Tornado outbreak Saturday - Central states

[dean]

nope, which is kinda suprising to me, but maybe they have a good reason for not issuing a PDS today.

[CrazyC83]

Yeah, the risk levels were:

Tornadoes
Probability of 2 or more tornadoes
Mod (40%)


Probability of 1 or more strong (F2-F5) tornadoes
Mod (40%)



Wind
Probability of 10 or more severe wind events
Mod (60%)


Probability of 1 or more wind events > 65 knots
Mod (40%)



Hail
Probability of 10 or more severe hail events
Mod (60%)


Probability of 1 or more hailstones > 2 inches
Mod (40%)


Combined Severe Hail/Wind
Probability of 6 or more combined severe hail/wind events
High (80%)


Not exactly PDS criteria.

I personally think that for a PDS Tornado Watch to be issued, the probabilities in the tornado column need to be 70/50 at least or 90/70 in the wind column, although I have seen them issue PDS watches for levels below such.

There have been major outbreaks on days without PDS watches though...

[CrazyC83]

MESOSCALE DISCUSSION 1973
NWS STORM PREDICTION CENTER NORMAN OK
0324 PM CDT SAT SEP 16 2006

AREAS AFFECTED...ERN SD...SWRN MN...NERN NEB AND NWRN IA

CONCERNING...TORNADO WATCH 774...

VALID 162024Z - 162200Z

STRONG ASCENT WITHIN LEFT-EXIT REGION OF THE MID-LEVEL JETLET
CONTINUES TO SPREAD NEWD ACROSS CNTRL SD AT MID-AFTN. SFC LOW WAS
INTENSIFYING NEAR WINNER WITH THE LOW-LEVEL FLOW STRENGTHENING AND
BACKING ACROSS ERN NEB INTO SERN SD...COINCIDENT WITH INCREASING
PRESSURE FALLS. THERMAL RIDGE WAS NOSING INTO SERN SD AND
MAINTENENCE OF MID 60S SFC DEW POINTS WAS RESULTING IN MLCAPES OF
1500-2000 J/KG. FURTHER WARMING WILL RESULT IN WEAKENING CINH AND
GREATER POTENTIAL FOR SFC-BASED TSTM INITIATION.

CONSIDERABLE ELEVATED CONVECTION SHOULD CONTINUE NWD ACROSS AREAS
NEAR/W OF KHON AND KABR THROUGH LATE AFTN WHERE THE STRONGEST ASCENT
WILL OCCUR. PRIMARY SEVERE THREATS SHOULD EVOLVE ACROSS SERN-ECNTRL
SD...EXTREME NERN NEB...SWRN MN AND NWRN IA A LITTLE LATER THIS
AFTN. A PRESSURE RISE/FALL COUPLET APPEARS TO BE DEVELOPING ACROSS
CNTRL NEB AND WILL PROBABLY STRENGTHEN THE DRYLINE FROM NEAR
KMHE-KOFK BY 21-22Z. TSTMS SHOULD DEVELOP VCNTY THIS FEATURE AND
MOVE ENEWD TOWARD SWRN MN AND NWRN IA BY EARLY EVE.

GIVEN THE INCREASING SFC FLOW...LOW-LEVEL HODOGRAPHS ARE BECOMING
ENLARGED AND THE FAVORABLY MOIST BOUNDARY LAYER WILL SUPPORT
TORNADOES WITH DISCRETE SUPERCELLS. CURRENTLY...THE HIGHEST
PROBABILITIES FOR TORNADOES WILL BE FOR THOSE STORMS THAT MOVE OFF
THE DRYLINE AND TRACK ENEWD ALONG A WARM FRONT ACROSS ECNTRL/SERN SD
INTO SWRN MN. OTHERWISE...VERY LARGE HAIL AND DAMAGING WINDS WILL
BE LIKELY WITH ANY TSTM. ANOTHER TORNADO WATCH MAY BE REQUIRED EAST
AND SOUTHEAST OF WT 774 BY EARLY THIS EVENING.

