODAY THROUGH MONDAY AFTERNOON/...
Issued at 343 AM CDT Sun Jul 13 2025

Early this morning, observations from around the region indicate
some lingering smoke across the eastern Dakotas with visibilities in
the 6 to 8 mile range. Still expect this smoke to exit to the east
this morning.

Generally dry and hot conditions expected today with an upper ridge
building from the west and sfc high pressure across north central
SD. The one wrench in the works may be a very weak sfc trough that
will extend northeast through southeast SD into MN this afternoon.
There is a narrow corridor of 2000 to 3000 J/kg of MUCAPE and 35 kts
of bulk shear with no capping. Again, the limiting factor will be
very little forcing but NSSL WRF maintains a narrow line of
thunderstorms developing around 21z with the CAPE. High temperatures
top out in the upper 80s to lower 90s today.

For Monday, there is a marginal risk (1 out of 5) for severe
thunderstorms northwest of a line from Murdo to Aberdeen. This
activity will be associated with a cold front moving through and
looks to hold off until Monday evening. See long term discussion for
further details. Ahead of the front, southerly winds will increase
which will push dewpoints and temperatures up. May need a heat
headline across the southwest cwa Monday afternoon, but current
forecast is just below criteria. There are some model differences in
timing of clouds and storms moving into central SD which is leading
to lower confidence in hourly temps and apparent temps.

&&

.LONG TERM /MONDAY EVENING THROUGH SATURDAY/...
Issued at 343 AM CDT Sun Jul 13 2025

Starting off the long term Monday evening, models overall agree on a
lee surface low forecasted to be centered over the western Dakotas
and eastern MT/WY with its west to east frontal boundary extending
from MT through ND/MN and lee surface trough extending southward
from the low. This low and cold front will track slowly southeast
over the area through Tuesday, with the CWA forecasted to be behind
the fropa by Tuesday night/early Wednesday morning. High pressure
from Canada will continue to dip southeastward behind this system
and center over the Northern Plains Thursday, shifting eastward
Friday. Otherwise, zonal flow will continue through much of next
week with a broad ridge pattern forming over the Rockies into next
weekend with several embedded shortwaves.

Precipitation wise, pops will increase from northwest to southeast
over the CWA Monday evening into Monday night with widespread pops
of 35-70% chance on Tuesday (highest over the eastern half of SD).
Pops increase to 50-70% Tuesday evening into Wednesday morning over
the entire CWA, associated with the fropa. Shower and thunderstorm
chances (25-40%) continue through Wednesday before precip diminishes
northwest to southeast over the CWA Wednesday evening/night as the
high moves in. There is a marginal risk (level 1 out of 5) along and
west of a line from Aberdeen to Murdo Monday evening which lies
ahead of the front/low and east of the axis of the lee trough.
Dewpoints will overall range in the upper 50s/60s, CAPE values 1000-
2000j/kg, steep lapse rates, and marginal shear of 20-30kts. This
could lead to isolated severe storms (with help from the shortwave
aloft) with wind gusts of 60 mph being the main threat. Elevated
severe threat is possible behind the fropa as well which then would
be more of a hail threat along with the wind. For Tuesday, the risk
of severe weather continues with a marginal risk covering almost our
entire CWA with similar severe parameters.

Ahead of the slow moving front, NAEFs indicates mean specific
humidity about 1 standard deviation above climo at 850mb-925mb with
PWAT values 1.25 to 1.50" highest over James River Valley and
eastward. This is about 1 standard deviation above climo. However EC
EFI only indicates values of 0.5-0.6 over extreme northeastern SD
into west central MN. So with the possibility of severe weather,
higher rainfall amounts could be an issue with any slow moving
and/or training/backbuilding storms especially over the eastern half
of SD which has already dealt with flooding this season. Probability
of 1" of rainfall is 20-40% east of the James River, highest along
and east of a line from Sisseton through Watertown.

Highs will range in the 70s and 80s Tuesday but behind the cold
front and incoming high, 850mb temps will drop to 11 to 14C
Wednesday afternoon and 11 to 16C Thursday afternoon, which runs
about 1 standard deviation below climo, per NAEFS. Highs will run in
the upper 60s to the upper 70s, which is about 10-15 degrees below
normal. EC EFI still indicates -0.5 to -0.8 for both TMax and TMIN
these days over portions of the CWA with a shift of tails of zero.
Temps will warm back up Friday into the weekend.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 613 AM CDT Sun Jul 13 2025

Terminals KABR,KATY,KPIR,KMBG

Brief MVFR morning fog in the east will quickly dissipate after
sunrise. Otherwise, VFR conditions are expected.

&&

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

$$

SHORT TERM...20
LONG TERM...MMM
AVIATION...20