Tornadoes and Flash Flooding in Oklahoma, April 17, 2013

Name: Tornadoes and Flash Flooding in Oklahoma, April 17, 2013
Start: 2013-04-17T14:15
End: 2013-04-17T22:55
Location: Oklahoma

April 17, 2013 · NWS OUN · 60 events in 18 counties and zones

Where it happened

Every event with a place to put it. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: $700,000
Crop damage: None recorded
Events: 60

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS OUN wrote it up.

A strong warm front became stationary along the interstate 44 corridor during the early afternoon of the 17th. Through the day, areas south of the warm front and east of a well-defined dryline became very unstable. As a large upper trough shifted into the Southern Plains, scattered thunderstorms developed near the dryline/warm front triple point. As these storms moved eastward into the highly unstable warm sector, they became supercellular. These storms produced all facets of severe weather, including very large hail, damaging straight line winds, and a few brief tornadoes. Training of supercells also led to flash flooding over portions of southwest Oklahoma around the Wichita Mountains Wildlife Refuge. Storms eventually shifted eastward and weakened overnight as a cold front pushed through Oklahoma.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Norman, OK wrote its last area forecast discussion before the first event at Apr 17, 12:54 PM CST, 1 hour 21 minutes earlier.

Area forecast discussion, Apr 17, 12:54 PM CST, 1 hour 21 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
154 PM CDT WED APR 17 2013

.DISCUSSION...

...TORNADOES POSSIBLE THROUGH LATE TONIGHT ACROSS MOST OF THE
FORECAST AREA...

THE WARM FRONT HAS SOMEWHAT STALLED CURRENTLY NEAR THE I44
CORRIDOR AS THE COLDER AIRMASS HAS BEEN "REINFORCED" WITH
ONGOING ELEVATED MOIST CONVECTION/STRATUS NORTH OF THE BOUNDARY.
CLEARING ACROSS SOUTHWESTERN OK AND W TX HAS ALSO BEEN OBSERVED
OVER THE LAST COUPLE OF HOURS NEAR THE SFC LOW. AS A WEAK
SHORTWAVE TROUGH LIFTS OVER WESTERN OK THIS AFTERNOON AND THE
DRYLINE SURGES EASTWARD...COVERAGE WILL CONTINUE TO INCREASE BOTH
IN THE WARM SECTOR ESPECIALLY NEAR SSW OK/W N TX WHERE DEEP
MOISTURE CONVG IS EXPECTED WITH 0 CIN...HIGH INSTABILITY...AND
SFC CONVG NEAR THE DEVELOPING TRIPLE POINT. THESE DISCRETE STORMS
WILL THEN MOVE NE PERHAPS TRAVERSING THE WARM FRONT/STATIONARY
BOUNDARY. A TORNADO WATCH IS NOW IN EFFECT UNTIL 11 PM FOR MOST OF
THE FA WITH STRONG LOW LEVEL SHEAR...MOD TO HIGH INSTABILITY...AND
THE FRONT IN PLACE COMBINED WITH VERY LITTLE TO NO CIN. THE 15Z
OUN SOUNDING HAD 0 CIN. LATER TONIGHT AS PRESSURE RISES RAPIDLY
INCREASE NEAR EASTERN CO/WESTERN KS...ANOTHER COLD FRONT WILL DIVE
SOUTH. STRONG SFC CONV ALONG THIS FRONT MAY RESULT IN A SQUALL
LINE DEVELOPING SOMEWHERE NEAR OR JUST SOUTH OF THE I44 CORRIDOR
RESULTING IN MORE OF A DAMAGING WIND/HAIL THREAT THROUGH THE LATE
EVENING HOURS. IN ADDITION...LOCALIZED FLASH FLOODING WILL BE
POSSIBLE INITIALLY WITH TRAINING STORMS AND THEN WITH THE POSSIBLE
SLOW MOVING SQUALL LINE.

MUCH COLDER TEMPS WILL ACCOMPANY THE COLD FRONT TOMORROW...WITH
HIGH ONLY CLIMBING INTO THE 40S AND 50S. BY FRIDAY MORNING
FREEZING TEMPERATURES WILL DEVELOP MAINLY ALONG AND NORTH OF I44.
FOR NOW...WE WILL NOT ISSUE ANY HEADLINES FOR THIS GIVEN THE HIGH
IMPACT SEVERE EVENT AT STAKE BUT WILL PASS THIS ALONG TO THE MID
SHIFT. A SLOW WARM UP IS ANTICIPATED SAT-MONDAY...BUT YET ANOTHER
COLD FRONT APPEARS IT WILL IMPACT THE REGION BY TUESDAY. AN UPPER
LEVEL TROUGH WILL ALSO SUPPORT INCREASING RAIN CHANCES EARLY NEXT
WEEK. CHC POPS LOOK REASONABLE FOR THE MOMENT ACROSS NORTH CENTRAL
OK.

&&

.PREV DISCUSSION... /ISSUED 1240 PM CDT WED APR 17 2013/

DISCUSSION...
18Z AVIATION DISCUSSION FOLLOWS....

