Expires:No;;027299
FXUS63 KFSD 091053
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
Issued by National Weather Service Aberdeen SD
553 AM CDT Wed Apr 9 2025

.KEY MESSAGES...

- A second round of light showers is possible late this 
  afternoon through late evening. Total rainfall just a few 
  hundredths if any.

- High/Very High Grassland Fire Danger today. Red Flag warning
  has been issued for southeast South Dakota/northeast Nebraska.
  Afternoon humidity down to around or below 20% and northwest
  winds 20-35 mph. 

- Mild temperatures and steady warming trend through the
  weekend. Highs in the 70s to near 80 Sat/Sun (15-20 degrees
  above normal). 

- Low chances for moisture (20-30%) Sunday.

&&

.DISCUSSION...
Issued at 254 AM CDT Wed Apr 9 2025

CAMS support shower activity will effectively diminish as it 
continues east southeast into through South Dakota and 
surrounding areas. NAM BUFKIT soundings are also in agreement, 
but will maintain some low POPs and mention of showers in the 
near term. CAMS are also hinting at some additional isolated 
light shower activity then coming down out of northeast South 
Dakota as the upper wave heads east with the surface low in 
western Minnesota. NAM BUFKIT profiles here hint at 
skinny/elevated CAPE of a few j/kg up above the freezing level
and inverted V soundings with bases up around 6.5kft. 
Unidirectional northwesterly flow suggests some gustiness 
possible with these "convective" showers which will do more to 
enhance the fire danger (ie erratic winds) then any moisture 
that these could provide. 

Winds will take on a bit more northerly trajectory for Thursday, 
with weak cold advection. This may give winds a bit of a boost but 
also increase relative humidity and models are showing a layer of 
low stratus coming down through the eastern Dakotas and Minnesota. 
Mixed winds top out in the 20s in NAM BUFKIT profiles, but with 
warming aloft will also feature a much shallower mixed layer.

Ridging aloft dominates Friday and begins to fold over in the 
presence of an upper trough moving across the Pacific Northwest
Saturday. West-Southwesterly upper flow ahead of an upper low 
over Montana will mean a mild elevated mixed layer with 700mb 
temperatures up to 2 standard deviations above climo. This will 
result in a very mild weekend, with the NBM probability of 
warming above 80 degrees now at about 50 percent along/west of 
highway 281 Saturday and broadly around 40 percent for Sunday.

&&

.FIRE WEATHER...
Issued at 425 PM CDT Tue Apr 8 2025

Despite initial cloudiness early this morning, clearing is prevalent 
across western South Dakota and is headed in this direction. Winds 
will shift to northwesterly and deep mixing up past 6kft will allow 
for winds to increase and the humidity to continue to drop. BUFKIT 
mixed winds are topping out in the mid 20 to low 30kt range. 
 
CAMS support some convection with mid-level instability, however
these instability showers will be occurring well above the 
freezing level, meaning much of the precipitation will evaporate
or sublimate before reaching the surface. Gusty winds, however 
would prevail in this type of environment, and thus expect any 
showers to generate erratic winds and merely increase the risk 
to firefighting activities. 

Wind speed diminish and relative humidity values recover this 
evening. Northerly winds return during the day Thursday with 
slightly cooler temperatures and a touch higher humidity 
expected.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 549 AM CDT Wed Apr 9 2025

VFR conditions for all terminals. Winds will shift to
northwesterly and increase through the morning. 

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Red Flag Warning from 1 PM this afternoon to 8 PM CDT this 
     evening for SDZ038>040-050-052>071.
MN...None.
IA...None.
NE...Red Flag Warning from 1 PM this afternoon to 8 PM CDT this 
     evening for NEZ013-014.

&&

$$

DISCUSSION...MC
AVIATION...MC
FIRE WEATHER...MC