..RACY.. 09/16/2006


ATTN...WFO...MPX...DMX...FGF...FSD...OAX...ABR...LBF...UNR...

42180016 45920079 45899561 44689469 42369511 41819635

[CrazyC83]

One other thing: the Sioux Falls radar is down for maintenance, possibly due to a lightning strike last night. It was supposed to be back up by 3pm but has not happened.

The first supercell is developing in its range too...this could be scary! Storm spotters will be lifesavers if anything in that area form into twisters...

[CrazyC83]

Welcome to the Second Season!

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
346 PM CDT SAT SEP 16 2006

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* TORNADO WARNING FOR...
HANSON COUNTY IN SOUTHEAST SOUTH DAKOTA
WESTERN MCCOOK COUNTY IN SOUTHEAST SOUTH DAKOTA

* UNTIL 415 PM CDT

* AT 346 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO 8 MILES
SOUTHWEST OF EMERY...OR ABOUT 22 MILES SOUTHEAST OF MITCHELL...
MOVING NORTHEAST AT 45 MPH.

* THE TORNADO WILL BE NEAR...
EMERY AROUND 355 PM CDT...

THIS WARNING REPLACES THE SEVERE THUNDERSTORM WARNING PREVIOUSLY
ISSUED FOR THE WARNED AREA.

THIS IS AN EXTREMELY DANGEROUS AND LIFE THREATENING SITUATION. TAKE
COVER NOW.

[WindRunner]

Dang . . . quarter-mile wide tornado 30nm from KFSD (Sioux Falls) and their radar is down

SVR with SVS:

Code: Select all

WWUS53 KFSD 162117
SVSFSD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
417 PM CDT SAT SEP 16 2006

SDC087-099-162200-
/O.CON.KFSD.TO.W.0024.000000T0000Z-060916T2200Z/
MINNEHAHA SD-MCCOOK SD-
417 PM CDT SAT SEP 16 2006

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 500 PM CDT FOR MCCOOK
AND NORTHWESTERN MINNEHAHA COUNTIES...

AT 415 PM CDT...LOCAL LAW ENFORCEMENT REPORTED A TORNADO WITH DEBRIS
CROSSING HIGHWAY 81 JUST SOUTH OF INTERSTATE 90.  THIS TORNADO WAS
LOCATED 5 MILES SOUTHEAST OF SALEM...OR ABOUT 21 MILES NORTHWEST OF
PARKER...MOVING NORTHEAST AT 35 MPH.

THE TORNADO WILL BE NEAR...
   MONTROSE AROUND 425 PM CDT...

A TORNADO HAS BEEN CONFIRMED. TAKE COVER IN A STURDY BUILDING NOW.
MOBILE HOMES AND VEHICLES ARE NOT SAFE.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 1000 PM CDT SATURDAY EVENING
FOR NORTHEAST NEBRASKA AND SOUTHEASTERN SOUTH DAKOTA.

LAT...LON 4368 9747 4356 9733 4384 9685 4385 9720

$$

CHAPMAN



======================================================================
WFUS53 KFSD 162113
TORFSD
SDC087-099-162200-
/O.NEW.KFSD.TO.W.0024.060916T2112Z-060916T2200Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
412 PM CDT SAT SEP 16 2006

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* TORNADO WARNING FOR...
  MCCOOK COUNTY IN SOUTHEAST SOUTH DAKOTA
  NORTHWESTERN MINNEHAHA COUNTY IN SOUTHEAST SOUTH DAKOTA

* UNTIL 500 PM CDT

* AT 412 PM CDT...TRAINED WEATHER SPOTTERS REPORTED A QUARTER MILE
  WIDE TORNADO 5 MILES NORTHWEST OF CANISTOTA...OR ABOUT 20 MILES
  NORTHWEST OF PARKER...MOVING NORTHEAST AT 35 MPH.

