Area Forecast Discussion
Issued by NWS Sioux Falls, SD

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

FXUS63 KFSD 122123

Area Forecast Discussion
National Weather Service Sioux Falls SD
323 PM CST Sun Feb 12 2017

.SHORT TERM...(This evening through Monday)
Issued at 322 PM CST Sun Feb 12 2017

A mild day will lead into a mild night with mild conditions again on
Monday. Surface high pressure will drift south of the area tonight
and allow winds to diminish, then gradually pick up from the west
and southwest after midnight, especially north of Interstate 90.
Nothing overly strong but back up to around 10 or 12 mph. There will
be a small threat for fog but confidence not quite high enough to
mention. Monday will see highs climb into the 40s in most locations,
likely reaching the lower 50s in areas with no snow cover.

.LONG TERM...(Monday night through Sunday)
Issued at 322 PM CST Sun Feb 12 2017

On Tuesday, upper low pressure moves southeastward across the Great
Lakes bringing a bit of back door cooling into the forecast area.
That said, 925mb temperatures are still quite mild and with a breezy
northwest flow, the mixing depth is rather deep for this time of
year. Therefore highs will still be in the lower to mid 40s which is
10 to 15 degrees above normal. The various models are not agreeing
on stratus potential behind this wave for Tuesday, in that the GFS
is most aggressive with it at least during the morning. Meanwhile,
the ECMWF and NAM really do not show any cold air advection stratus
moving southward into this region. At any rate, even the GFS burns
it off by the afternoon hours which should help for a warmup.

Then the warming trend begins. 925mb temperatures are several
standard deviations above normal for this time of year for the rest
of the week and right through the weekend. Raised highs above
superblend values each and every day beginning on Wednesday, by
primarily blending in warmer ECMWF highs and/or raw model consensus
highs into the superblend. In addition, it does not even look that
windy so it looks very pleasant coming up. The warmest day of the
week still looks like Friday, with blended highs producing upper 50s
to lower 60s and given the forecast 925mb temperatures of +10 to
+14C forecast, even these highs may be a bit conservative. One thing
to watch for however is by Friday, the upper flow is decidedly out
of the southwest as upper troughing digs into the southwest United
States. Therefore the threat for thick high clouds is always present
which could hinder high temperatures somewhat this time of year.
Saturday will be a little cooler then Friday as the various
deterministic models still show a short wave passage to our north
Friday night. But highs on Saturday should still be in the lower to
mid 50s. The next weather maker will come at the very tail end of
the extended forecast or just beyond Sunday as the aforementioned
upper trough moves eastward into the plains Sunday night and Monday.
That will likely give a chance for showers and thunderstorms by
Sunday night and Monday.


.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1136 AM CST Sun Feb 12 2017

VFR through the period.




AVIATION...08 is the U.S. government's official web portal to all federal, state and local government web resources and services.