821
FXUS63 KABR 110510
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
1210 AM CDT Thu Jul 11 2024

.KEY MESSAGES...

- High confidence in hot and muggy conditions Friday through
  Sunday. High temperatures will be in the 90s (5-10 degrees
  above average) with dewpoints in the mid to upper 60s. This will
  result in heat index values in the mid and upper 90s with a few
  spots to 100 degrees during the afternoon hours.

- Temperatures will moderate with lower humidity for the first half
  of next week.

&&

.UPDATE...
Issued at 841 PM CDT Wed Jul 10 2024

The current forecast looks good overall. No changes planned at
this time.

UPDATE Issued at 622 PM CDT Wed Jul 10 2024

Aviation discussion updated below for the 0Z TAFs.

&&

.SHORT TERM /THIS EVENING THROUGH THURSDAY NIGHT/...
Issued at 315 PM CDT Wed Jul 10 2024

Much of the anticipated convection today has remained in MN, as many
CAMs showed earlier today. We did have a couple showers develop near
KATY and drift south out of the CWA, but aside from that, nothing
else in our area currently. Still not out of the question to see
some more development in our far southeast area, so will leave
slight chances (20%) in the forecast.

As the night progresses, surface high pressure will begin to shift
east of the area and allow for light southerly winds to return.
These winds will increase through the day Thursday, eventually
becoming breezy across central SD. Warm air advection will also ramp
up, especially over central SD where 850mb temps climb to around
+20C to +22C. Readings are a few degrees cooler over the eastern
CWA, but that said, mid to upper 80s will be common over the east on
Thursday, with readings around 90 degrees or into the low 90s across
central SD.

Light south breezes should be maintained Thursday night with a bit
of a pressure gradient in place. With these winds, lows should stay
in the mid 60s for many locations.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 315 PM CDT Wed Jul 10 2024

The overall upper flow pattern remains pretty consistent the latest
model guidance compared to previous runs. An expansive mid level
high will remain essentially centered over the Four Corners region
of the southwest CONUS through the first portion of this period.
Across our region, the associated ridge will try and nose towards us
but periodic mid level waves in the quasi-zonal flow across the
Northern Rockies/High Plains and Northern Plains will more or less
keep that at bay. Some of these disturbances could pose a risk for
scattered convection across the Dakotas late in the week and over
the course of the weekend. Timing and location of any such activity
is hard to pin point at this time, but trends have been pointed to
locales farther north and east in the region for seeing the best
chances for this as weaknesses in the mid level ridge could be more
pronounced across ND, northwest MN and northeast SD/west central MN.
NBM PoPs will continue to advertise up to 15-20% for our
northern/northeastern zones for Friday and again during the course
of the latter half of the weekend.

The bigger story line in this period will be the increasing heat and
humidity that still anticipated to build late this week and persist
through the weekend. Ensemble mean 850mb temperatures on Friday
range from +18C to +25C from east to west across the CWA. On
Saturday, the range climbs to +21C to +26C and +23C to +28C on
Sunday respectively. Under this pattern, we definitely will realize
high temperatures in the 90s, with perhaps a few locales getting
closer to the century mark, especially Saturday and Sunday. With dew
point temperatures in the 60s, close to low 70s...this will be our
areas first real stretch of downright muggy conditions for the
season. At this point, heat index values will approach or exceed 100
degrees for some of our zones, especially across our
southern/southwestern zones on Saturday and perhaps on Sunday as
well. Will continue to message this increasing heat in the HWO,
Weather Story and Social Media products. Some relief looks to work
back into the region early-mid next week. Another successive couple
of mid level disturbances with the passage of a frontal boundary or
two will give our area some better chances for precip and somewhat
cooler, less humid conditions.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1210 AM CDT Thu Jul 11 2024

Terminals KABR,KATY,KPIR,KMBG

While VFR conditions can be expected for all terminals through the
valid taf period, will need to monitor the potential of fog at KATY
and KABR around sunrise. Southerly winds will develop today, with
gusts of 20 knots affecting all terminals except KATY this
afternoon.

&&

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

$$

UPDATE...SD
SHORT TERM...TMT
LONG TERM...Vipond
AVIATION...KF