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000
FXUS63 KFSD 120329
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1029 PM CDT Thu Apr 11 2024

.KEY MESSAGES...

- Above average temperatures return this weekend with high
temperatures into the 70s and 80s. Continued warm and breezy
conditions could lead to elevated fire danger.

- Confidence continues to increase in rain chances (50%-80%)
returning as early as Monday evening through Tuesday as a low
pressure system passes through the region.

&&

.DISCUSSION...
Issued at 244 PM CDT Thu Apr 11 2024

A weak ridge of high pressure will build south into the area
tonight, bringing cooler morning lows and lighter winds. Any light
showers associated with the weak wave moving into MN and IA will be
out of the area by early to mid evening as clouds clear from west to
east. Lows mostly low to mid 30s.

Friday will be a pleasant day as this ridge of high pressure moves
east with light winds and clear skies are expected. Highs will range
from the upper 60s in central SD to around 60 in southwest MN.

Southerly flow will increase from west to east Friday night which
will bring milder lows, ranging from the mid 40s in central SD to
the upper 30s east of I-29.

The weekend begins on a quiet note as upper level ridging remains
parked over the the central US. Warm air advection (WAA) will remain
modest beneath the ridge, pushing 850 mb temperatures up to +15 to
+20 degrees C aloft. These very warm temperatures will reside in the
97.5th percentile per NAEFS climatology. Mixing these warm
temperatures to the surface will result in above average high
temperatures up into the 80s. An incoming weak surface low pressure
system will have a tighter surface pressure gradient out ahead of
it, contributing to breezy southwesterly winds. With breezy winds
and very warm temperatures in place, elevated fire danger is
possible. A cold front tied to the surface low pressure system will
pass through the forecast area during the evening and overnight
hours. While cooler northerly winds are expected behind the front,
low temperatures will only fall to the upper 40s to low 50s
overnight.

Upper level ridging continues to sit over the area on Sunday. 850 mb
temperatures will cool a bit behind the previously mentioned cold
front, down to +11 to +16 degrees C. Mixing this to the surface will
result in cooler, but still above average high temperatures into the
mid 70s to low 80s. Surface high pressure will be passing through
the Upper Midwest, allowing for light easterly winds to persist
through the day. Could still be some elevated fire danger if winds
were to strengthen a bit. Will keep an eye on this period of time
for this potential. The surface high looks to depart the area during
the evening and overnight hours, setting up breezy southeasterly
return flow. The southeasterly winds will keep low temperatures
warmer then the previous days lows, with lows falling to the 50s.

A strong upper level trough is poised to eject into the Plains
states on Monday, brining the next chance for rain to the area.
Renewed WAA ahead of the incoming upper wave will push 850 mb
temperatures up to +17 degrees C to +20 degrees C, making for a very
warm day with high temperatures well into the 80s. Ensembles support
this as they all show a >90% chance for high temperatures to exceed
70 degrees F and a 60-80% chance for exceeding 80 degrees F. A
strengthening lee cyclone will tighten the surface pressure
gradient, resulting in breezy southeasterly winds across the area.
This could lead to another chance for elevated fire danger but this
potential is questionable as dew points increase throughout the day.
Increasing low level moisture will also bring some potential for
showers and thunderstorms. Medium range guidance continues to vary
in the evolution of the upper level wave so confidence is low (<30%
chance) in any severe storm potential. However, ensembles continue
to show moderate to high probabilities (50-80% chance) for exceeding
a tenth of an inch of rain.

Rain chances continue on Tuesday as the upper level low looks to
move overhead. Ensembles slightly increase their probabilities for
exceeding a tenth of an inch of rain up to a 60-90% chance. With the
upper low overhead, high temperatures look to cool, although remain
above average in the 60s. The middle of the week looks cloudy with
continued chances for rain as a second upper level wave rotates into
the Northern Plains. High temperatures look to cool closer to
seasonable with highs in the 50s and 60s.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1027 PM CDT Thu Apr 11 2024

VFR conditions expected through the TAF period. Light
northwesterly winds will transition to southeasterly by Friday
evening.

&&

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

&&

$$

DISCUSSION...Meyers/08
AVIATION...JM