Severe Thunderstorm Warning 137, NWS Sioux Falls, SD

060 
WWUS53 KFSD 222121
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
421 PM CDT FRI JUL 22 2016

SDC005-222145-
/O.CON.KFSD.SV.W.0137.000000T0000Z-160722T2145Z/
BEADLE SD-
421 PM CDT FRI JUL 22 2016

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 445 PM CDT
FOR NORTHWESTERN BEADLE COUNTY...

AT 421 PM CDT...A SEVERE THUNDERSTORM WAS LOCATED OVER
SPOTTSWOOD...OR 14 MILES SOUTH OF REDFIELD...MOVING SOUTHEAST AT 25
MPH.

HAZARD...70 MPH WIND GUSTS AND PING PONG BALL SIZE HAIL. 

SOURCE...RADAR INDICATED. 

IMPACT...PEOPLE AND ANIMALS OUTDOORS WILL BE INJURED. EXPECT HAIL 
         DAMAGE TO ROOFS...SIDING...WINDOWS...AND VEHICLES. EXPECT 
         CONSIDERABLE TREE DAMAGE. WIND DAMAGE IS ALSO LIKELY TO 
         MOBILE HOMES...ROOFS...AND OUTBUILDINGS. 

THIS SEVERE STORM WILL BE NEAR...
  HITCHCOCK AROUND 430 PM CDT. 

OTHER LOCATIONS IMPACTED BY THIS SEVERE THUNDERSTORM INCLUDE
BROADLAND.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
BUILDING.

THIS THUNDERSTORM IS CAPABLE OF PRODUCING ALL TYPES OF SEVERE
WEATHER INCLUDING EXTREMELY LARGE HAIL...DESTRUCTIVE STRAIGHT LINE
WINDS AND TORNADOES. MOVE QUICKLY TO A SAFE SHELTER...SUCH AS AN
INTERIOR ROOM... A BATHROOM OR CLOSET OR BASEMENT.

TORRENTIAL RAINFALL IS OCCURRING WITH THIS STORM...AND MAY LEAD TO
FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED ROADWAYS.

&&

LAT...LON 4463 9821 4444 9807 4429 9860 4444 9864
      4463 9866
TIME...MOT...LOC 2121Z 323DEG 23KT 4467 9848 

HAIL...1.50IN
WIND...70MPH
 
$$

WEISSER

Area Forecast Discussion
National Weather Service Sioux Falls SD
302 PM CDT FRI JUL 22 2016

.SHORT TERM...(This evening through Saturday)
Issued at 301 PM CDT Fri Jul 22 2016

A couple of areas of focus for tonight and Saturday. Watching
thunderstorms firing along an area of convergence in northeast South
Dakota and tracking southeast along the instability axis this
evening. These storms have become more surface based as they move
into the mid and upper 70s dewpoints across central and southern
South Dakota. Good bulk shear values, very steep lapse rates, and
strong instability will keep severe storms a threat into the highway
14 corridor, with additional development likely to the southwest of
this storm along the outflow boundary. The main threat will be large
hail to 2 inches and 70 mph wind gusts. The question will be how
long these storms can hold up given the somewhat weaker shear seen
closer to the I-90 corridor and the lower dewpoints across far
northeast South Dakota potentially advecting into storms. Models of
course are not handling this convection well, and the CAMS that do
depict this activity dissipate it near our northern border. Will
leave in a 20 to 40 percent chance in our north, extending to a 20
percent elsewhere where these is less certainty that storms will
propagate overnight.