AVIATION...
A VERY SHARP STATIONARY FRONT ACROSS OK/TX...FROM KSWO TO KPWA TO
HKBR AT THIS TIME...WILL DIVIDE VERY WARM HUMID AIR FROM COOL VERY
HUMID AIR. LOW CEILINGS...MIST AND FOG WILL CONTINUE TO BE
WIDESPREAD THIS AFTERNOON NORTH OF THE FRONT. TSRA ARE LIKELY
ALONG AND N OF THE FRONT THIS AFTERNOON...AND SEVERE TSRA ARE
POSSIBLE NEAR THE FRONT AND SOUTH OF IT. LARGE HAIL MAY OCCUR WITH
TSRA FARTHER N THIS AFTERNOON. HAVE NOTED IN TAFS THE MOST LIKELY
CONVECTIVE OUTCOME...BUT THERE IS ENOUGH UNCERTAINTY THAT THIS
FORECAST SHOULD BE USED WITH EXTRA CAUTION. THE FRONT WILL BECOME
A COLD FRONT LATE TODAY AND OVERNIGHT. TSRA ARE EXPECTED TO FOCUS
INTO A SQUALL LINE ALONG THE FRONT...AND REACH KOKC/KOUN/KLAW/KSPS
AROUND 0500Z TO 0600Z...THEN CONTINUE TO ADVANCE SE OVERNIGHT.
POST-FRONTAL TSRA WILL CONTINUE A FEW HOURS...THEN GRADUAL
CLEARING WILL BEGIN...ALONG WITH RATHER STRONG N TO NW WINDS. SOME
LLWS IS POSSIBLE JUST N OF THE FRONT THIS
AFTERNOON/EVENING...ESPECIALLY AT KPNC...WHERE LLWS HAS BEEN
INCLUDED IN THE TAF. -SN MAY OCCUR IN NW OK LATE TONIGHT.

PREV DISCUSSION... /ISSUED 1116 AM CDT WED APR 17 2013/

UPDATE...
COMPLEX SEVERE WEATHER SITUATION CONTINUES TO UNFOLD. WARM FRONT
HAS LIFTED NORTH IN THE METRO AREA CURRENTLY LYING ACROSS THE
OKLAHOMA CITY METRO /73 OVER 68 AT WILL ROGERS AIRPORT AND 56 OVER
52 AT WILEY POST AIRPORT./ THIS FRONT HAS SLOWED OR STALLED THIS
MORNING. DEVELOPMENT OF ELEVATED PRECIPITATION ABOVE THE FRONTAL
SURFACE AND PERSIST NORTH WINDS ACROSS NORTHWEST OKLAHOMA AND
KANSAS LIKELY ARE SIGNALS THAT THE FRONT WILL LIKELY NOT MOVE
NORTH MUCH FARTHER. MESOSCALE MODELS ALSO INDICATE THAT THE FRONT
MAY START MOVING SOUTH AGAIN LATER THIS AFTERNOON. ANOTHER ISSUE
IS THAT CONVECTIVE INHIBITION LOOKS TO REMAIN SMALL SO STORM
DEVELOPMENT APPEARS LIKELY... MAY BE RELATIVELY WIDESPREAD AND
DEVELOP EARLY /DEPENDING ON HOW SOON STRATUS THINS./ T 16Z
SOUNDING FROM OUN MAY SHED MORE LIGHT ON THIS. THERE IS ALSO A
PERSISTENT SIGNAL OF THE DEVELOPMENT OF A SURFACE LOW THIS
AFTERNOON... MOST LIKELY ACROSS SOUTHWEST OKLAHOMA.

RESULTANT ISSUES ARE... /1/ TEMPERATURE GRADIENT WILL LIKELY
REMAIN STRONG ACROSS THE WARM FRONT. THIS MEANS THAT THE WARM
FRONT AS A SOURCE OF ENHANCED VORTICITY WITH STORMS ALONG THE
BOUNDARY WILL NOT BE IDEAL AS ANY STORM WOULD QUICKLY BECOME
ELEVATED ABOVE THE FRONTAL BOUNDARY IF IT GETS EVEN A SHORT
DISTANCE NORTH OF THE FRONT. IF WINDS STAY NORTHERLY IN THE COOL
SECTOR... THAT WILL NOT BE AN IDEAL WIND PROFILE EITHER. /2/ THE
BEST LOW-LEVEL WIND SHEAR WILL BE IN THE VICINITY OF THE SURFACE
LOW/TRIPLE POINT LIKELY TO DEVELOP ACROSS SOUTHWEST OKLAHOMA THIS
AFTERNOON AND MOVE TOWARD CENTRAL OKLAHOMA THIS EVENING. THIS WILL
BE THE AREA OF MOST CONCERN FOR TORNADO DEVELOPMENT... ALTHOUGH
TORNADOES WILL BE POSSIBLE THROUGHOUT THE WARM SECTOR. /3/ IT
REMAINS UNCERTAIN WHAT WILL RESULT FROM THE BALANCE OF DELAYED
WARMING DUE TO STRATUS AND THE APPARENT LOW CIN WHICH WOULD
OTHERWISE FAVOR EARLY AND/OR WIDESPREAD DEVELOPMENT. /4/ EVEN
NORTH OF THE SURFACE FRONT... ELEVATED STORMS WITH A RISK OF LARGE
HAIL WILL PERSIST.

CURRENT THOUGHTS ARE THAT SCATTERED STORMS WILL LIKELY DEVELOP
EARLY TO MID AFTERNOON WITH THE POTENTIAL OF SUPERCELL
DEVELOPMENT IN THE WARM SECTOR. ELEVATED SEVERE STORMS WILL ALSO
BE LIKELY NORTH OF THE WARM FRONT. DURING THE EVENING... STORMS
WILL BECOME MORE WIDESPREAD AS THE FRONT MOVES THROUGH AND DEVELOP
INTO A SQUALL LINE.

THERE IS STILL SOME UNCERTAINTIES /MORE THAN USUAL/ ON HOW THINGS
WILL EVOLVE... ESPECIALLY WITH RESPECT TO THE COUNTERACTING
INFLUENCES OF CIN VS. DELAYED WARMING. BUT THE RISK OF SIGNIFICANT
SEVERE WEATHER STILL EXISTS... ESPECIALLY FROM SOUTHWEST TO
CENTRAL PORTIONS OF THE FORECAST AREA.

SPEG.

PREV DISCUSSION... /ISSUED 618 AM CDT WED APR 17 2013/

AVIATION...
12Z TAFS... FOG/DRIZZLE AND VARIABLE CEILINGS THIS MORNING.
CEILINGS WILL IMPROVE MOST PLACES TO MVFR/VFR BEFORE LOWERING
AGAIN TONIGHT. SCATTERED/WIDESPREAD SHOWERS/STORMS TO DEVELOP THIS
AFTERNOON/NIGHT. STRONG VARIABLE WINDS AND HAIL WILL BE POSSIBLE
WITH SOME OF THE STORMS. A STRONG COLD FRONT WILL CROSS THE REGION
TONIGHT.

