Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 271722
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1222 PM CDT TUE SEP 27 2016

.SHORT TERM...(Today and Tonight)
Issued at 252 AM CDT Tue Sep 27 2016

Quiet weather will continue across the area for today, with
conditions similar to yesterday. It will be breezy once again,
though winds speeds will not be quite as strong as on Monday with
mixed layer winds running slightly lower at 15 to 25 kts. Strongest
winds will be over southwestern MN into the Iowa Great Lakes area.
Highs will range from the mid 60s over parts of southwest MN to mid
70s through south central SD.

For tonight, winds drop off with lows again just below seasonal
normals - in the lower to mid 40s, with some localized cooler spots.
Will see an increase in clouds from east central SD through
southwestern MN/northwest IA later in the night as a vort lobe wraps
southward around the upper level low situated over the western Great
Lakes region.

.LONG TERM...(Wednesday through Monday)
Issued at 252 AM CDT Tue Sep 27 2016

As lobe of strong Great Lakes upper low wraps south of the feature
early Wednesday, weak stratus surge will continue to wrap south and
westward into the CWA through Minnesota and Iowa with off surface
flow starting to see a gradually increasing easterly component.
Subsidence should work on the cloud shield on the western flank, but
even if clouds thin/break during the midday and afternoon, will
likely see some scattered to broken stratocumulus with solar input.
As a result of the clouds and subsidence inversion around the ridge
axis, mixing depths will be limited, and highs will likely struggle
to lower 60s in much of southwest MN and northwest IA, while more
sunshine and a bit warmer air along the ridge axis near the James
Valley allows temps into the upper 60s.

Perishable flat cumulus field will slowly dwindle during the
subsident evening with elongated surface ridge axis bisecting the
CWA from northeast to southwest.  This should set up another
seasonally cool night with mainly lower to mid 40s for lows, warmest
in slightly more gradient and a bit moisture low-level trajectory
into northwest Iowa.

Thursday and Friday will see gradual narrowing of amplified upper
ridge, but area safely in the middle of such feature. Should be a
mainly clear period, with usual watch on impact of easterly flow and
potential for a few clouds to advect westward from vicinity of large
upper low. Gradually the eastward shift in low-level ridge axis
should eliminate the threat.  Saturday will be much of the same, but
perhaps a few more higher level clouds as weak wave shears into the
ridge. Overall, temps seasonable in the upper 60s to mid 70s for
highs, and mid 40s to lower 50s for lows.  As southerly winds begin
to increase by Friday/Friday night in southeast SD, will start to
pick up a few more of the lower 50s.  Ensembles indicating very
little range to the forecast for several days, emphasizing
consistency in solutions late week.

Extended range continues to advertise a slowing of the precipitation
threat which originally looked to reveal more in Sunday afternoon,
but now should hold off until Sunday night or Monday as leading wave
in large western trough lifts northeast through the plains.
Increasing moisture/clouds should work on shrinking up the diurnal
change, mainly on the lows side with lows in the lower to mid 50s by
Monday and Tuesday, while highs slip back to upper 60s to lower 70s.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1220 PM CDT Tue Sep 27 2016

VFR conditions, however gusty winds, are expected through 00z
Wednesday. Thereafter, a wedge of stratus will move southward
along and east of I-29 bringing MVFR ceilings tonight into
Wednesday morning.

&&

.FSD Watches/Warnings/Advisories...
SD...None.
MN...None.
IA...None.
NE...None.
&&

$$

SHORT TERM...JM
LONG TERM...Chapman
AVIATION...BT



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