Alert archive / Oklahoma / Flash Flood Warnings in 2009

Flash Flood Warning 24, NWS Norman, OK

August 17, 2009Blaine County, Oklahoma

NWS Norman, OK issued this flash flood warning at Aug 17, 2009, 7:06 PM CDT for Blaine County, Oklahoma. It was in force for 6 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Aug 17, 2009, 7:06 PM CDT (00:06 UTC)
Expired
Aug 18, 2009, 1:00 AM CDT
In force
6 hr
Issued by
NWS Norman, OK
Area
Storm-based polygon
Flood severity
None

County Blaine County, OK

The radar

The Vance AFB radar (KVNX), 100 km from the middle of the area, began a volume at 00:09 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Lamont, OK (KLMN), launched 00:00Z, 0.1 hours before the alert went out and 119 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Lamont, OK at 00:00Z on 2009-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1107 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lamont, OK at 00:00Z on 2009-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 118 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
1107 J/kg
Mixed-layer CIN
-151 J/kg
Mixed-layer LCL
1021 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
118 m²/s²
0-3 km storm-relative helicity
251 m²/s²
Significant tornado parameter
0.5
Supercell composite
12.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood warning went out, 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 this flash flood warning went out at Aug 17, 6:30 PM CDT, 36 minutes earlier.

Area forecast discussion, Aug 17, 6:30 PM CDT, 36 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
630 PM CDT MON AUG 17 2009

.AVIATION...
OUTFLOW BOUNDARY EXTENDS FROM NEAR KOKC TO SOUTH OF KGAG.
SCATTERED THUNDERSTORMS ARE EXPECTED MAINLY NORTH OF THIS BOUNDARY
ALTHOUGH THE SPECIFIC TIMING FOR AFFECTING SPECIFIC TAF SITES IS
QUITE UNCERTAIN GIVEN THE SCATTERED NATURE OF THE CONVECTION. THE
OUTFLOW BOUNDARY WILL ALSO GIVE SOME VARIABLE WIND DIRECTION OVER
TIME AT THE NORTHERN AND CENTRAL OKLAHOMA TAF SITES.

&&

.PREV DISCUSSION... /ISSUED 259 PM/

DISCUSSION...TODAY OUR FOCUS IS ON THE SHORT TERM POTENTIAL FOR
HEAVY RAINFALL. THERE ARE NUMEROUS INGREDIENTS IN PLACE...INCLUDING
A STATIONARY FRONT BENEATH PARALLEL UPPER FLOW...AND ABUNDANT
MOISTURE. ACTIVITY IS EXPECTED INITIALLY ALONG AN OUTFLOW BOUNDARY
FROM THE OKLAHOMA CITY AREA...WESTWARD TO NEAR ARNETT. STEEP LAPSE
RATES SUPPORT THE THREATS OF DAMAGING WINDS AND SOME LARGE
HAIL...ESPECIALLY DURING THE EVENING. THESE LAPSE RATES WOULD TEND
TO FAVOR COLD POOLS TO KEEP STORMS MOVING...BUT THE COLD POOLS WILL
MEET RESISTANCE FROM AN EASTERLY TO SOUTHERLY LOW LEVEL JET.
THIS...ALONG WITH SLOW MOTION OF INDIVIDUAL CELLS...AND INCREASING
SYNOPTIC SCALE LIFT OVER NORTHERN OKLAHOMA...SUGGESTS REPEATED HEAVY
RAIN MAY OCCUR ALONG AND NORTH OF THE INITIAL LINE OF THUNDERSTORMS.

THIS REASONING LED TO THE FLASH FLOOD WATCH FOR COUNTIES ALONG AND
NORTH OF INTERSTATE 40. THE LARGE SCALE PATTERN WILL REMAIN IN PLACE
THROUGH TUESDAY NIGHT...AND THE FLOOD WATCH WILL NEED TO BE
REVISITED AND POSSIBLY EXTENDED IN TIME AFTER SEEING THE OUTCOME OF
THE MONDAY NIGHT CONVECTION.