PREV DISCUSSION... /ISSUED 351 AM CDT WED APR 17 2013/

DISCUSSION...
SEVERE WEATHER EXPECTED TODAY/TONIGHT. COLD CONDITIONS THURSDAY AND
FRIDAY.

THIS MORNING... MOST OF THE OVERNIGHT/MORNING CONVECTION THAT THE
MODELS HAD BEEN SHOWING THE PAST FEW DAYS HAS NOT REALLY DEVELOPED
IN THE FA AND IS OCCURRING JUST NORTH IN KANSAS. A FEW SHOWERS STILL
NOT OUT OF THE QUESTION IN NORTHERN OK THIS MORNING BUT FOR THE MOST
PART EXPECT THE TREND OF EVERYTHING IN KANSAS TO CONTINUE THIS
MORNING. FOG HAS DEVELOPED ACROSS PARTS OF THE AREA NORTH OF A WARM
FRONT. A FEW LOCATIONS ARE ALREADY REPORTING DENSE FOG. SO WILL
ISSUE A DENSE FOG ADVISORY FOR THE NW PART OF THE FA WHERE IT IS
MOST LIKELY TO OCCUR AND LAST THE LONGEST. AREAS OF DRIZZLE COULD
ALSO DEVELOP ACROSS THE NORTHERN HALF OF THE FA THIS MORNING.

THE WARM FRONT WILL CONTINUE TO LIFT NORTH TODAY AND IS EXPECTED TO
EXTEND FROM WEST CENTRAL TO NORTH CENTRAL OK BY THIS AFTERNOON. A
DRYLINE IS ALSO EXPECTED TO EXTEND SOUTH FROM THE WARM FRONT NEAR
THE OK TX STATE-LINE. THERE IS STILL SOME DISAGREEMENT/UNCERTAINTY
ON THE POSITION OF THE WARM FRONT THIS AFTERNOON WHICH COULD HAVE AN
IMPACT ON THE SEVERE WEATHER THIS AFTERNOON/EVENING. MEANWHILE... AN
UPPER STORM SYSTEM WILL ALSO MOVE EAST AFFECTING THE AREA.
THUNDERSTORMS ARE EXPECTED TO DEVELOP NEAR THE FRONT AND POSSIBLY
THE DRYLINE THIS AFTERNOON... IN THE WARM SECTOR. THESE STORMS...
ESPECIALLY IF THEY CAN STAY DISCRETE SUPERCELLS... WILL LIKELY BE
SEVERE DUE TO THE INSTABILITY AND FAVORABLE WIND SHEAR... WITH VERY
LARGE HAIL... DAMAGING WINDS... AND TORNADOES POSSIBLE.

A COLD FRONT IS EXPECTED TO MOVE ACROSS THE REGION TONIGHT INTO
THURSDAY. SHOWERS/STORMS WILL CONTINUE TO DEVELOP ALONG AND BEHIND
THIS FRONT. SEVERE STORMS WILL REMAIN POSSIBLE OVERNIGHT BUT THE
TORNADO POTENTIAL WILL DIMINISH LATER THIS EVENING. HEAVY RAIN WILL
ALSO BE POSSIBLE... WHICH COULD CAUSE SOME LOCALIZED FLOODING IN
SOME AREAS.

COLD AIR WILL MOVE INTO THE REGION BEHIND THE COLD FRONT TONIGHT
INTO THURSDAY. LIGHT SNOW AND MAYBE SLEET MAY OCCUR IN NW PARTS OF
THE FA OVERNIGHT BEFORE THE PRECIP ENDS. THE WINDOW OF OPPORTUNITY
FOR THIS IS EXPECTED TO BE BRIEF AND THE PRECIP LIGHT SO NO
SIGNIFICANT IMPACTS ARE ANTICIPATED. THE PRECIPITATION WILL END FROM
WEST TO EAST THURSDAY.

TEMPERATURES WILL BE COLD TONIGHT BUT CURRENTLY FORECASTED TO REMAIN
NEAR AND ABOVE FREEZING. HOWEVER... MUCH COLDER TEMPERATURES ARE
EXPECTED THURSDAY NIGHT WITH MUCH OF THE AREA AOB FREEZING.
TEMPERATURES WILL WARM THIS WEEKEND WITH ANOTHER COLD FRONT AND
UPPER SYSTEM EXPECTED EARLY NEXT WEEK WHICH COULD BRING ANOTHER
ROUND OF SHOWERS/STORMS AND COLD WEATHER.

&&

.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK  40  50  31  60 /  80  10  10  10
HOBART OK         38  51  28  61 /  80  10  10   0
WICHITA FALLS TX  44  56  31  64 /  70  10  10   0
GAGE OK           32  46  28  63 /  30  10  10   0
PONCA CITY OK     39  48  28  59 /  80  20  10  10
DURANT OK         59  59  34  60 /  80  50  10  10

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&

26/03

Hazardous weather outlook, Apr 17, 11:45 AM CST, 2 hours 30 minutes before

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE NORMAN OK
1245 PM CDT WED APR 17 2013

OKZ004>048-050>052-TXZ083>090-181000-
HARPER-WOODS-ALFALFA-GRANT-KAY-ELLIS-WOODWARD-MAJOR-GARFIELD-NOBLE-
ROGER MILLS-DEWEY-CUSTER-BLAINE-KINGFISHER-LOGAN-PAYNE-BECKHAM-
WASHITA-CADDO-CANADIAN-OKLAHOMA-LINCOLN-GRADY-MCCLAIN-CLEVELAND-
POTTAWATOMIE-SEMINOLE-HUGHES-HARMON-GREER-KIOWA-JACKSON-TILLMAN-
COMANCHE-STEPHENS-GARVIN-MURRAY-PONTOTOC-COAL-COTTON-JEFFERSON-
CARTER-JOHNSTON-ATOKA-LOVE-MARSHALL-BRYAN-HARDEMAN-FOARD-WILBARGER-
WICHITA-KNOX-BAYLOR-ARCHER-CLAY-
1245 PM CDT TUE APR 17 2013

THIS HAZARDOUS WEATHER OUTLOOK COVERS NORTHERN...WESTERN...
CENTRAL...AND SOUTHERN OKLAHOMA...AND WESTERN NORTH TEXAS.

