Red Flag Warning 1, NWS Sioux Falls, SD

157 
WWUS83 KFSD 282356
RFWFSD

URGENT - FIRE WEATHER MESSAGE
National Weather Service Sioux Falls SD
556 PM CST Tue Jan 28 2025

IAZ012-013-020-021-031-NEZ013-014-SDZ068>071-290100-
/O.EXP.KFSD.FW.W.0001.000000T0000Z-250129T0000Z/
Sioux-O'Brien-Plymouth-Cherokee-Woodbury-Dixon-Dakota-Bon Homme-
Yankton-Clay-Union-
556 PM CST Tue Jan 28 2025

...RED FLAG WARNING WILL EXPIRE AT 6 PM CST THIS EVENING FOR WIND
AND LOW RELATIVE HUMIDITY FOR SOUTHEAST SOUTH DAKOTA,
NORTHWEST IOWA AND FAR NORTHEAST NEBRASKA...

Northwest winds will diminish quickly after sunset.

$$

Area Forecast Discussion
National Weather Service Sioux Falls SD
1045 AM CST Tue Jan 28 2025

.KEY MESSAGES...

- Unseasonably warm temperatures, and low relative humidity will
  result in elevated to near-critical fire danger today. West
  winds will increase this morning, gusting 30 to 45 mph by
  afternoon. Please use caution with sources of sparks.

- Very warm temperatures in the 40s and 50s will continue
  through the rest of this week. Today and Thursday are likely
  to be the warmest days, with Wednesday being a bit cooler.
  Today, a few cities may come close to meeting or breaking high
  temperature records. Stay tuned to see what happens!

- Dry weather continues until Thursday evening when a low (<30%)
  chance of light rain exists for areas along and south of
  Highway 20. Rain should be clear of the area by Friday mid-
  morning.

- By next week, a more active pattern looks to bring multiple
  chances of precipitation to the area.

&&

.DISCUSSION...
Issued at 319 AM CST Tue Jan 28 2025

THIS MORNING: Satellite shows an area of cirrus clouds over North
Dakota slowly working their way south. Otherwise clear skies and
light winds will aid in efficient radiational cooling through
Tuesday morning. HREF guidance indicates a 20-30% probability of fog
development. However, winds at the surface remain around 5 to 10
mph. This is likely too mixy for fog formation. However, given the
probabilities, patchy fog in low laying areas is not out of the
question. Since confidence is low, have left fog out of the forecast
for now, but will continue to monitor and update if needed.

TODAY: A swift moving clipper system is poised to move through the
Great Lakes region today. An associated short wave trough axis will
pass over our region at the same time, bringing a stout push of WAA
and a drying air mass. Temperatures in the 925 mb level will
warm to 2 to 4 degrees C. Model soundings indicate good mixing
through this layer, which will translate to warm afternoon
temperatures in the 40s and 50s, warmest along our southern
Missouri River counties. As a westerly flow regime tends to
outperform high temperatures, have blended NBM/NMB90 for highs.

A strong 40-50 kt 850 mb low level jet will develop behind the
trough axis this afternoon. While model soundings do not indicate we
will mix quite that high, the potential is there. We will, however,
tap into the stronger 30-40 kt winds above 925 mb. Mixing those down
to the surface will result in another breezy afternoon with westerly
winds becoming northwesterly at 20-25 mph and gusts of 30-40 mph.
Downslope enhancement on the eastern side of Buffalo Ridge may
result in locally higher gusts up to 45 mph briefly this afternoon.
The combination of gusty winds, dry air (dew points generally less
than 25 deg F), and warm temperatures will result in minimum
relative humidity values falling to less than 35% for most of the
region. Areas along the southern Missouri River counties will see
the lowest values dipping down to less than 30%. While this is above
critical thresholds for fire headlines, this will still result
in another day of High to Very High grassland fire danger. In
these conditions, fires have the potential to catch and spread
quickly, so please use caution around sources of sparks. Wind
gusts are expected to fall off quickly after sunset, becoming
light at 5-10 mph. While overnight winds will likely remain too
high for fog development, another night with clear skies and
effective radiational cooling could allow some patchy fog in low
laying areas to develop. Lows will fall into the mid 20s.

WEDNESDAY: Northwesterly flow aloft dominates as the SPG relaxes.
Winds will become southerly around 10 mph as an upper closed low
moves over the Four Corners region, and surface high pressure
develops over the central Plains Wednesday afternoon. CAA lingers
from the overnight into early afternoon, limiting our highs for
Wednesday slightly, in the 40s. However, this is still 15-20 degrees
warmer than average for this time of year.

THURSDAY: As the week continues, we'll see flow aloft to our north
become more westerly, as the closed upper low to the southwest
ejects out over the southern Plains. While there is low model
agreement on track at this time, the GFS and ECMWF do have the
system tracking far enough north to impact our southern counties,
mostly along and south of Highway 20 Thursday evening and overnight.
Ensembles indicate that there exists a 10-30% probability of
receiving 0.1" of liquid equivalent precipitation. Ensemble
temperatures indicate we should be warm enough that any
precipitation that does fall should be in the form of rain. Highs
for Thursday will be again in the 40s and 50s.

FRIDAY AND THE WEEKEND: Any lingering precipitation should be east
of the area by Friday mid-morning. Winds behind the system become
northerly and bring down some cooler air, decreasing Friday's highs
to 30s and 40s. Mostly zonal flow aloft continues through the
weekend and first part of next week. Long term guidance indicates
the passage of a few shortwaves, each with the potential to bring
some precipitation to the area. However, details at this time are
too sparse to have confidence in precipitation type or total.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1041 AM CST Tue Jan 28 2025

VFR conditions expected through the period with some high level
cirrus streaming overhead. Main aviation concern will be
westerly winds gusting between 30-40 kts this afternoon. These
winds should begin to fall off fairly quickly after sunset this
evening dropping below 15 kts out of the west toward and after
midnight.

&&

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

&&

DISCUSSION...AJP
AVIATION...Kalin

Hazardous Weather Outlook
National Weather Service Sioux Falls SD
330 AM CST Tue Jan 28 2025

IAZ001>003-012>014-020>022-031-032-MNZ071-072-080-081-089-090-097-
098-NEZ013-014-SDZ038>040-050-052>071-290930-
Lyon-Osceola-Dickinson-Sioux-O'Brien-Clay-Plymouth-Cherokee-
Buena Vista-Woodbury-Ida-Lincoln-Murray-Cottonwood-Nobles-Jackson-
Pipestone-Rock-Dixon-Dakota-Beadle-Kingsbury-Brookings-Gregory-
Jerauld-Sanborn-Miner-Lake-Moody-Brule-Aurora-Davison-Hanson-McCook-
Minnehaha-Charles Mix-Douglas-Hutchinson-Turner-Bon Homme-Yankton-
Union-
330 AM CST Tue Jan 28 2025

This Hazardous Weather Outlook is for northwest Iowa, west central
Iowa, southwest Minnesota, northeast Nebraska, central South
Dakota, east central South Dakota, south central South Dakota and
southeast South Dakota.

.DAY ONE...Today and tonight.

Westerly winds will increase this morning, gusting to 30-45 mph this
afternoon. Warm temperatures and low relative humidity will result in
elevated fire danger today.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.