Harrisburg, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

617
FXUS63 KFSD 061126
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
626 AM CDT Sun Oct 6 2024

.KEY MESSAGES...

- Elevated fire concerns today - especially this afternoon near
  the Buffalo Ridge. Strongest winds and lowest humidity values
  will be offset in timing today; however, precautions should be
  taken to prevent fire start.

- Low (35% or less) chance for patchy frost in low lying areas
  tonight into Monday morning.

- Little to no precipitation expected through at least the end
  of the week. This along with warmer than average temperatures
  keep the focus on fire weather.

&&

.DISCUSSION...
Issued at 347 AM CDT Sun Oct 6 2024

CURRENT THROUGH TONIGHT: Breezy west to northwest winds have
remained in place overnight due to a compressed surface pressure
gradient, with gusts as high as 30 mph expected through the morning
hours. Winds taper off from west to east, with gusts mainly 20 to 25
mph after noon as surface high pressure slides in from the west.
Although elevated fire danger is expected for much of the area,
greater concern exists for areas near/along the Buffalo Ridge this
afternoon where low RH and stronger winds may coincide for an hour
or two. More details in the Fire Weather section of this discussion.
Northwesterly surface winds and flow aloft bring the return of
near/slightly above average temperatures today as we warm this
afternoon into the mid 60s to lower 70s with lots of sunshine.

For tonight, surface high pressure keeps skies mostly clear and
leads to light and variable winds. This combination may lead to
patchy frost development overnight into Monday morning, with
ensemble probabilities 35% or less focused along river valleys and
other low lying areas. One concern is that although lows fall into
the mid 30s to near 40, the air may be dry enough to preclude frost
development. Regardless, those with sensitive vegetation outdoors
should keep an eye on the forecast and take precautions if needed.

MONDAY/TUESDAY: Northwesterly flow aloft continues into the early
part of next week with ridging in the west. With the northwesterly
flow regime, expect an increase in wildfire smoke aloft Monday into
Tuesday. Increased sky cover into early Tuesday based on the latest
HRRR/RAP runs. These models so far show very low concentrations of
surface smoke moving into the region, but those who are sensitive to
smoke should keep an eye on air quality early next week. Surface
high slides east on Monday night. A couple of short waves track
through the region early next week, but with a continued absence of
any lower level moisture, just anticipate some increases in cloud
cover. Highs warm back into the mid and upper 70s for much of the
area Tuesday, with lows in the 40s. Still could see areas of
elevated fire danger with low humidity, but lighter winds may temper
concerns somewhat.

MID AND LATE WEEK: Ridge axis builds and slides east mid week,
flattening out with more quasi zonal flow in place for late week.
Another short wave or two move through the region, but again, a lack
of low level moisture keeps the forecast dry at least through the
work week. In fact, through Friday night, ensemble probability of
measurable precipitation (0.01" or more) is less than 10%. Do expect
continued warmth, with moderate to high (> 35%) chances of
widespread highs over 80 degrees by Thursday. Highs in the 80s are
expected, with lows in the upper 40s and 50s. Given dry weather,
warm temperatures, and curing fuels, elevated fire danger continues
through the week.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 617 AM CDT Sun Oct 6 2024

Stratus has been sliding south this morning through MN, with
sites mainly reporting ceilings around 3500 ft. Areas which are
reporting lower than that have remained FEW to SCT, so think
that VFR ceiling prevail this morning. Outside of this morning`s
stratus, VFR conditions expected through the period.

Patchy LLWS lingers through about 14z this morning for areas
east of I-29 and west of the Buffalo Ridge due to change in
direction (more west vs northwest) and as well lack of gusts.
Winds this morning have been gusting to around 35 knots
near/along the Buffalo Ridge with gusts elsewhere around 25
knots. Northwest winds taper off from west to east through the
day today, with 20-25 knot gusts for most of the area through
the daylight hours. Winds drop off quickly after sunset becoming
light and variable overnight.

&&

.FIRE WEATHER...
Issued at 347 AM CDT Sun Oct 6 2024

Elevated fire concerns continue today. Northwesterly winds this
morning and early afternoon could gust as high as 30 mph, with
sustained winds around 15-20 mph. Winds taper off from west to east
through the late morning and early afternoon but remain breezy with
gusts around 15 to 20 mph into the evening. Minimum RH values today
will be in the 25 to 30% range. However, most of the area will see a
significant offset in the timing the strongest winds and lowest
humidity values. Based on the timing, there could be a brief window
between 1 PM CDT to 5 PM CDT where areas along and near the Buffalo
Ridge could see locally near critical conditions. In this area,
gusts near 25 mph may coincide with RH values near 25-30% although
again - the strongest winds will occur earlier in the day with the
lower RHs later. Thus, did not issue any fire headlines this
morning. Expect winds to drop off quickly after sunset while RHs
improve.

With dry weather and continued above average temperatures, elevated
fire concerns are expected through this week. Winds are currently
expected to remain light, which could temper concerns slightly.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.

&&

$$

DISCUSSION...SG
AVIATION...SG
FIRE WEATHER...SG