Flash Flood Warning 21, NWS Sioux Falls, SD

774 
WGUS73 KFSD 262043
FFSFSD

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
343 PM CDT TUE JUL 26 2016

SDC005-262215-
/O.CON.KFSD.FF.W.0021.000000T0000Z-160726T2215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BEADLE SD-
343 PM CDT TUE JUL 26 2016

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 515 PM CDT FOR
NORTHWESTERN BEADLE COUNTY...

AT 336 PM CDT...DOPPLER RADAR INDICATED THUNDERSTORMS THAT WERE
PRODUCING HEAVY RAIN ACROSS THE WARNED AREA HAVE WEAKENED AND MOVED
OFF TO THE EAST. 

THE AREA OF BIGGEST CONCERN RESIDES NORTHEAST OF WESSINGTON...AND
NORTHWEST OF WOLSEY. IN PARTICULAR...DOPPLER RADAR ESTIMATES OVER
FOUR INCHES OF RAIN FELL IN A SHORT AMOUNT OF TIME CENTERED ABOUT 5
MILES NORTHEAST OF WESSINGTON. TO THE NORTHWEST, THE HAND COUNTY
EMERGENCY MANAGER REPORTED 4.5 INCHES OF RAIN...8 MILES NORTH OF
SAINT LAWRENCE. THIS GIVES AN EXAMPLE OF THE AMOUNT OF RAIN THAT
FELL IN A NARROW AREA ENCOMPASSING THESE LOCATIONS. 

FLASH FLOODING WILL REMAIN OVER RURAL AREAS OF NORTHWESTERN BEADLE
COUNTY.  BUT WITH NO ADDITIONAL STORM REDEVELOPMENT...IT LIKELY WILL
NOT TAKE EXCESS WATER LONG TO FINISH RECEDING. IF FLASH FLOODING IS
OBSERVED...PLEASE RELAY THIS INFORMATION TO LOCAL LAW ENFORCEMENT
AGENCIES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...FARMLAND...AND OTHER LOW LYING
SPOTS.

&&

LAT...LON 4458 9847 4446 9841 4446 9870 4461 9870

$$

MJF

542 
WGUS73 KFSD 262134
FFSFSD

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
434 PM CDT TUE JUL 26 2016

SDC005-262143-
/O.CAN.KFSD.FF.W.0021.000000T0000Z-160726T2215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BEADLE SD-
434 PM CDT TUE JUL 26 2016

...THE FLASH FLOOD WARNING FOR NORTHWESTERN BEADLE COUNTY IS
CANCELLED...

THE HEAVY RAIN HAS ENDED. FLOODING IS NO LONGER EXPECTED TO POSE A
THREAT. THE AREA WILL BE MONITORED FOR ANY REDEVELOPING STORMS.

LAT...LON 4458 9847 4446 9841 4446 9870 4461 9870

$$

MJF

Area Forecast Discussion
National Weather Service Sioux Falls SD
1217 PM CDT TUE JUL 26 2016

.SHORT TERM...(Today and Tonight)
Issued at 401 AM CDT Tue Jul 26 2016

Large scale pattern this morning more or less a zonal mid-level flow
across the northern plains, with a couple of weaker disturbances
back toward northwest South Dakota and southwest Montana which will
be traversing the region through tonight.  Leading wave has kept a
bit of vigorous convection going along the northern SD border on the
nose of 35-40 kt LLJ through the night, but other than weaker cells
moving toward central SD which could limp into KHON area during the
early to mid-morning, not likely to see much activity well through
the day.  Focus for storms will remain largely near the frontal
boundary as it slowly sinks southward from a southeast ND to
northwest SD line - remaining north of the CWA through the day.
Large scale warm layer aloft will shoot out ahead of the approaching
waves ahead of the advancing frontal boundary, and somewhat limited
return of low level moisture should mean it will be enough to
effectively cap the environment through the day ahead of the frontal
convergence.  With warm push at lower levels squeezing ahead of the
boundary, could see zone of temperatures push into the lower 90s
from south central SD toward east central SD and toward the KMML
area this afternoon, with generally mid-upper 80s to the southeast.

Montana wave will be pushing into western South Dakota by evening,
and looks to be vigorous enough to initiate convection over the
western and northern portions of the state by very late afternoon or
early evening.  Lower level southerly flow does weaken somewhat by
late day, and this will decrease shear potential through the 0-1km
layer heading into the evening, and also keep 0-6km shear on the
order of 40-45 knots. Orientation of shear vectors again suggests
that storms should be more linear by the time they approach the
lower Brule areas in the evening.  Large amounts of DCAPE would put
a good weight into the damaging wind bin for severe weather threat
mainly this evening, generally southwest of a Wessington Springs to
Tyndall line where a more organized system is of greater likelihood.
A more isolated threat would exist as far east as MML-FSD-SUX,
perhaps marginally large hail but again more likely wind.  Best
elevated lapse rates appear to remain across the southwest half of
the CWA through the night, and even with wave sliding across the
area during the night, tendency for stronger storms to settle with
more of a southeastward/southward tracking through the evening could
see storms tend to dissipate or weaken as they approach the mid I-29
corridor later in the night.

One potential fly in the ointment would be the location of the ridge
axis this morning, and will have to watch light wind locations for
some potential patchy fog in areas from around KSUX eastward to KSLB.

