Severe Thunderstorm Warning 166, NWS Sioux Falls, SD

638 
WWUS53 KFSD 242150
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
450 PM CDT Tue Sep 24 2019

IAC021-035-093-149-193-242215-
/O.CON.KFSD.SV.W.0166.000000T0000Z-190924T2215Z/
Cherokee IA-Woodbury IA-Plymouth IA-Buena Vista IA-Ida IA-
450 PM CDT Tue Sep 24 2019

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM CDT
FOR SOUTHERN CHEROKEE...NORTHEASTERN WOODBURY...SOUTHEASTERN
PLYMOUTH...SOUTHWESTERN BUENA VISTA AND NORTHERN IDA COUNTIES...

At 450 PM CDT, a severe thunderstorm was located over Quimby, or 11
miles south of Cherokee, moving northeast at 40 mph.

HAZARD...Golf ball size hail and 60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect hail 
         damage to roofs, siding, windows, and vehicles. Expect wind 
         damage to roofs, siding, and trees.

This severe storm will be near...
  Aurelia around 510 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until midnight CDT for northwestern
and west central Iowa.

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

&&

LAT...LON 4257 9613 4282 9551 4256 9534 4256 9539
      4249 9539 4234 9600
TIME...MOT...LOC 2150Z 245DEG 35KT 4260 9562 

TORNADO...POSSIBLE
HAIL...1.75IN
WIND...60MPH
 
$$

JM

170 
WWUS53 KFSD 242211
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
511 PM CDT Tue Sep 24 2019

IAC021-035-093-149-193-242221-
/O.EXP.KFSD.SV.W.0166.000000T0000Z-190924T2215Z/
Cherokee IA-Woodbury IA-Plymouth IA-Buena Vista IA-Ida IA-
511 PM CDT Tue Sep 24 2019

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN CHEROKEE...
NORTHEASTERN WOODBURY...SOUTHEASTERN PLYMOUTH...SOUTHWESTERN BUENA
VISTA AND NORTHERN IDA COUNTIES WILL EXPIRE AT 515 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.

A Tornado Watch remains in effect until midnight CDT for northwestern
and west central Iowa.

LAT...LON 4257 9613 4282 9551 4256 9534 4256 9539
      4249 9539 4234 9600
TIME...MOT...LOC 2211Z 245DEG 35KT 4268 9538 

$$

JM

AREA FORECAST DISCUSSION
National Weather Service Sioux Falls SD
1258 PM CDT Tue Sep 24 2019

.SHORT TERM...(Today and Tonight)
Issued at 246 AM CDT Tue Sep 24 2019

Another quiet overnight period as surface high pressure slowly
drifts eastward away from the region. Surface cold front that will
be of focus later this afternoon currently evident across western
ND.

First half of the day remains on the quiet side with some upper
level clouds occasionally filtering overhead and temperatures
running in the upper 70s to mid 80s. Continued trend as of late of
hedging temperatures upwards toward ensemble mean values.

Front enters our western forecast area by mid to late morning and
should sit near the I-29 corridor by mid to late afternoon. Forecast
soundings suggest capping inversion holds until at least this point,
perhaps closer to early evening. This would put the better
thunderstorm chances into NW IA with CI likely to have occurred by
the time the front reaches a Sioux City to Spencer line, which also
happens to coincide with the Enhanced risk from SPC. Further
northwest, front may very well come thru as a non-event and thus
only slight and chance level POPs warranted.

Instability and shear parameter spaces would suggest that once
storms do develop, a risk of strong to severe storms certainly
exists. Steep mid level lapse rates should drive MLCAPE values
upwards of 2500-3500 J/kg and the arrival of upper level jet will
result in deep layer shear values of at least 35-40 kts. Primary
threat with any storms in our area appears to be large hail with fat
CAPE profiles in the hail growth zone, which is also supported by
analogs. DCAPE values in excess of 1000 would keep some wind threat
as a concern, especially if upscale growth can occur. Low level
shear fairly unidirectional, although if surface winds can become
locally backed, hodographs would suggest at least some conditional
threat for a tornado or two. Front remains quite progressive which
should help mitigate any significant heavy rain threat.

