882 
FXUS63 KFSD 051725
AFDFSD

AREA FORECAST DISCUSSION
National Weather Service Sioux Falls SD
1225 PM CDT Mon Oct 5 2020

.SHORT TERM...(Today and Tonight)
Issued at 238 AM CDT Mon Oct 5 2020

Quiet weather across the region with surface high pressure to our 
east and surface trough pushing into the Northern Plains. Southerly 
winds have remained elevated overnight which has helped keep lows 
milder than readings yesterday at this time. 

This southerly flow will also usher in warmer temperatures for the 
afternoon today and have pushed temperatures to the upper half of 
available guidance, or mid 70s to lower 80s. Will see breezy 
southerly winds this morning transition to breezy northwesterly 
winds by the afternoon as the previously mentioned surface trough 
pushes through. This, combined with the dry conditions, will result 
in enhanced fire weather concerns which are discussed further in the 
Fire Weather section. 

Quiet weather continues thru Monday night and into Tuesday with 
another breezy and mild day expected for Tuesday. Forecast soundings 
show the potential for pretty good mixing and thus have again 
trended temperatures to the upper half of guidance or mid 70s to mid 
80s. Momentum transfer suggests that westerly winds may gust as high 
as 20-35 mph, again resulting in fire weather concerns. Mostly clear 
skies should prevail both Monday and Tuesday. 

.LONG TERM...(Tuesday through Sunday)
Issued at 238 AM CDT Mon Oct 5 2020

Not much of note thru much of the extended periods of the forecast 
with mid/upper level ridging amplifying to our west and shifting 
eastward thru the week. This keeps temperatures above normal with 
the coolest day expected Wednesday (upper 60s to upper 70s) and the 
warmest day likely Friday (80s). Southerly winds also look to be on 
the breezy side Thursday as the SPG tightens ahead of a weak wave 
moving thru the flow. Precipitation chances are nonexistent into the 
weekend before perhaps some hope for rain enters the picture early 
next week with the arrival of an upper level trough. 

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1217 PM CDT Mon Oct 5 2020

VFR condition through the period. Surface trough working through
the area with gusty northwest winds developing behind the front.
Gusts should gradually subside this evening. Winds will increase
after 15Z Tuesday as momentum mixes from aloft towards the
surface. 

&&

.FIRE WEATHER...
Issued at 346 PM CDT Sun Oct 4 2020

Fire weather concerns certainly elevated the next couple of days 
across the area with the antecedent dry fuels in place. The first 
period of concern starts today, with the focus across the Missouri
River Valley, namely fire zones SD255 and SD258, which are also 
highlighted in an Elevated risk from SPC. Will likely see RH 
values drop to near-critical or perhaps critical values (around 25
percent) for a period with the surface trough passage. 
Northwesterly winds should then increase behind this passage 
(gusts 20-30 mph), particularly west of the James River. The 
question is if there is sufficient overlap between these two 
periods to meet warning criteria. HREF guidance probabilities 
would suggest convincingly no. Considered a Red Flag Warning for 
the previously mentioned zones for today but given the borderline 
nature of the values, will highlight thru other means instead. 

Concerns become more widespread for Tuesday with forecast soundings 
suggesting better mixing potential. This would put most areas in the 
upper 70s to 80s for high temperatures with resultant minimum RH 
values falling to 20 to 30 percent. Momentum transfer off of 
forecast soundings would also suggest the potential for gusts to 
near 30-35 mph as well. SPC has highlighted areas near and west of 
the James River in an Elevated outlook category. Again gave strong 
consideration to a Fire Weather Watch but after collaborating with 
neighboring offices, will allow future shifts to take another
look.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&

$$

SHORT TERM...Kalin
LONG TERM...Kalin
AVIATION...BT
FIRE WEATHER...Kalin