.LONG TERM...(Wednesday through Monday)
Issued at 401 AM CDT Tue Jul 26 2016

Wednesday continues to look unsettled as shortwave energy moves
through the region.  There should be a good deal of scattered
showers and a few thunderstorms to begin the day well ahead of a
surface boundary lagging back towards central South Dakota. The
big question is how long this activity will last, and how quickly
downstream areas from convection and areas just ahead of the
advancing front can destabilize later in the afternoon. While the
low-lvl lapse rates are somewhat questionable, cooling
temperatures aloft do indicate steepening lapse rates in the
afternoon, yielding MLCAPE values upwards of 1500-2000 J/KG. Shear
however remains somewhat marginal, which could limit the overall
severe weather potential.

Scattered convection will move southeast through the evening hours,
and latest guidance has trended significantly drier for Thursday
and Thursday night. The only fly in the ointment to an otherwise
pleasant day on Thursday will be a low end risk for scattered
diurnal based storms in NW Iowa Thursday afternoon.

We'll begin to see the next shortwave move into the Plains by
Friday, and this wave may bring higher rain chances to the local
area by Friday night into Saturday. The general trends would favor
dry conditions for Sunday through Tuesday as mid-lvl ridging
increases.

Temperatures through the medium range will average near to below
normal for Wednesday through Saturday. Temperatures by Sunday and
into next week will trend above the seasonal normals with heat
index values pushing 100 degrees once again.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1215 PM CDT Tue Jul 26 2016

VFR through the period. Isolated to scattered thunderstorms along
and west of the James River Valley through the evening, with the
chances expanding east through the night. Additional shower and
thunderstorm activity will remain possible through Wednesday
morning. Brief MVFR conditions will be possible within the
stronger thunderstorms.

&&

.FSD Watches/Warnings/Advisories...
SD...None.
MN...None.
IA...None.
NE...None.
&&

SHORT TERM...Chapman
LONG TERM...Dux
AVIATION...08

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SIOUX FALLS SD
437 AM CDT TUE JUL 26 2016

SDZ050-052-057-058-063-064-068-270945-
GREGORY-JERAULD-BRULE-AURORA-CHARLES MIX-DOUGLAS-BON HOMME-
437 AM CDT TUE JUL 26 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL SOUTH
DAKOTA...SOUTH CENTRAL SOUTH DAKOTA AND SOUTHEAST SOUTH DAKOTA.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS ARE EXPECTED TO DEVELOP INTO A BROKEN LINE ACROSS
CENTRAL SOUTH DAKOTA BY VERY EARLY EVENING...AND THESE STORMS
SHOULD PROGRESS ACROSS AREAS WEST OF THE JAMES RIVER DURING THE
EVENING HOURS. WHILE STORMS COULD PRODUCE HAIL UP TO HALF DOLLAR
SIZE...A HIGHER THREAT WILL BE FOR DAMAGING WINDS UP TO AROUND 70
MPH.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

AN ISOLATED STRONG TO SEVERE STORM WITH HAIL AND WIND WILL BE
POSSIBLE IN THE AFTERNOON SOUTH OF INTERSTATE 90.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS POSSIBLE BETWEEN 7 PM AND MIDNIGHT.

IAZ001-012-020-031-MNZ071-072-080-089-097-098-NEZ013-014-
SDZ038>040-053>056-059>062-065>067-069>071-270945-
LYON IA-SIOUX-PLYMOUTH-WOODBURY-LINCOLN MN-LYON MN-MURRAY-NOBLES-
PIPESTONE-ROCK-DIXON-DAKOTA-BEADLE-KINGSBURY-BROOKINGS-SANBORN-
MINER-LAKE-MOODY-DAVISON-HANSON-MCCOOK-MINNEHAHA-HUTCHINSON-
TURNER-LINCOLN SD-YANKTON-CLAY SD-UNION-
437 AM CDT TUE JUL 26 2016

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

THUNDERSTORMS WILL MOVE IN DURING THE EVENING AND EARLY OVERNIGHT
HOURS. WHILE STORMS WILL LIKELY BE WEAKENING AS THEY MOVE INTO
THE AREA LATER IN THE NIGHT TOWARD INTERSTATE 29...AN ISOLATED
STORM WILL BE CAPABLE OF WIND GUSTS TO 60 MPH...WITH A LESSER
THREAT FOR HAIL UP TO QUARTER SIZE.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

AN ISOLATED STRONG TO SEVERE STORM WITH HAIL AND WIND WILL BE
POSSIBLE IN THE AFTERNOON AND EARLY EVENING GENERALLY SOUTH OF
INTERSTATE 90.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS POSSIBLE BETWEEN 8 PM AND 1 AM.

IAZ002-003-013-014-021-022-032-MNZ081-090-270945-
OSCEOLA-DICKINSON-O'BRIEN-CLAY IA-CHEROKEE-BUENA VISTA-IDA-
COTTONWOOD-JACKSON-
437 AM CDT TUE JUL 26 2016

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

.DAY ONE...TODAY AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

AN UNSETTLED WEATHER PATTERN WILL MOVE INTO THE REGION WITH A
CHANCE FOR THUNDERSTORMS WEDNESDAY AND WEDNESDAY NIGHT...AND AGAIN
BY FRIDAY AND FRIDAY NIGHT. A FEW STORMS ON WEDNESDAY AFTERNOON
AND EVENING COULD BE SEVERE SOUTH OF INTERSTATE 90 WITH LARGE HAIL
AND DAMAGING WIND. AFTER WEDNESDAY...THE THREAT OF SEVERE WEATHER
APPEARS TO BE LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT.