420
FXUS63 KABR 181919
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
219 PM CDT Tue Jun 18 2024

.KEY MESSAGES...

- Cool with drying conditions tonight/Wednesday.

- Active again for the latter half of the work week into the
  weekend. There is a 60-90% chance of precipitation at its peak
  Thursday night/Friday.

&&

.SHORT TERM /THIS EVENING THROUGH WEDNESDAY NIGHT/...
Issued at 218 PM CDT Tue Jun 18 2024

The front has crossed into far eastern South Dakota/western
Minnesota and sites that are ahead of the front winds are quickly
moving to a southwest low level wind. Thus the severe weather threat
is also outside the CWA, even though we are seeing some weak
convective elements still in Roberts/Grant/Deuel/Big Stone counties.
Meanwhile the rest of the CWA is ensconced in low clouds/sprinkles
and cold advection. High pressure builds into the region for dry
conditions tonight/Wednesday, but still under a southwest flow
regime, and as such by late Wednesday we begin to see some mid
level moisture/warm advection instability. Profiles are again very
dry below 10-12kts along with a dry subcloud layer, and as such
altocumulus showers should produce little more than virga. Moisture
increases between 6-10kft, improving chances for light shower/weak
thunderstorm activity early Thursday but other than light shower
activity little moisture potential exists with the NBM probability
of 0.25 inches at only 20 percent across the far south of the CWA.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 218 PM CDT Tue Jun 18 2024

Thursday morning starts the long term period with southwesterly flow
aloft. This continues through Saturday morning when a trough starts
to move across the region, stretching down from Canada, bringing the
winds around to more of a westerly direction. Sunday night, a ridge
builds into the region, but we return to generally westerly flow by
Monday afternoon which will last through the end of the period.

Some precip is possible Thursday (25-45% chance) into Friday (60-90%
chance) as warm, moist air is brought up from the Gulf of Mexico and
mixes with a lee side trough from the Rockies. Thursday, the warm
front is draped across southern NE, this will make its way north
into southern SD where the higher PoPs are located. Some
thunderstorms are expected Thursday but not expected to be severe as
lapse rates and instability values are rather lacking. Thursday
night into Friday, the cold front moves north and east across the
region and brings the higher chances for precipitation. Higher
chances linger over far northeast SD and west central MN into
Saturday morning. Friday afternoon, some models are showing MLCAPE
values between 1500 and 2000 J/kg in eastern SD, but bulk shear
values max out around 30 kts so severe thunderstorms are unlikely.
NAEFS PWAT values are in the 99 to 99.5 percentile with values up to
1.75 inches over the James Valley starting Thursday morning and
continuing into Saturday morning. NBM is showing 50 to 80% chances
for more than 0.5" in 24 hours (ending Friday evening) for areas
east of the Missouri River and 50 to 60% chances for more than an
inch for areas east of the James River.

Temperatures on Thursday are expected to be pretty mild with highs
in the low 70s. Friday, we get some strong WAA that will raise
temperatures into the low to possibly mid 80s despite the rain and
cloud cover. Temperatures continue to heat up going into next work
week. Winds don`t look to be much of an issue during the long term.
However, winds can become gusty in and around thunderstorms, if any
form.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1225 PM CDT Tue Jun 18 2024

Terminals KABR,KATY,KPIR,KMBG

A mix of MVFR/IFR CIGS follows a cold front that should pass
through KATY shortly and has already impacted the other CWA
terminals. CIGS will gradually improve through the
evening/overnight as drier air moves in on a northwest wind.


&&

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

$$

SHORT TERM...Connelly
LONG TERM...KK
AVIATION...Connelly