.DAY ONE...THIS AFTERNOON AND TONIGHT...

THUNDERSTORM OUTLOOK...
SCATTERED TO NUMEROUS SEVERE THUNDERSTORMS ARE STILL EXPECTED THIS
AFTERNOON AND TONIGHT. THERE IS A MODERATE RISK OF SEVERE STORMS
ACROSS MUCH OF OKLAHOMA AND WESTERN NORTH TEXAS THIS AFTERNOON THROUGH
TONIGHT. A SLIGHT RISK EXISTS THIS AFTERNOON AND EARLY EVENING ACROSS
NORTHWEST AND FAR WESTERN OKLAHOMA.

LOCATION...
THE MODERATE RISK AREA INCLUDES LOCATIONS EAST OF A HOLLIS...TO
CLINTON...TO MEDFORD LINE AND INCLUDES THE OKLAHOMA CITY METRO AREA...
WICHITA FALLS...ENID...PONCA CITY...STILLWATER...ADA...ARDMORE...
AND DURANT. THE SLIGHT RISK AREA IS WEST OF THIS LINE AND INCLUDES
ELK CITY...WOODWARD...AND ALVA.

TIMING...
THE MOST LIKELY TIME FOR SUPERCELLS AND SIGNIFICANT SEVERE STORMS
WITH THE BASEBALL-SIZE HAIL AND GREATEST RISK FOR TORNADOES IS BETWEEN
4 PM AND 10 PM...PRIMARILY FROM SOUTHWEST OKLAHOMA AND WESTERN NORTH
TEXAS...INTO CENTRAL AND SOUTH-CENTRAL OKLAHOMA. ADDITIONAL STORMS
ARE LIKELY OUTSIDE OF THIS TIME FRAME WITH THE PRIMARY CONCERNS BEING
HAIL TO THE SIZE OF GOLF BALLS AND DAMAGING WIND GUSTS OF 75 MPH.

IMPACTS...
VERY LARGE AND DAMAGING HAIL AND TORNADOES WILL BE THE MAIN HAZARDS
WITH SUPERCELLS LATE THIS AFTERNOON THROUGH MID-EVENING. GOLF BALL
SIZE HAIL AND DAMAGING WINDS UP TO 75 MPH ARE POSSIBLE AS WELL.

RECOMMENDED ACTIONS...
STORM SPOTTER GROUPS AND EMERGENCY MANAGEMENT PERSONNEL ACROSS THE
AREA SHOULD PLAN FOR SEVERE WEATHER OPERATIONS THIS AFTERNOON
AND TONIGHT.

DISCUSSION...
SCATTERED TO NUMEROUS THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER WESTERN
INTO CENTRAL OKLAHOMA THIS AFTERNOON. LARGE HAIL WILL BE THE PRIMARY
CONCERN INITIALLY. TOWARD AND AFTER 4 PM...SUPERCELL INITIATION WILL
BECOME POSSIBLE ACROSS FAR SOUTHWEST OKLAHOMA AND WESTERN NORTH TEXAS.
VERY LARGE HAIL AND TORNADOES APPEAR LIKELY WITH ANY SUPERCELL THAT IS
ABLE TO DEVELOP. THESE STORMS ARE EXPECTED TO MOVE EAST AND NORTHEAST
INTO CENTRAL AND SOUTH-CENTRAL OKLAHOMA.

DURING THE LATE EVENING AND OVERNIGHT HOURS...A STRONG COLD FRONT WILL
MOVE SOUTH OVER THE REGION AND BE ACCOMPANIED BY A SQUALL LINE OF STORMS
WHICH WILL HAVE THE PRIMARY HAZARDS OF GOLF BALL SIZE HAIL AND DAMAGING
WIND GUSTS OF 75 MPH.

PROBABILITY TABLE...
VALID THROUGH 700 AM CDT THURSDAY APR 18.
PROBABILITY OF THUNDERSTORMS OCCURRING IN THE
              NWS NORMAN COUNTY WARNING AREA...100 PERCENT.
PROBABILITY OF SEVERE STORMS IF STORMS OCCUR...100 PERCENT.

OTHER HAZARDOUS WEATHER...
HEAVY RAINFALL OF 1 TO 3 INCHES FROM A SLOW MOVING SQUALL LINE
MAY CAUSE FLOODING IN A FEW LOCATIONS TONIGHT...MAINLY EAST OF
A WICHITA FALLS...TO OKLAHOMA CITY...TO PONCA CITY LINE.

A SLEET AND SNOW MIXTURE IS POSSIBLE AFTER MIDNIGHT ACROSS PARTS OF
FAR WESTERN AND NORTHERN OKLAHOMA. SIGNIFICANT IMPACTS ARE NOT
EXPECTED.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY...

THUNDERSTORM OUTLOOK...
THUNDERSTORMS WILL LINGER ACROSS PARTS OF SOUTH-CENTRAL AND
SOUTHEAST OKLAHOMA ON THURSDAY. SEVERE STORMS ARE UNLIKELY AFTER
7 AM THURSDAY.

THUNDERSTORM CHANCES WILL RETURN SUNDAY THROUGH TUESDAY ACROSS PARTS
OF THE AREA.

