Severe Thunderstorm Warning 199, NWS Sioux Falls, SD

513 
WWUS53 KFSD 122314
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
614 PM CDT SAT AUG 12 2017

SDC053-122330-
/O.CON.KFSD.SV.W.0199.000000T0000Z-170812T2330Z/
Gregory SD-
614 PM CDT SAT AUG 12 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 630 PM CDT
FOR SOUTHWESTERN GREGORY COUNTY...

At 614 PM CDT, a severe thunderstorm was located 13 miles south of
Gregory, or 19 miles northeast of Springview, moving southeast at 15
mph.

HAZARD...60 mph wind gusts and quarter size hail. 

SOURCE...Radar indicated. 

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees. 

This severe thunderstorm will remain over mainly rural areas of
southwestern Gregory County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4315 9954 4300 9925 4300 9953
TIME...MOT...LOC 2314Z 319DEG 14KT 4304 9949 

HAIL...1.00IN
WIND...60MPH
 
$$

Hanko

364 
WWUS53 KFSD 122325
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
625 PM CDT SAT AUG 12 2017

SDC053-122331-
/O.EXP.KFSD.SV.W.0199.000000T0000Z-170812T2330Z/
Gregory SD-
625 PM CDT SAT AUG 12 2017

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN GREGORY COUNTY
WILL EXPIRE AT 630 PM CDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore the warning will be allowed to expire.  However small hail
and heavy rain are still possible with this thunderstorm.

A severe thunderstorm watch remains in effect until midnight CDT for
south central South Dakota.

LAT...LON 4315 9954 4300 9925 4300 9953
TIME...MOT...LOC 2321Z 305DEG 13KT 4303 9946 

$$

Hanko

Area Forecast Discussion
National Weather Service Sioux Falls SD
317 PM CDT Sat Aug 12 2017

.SHORT TERM...(This evening through Sunday)
Issued at 316 PM CDT Sat Aug 12 2017

At 2 pm this afternoon isolated thunderstorms continued between
Huron and Pierre where then have meandered for much of the day. The
latest water vapor loops show a nice wave across North Dakota with a
moderate jet max wrapping around the south side of this low
pressure. The stronger EML was just moving into western SD with a
nice dry slot poking into northwest South Dakota. As this upper
level support moves farther out onto the Plains it should interact
with some moderately unstable air in central and western parts of
South Dakota. Strong to severe thunderstorms will likely develop in
those areas by mid to late afternoon and could push into areas west
of the James River by about 6 to 7 pm. At this time the instability
to the east of the Missouri River drops off quickly which should
keep the severe threat west of the Missouri River. Not out of the
question however to get a few severe storms into locations west of
the James River before 10 pm CDT. There will also be a threat for
some strong to lower end severe storms mid afternoon with daytime
heating near the Missouri River.

After 10 pm the small severe weather threat should be over and a
band of moderate showers with isolated thunderstorms will continue
to press east into east central SD, southwest MN and finally
northwest IA.

The threat for showers and thunderstorms will continue into Sunday
afternoon with the chances slowly ending from west to east. If
everything comes together tomorrow an isolated severe storm would be
possible in far east central SD, southwest MN and northwest IA but
for now that threat is a little too low to be concerned about right
now.

.LONG TERM...(Sunday night through Saturday)
Issued at 316 PM CDT Sat Aug 12 2017

Slow moving upper level trough exits the region Sunday night.
Ongoing scattered shower and thunderstorm activity across the bulk
of the area will diminish from west to east overnight. Isolated to
scattered showers or thundershowers may linger into Monday morning
with a break in activity likely around midday. Not a great deal of
model agreement, but the GFS and NAM indicate that by late afternoon
or early evening, a warm front lifts northward into the Missouri
Valley then north of I-90 overnight. The CMC and ECMWF are far less
bullish with this activity. Will go with scattered showers and
thunderstorms lifting northward into Iowa and southeast SD in the
evening and into SW Minnesota late, but confidence remains somewhat
low with the uncertainty of how quickly the front lifts northward.

Potent trough begins pushing into the northern High Plains on
Tuesday, however there remains some timing differences in how
quickly a wave lifts into the eastern Dakotas. The CMC remains the
slowest model and is something of an outlier. Scattered showers and
thunderstorms will remain possible through the day Tuesday. Went
ahead and boosted pops into the 60 to 80 percent range on Tuesday
night, with most models bringing the potent wave into the region
around this time. Scattered showers and storms remain possible into
Wednesday morning, but will begin to taper off through  Precipitable
water values are pretty hefty, with model QPF values pretty high.
Areas that do see thunderstorms could see some decent rainfall
amounts. But as is typical with convection, not every location will
see significant rainfall.

Models diverge even further late in the week, although it does look
like the active weather pattern continues. Not enough confidence in
any one solution, but it does look like a wave rolls across the
northern Plains around the Friday or Friday night time frame.
Temperatures remain slightly below normal through the extended
forecast.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1148 AM CDT Sat Aug 12 2017

VFR conditions through most of the afternoon and evening. Showers
and thunderstorms should expand in coverage in central SD late
this afternoon, then work east overnight into Sunday morning. As
the showers move through late tonight into Sunday morning an MVFR
ceiling will become likely.

&&

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

SHORT TERM...08
LONG TERM...
AVIATION...08

Hazardous Weather Outlook
National Weather Service Sioux Falls SD
419 AM CDT Sat Aug 12 2017

IAZ001>003-012>014-020>022-031-032-MNZ071-072-080-081-089-090-097-
098-NEZ013-014-SDZ039-040-054>056-060>062-065>071-130930-
Lyon IA-Osceola-Dickinson-Sioux-O'Brien-Clay IA-Plymouth-Cherokee-
Buena Vista-Woodbury-Ida-Lincoln MN-Lyon MN-Murray-Cottonwood-
Nobles-Jackson-Pipestone-Rock-Dixon-Dakota-Kingsbury-Brookings-
Miner-Lake-Moody-Hanson-McCook-Minnehaha-Hutchinson-Turner-
Lincoln SD-Bon Homme-Yankton-Clay SD-Union-
419 AM CDT Sat Aug 12 2017

This Hazardous Weather Outlook is for portions of northwest Iowa,
west central Iowa, southwest Minnesota, northeast Nebraska, east
central South Dakota, and southeast South Dakota.

.DAY ONE...Today and Tonight

There is a chance of thunderstorms tonight. These storms are not
expected to be severe.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

There is a chance of thunderstorms on Sunday. This activity is not
expected to be severe.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

SDZ038-050-052-053-057>059-063-064-130930-
Beadle-Gregory-Jerauld-Sanborn-Brule-Aurora-Davison-Charles Mix-
Douglas-
419 AM CDT Sat Aug 12 2017

This Hazardous Weather Outlook is for portions of central South
Dakota, east central South Dakota, south central South Dakota,
and southeast South Dakota.

.DAY ONE...Today and Tonight

There is a chance of thunderstorms this afternoon into this
evening. A few storms may produce winds up to 60 mph and hail to
the size of quarters.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

Additional storms are possible on Sunday. If they develop, an
isolated storm may be capable of producing hail to the size of
quarters.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is possible after 4 pm.