602
FXUS63 KABR 131727 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1227 PM CDT Thu Jun 13 2024

.KEY MESSAGES...

- A more active weather pattern sets up on Friday afternoon and
  continues into early next week. This will bring multiple
  opportunities for showers and thunderstorms to the region (near
  50% chance). The greatest chance for severe weather (15%) is
  highlighted by the Storm Prediction Center on Monday east of the
  James Valley.

&&

.UPDATE...
Issued at 1224 PM CDT Thu Jun 13 2024

See updated aviation discussion below.

UPDATE Issued at 1008 AM CDT Thu Jun 13 2024

The shower and thunderstorm activity that occurred earlier this
morning has now pushed south and east of the area. The remainder
of the daytime period will be dry. No changes made to winds or
temperatures at this time.

&&

.SHORT TERM /TODAY THROUGH FRIDAY AFTERNOON/...
Issued at 442 AM CDT Thu Jun 13 2024

Showers and thunderstorms continue to traverse through the
baroclinic zone early this morning. Some of these storms may have
small hail with them but are not expected to become severe. Storms
should exit to the south and east late this morning as drier air
intrudes on upper and mid level westerlies.

Sfc high pressure builds in from the northwest this afternoon
leaving the region dry with seasonable or slightly above normal
temperatures. The high quickly exits on Friday, and a Rocky Mountain
low along with shortwave energy riding an upper ridge will begin to
affect central SD by afternoon. Southerly flow will help draw
moisture into the region again, but precip should remain mostly west
of the James Valley during the daytime Friday. Best forcing with the
shortwaves remains south of I-90, so while there is still a marginal
risk (1 out of 5) in place for Jones county, most areas are only
expected to see general thunder.

&&

.LONG TERM /FRIDAY EVENING THROUGH WEDNESDAY/...
Issued at 442 AM CDT Thu Jun 13 2024

A persistent upper level trough over the Pacific Northwest will
cause southwesterly flow aloft over the region through the long term
portion of the forecast. Multiple low pressure systems will travel
through the forecast area with each system producing showers and
thunderstorms.

The first storm system of interest occurs Friday night through
Saturday morning. There has been a shift southward with the heaviest
pcpn associated with this storm, with this CWA having a 5-25% chance
of seeing an inch of QPF over a 24 hour period ending at 0Z. There
is a higher potential for moderate rainfall over southeast SD and
into eastern Nebraska. After this initial storm pushes east of the
region, there appears to be a period of dry conditions Saturday
afternoon through perhaps 6Z Monday.

The next storms system may impact the CWA as soon as 12Z Monday, or
perhaps later in the day per the deterministic GFS. In fact, the
latest GFS indicates mostly dry condition across the CWA on Monday
with convection remaining south over Southeast SD and Iowa. However,
the GFS is currently an outlier with both the ECMWF and Canadian
suggests storms over north-central and into ND with a northward
lifting warm front and inverted surface trough. The environment does
become unstable behind the warm front with MuCAPE exceeding 2500
J/kg. However, 700 mb temps also soar above +12C, perhaps capping
off convection until late afternoon, or after 0Z Tuesday. While the
setup favors severe storms Monday evening, overall forecast
confidence is on the low side. A similar setup develops again on
Tuesday with an unstable, but perhaps capped environment over eastern
South Dakota with convection possible behind a surface low. The
Pacific Northwest trough approaches the region midweek, with cooler
700 mb temps, and persistent storm systems progressing through the
region.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1224 PM CDT Thu Jun 13 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions will prevail across the area through the TAF
period. Northwest winds will gust to around 20 knots across the
eastern part of the region this afternoon. Light and variable
winds will occur during the nighttime hours and across the east
Friday morning. Winds will become southeasterly across central
South Dakota Friday morning, and will increase into the 15 to 25
knot range.

&&

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

$$

UPDATE...Parkin
SHORT TERM...Wise
LONG TERM...SD
AVIATION...Parkin