OTHER HAZARDOUS WEATHER...
LOCALLY HEAVY RAIN AND FLOODING ARE POSSIBLE ACROSS SOUTH-CENTRAL AND
SOUTHEAST OKLAHOMA WHERE THUNDERSTORMS LINGER THURSDAY MORNING.

SUBFREEZING TEMPERATURES ARE POSSIBLE FRIDAY MORNING ACROSS MUCH
OF THE AREA.

THE NEXT SCHEDULED HAZARDOUS WEATHER OUTLOOK WILL BE ISSUED BY
5 AM THURSDAY MORNING...WITH UPDATES AS NEEDED.

MBS/11

In the hours before

Special weather statement, Apr 17, 12:02 PM CST, 2 hours 13 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NORMAN OK
102 PM CDT WED APR 17 2013

OKZ004-005-010-011-015-171830-
HARPER OK-WOODWARD OK-WOODS OK-DEWEY OK-MAJOR OK-
102 PM CDT WED APR 17 2013

...SIGNIFICANT WEATHER ADVISORY FOR EASTERN HARPER...NORTHEASTERN
WOODWARD...WOODS...NORTHWESTERN DEWEY AND WESTERN MAJOR COUNTIES
UNTIL 130 PM CDT...

AT 101 PM CDT...STRONG THUNDERSTORMS WERE ALONG A LINE EXTENDING
FROM 13 MILES NORTHEAST OF SELMAN TO QUINLAN TO 5 MILES SOUTH OF
CESTOS...MOVING NORTH-NORTHEAST AT 65 MPH.

HAZARDS INCLUDE...
HAIL UP TO THE SIZE OF NICKELS...

LAT...LON 3700 9858 3620 9875 3589 9916 3647 9931
      3700 9952
TIME...MOT...LOC 1801Z 199DEG 57KT 3691 9929 3644 9901 3607 9910

..SPEG.

Local storm report, Apr 17, 12:07 PM CST, 2 hours 8 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
107 PM CDT WED APR 17 2013

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0102 PM     HAIL             MOORELAND               36.44N 99.21W
04/17/2013  E0.25 INCH       WOODWARD           OK   TRAINED SPOTTER

&&

MDAY

Special weather statement, Apr 17, 12:45 PM CST, 1 hour 30 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NORMAN OK
145 PM CDT WED APR 17 2013

OKZ034>036-171900-
GREER OK-KIOWA OK-JACKSON OK-
145 PM CDT WED APR 17 2013

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN GREER...WESTERN
KIOWA AND NORTHERN JACKSON COUNTIES UNTIL 200 PM CDT...

AT 144 PM CDT...A STRONG THUNDERSTORM WAS LOCATED 5 MILES EAST OF
DUKE...MOVING NORTHEAST AT 35 MPH. ANOTHER STRONG STORM IS ALSO
DEVELOPING 5 MILES NORTH OF BLAIR.

HAZARDS INCLUDE...
HAIL UP TO ONE-HALF INCH DIAMETER...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

STORM INTENSITY IS INCREASING AND SEVERE WEATHER MAY DEVELOP
RAPIDLY. STAY ALERT AND LISTEN FOR WARNINGS.

&&

LAT...LON 3504 9934 3485 9902 3454 9946 3467 9962
TIME...MOT...LOC 1844Z 223DEG 31KT 3467 9948

..SPEG.

Special weather statement, Apr 17, 12:49 PM CST, 1 hour 26 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NORMAN OK
149 PM CDT WED APR 17 2013

TXZ083>085-171900-
WILBARGER TX-HARDEMAN TX-FOARD TX-
149 PM CDT WED APR 17 2013

...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN WILBARGER...
SOUTHEASTERN HARDEMAN AND EAST CENTRAL FOARD COUNTIES UNTIL 200 PM
CDT...

AT 148 PM CDT...STRONG THUNDERSTORMS WERE ALONG A LINE EXTENDING
FROM 6 MILES SOUTHEAST OF CHILLICOTHE TO THALIA...MOVING NORTHEAST
AT 30 MPH.

HAZARDS INCLUDE...
HAIL UP TO THE SIZE OF NICKELS...
WIND GUSTS TO 50 MPH...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

STORM INTENSITY IS INCREASING AND SEVERE WEATHER MAY DEVELOP
RAPIDLY. STAY ALERT AND LISTEN FOR WARNINGS.

&&

LAT...LON 3439 9947 3437 9944 3439 9943 3438 9940
      3445 9939 3446 9937 3441 9932 3441 9929
      3440 9926 3439 9927 3433 9921 3430 9921
      3391 9952 3400 9962
TIME...MOT...LOC 1848Z 209DEG 28KT 3417 9945 3402 9952

..SPEG.

Special weather statement, Apr 17, 12:50 PM CST, 1 hour 25 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NORMAN OK
150 PM CDT WED APR 17 2013

OKZ004-005-010-171915-
HARPER OK-WOODWARD OK-WOODS OK-
150 PM CDT WED APR 17 2013

...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL HARPER...
NORTHEASTERN WOODWARD AND WOODS COUNTIES UNTIL 215 PM CDT...

AT 150 PM CDT...STRONG THUNDERSTORMS EXTENDED FROM 8 MILES EAST OF
SELMAN...TO 10 MILES NORTHEAST OF FREEDOM...TO WAYNOKA...MOVING
NORTHEAST AT 40 MPH.

HAZARDS INCLUDE...
HAIL UP TO THE SIZE OF NICKELS...
WIND GUSTS TO 50 MPH...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MONITOR THE WEATHER SITUATION CLOSELY AND BE ALERT FOR THREATENING
WEATHER CONDITIONS.

&&

LAT...LON 3699 9854 3694 9854 3648 9870 3683 9950
      3684 9950 3700 9933
TIME...MOT...LOC 1850Z 214DEG 36KT 3680 9934 3686 9897 3661 9886

Special weather statement, Apr 17, 1:46 PM CST, 29 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NORMAN OK
246 PM CDT WED APR 17 2013

OKZ036-172015-
JACKSON OK-
246 PM CDT WED APR 17 2013

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL JACKSON COUNTY UNTIL 315
PM CDT...