* THE TORNADO WILL BE NEAR...
   MONTROSE AROUND 420 PM CDT...

A LARGE TORNADO HAS BEEN CONFIRMED. TAKE COVER IN A STURDY BUILDING
NOW. MOBILE HOMES AND VEHICLES ARE NOT SAFE.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 1000 PM CDT SATURDAY EVENING
FOR NORTHEAST NEBRASKA AND SOUTHEASTERN SOUTH DAKOTA.

LAT...LON 4368 9747 4356 9733 4384 9685 4385 9720

$$

CHAPMAN


EDIT: Also producing a huge amount of lightning, total strikes around 2,000 in the last 20 minutes with this cell.

[CrazyC83]

This is an extremely dangerous situation. If you live there, prepare to take life-saving cover immediately!

[CrazyC83]

MESOSCALE DISCUSSION 1975
NWS STORM PREDICTION CENTER NORMAN OK
0408 PM CDT SAT SEP 16 2006

AREAS AFFECTED...TX PANHANDLE...WRN OK...CNTRL AND SRN KS

CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY

VALID 162108Z - 162245Z

SCATTERED STORMS ARE EXPECTED TO DEVELOP ALONG THE DRYLINE BEFORE
00Z. A FEW TORNADOES WILL BE POSSIBLE ALONG WITH LARGE HAIL AND
DAMAGING WIND. A WW IS LIKELY.

STRONG INSTABILITY HAS DEVELOPED E OF THE DRYLINE WITH MLCAPE IN
EXCESS OF 3000 J/KG. MODIFIED 18Z OUN SOUNDING AS WELL AS FORECAST
SOUNDINGS INDICATE CIN IS NEARLY GONE. CONTINUED HEATING...ALONG
WITH STRONG CONVERGENCE ALONG DRYLINE WITH BACKING LOW LEVEL JET
WILL MAINTAIN LOW LEVEL MOISTURE CONVERGENCE AND LIFT WITHIN THIS
ZONE...FAVORING DEEP MOIST CONVECTION BETWEEN 21-03Z.

AREA WIND PROFILERS INDICATE FAVORABLE SHEAR FOR SUPERCELLS. SOME OF
THESE MAY BE TORNADIC ACROSS KS AND NWRN OK GIVEN 0-1 SRH VALUES OF
100-150 M2/S2.

..JEWELL.. 09/16/2006


ATTN...WFO...TOP...ICT...OUN...DDC...LUB...AMA...

39069845 38919747 37979753 35789854 34559928 34480008
34630077 34810119 35150142 35470152 36540087 37800004
38949944

[CrazyC83]

SEL5

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 775
NWS STORM PREDICTION CENTER NORMAN OK
355 PM CDT SAT SEP 16 2006

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

WESTERN IOWA
NORTH CENTRAL AND NORTHEAST KANSAS
CENTRAL AND EASTERN NEBRASKA

EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 355 PM UNTIL
1100 PM CDT.

TORNADOES...HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 90 STATUTE
MILES EAST AND WEST OF A LINE FROM 30 MILES NORTH OF COLUMBUS
NEBRASKA TO 35 MILES SOUTH SOUTHEAST OF CONCORDIA KANSAS. FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU5).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

OTHER WATCH INFORMATION...CONTINUE...WW 774...

DISCUSSION...AIR MASS HAS BECOME VERY UNSTABLE AHEAD OF ADVANCING
DRYLINE MOVING THRU CENTRAL NEB WITH MLCAPE VALUES BETWEEN 1500-3000
J/KG. STRONG MID/UPR LEVEL JET STREAK IS MOVING INTO WRN NEB
ENHANCING VERTICAL WIND PROFILES ACROSS THE REGION. SEVERE
STORMS/SUPERCELLS ARE EXPECTED TO DEVELOP ALONG/AHD OF ADVANCING
DRYLINE NEXT FEW HOURS.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 23035.