Activity may lull in the late morning on Saturday, however concern
once again turns to an advancing cold front dropping into south
central South Dakota late morning and tracking through eastern south
Dakota in the afternoon. Temperatures will be tricky to forecast
given the still very warm temperatures aloft and the potential for
enhanced mixing with winds turning southwest ahead of the front.
Furthermore, clouds and earlier convection may prove to be a
limiter. Think there is strong enough potential for peak heating in
the James Valley in particular, so went ahead and upped highs here a
few more degrees into the mid and upper 90s and a degree or two
elsewhere. With dewpoints likely to remain in the 70s, heat index
values reach the century mark once again in most of southeast SD,
northeast NE and our far eastern Iowa counties. Went ahead and
extended the excessive heat warning in these locations. With
afternoon heating and the arrival of the front, isolated to
scattered storms again become possible in the highway 14 corridor
and much southeast SD in the afternoon. Shear is marginal and
becomes poor across our southeastern half of the region. Lapse rates
and elevated instability is good, but think that the bulk of
activity will hold off until late afternoon.

.LONG TERM...(Saturday night through Friday)
Issued at 301 PM CDT Fri Jul 22 2016

Storms lingering east of the James River early saturday evening will
decrease from the west Saturday night and should end in all of
southwest Minnesota and northeast Iowa by around 4am. Decent
lingering MUCAPE of 3000-5000 J/kg at the start of the evening as
the front pushes east could continue to bring a severe threat for a
few hours. Models appear to agree on the push of drier and stable
air getting all the way southeast through the area. Temperatures
and dew points will finally slip from the northwest as skies clear,
and temperatures by daybreak Sunday will fall to a much more
tolerable lower 60s northwest to around 70 southeast.

Sunday through Monday looks generally dry and mild, close to
midsummer normals, as the inflow of cooler stable air and the surface
ridge moving over the area provide mostly clear skies. The only
question deals with the previous potential of enough moisture and
instability return Sunday night as the front stalls to bring a small
threat of storms to the Sioux City area. That no longer looks like a
real threat. High temperatures will be in the 80s, except for a
little warming to a fairly dry 90 or two west of the James River on
Monday.

Monday night, as the wave bringing the drying moves east, the
flow aloft settles into a westerly regime, with some warming
mainly aloft, and a slow return of moisture and modest instability.
Hard to time weak waves will be the main trigger for scattered storm
initiation, and I have no quarrel with the extended guidance modest
chance of storms for the rest of the forecast period, through next
Friday. Strong ridging is held in the southern plains by the models,
so temperatures will generally stay near normal, with maybe a little
warming on nighttime lows. There could be a slight trend to cooling
later in the week, besides daytime cooling for clouds and storms, as
the upper flow starts to trend slightly to the west northwest. No
return to extreme heat highlights in any event.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1241 PM CDT Fri Jul 22 2016

mainly vfr conditions are expected through the forecast period. A
scattered deck of flat cumulus at around 1500 to 3000 ft agl is
expected to continue burning off through the mid afternoon. Deck
is likely to be broken to overcast across northwest Iowa, but
should also decrease in coverage this afternoon. Scattered
thunderstorms are expected to develop mainly after midnight, with
the best chances across the highway 14 corridor, however a 20 to
30 percent chance exists elsewhere through 15z. Given the spotty
chances of storms, will leave out mention in tafs for now.

&&

.FSD Watches/Warnings/Advisories...
SD...Excessive Heat Warning until 7 PM CDT Saturday for SDZ038-039-
     050-052>055-057>071.

     Excessive Heat Warning until 7 PM CDT this evening for SDZ040-
     056.

MN...Excessive Heat Warning until 7 PM CDT this evening for MNZ071-
     072-080-081-089-090-097-098.

IA...Excessive Heat Warning until 7 PM CDT Saturday for IAZ001-012-
     020-031.

     Excessive Heat Warning until 7 PM CDT this evening for IAZ002-
     003-013-014-021-022-032.

NE...Excessive Heat Warning until 7 PM CDT Saturday for NEZ013-014.