WE ADJUSTED GFS GUIDANCE POPS UPWARD IN DAYS 1-3...BUT MOST
SIGNIFICANTLY FOR TONIGHT...WHERE THE NAM AND LOCAL WRF HAD A BETTER
HANDLE ON THE OUTFLOW BOUNDARY AND MORE SOUTHERLY SWATH OF
PRECIPITATION. MUCH LIKE TODAY...THERE SHOULD BE A THUNDERSTORM
COMPLEX ONGOING IN NORTHERN OKLAHOMA TUESDAY MORNING. MODELS HAVE A
CONSISTENT SIGNAL FOR STRONG LIFT AND ANOTHER ASSOCIATED COMPLEX IN
NORTHWEST OKLAHOMA WEDNESDAY MORNING. THE GFS GUIDANCE FOR HIGH
TEMPERATURES DID NOT REFLECT THE CONVECTION WELL...SO WE ADJUSTED
TEMPERATURES DOWNWARD ALONG A GRADIENT FROM INTERSTATE 40 NORTHWARD.

A COLD FRONT WILL SWEEP THROUGH LATE WEDNESDAY INTO THURSDAY...WITH
A CONTINUED CHANCE FOR STORMS ALONG THE FRONT...AND DRIER...MORE
STABLE AIR BEHIND IT.

&&

.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK  72  90  74  95 /  40  20  20  20
HOBART OK         75  94  75 100 /  20  20  30  10
WICHITA FALLS TX  75 100  77 102 /  10  10  10  10
GAGE OK           66  82  68  93 /  70  30  60  20
PONCA CITY OK     72  81  76  92 /  70  50  40  30
DURANT OK         74  99  75  95 /  10  10  10  20

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH THROUGH TUESDAY MORNING FOR OKZ004>020-024>026.

TX...NONE.
&&
Hazardous weather outlook, Aug 17, 12:00 PM CDT, 7 hours 6 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORMAN OK
1200 PM CDT MON AUG 17 2009

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-
1200 PM CDT MON AUG 17 2009

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

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

THUNDERSTORM OUTLOOK...
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH TONIGHT
ACROSS PORTIONS OF OKLAHOMA.

LOCATION...
THE SLIGHT RISK AREA IS NORTH OF INTERSTATE 40.

TIMING...
THE MOST LIKELY TIME FOR SEVERE THUNDERSTORMS WILL BE FROM LATE
AFTERNOON THROUGH EARLY TUESDAY MORNING.

RECOMMENDED ACTIONS...
STORM SPOTTER GROUPS AND EMERGENCY MANAGEMENT PERSONNEL ACROSS THE
RISK AREA SHOULD PLAN FOR SEVERE WEATHER OPERATIONS FROM THIS
AFTERNOON UNTIL EARLY TUESDAY MORNING.

DISCUSSION...
MODERATE INSTABILITY... COMBINED WITH SURFACE BOUNDARIES... AN UPPER
LEVEL TROUGH... AND MODERATE VERTICAL WIND SHEAR... WILL BRING A
CHANCE OF SEVERE THUNDERSTORMS TO NORTHERN OKLAHOMA LATER TODAY. INSOLATION
AND AN OUTFLOW BOUNDARY ACROSS CENTRAL OKLAHOMA WILL PROVIDE
SUFFICIENT LIFT FOR THUNDERSTORMS LATER THIS AFTERNOON.
THUNDERSTORMS WILL BE CAPABLE OF PRODUCING VERY HEAVY RAIN AND
LOCALIZED FLOODING. A FEW THUNDERSTORMS MAY ALSO MAKE LARGE HAIL AND
DAMAGING WINDS.

PROBABILITY TABLE...
VALID THROUGH 700 AM CDT TUESDAY AUG 18.
PROBABILITY OF THUNDERSTORMS OCCURRING IN THE
              NWS NORMAN COUNTY WARNING AREA...100 PERCENT.
PROBABILITY OF SEVERE STORMS IF STORMS OCCUR...70 PERCENT.

OTHER HAZARDOUS WEATHER...
A FLOOD WATCH IS EFFECTIVE FOR THE NORTHERN HALF OF OKLAHOMA FROM
LATE THIS AFTERNOON THROUGH MID-DAY TUESDAY.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY...

THUNDERSTORM OUTLOOK...
SEVERE THUNDERSTORMS ARE POSSIBLE TUESDAY AND TUESDAY NIGHT.
THUNDERSTORM CHANCES RECEDE BEYOND WEDNESDAY MORNING.