AT 244 PM CDT...A STRONG THUNDERSTORM WAS LOCATED 4 MILES NORTHEAST
OF ELMER...MOVING NORTH AT 35 MPH. THIS STORM WILL MOVE TOWARD ALTUS.

HAZARDS INCLUDE...
HAIL UP TO THE SIZE OF NICKELS...

LAT...LON 3481 9939 3481 9925 3486 9919 3485 9915
      3480 9915 3477 9917 3476 9915 3475 9918
      3473 9915 3471 9916 3470 9912 3449 9922
      3444 9923 3448 9944
TIME...MOT...LOC 1944Z 192DEG 31KT 3454 9932

..SPEG.

The radar

The Altus AFB radar (KFDR), 91 km away, was scanning. The volume nearest the first event began at 20:16 UTC.

Open the radar archive at this moment

Event by event

42 hail, 11 thunderstorm wind, 5 flash flood, 2 tornado. Local standard time, as filed.

Hail, Washita

When: April 17, 2:15 PM CST
Where: Washita County, 5.53 mi S of Cloud Chief
Measured: 1 in hail
Reported by: Public
Coordinates: 35.170, -98.840

Hail, Washita

When: April 17, 2:28 PM CST
Where: Washita County, 0.56 mi W of Cowden
Measured: 1 in hail
Reported by: Public
Coordinates: 35.250, -98.720

Hail, Tillman

When: April 17, 2:38 PM CST
Where: Tillman County, 6.86 mi WSW of Frederick
Measured: 1.25 in hail
Reported by: Storm Chaser
Coordinates: 34.350, -99.130

No damage was reported.

Hail, Tillman

When: April 17, 2:42 PM CST
Where: Tillman County, 4.48 mi SSE of Tipton Arpt
Measured: 1.5 in hail
Reported by: Amateur Radio
Coordinates: 34.400, -99.140

No damage was reported.

Hail, Tillman

When: April 17, 3:10 PM CST
Where: Tillman County, Manitou
Measured: 1 in hail
Reported by: Amateur Radio
Coordinates: 34.510, -98.980

Hail, Harmon

When: April 17, 4:12 PM CST
Where: Harmon County, 3.68 mi WNW of Gould
Measured: 1.25 in hail
Reported by: COOP Observer
Coordinates: 34.690, -99.830

No damage was reported.

Hail, Comanche

When: April 17, 4:15 PM CST
Where: Comanche County, 0.57 mi E of Cache
Measured: 1.75 in hail
Reported by: Amateur Radio
Coordinates: 34.630, -98.620

No damage was reported.

Hail, Canadian

When: April 17, 4:25 PM CST
Where: Canadian County, Richland
Measured: 1 in hail
Reported by: Public
Coordinates: 35.580, -97.800

Hail, Comanche

When: April 17, 4:26 PM CST
Where: Comanche County, 4.48 mi NE of Faxon
Measured: 1.75 in hail
Reported by: Storm Chaser
Coordinates: 34.510, -98.530

No damage was reported.

Hail, Comanche

When: April 17, 4:30 PM CST
Where: Comanche County, 1.49 mi NNW of Mt Scott
Measured: 1.75 in hail
Reported by: Amateur Radio
Coordinates: 34.760, -98.540

No damage was reported.

Hail, Comanche

When: April 17, 4:46 PM CST
Where: Comanche County, Elgin
Measured: 1.75 in hail
Reported by: Amateur Radio
Coordinates: 34.780, -98.290

No damage was reported.

Thunderstorm Wind, Tillman

When: April 17, 4:46 PM CST
Where: Tillman County, 2.15 mi NNE of Frederick
Measured: 59 kt (68 mph) measured gust
Reported by: Trained Spotter
Coordinates: 34.420, -99.010

Winds were generated by the rear flank downdraft of a supercell thunderstorm.

Hail, Jackson

When: April 17, 4:49 PM CST
Where: Jackson County, 2.37 mi NNE of Elmer
Measured: 1.75 in hail
Reported by: Amateur Radio
Coordinates: 34.510, -99.330

Hail, Beckham

When: April 17, 4:59 PM CST
Where: Beckham County, Elk City
Measured: 1 in hail
Reported by: Trained Spotter
Coordinates: 35.410, -99.420

Hail, Caddo

When: April 17, 5:24 PM CST
Where: Caddo County, 2.27 mi W of Cyril
Measured: 1.25 in hail
Reported by: Amateur Radio
Coordinates: 34.900, -98.240

Thunderstorm Wind, Caddo

When: April 17, 5:25 PM CST
Where: Caddo County, Cyril
Measured: 52 kt (60 mph) measured gust
Reported by: Amateur Radio
Coordinates: 34.900, -98.200

No damage was reported.

Hail, Comanche

When: April 17, 5:29 PM CST
Where: Comanche County, 0.57 mi E of Cache
Measured: 2.75 in hail
Reported by: Trained Spotter
Coordinates: 34.630, -98.620

No damage was reported.

Hail, Comanche

When: April 17, 5:31 PM CST
Where: Comanche County, 2.15 mi SSE of Cache
Measured: 2.25 in hail
Reported by: Storm Chaser
Coordinates: 34.600, -98.620

No damage was reported.

