Area Forecast Discussion Issued by NWS Sioux Falls, SD
000
FXUS63 KFSD 120346
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
1046 PM CDT Mon Mar 11 2024
.KEY MESSAGES...
- Critical fire danger continues through the Tri-State area
into early evening.
- Record temperatures experienced on Monday will continue into
Tuesday and Wednesday, though lower probabilities of
breaking records through mid-week.
- Shifting storm track leads to higher probabilities of rain
(as high as 80%) late Wednesday into Thursday, and meaningful
rain potential. Though there remains considerable spread in
model data, and this forecast may continue to change.
- Cooler temperatures now expected for the weekend, with highs
closer to seasonal normals.
&&
.DISCUSSION...
Issued at 251 PM CDT Mon Mar 11 2024
THIS AFTERNOON: A day full of records, dry air, gusty winds, and
critical fire weather conditions. It should be no surprise give
the seasonally warm low-lvl temperatures, deep mixing, and
drought conditions that temperatures are soaring to record
levels this afternoon. We`re likely going to mix into the
600:700 mb layer this afternoon which will push wind gusts into
the 25 knot range at times along and east of I-29. The mixdown
of dry air has led to RH values as low as 10% in a few areas.
While not an extreme fire weather day due to the winds,
widespread critical fire weather conditions will continue into
early evening.
TONIGHT: A weak surface trough slides into the area tonight,
inducing a period of variable winds. Given the light winds and dry
airmass lingering, we should cooler temperatures develop by
daybreak. Only issue could be increase of cirrus that could serve as
a thin blanket to strong radiational cooling.
TUESDAY: Another warm and very dry day is expected on Tuesday. We`ll
likely mix as deep as 800 mb in most locations, and given the
lingering warm air, this should push high temperatures into the
upper 60s in most locations. Winds though will be much weaker,
gusting into the 10-13 knot range in the afternoon.
WEDNESDAY-FRIDAY: Outside of the record temperatures and dry air
today, there has been much interest in an increasing rain chance
headed into the region late Wednesday and continuing through
Thursday. An upper trough will begin to move into the West Coast
early Tuesday, with energy digging towards the Four Corners region
by Wednesday. A separate piece of energy is expected to eject
out of this trough and move into the Plains by Wednesday night.
Uncertainty in the forecast remains focused on the track and
intensity of this wave moving into the mid-Missouri River
valley. 12Z guidance now takes the lee side low that develops
over the Oklahoma Panhandle slightly further northwest, across
Omaha, Des Moines, and then east into Northern Illinois.
Guidance has also trended a bit deeper with the upper wave,
inducing a stronger 850mb circulation and resulting in a
stronger influx of low-lvl northwest into the baroclinic zone.
The wave moving under the left-exit region of the upper jet
would support an increased risk of meaningful rain.
From an ensemble perspective, the biggest shift today has been from
the GEFS, where just 24 hours ago the of 0.10" of QPF were as
low as 30-40%, and are now pushing 70-80, even as high as the
I-90 corridor. The ECM has been more consistent with this
system, with some trends towards and even further north track.
All that said, these model trends have pushed the overall PoP
higher and further northwest, along with increasing the QPF
potential. 0.50" probabilities are now over 50% south of I-90,
with 1.00" probabilities over 20%. With this system finally
reaching shore tonight into Tuesday, will be interesting to
watch if this trend continues.
With a slightly more southwest flow Wednesday, temperatures have
been pushed upwards and back into the mid-60s. Cooler temperatures
arrive Thursday, with a cautious eye on the degree of dynamical and
evaporative cooling Thursday into Thursday night (ala the 12Z NAM),
which could support some changeover to snow.
SATURDAY-SUNDAY: A brief break on Friday with above normal
temperatures behind the departing wave. However, guidance continues
to favor a deeper trough dropping southward out of Canada this
upcoming weekend. A stronger cold front may move through the
area Saturday, dropping temperatures closer to seasonal normals.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 1046 PM CDT Mon Mar 11 2024
VFR conditions are expected for the TAF period. The low level jet
(LLJ) has begun to strengthen this evening and is bringing low level
wind shear (LLWS) to parts of northwest Iowa, including to KSUX. The
LLJ will wane through the overnight hours and end the LLWS. A cold
front continues to push through the area late this evening and will
turn the surface winds to out of the northwest for the overnight
hours. Winds will turn out of the east/northeast for the day
tomorrow and will remain light at 5-10 knots. These light winds will
finish out the TAF period.
&&
.FIRE WEATHER...
Issued at 300 PM CDT Mon Mar 11 2024
Record temperatures, extremely dry air, and increasing winds
will continue through the afternoon hours and even into the
early evening. The current red flag warning continues to remain
valid.
Tuesday will feature another very warm and dry day as
temperatures rise near 70 degrees. Relative humidity values will
again fall into the 20 to 25 percent range in the afternoon.
However, unlike today, winds will remain much lower. Afternoon
gusts will only climb into the 10 to 13 knot range, keeping away
critical fire danger conditions.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
DISCUSSION...Dux
AVIATION...Meyers
FIRE WEATHER...Dux