OTHER HAZARDOUS WEATHER...
A FLOOD WATCH IS EFFECTIVE FOR THE NORTHERN HALF OF OKLAHOMA UNTIL
MID-DAY TUESDAY. THUNDERSTORMS TUESDAY MORNING WILL LIKELY GENERATE
VERY HEAVY RAINFALL.

THE NEXT SCHEDULED HAZARDOUS WEATHER OUTLOOK WILL BE ISSUED AT 7 AM
TUESDAY.

In the hours before

Special weather statement, Aug 17, 5:47 PM CDT, 1 hour 19 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NORMAN OK
547 PM CDT MON AUG 17 2009

OKZ015-017-172330-
DEWEY OK-BLAINE OK-
547 PM CDT MON AUG 17 2009

...SIGNIFICANT WEATHER ADVISORY...

THIS SIGNIFICANT WEATHER ADVISORY IS FOR BLAINE AND DEWEY COUNTIES.

A STRONG THUNDERSTORM WAS LOCATED 5 MILES SOUTHWEST OF EAGLE CITY AT
546 PM CDT...MOVING EAST AT 15 MPH. SMALL HAIL AND WINDS AROUND 50
MPH ARE LIKELY. ADDITIONAL THUNDERSTORMS WERE FORMING ON AN OUTFLOW
BOUNDARY EXTENDING WEST TOWARD TALOGA. SEVERE WEATHER IS POSSIBLE AS
STORM STRENGTHEN THIS EVENING.

LAT...LON 3577 9821 3585 9890 3599 9905 3616 9862
      3616 9822

BURKE
Special weather statement, Aug 17, 6:36 PM CDT, 30 minutes before
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Local storm report, Aug 17, 6:45 PM CDT, 21 minutes before
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Special weather statement, Aug 17, 6:53 PM CDT, 13 minutes before
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Special weather statement, Aug 17, 6:55 PM CDT, 11 minutes before
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Special weather statement, Aug 17, 6:57 PM CDT, 9 minutes before
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The office that day

Everything else NWS Norman, OK issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 17, 7:13 PM CDTSevere Thunderstorm WarningOUNGrant, Kay62 min
Aug 17, 7:30 PM CDTSevere Thunderstorm WarningOUNBlaine, Canadian, Kingfisher75 min
Aug 17, 7:41 PM CDTSevere Thunderstorm WarningOUNCuster, Dewey, Roger Mills64 min
Aug 17, 8:12 PM CDTSevere Thunderstorm WarningOUNGrant, Kay63 min
Aug 17, 8:29 PM CDTFlash Flood WarningOUNBlaine5 hr
Aug 17, 8:34 PM CDTSevere Thunderstorm WarningOUNBlaine, Caddo, Canadian, Custer, Kingfisher56 min
Aug 17, 8:37 PM CDTFlash Flood WarningOUNGrant, Kay6 hr
Aug 17, 9:11 PM CDTSevere Thunderstorm WarningOUNGrant64 min
Aug 17, 9:31 PM CDTSevere Thunderstorm WarningOUNBlaine, Caddo, Canadian, Grady, Kingfisher74 min
Aug 17, 9:38 PM CDTSevere Thunderstorm WarningOUNKay37 min
Aug 17, 10:16 PM CDTSevere Thunderstorm WarningOUNGrant, Kay59 min
Aug 18, 1:08 AM CDTAreal Flood WarningOUNBlaine6 hr
Aug 18, 2:34 AM CDTAreal Flood WarningOUNGrant, Kay10 hr
Aug 18, 6:44 AM CDTAreal Flood AdvisoryOUNBlaine4 hr
Aug 18, 8:25 AM CDTRiver Flood WarningOUNGrant, Kay, Noble24 hr
Aug 18, 8:54 AM CDTAreal Flood AdvisoryOUNNoble, Payne5 hr
Aug 18, 10:34 AM CDTAreal Flood AdvisoryOUNBlaine, Caddo, Custer, Washita3 hr
Aug 18, 11:51 AM CDTRiver Flood WarningOUNBlaine, Caddo, Canadian, Custer15 hr

Nearby

Flash Flood Warnings in Oklahoma, 2009Every flash flood warning in 2009

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.