Hail, Comanche

When: April 17, 5:31 PM CST
Where: Comanche County, 1.33 mi WNW of Cache
Measured: 1.75 in hail
Reported by: Storm Chaser
Coordinates: 34.640, -98.650

Hail, Kiowa

When: April 17, 5:33 PM CST
Where: Kiowa County, 2.36 mi SSW of Snyder
Measured: 2 in hail
Reported by: Storm Chaser
Coordinates: 34.630, -98.970

Hail, Comanche

When: April 17, 5:33 PM CST
Where: Comanche County, 1.33 mi WNW of Cache
Measured: 1.75 in hail
Reported by: Storm Chaser
Coordinates: 34.640, -98.650

Hail, Kiowa

When: April 17, 5:35 PM CST
Where: Kiowa County, Snyder
Measured: 1.75 in hail
Reported by: Amateur Radio
Coordinates: 34.660, -98.950

Hail, Kiowa

When: April 17, 5:36 PM CST
Where: Kiowa County, 2.36 mi SSW of Snyder
Measured: 2 in hail
Reported by: Storm Chaser
Coordinates: 34.630, -98.970

Tornado, Comanche

When: April 17, 5:50 PM CST to 5:56 PM CST
Where: Comanche County, 5.13 mi SE of Cache to 6.86 mi W of Lawton
Rating: EF0
Path length: 3.41 mi
Path width: 100 yd
Property damage: $200,000
Reported by: NWS Employee
Coordinates: 34.580, -98.563

The tornado was reported on the west side of Lawton. Minor damage was done to the Goodyear Tire Plant at southwest Lee and Goodyear Boulevards.

Hail, Grady

When: April 17, 6:16 PM CST
Where: Grady County, 2.26 mi W of Tabler
Measured: 1.75 in hail
Reported by: Amateur Radio
Coordinates: 35.040, -97.860

Hail, Comanche

When: April 17, 6:16 PM CST
Where: Comanche County, 1.13 mi W of Elgin
Measured: 1.75 in hail
Reported by: Amateur Radio
Coordinates: 34.780, -98.310

Hail, Comanche

When: April 17, 6:32 PM CST
Where: Comanche County, 2.07 mi S of Elgin
Measured: 1.25 in hail
Reported by: Amateur Radio
Coordinates: 34.750, -98.290

Hail, Caddo

When: April 17, 6:45 PM CST
Where: Caddo County, 2.27 mi W of Cyril
Measured: 1 in hail
Reported by: Amateur Radio
Coordinates: 34.900, -98.240

Hail, Cleveland

When: April 17, 7:00 PM CST
Where: Cleveland County, 1.32 mi WNW of (Oun)norman Westheimer Arpt
Measured: 1 in hail
Reported by: NWS Employee
Coordinates: 35.260, -97.490

Thunderstorm Wind, Comanche

When: April 17, 7:05 PM CST
Where: Comanche County, 2.07 mi S of Elgin
Measured: 61 kt (70 mph) estimated gust
Reported by: Amateur Radio
Coordinates: 34.750, -98.290

No damage was reported.

Hail, Comanche

When: April 17, 7:05 PM CST
Where: Comanche County, 2.07 mi S of Elgin
Measured: 1 in hail
Reported by: Amateur Radio
Coordinates: 34.750, -98.290

Hail, Comanche

When: April 17, 7:09 PM CST
Where: Comanche County, 0.89 mi SE of Fletcher
Measured: 1.25 in hail
Reported by: Storm Chaser
Coordinates: 34.810, -98.230

No damage was reported.

Hail, Tillman

When: April 17, 7:18 PM CST
Where: Tillman County, 4.49 mi NNE of Davidson
Measured: 1 in hail
Reported by: Amateur Radio
Coordinates: 34.300, -99.050

Hail, Oklahoma

When: April 17, 7:20 PM CST
Where: Oklahoma County, 0.69 mi N of (Tik)tinker Afb
Measured: 1 in hail
Reported by: Public
Coordinates: 35.420, -97.390

Thunderstorm Wind, Grady

When: April 17, 7:35 PM CST
Where: Grady County, 3.67 mi ENE of Norge
Measured: 52 kt (60 mph) estimated gust
Reported by: Amateur Radio
Coordinates: 35.010, -97.940

No damage was reported.

Thunderstorm Wind, Grady

When: April 17, 7:35 PM CST
Where: Grady County, Acme
Measured: 53 kt (61 mph) measured gust
Reported by: Mesonet
Coordinates: 34.800, -98.020

Thunderstorm Wind, Tillman

When: April 17, 7:35 PM CST
Where: Tillman County, 2.86 mi W of Grandfield
Measured: 52 kt (60 mph) estimated gust
Reported by: Amateur Radio
Coordinates: 34.230, -98.740

No damage was reported.

Tornado, Tillman

When: April 17, 7:35 PM CST to 7:45 PM CST
Where: Tillman County, 7 mi WNW of Grandfield to 2 mi NW of Grandfield
Rating: EF1
Path length: 5.21 mi
Path width: 200 yd
Property damage: $500,000
Reported by: Trained Spotter
Coordinates: 34.269, -98.803

Multiple spotter and storm chaser reports of a tornado. Damage occurred a the Grandfield airport. The tornado has been assigned a preliminary EF-1 rating.

Thunderstorm Wind, Oklahoma

When: April 17, 7:37 PM CST
Where: Oklahoma County, 7.07 mi ESE of (Tik)tinker Afb
Measured: 52 kt (60 mph) estimated gust
Reported by: NWS Employee
Coordinates: 35.380, -97.270

No damage was reported.

Thunderstorm Wind, Tillman

When: April 17, 7:37 PM CST
Where: Tillman County, 3.86 mi SSW of Loveland
Measured: 69 kt (79 mph) measured gust
Reported by: Storm Chaser
Coordinates: 34.250, -98.800

No damage was reported.

Flash Flood, Tillman

When: April 17, 7:45 PM CST
Where: Tillman County, 2.86 mi W of Grandfield to 2.85 mi W of Grandfield
Cause: Heavy Rain
Reported by: Amateur Radio
Coordinates: 34.230, -98.740

Training supercells lead to flash flooding in creeks and low lying areas over rural Tillman county. No major damage was reported and no injuries or fatalities occurred.

