048
FXUS63 KFSD 221758 AAB
AFDFSD

Area Forecast Discussion...UPDATED
National Weather Service Sioux Falls SD
Issued by National Weather Service Aberdeen SD
1258 PM CDT Sat Jun 22 2024

.KEY MESSAGES...

- Light showers and thunderstorms continue over southwestern
  Minnesota and northwestern Iowa. These are expected to move to
  out by early to mid afternoon.

- A low pressure system and cold front will trigger additional
  showers and thunderstorms this morning over central South
  Dakota. These showers will move eastward through the day and
  be east of the area by late afternoon/early evening.

- Ongoing flooding may worsen as the runoff from the last 24
  hours makes its way to the waterways. Record river flooding
  is likely on several basins.

- Conditions will quiet down through the upcoming weekend into
  early next week. Temperatures remain near seasonal normals.

- Pattern through next week doesn`t favor any long duration
  rain, but several brief risks for passing convection exist.

&&

.UPDATE...
Issued at 1236 PM CDT Sat Jun 22 2024

See updated aviation discussion below.

Issued at 1121 AM CDT Sat Jun 22 2024

Still some shower and thunderstorm activity occurring across
mainly the northern part of the CWA, but some shower activity
extends as far south as the Sioux Falls area. Expect this
activity to continue to push east and exit the area by early to
mid afternoon. No changes made to winds or temperatures at this
time.

&&

.DISCUSSION...
Issued at 355 AM CDT Sat Jun 22 2024

TODAY: Lingering showers and thunderstorms over northwestern Iowa
and central Minnesota will continue to push off to the east this
morning. Another round of showers and thunderstorms is possible as a
surface low and associated cold front move through late this
morning. The better environment for thunderstorms is located over
central Iowa. However, there is 500-800 J/kg of elevated
instability to work with. If convection does initiate, the main
threats will be moderate to briefly heavy rainfall, possibly
some small hail, and wind gusts to 50 mph. These storms should
be east of the area by late afternoon. Clouds will decrease from
west to east and we may catch a few peaks of sunshine before
sunset. Highs for this afternoon look to be in the mid to upper
70s with a few 80s along the Missouri River counties. A
pleasant overnight follows with mostly clear skies and lows in
the lower 60s.

SUNDAY: For Sunday, a weak high pressure ridge builds in from the
west. With rising heights we can expect a sunny day with warm
temperatures in the 80s, with the warmest temperatures again along
the Missouri River counties. Lows will be warm in the mid to
upper 60s. Late Sunday into early Monday, there is a low (<30%)
probability of some light showers. Confidence is low due to low
agreement in guidance. If showers develop, they will remain
light, producing a trace to a tenth or two.

MONDAY: Flow aloft becomes more zonal for Monday. Strong WAA and
southwesterly winds warm the 850mb temperatures into the upper 20s
Celsius! Good mixing will kick the highs up into low to mid 90s F at
the surface. Along with good mixing come gusty winds. Look for winds
to be southerly becoming southwesterly sustained at 15-20 mph with
gusts 25-30 mph by afternoon. A subtle mid-level wave and associated
cold front moves through late Monday into early Tuesday bringing a
chance for some showers and thunderstorms. Elevated instability is
sufficient to produce a few storms that could become strong to
severe. At this time model agreement is low, and therefore
confidence in thunderstorm development is low. Monday night lows
will be warm, in the upper 60-70s.

TUESDAY-SATURDAY: A series of short waves bring multiple rounds of
showers through Thursday. An upper trough approaches from the west
Thursday afternoon bringing our next chance for strong to severe
thunderstorms. Models are in fairly good agreement in the
development of the low pressure system, but they differ greatly in
timing and track. Definitely one to keep an eye on, especially
after the recent rains.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1233 PM CDT Sat Jun 22 2024

An area of showers and thunderstorms over southeast South Dakota
continue to track east and should be exiting into southern
Minnesota by 20Z. Until then, lingering IFR CIGS are still
possible. VFR conditions are anticipated thereafter.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Flood Watch until 7 PM CDT this evening for SDZ062-067.
MN...Flood Watch until 7 PM CDT this evening for MNZ081-089-090-098.
IA...Flood Watch until 7 PM CDT this evening for IAZ001>003-012>014.
NE...None.

&&

$$

UPDATE...Serr
DISCUSSION...AJP
AVIATION...Serr