203
FXUS63 KABR 070835
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
335 AM CDT Sun Jul 7 2024

.KEY MESSAGES...

- There is a 40% chance of precipitation in the form of showers and
thunderstorms this afternoon into the early evening hours. Severe
weather is not expected at this time, although lightning is expected.

- Isolated shower and thunderstorm chances (15-25%) remain in the
forecast on both Monday and Tuesday, mainly during the afternoon and
evening hours across northeastern SD into west central MN.

- Heat and humidity will be on the increase through the week into
the weekend. By Friday/Saturday temperatures will be about 5 to 10
degrees above average, with highs in the upper 80s to mid 90s and
lows in the upper 60s to near 70 with dewpoints well into the 60s to
near 70 degrees.

&&

.SHORT TERM /TODAY THROUGH MONDAY AFTERNOON/...
Issued at 333 AM CDT Sun Jul 7 2024

We have yet another day of mainly afternoon and early evening
convection, with the chance of precipitation being near 40%. While
there will again be another 500mb shortwave moving through this
afternoon (currently set up from northern MN through western ND and
northwestern SD), west to northwesterly flow has set up at the
surface. The surface trough will be in MN by the time we reach
daytime heating. Plenty of moisture remains, with dewpoints in the
upper 50s to low 60s today, and PW values are around 1". Expect
lightning to be the main concern with any stronger storms this
afternoon. However, we can`t rule out some small, mainly pea-sized
hail.

The broad surface high will continue to slowly build a ridge across
the Dakotas and western MN Monday, with the 500mb trough focused to
our east/across MN and WI. So, while there will again be the
potential for afternoon convection, it will become more limited in
intensity and coverage. The chance of precipitation Monday afternoon
is only 20%, and mainly east of the James River.

Confidence remains high in the temperature forecast, with little
spread in the probabilities through the short term period. For today
that means highs in the upper 70s to near 80 degrees.

&&

.LONG TERM /MONDAY EVENING THROUGH SATURDAY/...
Issued at 333 AM CDT Sun Jul 7 2024

Main themes again during the extended are the weakly unstable
atmosphere during the afternoons thanks to ample low level humidity
and relatively un-anomalous mid level temperatures, and the
eventual warmer air aloft and hotter temperatures.

Will once again enhance POPs for Tuesday afternoon over the NBM with
NAM BUFKIT profiles showing weak instability (skinny CAPE) and a
weakly sheared environment, under northwest flow with a subtle upper
wave in North Dakota. This is all while the persistent upper trough
is finally moving over into the eastern CONUS.

Thereafter, we start to see the ridge fold over into the Northern
Plains, as a surface high/heat dome shifts into the central Rockies.
Mid level temperatures begin to warm, and while not exceptionally
fast or anomalously high, enough to stabilize the atmosphere,
despite the presence of several subtle waves moving across the top
of this upper level high towards the Western Lakes region. We don`t
actually begin to see 700mb/850mb thermal anomalies begin to reach a
standard deviation above climo until the Friday/Saturday timeframe
however.

During the course of the extended, NBM box and whiskers for both
high and low temperatures show a slow steady increase with a fairly
confident range of only 3-5F. Additionally, there is generally a
slowly increasing trend in the 25th/75th percentile range of
dewpoints, with fewer/weaker transient systems allowing for the ET
of recent ample moisture to build up.  Forecast heat index values
currently reside below advisory criteria, however we are 1)
beginning to see low temperatures migrate into the mid/upper 60s to
near 70 and 2) the HeatRisk scale increases well into Moderate
category with some locations peaking at Major category. Still
suspect the NBM dewpoints are underrepresented given the current
growth stage of corn and the amount of moisture we have
received across the region over the last few weeks.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1214 AM CDT Sun Jul 7 2024

Terminals KABR,KATY,KPIR,KMBG

May see some MVFR cigs develop across far northeastern South Dakota
and west central Minnesota late tonight into early Sunday. Scattered
thunderstorms are possible across the area late Sunday afternoon
into Sunday evening. Periods of MVFR vsbys will be possible with the
thunderstorms. Otherwise, VFR conditions will prevail overnight
and through the day Sunday.


&&

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

$$

SHORT TERM...KF
LONG TERM...Connelly
AVIATION...Parkin