Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 252108
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
308 PM CST Sun Feb 25 2018

.SHORT TERM...(This evening through Monday)
Issued at 306 PM CST Sun Feb 25 2018

Main concern through tonight into Monday is potential for
drifting snow. This will generally be a greater concern during
daytime hours, when gusty west-southwest flow blows the fresh snow
onto sun-heated roads. Seeing this on area road cameras around
southwest MN and east central SD this afternoon, and may very well
see the same thing on Monday, as the gusty winds and sunshine are
expected to continue.

Specific to winds, 925mb flow of 25-30kts perpendicular to
Buffalo Ridge will maintain some gustiness along/downslope of the
Ridge, as well as other elevated portions of the CWA, through the
overnight hours. Remainder of the CWA should decouple this
evening, and will likely see elevation reflected in overnight
temperatures, coldest in the valleys and warmest in highest
elevations and downslope of the Buffalo Ridge in southwest MN.

925mb winds increase a bit more through the day Monday, while
850mb speeds climb to 40-50kts by mid-late afternoon. Do not
expect surface speeds to approach advisory criteria due to
strengthening inversion. However, could see gusts of 30-35mph in
southwest Minnesota, with 15-25mph gusts more common elsewhere.
Despite the inversion, the strong warming aloft should help push
temperatures into mid 30s-mid 40s for highs Monday, though readings
could certainly impacted by varying snow depth throughout the
region.


.LONG TERM...(Monday night through Sunday)
Issued at 306 PM CST Sun Feb 25 2018

Focus through the early part of the week is on temperatures, as
upper level pattern remains fairly quiet across the region through
early Wednesday. The warmth of Monday is short-lived, thanks to a
weak cool front which moves across the region Monday night/Tuesday.
Moisture is pretty sparse with the frontal passage, so expecting
only partly to mostly cloudy skies and no precipitation. Winds will
decrease as well, so drifting snow threat will likewise diminish.
Temperatures Tuesday/Wednesday will be a few degrees below normal as
February comes to a close. Lows will generally be in the 10-20F
range, with warmer readings in our far southeast Monday night,
dependent on the timing of the cool front. Highs Tuesday/Wednesday
will be in the 30s most areas.

The system which may impact southeast parts of our forecast area
late Wednesday into Wednesday night has trended farther southeast as
low pressure swings out across the Plains into the mid-Mississippi
Valley Wednesday evening. Still indications that light precip could
wrap around the system into southeast portions of the CWA Wednesday
afternoon/night, and will carry mid-range chance pops mainly east of
Highway 60, but latest model runs now keep most of our forecast area
dry through this midweek period. Slight cooling behind the system,
with highs Thursday in the lower-mid 30s at best. Could even be a
little cooler if raw model output verifies.

Stronger upper ridge builds into the northern Plains for the latter
part of the week, providing dry conditions and warming temperatures
for Friday and Saturday. A trough swinging out of the Rockies will
push the ridge east early next week, though models show very little
consensus on the timing/strength of this trough at this point. With
plenty of uncertainty, have made no adjustments to broad model blend
which depicts a chance of precipitation late Saturday night/Sunday.
Sunday looks to still be on the mild side for now, but if the faster
models verify, temperatures could end up 5-10 degrees colder.


&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1115 AM CST Sun Feb 25 2018

Patch of low MVFR-IFR stratus drifting east-southeast across from
east central SD into southwest MN to start the period. This should
exit eastern portions of the forecast area by 20Z. Gusty westerly
winds, especially along and east of the Buffalo Ridge in southwest
MN, could result in drifting snow and patchy blowing snow which
may reduce visibility at times. The winds gradually subside after
sunset, but could increase again by mid-morning Monday, so will
have to watch for similar conditions across parts of southwest MN
on Monday.

Remainder of the forecast area should see VFR conditions prevail
through the period, though may have to watch some valley areas for
patchy fog late tonight/toward sunrise Monday.


&&

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

$$

SHORT TERM...JH
LONG TERM...JH
AVIATION...JH



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