Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 261745
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1145 AM CST Sat Nov 26 2016

.SHORT TERM...(Today and Tonight)
Issued at 310 AM CST Sat Nov 26 2016

500 mb ridge is moving east across the north central CONUS. Moisture
streaming in out ahead of a large short wave just west of the CA
coast, is resulting in cirrus covering much of the CWA this morning.

Another quiet weather day as height rises ahead of the
aforementioned low over the Pacific ocean will bring mild high temps
in the mid 40`s to mid 50`s.  Filtered sun is expected today as
model time/height sections show a persistent layer of moisture from
300-500 mb, which will result in cirrus most of the day.

.LONG TERM...(Sunday through Friday)
Issued at 310 AM CST Sat Nov 26 2016

A strong upper low approaching from the southwest will bring
rain into the area Sunday afternoon, with rain chances increasing
steadily from the southwest starting just before noon. With the
system being stronger than on previous model runs, instability
sufficient for thunderstorms aloft is indicated to spread quickly
over most of the area during the peak Sunday afternoon and evening.
The NAM and GFS both show sufficient MUCAPE up to 500 j/kg. The
strength of the surface system, which will bring strong
southeasterly winds to northwest Iowa Sunday evening, would suggest
enough low level shear for severe storms. However, it can be seen on
BUFKIT model soundings that the lower levels will be too cool for
surface based convection, so will not mention severe storms, as per
the SPC day 2 outlook for this area. The strong Sunday evening winds
should be below wind advisory criteria.

High temperatures Sunday should be in the mid 40s to lower 50s.

With the best and deepest moisture shown staying south of the area,
rainfall amounts through Sunday night are expected to generally be
below a half inch. Thunderstorms could produce locally higher
amounts.

Cooling aloft could bring some snow mixing with rain in southeast
South Dakota late Sunday night and Monday. During this time,
precipitation over the area will become light and coverage will
decrease as the low, both at the surface and aloft, moves northeast
into North Dakota and northern Minnesota. The slow nature of the
cooling should keep any snow accumulations to less than one inch.

All models keep the low generally stationary over North Dakota and
northern Minnesota Monday night through Wednesday. This is close to
the earlier EC solution, that model being the only one showing this
scenario the previous two nights. Moisture flowing around the low
will result in areas of light precipitation during this time, mostly
north of Interstate 90. Continued slow cooling will tend to change
mixed rain and snow to mostly light snow, with some diurnal
variation in precipitation type due to the lower levels warming and
cooling a bit. The weak nature of the lift, and weak thermal
contrast will keep amounts light, with snow accumulations, if any,
an inch or less. As the low begins to move east by Thursday, some
light snow could linger that day in part of southwest Minnesota. Dry
weather should prevail over all of the area Friday.

High temperatures will be mostly in the 40s Monday, mid 30s to lower
40s Tuesday, and mostly in the lower to middle 30s the rest of the
week. These late week temperatures will be fairly close to normal
for the start of December.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1142 AM CST Sat Nov 26 2016

VFR conditions expected this afternoon. As flow goes light tonight,
models suggest low clouds and fog expanding from the north and
east into the forecast area. Areas east of I-29 appear to be a
fairly good bet to see IFR or lower conditions developing. Areas
further to the west are more questionable. Have introduced low
clouds and reduced visibility into the forecast, but visibilities
maybe lower than currently forecast.

Low clouds and fog will struggle to erode on Sunday with easterly
flow developing ahead of the next wave approaching.

&&

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

$$

SHORT TERM...Sally
LONG TERM...
AVIATION...BT



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