525
FXUS63 KABR 111527 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1027 AM CDT Thu Jul 11 2024

.KEY MESSAGES...

- While mainly dry weather will continue, isolated late evening
  and overnight showers and thunderstorms will be possible through
  at least the weekend due to weak disturbances moving through the
  region. Chances of precipitation are less than 30 percent not
  only through the weekend, but through the middle of next week.

- 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 1021 AM CDT Thu Jul 11 2024

Current forecast has things handled well through 00Z, so no big
updated planned. Skies will remain mostly sunny with southerly
breezes as highs rise into the 80s to around 90 degrees.

&&

.SHORT TERM /TODAY THROUGH FRIDAY AFTERNOON/...
Issued at 254 AM CDT Thu Jul 11 2024

At 07Z the surface high stretched from north central NE through
southeastern SD and through Lake Superior. At 500mb the northerly
flow continued with the ridge stretching from the southwestern U.S.
through MT and the western Dakotas. We`ll continue to see this ridge
slowly inch our direction. The main result will be increasing
temperatures and dewpoints. The changes will be limited today, with
temperatures at most locations 1-5 degrees higher than what was
realized Wednesday.

While dry weather is expected today, we won`t be able to completely
rule out showers and a few thunderstorms, with a 15-25% chance of
precipitation overnight tonight over mainly central SD. There will
be a 30-35kt low level jet developing overnight and a weak 500mb
wave rotating through central SD, helping to support the development
of showers and storms. We will need to monitor the latest model
trends as some solutions like the 00Z run of the FV3 are more robust
than others with a scattered line of storms over western SD by 00Z
Friday. At this point the consensus is to keep dry conditions going
along and east of the James River Valley. Will highlight the
potential for thunderstorms across central SD in the HWO.

Surface dewpoints will increase during the day Friday, getting into
the upper 60s. Temperatures again, an average of about 5F, topping
out in the 90s with a few mid 80s east the the James River Valley.

&&

.LONG TERM /FRIDAY EVENING THROUGH WEDNESDAY/...
Issued at 254 AM CDT Thu Jul 11 2024

The very summertime-like pattern continues as advertised for the
extended with an upper high over the Four Corners region, and zonal
flow with weak embedded waves for the northern tier of the country.
Guidance still has the warmest mid level temperatures for the
weekend, although it should be noted there has been a slight
increase in POPs/cloud cover associated with these ridge-riding
systems. A Sunday morning system actually has cause some of that
peak heat to shift away from the northeast of the state as
convection is likely to produce or form along a backdoor cold front
which all the major deterministic models are portraying. NBM
probabilities for seeing 100F are mainly limited to the Pierre area
regardless, with less than 10-20% probability for north central SD
into the James valley.  Current NBM dewpoints approaching 70F are
also appropriate as we are seeing CAMS come in with low 70s under
the southeast low level flow regime during the later portion of the
short term. I`m sure they will need a slight nudge upwards due to
evapotranspiration, but generally current NBM values are close
enough at this point. As such, NBM is generating widespread heat
index values in the upper 90s, with a few spots up around 100F.
After the weekend, we continue to see a drop in 850mb temperatures
as northwest flow over the western lakes region intensifies drawing
Canadian air into the region. This will also reduce dewpoints down
to closer to what we`ve seen over the previous few days this week
here.  The Four Corners high weakens, so these fairly seasonal
temperatures/modest humidity should dominate for several days to
come.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 608 AM CDT Thu Jul 11 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions should continue over the next 24 hours.
Shower and thunderstorm chances may develop across central SD,
near PIR/MBG, after 06Z. The chance of precipitation at that time
remains low, around 15% or less. As a result, it will be left out
of the aviation forecast. Winds will increase out of the south
5-20kts, highest over PIR/MBG during the afternoon and evening
hours.


&&

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

$$

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