...MCCARTHY

[WindRunner]

Another confirmed tornado, this one about 40nm SE of Aberdeen. Should see a SVR on the cell west of Aberdeen shortly as well.

Bad thing here is that the first two TORs of the day have been triggered by spottings, i.e. no lead time. Sure hope they start being able to see these coming soon . . .

Code: Select all

WFUS53 KABR 162129
TORABR
SDC025-162215-
/O.NEW.KABR.TO.W.0009.060916T2129Z-060916T2215Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE ABERDEEN SD
429 PM CDT SAT SEP 16 2006

THE NATIONAL WEATHER SERVICE IN ABERDEEN HAS ISSUED A

* TORNADO WARNING FOR...
  CLARK COUNTY IN NORTHEAST SOUTH DAKOTA...

* UNTIL 515 PM CDT

* AT 425 PM CDT...LOCAL LAW ENFORCEMENT REPORTED A TORNADO NEAR
  HILLCREST COLONY...MOVING NORTHEAST AT 15 MPH.

* THE TORNADO WILL BE NEAR...
  CROCKER AROUND 440 PM CDT...
  BRADLEY AROUND 455 PM CDT...

THIS IS AN EXTREMELY DANGEROUS AND POTENTIALLY LIFE THREATENING
SITUATION. IF YOU ARE IN THE PATH OF THIS TORNADO TAKE SHELTER NOW!

REPORT SEVERE WEATHER TO THE NEAREST LAW ENFORCEMENT AGENCY. THEY
WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE OFFICE IN
ABERDEEN.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 1000 PM CDT SATURDAY EVENING
FOR NORTHEASTERN SOUTH DAKOTA.

LAT...LON 4500 9789 4488 9770 4502 9751 4514 9753
      4515 9776

$$
HINTZ

EDIT: and the previous tornado has now reportedly dissipated per a SVS, though they have continued the warning due to the fact that doppler indicates another one forming, and have put another two counties under a TOR for it as well.

EDIT2: Also, the SVR for the cell west of Aberdeen got issued for nickel hail and 70mph winds, which appear likely after looking at the velocity data.

[CrazyC83]

http://www.keloland.com/netcast/Index.cfm - KELO-TV coverage

[CrazyC83]

AMAZING hook northwest of Sioux Falls...easily capable of an F3 or larger tornado...

[WindRunner]

Reports of a semi blown over on I-90 now.


And yes, KFSD is back, though it's running in VCP21 Better than nothing, though. Very impressive hook.

Also, new warning in in eastern SD with a very impressive couplet on it, 50kts GTG shear. And another warning just popped up as I was typing this for a storm just entering SD, where the crooked part of the southern border begins.

Going to be a very busy night . . .

[CrazyC83]

Brookings - population 18,000 - facing a direct hit from a new tornado...

[WindRunner]

AMAZING hook northwest of Sioux Falls...easily capable of an F3 or larger tornado...

That cell also contains 60dBz+ to over 25kft, beyond the -20C line . . . that should be some good hail . . .

[CrazyC83]

Yes...north end Sioux Falls under the gun too...

[CrazyC83]

When everything develops north and south, this could become the outbreak of the year...

[WindRunner]

Brookings - population 18,000 - facing a direct hit from a new tornado...

Last SVS reported rotating clouds near campus of SDSU . . . so hopefully the tornado won't come down until clear of the town. Decent hook starting to form with this Brookings cell, though the center of the hook is a few miles north of town now.

[CrazyC83]

Brookings - population 18,000 - facing a direct hit from a new tornado...

Last SVS reported rotating clouds near campus of SDSU . . . so hopefully the tornado won't come down until clear of the town. Decent hook starting to form with this Brookings cell, though the center of the hook is a few miles north of town now.

Yes, that we can only hope and pray. The cell is easily capable of a strong tornado.

[CrazyC83]

KELO: Structural damage reported in Colton, SD