&&

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

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SIOUX FALLS SD
348 PM CDT FRI JUL 22 2016

IAZ001-012-020-031-NEZ013-014-SDZ038-039-050-052>055-057>071-
232100-
LYON IA-SIOUX-PLYMOUTH-WOODBURY-DIXON-DAKOTA-BEADLE-KINGSBURY-
GREGORY-JERAULD-SANBORN-MINER-LAKE-BRULE-AURORA-DAVISON-HANSON-
MCCOOK-MINNEHAHA-CHARLES MIX-DOUGLAS-HUTCHINSON-TURNER-LINCOLN SD-
BON HOMME-YANKTON-CLAY SD-UNION-
348 PM CDT FRI JUL 22 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHWEST
IOWA...WEST CENTRAL IOWA...NORTHEAST NEBRASKA...CENTRAL SOUTH
DAKOTA...EAST CENTRAL SOUTH DAKOTA...SOUTH CENTRAL SOUTH DAKOTA
AND SOUTHEAST SOUTH DAKOTA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

OPPRESSIVE HEAT AND HUMIDITY WILL CONTINUE TODAY AS AFTERNOON HEAT
INDICES TOP OUT FROM 102 TO 112 DEGREES.

SCATTERED THUNDERSTORMS WILL BE POSSIBLE TONIGHT. ISOLATED STORMS
THIS EVENING...MAINLY WEST OF INTERSTATE 29 AND NORTH OF INTERSTATE
90...WILL BE CAPABLE OF PRODUCING DAMAGING WINDS AND LARGE HAIL.
ANY ADDITIONAL STORMS THAT MAY DEVELOP THROUGHOUT THE AREA LATE
TONIGHT WILL BE CAPABLE OF PRODUCING MARGINALLY DAMAGING WIND
GUSTS AND SMALL HAIL.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

TEMPERATURES WILL CLIMB INTO THE 90S ON SATURDAY. WITH SULTRY
CONDITIONS CONTINUING...HEAT INDICES WILL AGAIN APPROACH 100 TO
105 DEGREES.

AFTER A FEW EARLY DAY SHOWERS AND THUNDERSTORMS...ADDITIONAL
THUNDERSTORMS WILL BE POSSIBLE SATURDAY AFTERNOON AND EVENING.
SOME OF THESE STORMS MAY BE SEVERE PRODUCING LARGE HAIL AND
DAMAGING WINDS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL BE POSSIBLE...MAINLY ALONG AND NORTH OF
INTERSTATE 90 THIS EVENING.

IAZ002-003-013-014-021-022-032-MNZ071-072-080-081-089-090-097-098-
SDZ040-056-232100-
OSCEOLA-DICKINSON-O'BRIEN-CLAY IA-CHEROKEE-BUENA VISTA-IDA-
LINCOLN MN-LYON MN-MURRAY-COTTONWOOD-NOBLES-JACKSON-PIPESTONE-
ROCK-BROOKINGS-MOODY-
348 PM CDT FRI JUL 22 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHWEST
IOWA...WEST CENTRAL IOWA...SOUTHWEST MINNESOTA AND EAST CENTRAL
SOUTH DAKOTA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

OPPRESSIVE HEAT AND HUMIDITY WILL CONTINUE TODAY AS AFTERNOON HEAT
INDICES TOP OUT FROM 102 TO 112 DEGREES. AN EXCESSIVE HEAT WARNING
REMAINS IN EFFECT UNTIL 7 PM CDT.

SCATTERED THUNDERSTORMS WILL BE POSSIBLE TONIGHT...MAINLY AFTER
MIDNIGHT. IF ANY STORMS MANAGE TO DEVELOP...THEY WILL BE CAPABLE
OF PRODUCING MARGINALLY DAMAGING WIND GUSTS AND SMALL HAIL.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

TEMPERATURES WILL CLIMB INTO THE UPPER 80S TO MID 90S ON SATURDAY.
WITH SULTRY CONDITIONS...HEAT INDICES WILL APPROACH 95 TO 100
DEGREES.

AFTER A FEW EARLY DAY SHOWERS AND THUNDERSTORMS...ADDITIONAL
THUNDERSTORMS WILL BE POSSIBLE SATURDAY AFTERNOON AND EVENING.
SOME OF THESE STORMS MAY BE SEVERE PRODUCING LARGE HAIL AND
DAMAGING WINDS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED.