A strong mesolow/high couplet developed in the wake of a mesoscale convective system that moved across northeast Oklahoma during the afternoon of the 17th. The resulting pressure gradient produced wind gusts up to around 65 mph and some minor damage.
Every event with a place to put it; 5 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
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.
The episode as NWS TSA wrote it up.
A strong mesolow/high couplet developed in the wake of a mesoscale convective system that moved across northeast Oklahoma during the afternoon of the 17th. The resulting pressure gradient produced wind gusts up to around 65 mph and some minor damage.
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 Tulsa, OK wrote its last area forecast discussion before the first event at Apr 17, 2:50 PM CST, 25 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TULSA OK 350 PM CDT FRI APR 17 2009 .DISCUSSION... GOOD MOIST SOUTHERLY FEED DIRECTLY INTO NORTHEAST OKLAHOMA AND ADJACENT ARKANSAS TONIGHT IN ADVANCE OF SLOW MOVING UPPER LOW. PRECIPITABLE H2O VALUES IN 1.2 - 1.5 RANGE THIS EVENING..THUS CATEGORICAL SHOWERS AND SCATTERED THUNDER. EXPECT A GENERAL INCH OR TWO OF RAINFALL...ISOLATED HIGHER AMOUNTS. PRESSURE FALLS ALONG SOUTHWEST PERIPHERY CWA NEAR WEST EDGE PRECIP CAUSING WIND GUST NEAR 40. THINK MOST OF THAT WILL STAY WEST..BUT DID INCLUDE GUST 40 SOUTHWEST ZONES FOR SEVERAL HOURS. MODELS IN SOME DISARRAY ON HOW FAST SIGNIFICANT RAIN AREA WILL CLEAR FORECAST AREA SATURDAY. LIKELY WE WILL SEE A DRY SLOT FOR A TIME...THAN MORE SHOWERS AND THUNDER SATURDAY NIGHT AS H500 UPPER LOW CROSSES THE AREA. SUB MINUS 20 H500 TEMP NORTH OF I - 40 AND GREATER THAN 50 SFC DEWPOINT ALMOST GUARANTEE HAIL WITH STORMS THAT DO DEVELOP. INCLUDED IN SAT NIGHT FORECAST. WEATHER STILL NOT CLEAN SUNDAY IN THE WAKE OF COLD UPPER LOW. DRY AFTER SUNDAY WITH A BIG TIME WARM UP AROUND MID-WEEK. && .PRELIMINARY POINT TEMPS/POPS... TUL 57 73 51 67 / 100 40 60 40 FSM 58 72 55 70 / 100 70 70 40 MLC 58 72 51 68 / 80 50 50 20 BVO 55 74 48 66 / 100 40 70 40 FYV 55 69 49 64 / 100 70 70 50 BYV 55 69 51 64 / 80 70 80 60 MKO 56 71 52 69 / 100 50 60 40 MIO 57 73 52 64 / 90 50 70 60 F10 56 71 48 67 / 100 40 50 30 HHW 58 72 54 70 / 90 60 50 20 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && SHORT TERM...21 LONG TERM....21
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TULSA OK
329 PM CDT FRI APR 17 2009
ARZ001-002-010-011-019-020-029-OKZ049-053>076-181000-
ADAIR OK-BENTON AR-CARROLL AR-CHEROKEE OK-CHOCTAW OK-CRAIG OK-
CRAWFORD AR-CREEK OK-DELAWARE OK-FRANKLIN AR-HASKELL OK-LATIMER OK-
LE FLORE OK-MADISON AR-MAYES OK-MCINTOSH OK-MUSKOGEE OK-NOWATA OK-
OKFUSKEE OK-OKMULGEE OK-OSAGE OK-OTTAWA OK-PAWNEE OK-PITTSBURG OK-
PUSHMATAHA OK-ROGERS OK-SEBASTIAN AR-SEQUOYAH OK-TULSA OK-WAGONER OK-
WASHINGTON OK-WASHINGTON AR-
323 PM CDT FRI APR 17 2009
THIS OUTLOOK IS FOR NORTHWEST AND WEST CENTRAL ARKANSAS AS WELL AS
MUCH OF EASTERN OKLAHOMA.
.DAY ONE...TODAY AND TONIGHT.
SEVERE THUNDERSTORM.
RISK...LIMITED.
AREA...GENERALLY SOUTHWEST OF A LINE FROM BARTLESVILLE
TO FORT SMITH.
ONSET...THIS EVENING.
FLASH FLOOD.
RISK...LIMITED.
AREA...NORTHEAST OKLAHOMA.
ONSET...THIS EVENING.
HEAVY RAIN.
RISK...LIMITED.
AREA...EASTERN OKLAHOMA.
ONSET...THIS EVENING.
SIGNIFICANT WINDS.
RISK...LIMITED.
AREA...WEST OF A TULSA TO HUGO LINE.
ONSET...ONGOING...ENDING AFTER 6 PM.
DISCUSSION...
THUNDERSTORMS WILL CONTINUE TODAY AS MOISTURE RETURNS AHEAD OF A
STRONG AND SLOW MOVING UPPER STORM SYSTEM. INSTABILITY WILL REMAIN
LIMITED...WHICH WILL LIMIT THE SEVERE WEATHER POTENTIAL.
HOWEVER...GUSTY EAST WINDS NEAR 40 MPH AT TIMES WILL PERSIST FOR
A FEW MORE HOURS THIS AFTERNOON ALONG THE WESTERN EDGE OF THE AREA
OF RAIN CURRENTLY PASSING THROUGH SOUTHEAST OKLAHOMA. ADDITIONAL
THUNDERSTORMS WILL LIKELY DEVELOP TO THE WEST THIS AFTERNOON...AND
MOVE INTO EASTERN OKLAHOMA BY THIS EVENING...PROGRESSING EASTWARD
INTO ARKANSAS TONIGHT. CONDITIONS MAY BE SLIGHTLY MORE FAVORABLE
FOR SEVERE WEATHER DURING THIS TIME FRAME...HOWEVER THE OVERALL
PATTERN DOES NOT SUPPORT A WIDESPREAD SEVERE WEATHER EVENT. THE
MOST LIKELY SEVERE WEATHER THREAT APPEARS TO BE FROM LARGE HAIL.
SPOTTER AND EMERGENCY MANAGEMENT ACTION STATEMENT...
LOCAL SPOTTER NETWORKS MAY NEED TO DEPLOY BY LATE AFTERNOON...HOWEVER
A REGIONAL SPOTTER NETWORK IS NOT CURRENTLY ANTICIPATED DUE TO THE
EXPECTED ISOLATED COVERAGE OF ANY SEVERE WEATHER.
.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.
SATURDAY...THUNDERSTORM POTENTIAL.
SUNDAY THROUGH THURSDAY...NO HAZARDS.
EXTENDED DISCUSSION...
THUNDERSTORM CHANCES WILL CONTINUE THROUGH THE WEEKEND AS
THE UPPER STORM SYSTEM APPROACHES AND SLOWLY MOVES ACROSS
THE AREA. OVERNIGHT STORMS FROM FRIDAY NIGHT WILL LIKELY
BE ONGOING AFTER SUNRISE ON SATURDAY... WITH ADDITIONAL
DEVELOPMENT BOTH SATURDAY AND SUNDAY AFTERNOONS. CONDITIONS
WILL SUPPORT A RISK OF LARGE HAIL WITH THE STRONGEST STORMS
THAT DEVELOP DURING THIS TIME FRAME. DRY AND WARM WEATHER WILL
RETURN FOR MUCH OF NEXT WEEK.
WWW.SRH.NOAA.GOV/TULSA CONTAINS ADDITIONAL TABULAR AND GRAPHICAL
INFORMATION.The national radar mosaic for the moment the first event began.
5 high wind. Local standard time, as filed.
The Oklahoma Mesonet station southwest of Morris measured wind gusts near 60 mph for 15 minutes. Several awnings were blown off buildings in downtown Henryetta.
A tin barn was blown over and a car port was destroyed in and around Haskell.
Trees and power lines were blown down in Coweta.
Eight partial rows of siding were blown off a house.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oklahoma in 2009Every state in 2009This day in weather historyWarnings in Oklahoma, April 2009
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: 168453, 168456, 168455, 168452, 168458.