Any thunderstorms should clear the area by mid evening or so with a
return to quiet weather overnight. Reinforcing cold front arrives by
the overnight hours with a few high-res models picking up on the
potential for a few radar returns south of the I-90 corridor.
Soundings show a pretty good dry sub cloud layer an thus only
introduced sprinkle mention for the time being. Lows should be in
the 50s for most locations.

.LONG TERM...(Wednesday through Monday)
Issued at 246 AM CDT Tue Sep 24 2019

Base of the upper level trough slowly translates east for Wednesday
into Thursday which will cool temperatures back to near or below
normal values, or generally mid 60s to mid 70s. Precipitation
chances remain minimal although winds will be on the breezy side and
have nudged these values up a tad.

Latest guidances keeps upper level flow fairly zonal for late in the
week with a closed upper low slowly fading over the desert
southwest. By the second half of the weekend however, longwave
trough digs into the intermountain west and turns the upper level
flow back to a pronounced southwest flow. This will leave the
central US vulnerable to several rounds of precipitation, with exact
location quite dependent on the boundary location. The populated
blended POPs are likely too expansive temporally but tough to make
any meaningful changes at this range given wide range of solutions.
Will need to monitor for eventual boundary location though with
PWATs back into the upper echelons of climatology and thus heavy
rain a real threat for wherever more persistent boundary presence
exists. Temperatures also a bit tricky with nearly 5-8 standard
deviations in the ensemble guidance and thus will again stick with
the populated blended guidance.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1258 PM CDT Tue Sep 24 2019

Frontal zone and subtle leading pre-frontal trough working across
eastern SD at midday. Convection expected to develop along the
boundaries by mid to late afternoon, but likely this will occur
east of KSUX at this point. Surface wind gusts could approach 25
kts for KHON late afternoon before easing toward sunset, then
again on Wednesday could approach 25 kts for KHON/KFSD by 16-18z.
VFR conditions will prevail through the period.

&&

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

SHORT TERM...Kalin
LONG TERM...Kalin
AVIATION...Chapman

Hazardous Weather Outlook
National Weather Service Sioux Falls SD
352 AM CDT Tue Sep 24 2019

MNZ071-SDZ038>040-050-052>066-068>070-250900-
Lincoln-Beadle-Kingsbury-Brookings-Gregory-Jerauld-Sanborn-Miner-
Lake-Moody-Brule-Aurora-Davison-Hanson-McCook-Minnehaha-Charles Mix-
Douglas-Hutchinson-Turner-Bon Homme-Yankton-Clay-
352 AM CDT Tue Sep 24 2019

This Hazardous Weather Outlook is for southwest Minnesota, central
South Dakota, east central South Dakota, south central South Dakota
and southeast South Dakota.

.DAY ONE...Today and tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Periods of showers and thunderstorms return by later this weekend and
early next week, although details regarding any severe weather and
heavy rain risk remain uncertain.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

IAZ001>003-012>014-020>022-031-032-MNZ072-080-081-089-090-097-098-
NEZ013-014-SDZ067-071-250900-
Lyon-Osceola-Dickinson-Sioux-O'Brien-Clay-Plymouth-Cherokee-
Buena Vista-Woodbury-Ida-Murray-Cottonwood-Nobles-Jackson-Pipestone-
Rock-Dixon-Dakota-Lincoln-Union-
352 AM CDT Tue Sep 24 2019

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

.DAY ONE...Today and tonight.

Scattered thunderstorms are expected to develop along a cold front by
late afternoon and early evening, particularly near and southeast of
a Sioux City to Spencer line. A few of these storms may be strong to
severe with large hail up to tennis ball size the primary risk. A
secondary risk of damaging wind and an isolated tornado also cannot
be ruled out.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Periods of showers and thunderstorms return by later this weekend and
early next week, although details regarding any severe weather and
heavy rain risk remain uncertain.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed between 4 and 8 pm today.