Thunderstorm Wind, Tillman

When: April 17, 7:45 PM CST
Where: Tillman County, 2.86 mi W of Grandfield
Measured: 63 kt (72 mph) measured gust
Reported by: Mesonet
Coordinates: 34.230, -98.740

Flash Flood, Comanche

When: April 17, 7:50 PM CST to 10:50 PM CST
Where: Comanche County, 4.48 mi NNW of (Fsi)fort Sill to 4.59 mi NNW of (Fsi)fort Sill
Cause: Heavy Rain
Reported by: Amateur Radio
Coordinates: 34.730, -98.410

Training supercells lead to heavy rainfall and flash flooding north of Lawton. No major damage was reported and no injuries or fatalities occurred.

Thunderstorm Wind, Tillman

When: April 17, 7:50 PM CST
Where: Tillman County, 2.86 mi W of Grandfield
Measured: 56 kt (64 mph) measured gust
Reported by: Mesonet
Coordinates: 34.230, -98.740

Hail, Tillman

When: April 17, 7:50 PM CST
Where: Tillman County, 3.43 mi E of Grandfield
Measured: 2 in hail
Reported by: NWS Employee
Coordinates: 34.230, -98.630

No damage was reported.

Hail, Grady

When: April 17, 7:52 PM CST
Where: Grady County, 2.76 mi N of Rush Springs
Measured: 1 in hail
Reported by: Trained Spotter
Coordinates: 34.820, -97.960

Flash Flood, McClain

When: April 17, 7:53 PM CST to 10:53 PM CST
Where: McClain County, Newcastle to 0.1 mi N of Newcastle
Cause: Heavy Rain
Reported by: Trained Spotter
Coordinates: 35.250, -97.600

Persistent heavy rainfall from training supercell thunderstorms led to localized flash flooding in the Newcastle area. No major damage was reported and no injuries or fatalities occurred.

Hail, Grady

When: April 17, 7:53 PM CST
Where: Grady County, 2.76 mi N of Rush Springs
Measured: 2.5 in hail
Reported by: Amateur Radio
Coordinates: 34.820, -97.960

No damage was reported.

Flash Flood, Grady

When: April 17, 7:55 PM CST to 10:55 PM CST
Where: Grady County, 2.99 mi SSE of Chickasha Arpt to 2.29 mi W of Tabler
Cause: Heavy Rain
Reported by: Amateur Radio
Coordinates: 35.040, -97.950

Persistent heavy rainfall led to widespread flash flooding across Chickasha. No major damage was reported and no injuries or fatalities occurred.

Hail, Grady

When: April 17, 8:01 PM CST
Where: Grady County, 1.84 mi ENE of Agawam
Measured: 1.75 in hail
Reported by: Storm Chaser
Coordinates: 34.880, -97.920

No damage was reported.

Hail, Cotton

When: April 17, 8:18 PM CST
Where: Cotton County, 1.14 mi E of Cookietown
Measured: 1.25 in hail
Reported by: Trained Spotter
Coordinates: 34.270, -98.430

No damage was reported.

Hail, Grady

When: April 17, 8:25 PM CST
Where: Grady County, 0.69 mi N of Alex
Measured: 1 in hail
Reported by: Post Office
Coordinates: 34.930, -97.780

Hail, Cotton

When: April 17, 8:26 PM CST
Where: Cotton County, 2.38 mi WSW of Walters Arpt
Measured: 1 in hail
Reported by: Trained Spotter
Coordinates: 34.360, -98.450

Hail, Cotton

When: April 17, 8:29 PM CST
Where: Cotton County, 0.69 mi N of Walters
Measured: 1.75 in hail
Reported by: Trained Spotter
Coordinates: 34.360, -98.310

No damage was reported.

Hail, Lincoln

When: April 17, 9:09 PM CST
Where: Lincoln County, 4.17 mi WSW of Sparks
Measured: 1 in hail
Reported by: Emergency Manager
Coordinates: 35.590, -96.890

Hail, McClain

When: April 17, 9:12 PM CST
Where: McClain County, 1.83 mi WNW of Purcell
Measured: 1.5 in hail
Reported by: Trained Spotter
Coordinates: 35.020, -97.400

No damage was reported.

Hail, Stephens

When: April 17, 9:30 PM CST
Where: Stephens County, 5.35 mi NNW of Duncan
Measured: 1 in hail
Reported by: Trained Spotter
Coordinates: 34.570, -98.000

Flash Flood, Pottawatomie

When: April 17, 9:46 PM CST
Where: Pottawatomie County, 2.27 mi NE of Shawnee to 2.68 mi NW of Shawnee
Cause: Heavy Rain
Reported by: Trained Spotter
Coordinates: 35.354, -96.892

Heavy rainfall from several rounds of thunderstorms led to flooding in downtown Shawnee. Numerous streets were in curb deep water. No major damage was reported and no injuries or fatalities occurred.

Hail, Garvin

When: April 17, 10:05 PM CST
Where: Garvin County, Lindsay
Measured: 1 in hail
Reported by: Post Office
Coordinates: 34.840, -97.610

Thunderstorm Wind, Cleveland

When: April 17, 10:39 PM CST
Where: Cleveland County, 0.69 mi N of Lexington
Measured: 52 kt (60 mph) estimated gust
Reported by: Law Enforcement
Coordinates: 35.020, -97.340

No damage was reported.

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Thunderstorm Wind: Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.
Tornado: A violently rotating column of air in contact with the ground and extending from a thunderstorm, filed with its path, width and Fujita or Enhanced Fujita rating from the damage survey.
Flash Flood: Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Oklahoma in 2013 Every state in 2013 This day in weather history The tornado archive for Oklahoma, 2013 Warnings in Oklahoma, April 2013

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 446399, 446400, 446405, 446401, 446402, 446403, 446404, 446407, 446406, 446408, 446416, 446434, 446417, 446418, 446419, 446435, 446420, 446428, 446430, 446431, 446432, 446423, 446433, 446456, 446425, 446426, 446427, 446424, 446436, 446437, 446438, 446461, 446439, 446440, 446441, 446442, 446443, 446459, 446444, 446463, and more.