623
FXUS63 KABR 160848
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
348 AM CDT Sun Jun 16 2024

.KEY MESSAGES...

- Strong to severe thunderstorms are possible again late tonight
  into early Monday across the southern portions of the region.
  Large hail will be the main threat.

- The threat for strong to severe storms continue over the entire
  region Monday with large hail and wind gusts between 60-70mph as
  the main threats.

- A moderate risk (40%) for excessive rainfall/flooding exists
  over far northeastern SD into west central MN for Monday into
  Monday night where 2"+ could fall.

- After somewhat quieter weather conditions Tuesday and Wednesday,
  more active weather returns Thursday and Friday.

&&

.SHORT TERM /TODAY THROUGH MONDAY AFTERNOON/...
Issued at 342 AM CDT Sun Jun 16 2024

The main concern for the short term is the risk of severe weather
and the potential for heavy rain/flooding. Dry weather expected
today and this evening as a high pressure system moves in from the
west behind the cold front that continues its path into MN by this
afternoon. Aloft, a broad neg tilted longwave trough will deepen
today over the western CONUS as another mid level low moves in over
the Pacific Northwest. This leaves the Northern Plains on the PVA
side of trough as winds at mid levels will increase to 40-50kts this
evening out of the southwest. Within this flow our next shortwave
moves in this evening through the overnight. Late tonight, the
southern part of the cold front stalls out, becoming a stationary
front, which will drape from Nebraska and northeast through IA/MN. A
Co low will also be developing as well. To the north of the front,
CAMs indicate showers and thunderstorms developing and moving in
over south central SD around or shortly before midnight, and
spreading north and northeastward across the CWA through Monday
morning.

HREF indicates MUCape ranging from 500-1000 j/kg over the central
and southern CWA overnight with bulk shear pretty impressive ranging
from 60-75kts out of southwest. Dewpoints will also be in the lower
to mid 50s overnight across this area. 2-5km UH>75 m2s2 indicates
paintballs clustering more to the south and southeast of the CWA
(which the CAMs show this)but will clip parts of the southeastern
CWA, indicating organized convection. Several paintballs are spread
north of this, from south central to central CWA. Probability of
UH>75 ranges from 10-30% , highest over FSD WFO. Being north of this
front, will result in this being more elevated convection as several
soundings show this. Unidirectional flow results in long straight
hodographs as well, meaning large hail would be the main risk. If we
can advect this instability northward, hailstones could exceed 2".
Gusty severe winds are possible as well (60-70mph). Due to this the
SPC has a slight risk (2/5) for severe storms late tonight from
Pierre to Redfield to Watertown and south of here, where this better
instability lies. North of here a marginal risk is in place where
CAPE is less but still have the decent wind shear to allow for hail,
up to quarter size, and 60mph wind gusts.

12Z Monday the longwave trough becomes more neutral tilted over
the western CONUS with continuing southwesterly flow of shortwave
energy into the Northern Plains. The now warm front shifts just
slightly north during this time. So expect ongoing showers and
thunderstorms across the CWA along with the instability. A Slight
Risk (2/5)is in place over the entire CWA.

Our other concern will be the potential for heavy rain/flooding. IVT
indicates lots of moisture surging north/northeastward into the
Northern Plains with NAEFS indicating this moisture being 90-97.5%
above Climo for Monday. HREF PWAT values overnight through Monday
increase to 1.00-1.50", highest over southern/southeastern CWA, and
increasing to around 1.70" by Monday afternoon in this area. NAEFS
shows PWAT values 90-97.5% above climo. This makes QPF, per EFI,
ranging from 0.5-0.6 with a shift of tails of 0-1, with 1 over
eastern to far northeastern SD into western MN. Total QPF looks to
range from half an inch over our northwestern CWA to 1-2+ inches,
highest over eastern to northeastern SD into west central MN. Due to
this threat of heavy rain/flooding, the WPC has a slight risk (15%)
of heavy rainfall over the southeastern CWA for tonight and moderate
risk (40%) from Watertown and north into Sisseton along with west
central SD.

&&

.LONG TERM /MONDAY EVENING THROUGH SATURDAY/...
Issued at 342 AM CDT Sun Jun 16 2024

Warm front moves northward into eastern SD Monday night, with a
wave of low pressure moving northeast along the front, ending up
over eastern SD by 12Z Tuesday. Impressive low-level jet on the
order of 50 to 60 knots sets up over the eastern CWA Monday night,
with moisture advection surging northward. Parameters continue to
support potential for severe storms (MUCAPE 2000+ J/KG) with heavy
rain a concern as well. NAEFS/ENS mean precipitable water values are
around 1.50 to 1.75in across eastern SD into western MN, which are
in the 90th-97.5th percentile (ENS 12Z) or even 97.5th-99th
percentile (NAEFS 00Z). Even seeing signals across the eastern CWA
in the EC 100-yr ARI for 24-hr rainfall. GEFS/GEPS/ENS 75th
percentile 24-hr precip ending 06Z Tues are generally 1.50-2in. With
the eastern CWA already rather wet, may need to consider flood/flash
flood watch headlines in later shifts.

On Tuesday, cold front will be gradually making its way eastward
across the CWA, with eastern areas still in the threat (20-50%
chances) for showers and thunderstorms. Severe storm and heavy rain
threat will certainly be shifting eastward into MN though at this
time. Will also see drier air advecting eastward through the day in
the wake of the cold front.

More active weather looks to set up Thursday into Friday as another
frontal boundary splays out across the region and southwest flow
aloft continues. Rainfall becoming likely (60-70%) once again
Thursday night and Friday noted by inherited NBM PoPs. Probably
cannot rule out increasing potential for strong to severe storms,
with dewpoints increasing into the 60s once again and joint
probabilities for CAPE/CIN/shear also showing increasing percentages.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1228 AM CDT Sun Jun 16 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions continue through the TAF period. Showers and
thunderstorms will move in late tonight (Sunday), mainly
affecting KPIR and possibly KMBG towards the very end of the TAF
period.


&&

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

$$

SHORT TERM...MMM
LONG TERM...TMT
AVIATION...MMM