Alert archive / Oklahoma / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 481, NWS Tulsa, OK

September 7, 1999Delaware County, Oklahoma

NWS Tulsa, OK issued this severe thunderstorm warning at Sep 7, 1999, 7:26 PM CDT for Delaware County, Oklahoma. It was in force for 34 min. 1 report came from inside the area while it was in force.

The area

The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties, with what was reported inside it.

The facts

Issued: Sep 7, 1999, 7:26 PM CDT (00:26 UTC)
Expired: Sep 7, 1999, 8:00 PM CDT
In force: 34 min
Issued by: NWS Tulsa, OK
Area: Whole counties; the outline is the Mesonet’s reconstruction

County Delaware County, OK

What was reported inside it

Time	Report	Where	Remark
Sep 7, 7:40 PM CDT	Hail 1.75	West Siloam Spgs, OK

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Sep 7, 4:00 PM CDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Springfield, MO (KSGF), launched 00:00Z, 0.4 hours before the alert went out and 109 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1500 J/kg
Mixed-layer CIN: -29 J/kg
Mixed-layer LCL: 1775 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 47 m²/s²
0-3 km storm-relative helicity: 70 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 2.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

524 
WUUS54 KTSA 080027 RRA
SVRTUL
OKC041-080100-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE TULSA OK
726 PM CDT TUE SEP 7 1999

THE NATIONAL WEATHER SERVICE IN TULSA HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  DELAWARE COUNTY IN NORTHEAST OKLAHOMA

* UNTIL 800 PM CDT

* AT 726 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 8 MILES SOUTH OF COLCORD...MOVING NORTHEAST AT
  20 MPH.

* SOME LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE...COLCORD AND 
KANSAS.

HAIL TO THE SIZE OF NICKELS AND WIND GUSTS TO 60 MPH CAN BE EXPECTED 
IN THE WARNED AREA.

LAT...LON 3616 9480 3614 9470 3624 9457 3648 9463

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, 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 this severe thunderstorm warning went out at Sep 7, 3:35 PM CDT, 3 hours 51 minutes earlier.

Area forecast discussion, Sep 7, 3:35 PM CDT, 3 hours 51 minutes before

EASTERN OKLAHOMA/NORTHWEST ARKANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TULSA OK
335 PM CDT TUE SEP 7 1999

PROBLEM(S) OF THE DAY:
POPS
TEMPERATURES

RADAR...SAT PICS AND LIGHTNING DATA SHOWING SCATTERED SHOWERS AND
THUNDERSTORMS DEVELOPING AT FORECAST TIME.  APPARENTLY THESE ARE DUE
TO STRONG HEATING...BROKEN CAP AND A SHORTWAVE DEPICTED BY BOTH THE
ETA AND NGM OVER EASTERN OKLAHOMA AND EASTERN KANSAS LATE THIS
AFTERNOON AND EVENING.  ALL IN ALL FWC'S 50 PERCENT POPS FOR TONIGHT
DO NOT LOOK BAD SO HAVE STUCK WITH THEM.  THIS AFTERNOON'S CONVECTION
MAY DIE DOWN THIS EVENING BUT THERE WILL A CHANCE FOR MORE WITH THE
WELL ADVERTISED FRONTAL PASSAGE.

THE MODELS HAVE THE SAME GENERAL IDEA WITH THE FRONT BUT DIFFER SOME
IN SPEED.  MOS WANTS WINDS TO SHIFT LATE TONIGHT AT KTUL WHILE
SURFACE WINDS FROM ETA AND AVN WOULD INDICATE A FRONTAL PASSAGE
SOMETIME DURING THE MORNING.  HAVE SIDED WITH THE ETA AND AVN BASED
ON THE DYNAMICS DRIVING THE FRONT BEING WELL TO THE NORTH OVER THE
UPPER MIDWEST.   THINK POPS TOMORROW WILL BE BEST IN THE SOUTH WHERE
THE FRONT WILL PASS AFTER SOME DECENT HEATING OCCURS.  FRONT DOES NOT
QUITE CLEAR THE RED RIVER COUNTIES UNTIL TOMORROW EVENING SO WILL
CARRY SOME POPS THERE TOMORROW NIGHT.

QUESTION IS WHAT WILL TEMPS DO.  LOWEST 8H TEMPS OCCUR THURSDAY BUT
SHOULD HAVE FULL SUN THAT DAY. COULD HAVE SOME CLOUDINESS TOMORROW
DUE TO THE TSRA THREAT.  THUS...HAVE GONE FOR SIMILAR TO SLIGHTLY
WARMER TEMPS THURSDAY AS TOMORROW.  COOLEST TEMPERATURES NIGHTTIME
WISE WILL LIKELY OCCUR THURSDAY NIGHT AS VERY DRY AIR FULLY SETTLES
IN OVER THE AREA AND WINDS BECOME CALM.  SHOULD SEE A WARMUP
BEGINNING FRIDAY AS THERMAL GRADIENT BEGINS TO SHIFT EAST.

THE EXTENDED FORECAST IS ANOTHER CHALLENGE.  BOTH THE ECWMF AND MRF
ARE SIMILAR THURSDAY NIGHT INTO SATURDAY WITH A WAV FLATTENING THE
WESTERN RIDGE.  FROM THERE THEY DIVERGE.  THE MRF BRINGS THE WAVE
THROUGH KANSAS AND MISSOURI WITH LITTLE SURFACE REFLECTION.  THE
ECMWF CUTS OFF A LOW OVER MINNESOTA AND DRIVES A COLD FRONT ACROSS
THE AREA SATURDAY NIGHT.  IN STAYING THE COURSE OF THE MID SHIFTS
IDEAS AND KNOWING THE PATTERN WE HAVE BEEN IN HAVE LOOSELY FOLLOWED
THE ECMWF.  WILL KEEP WARMUP AND SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS IN THE FORECAST WE HAVE FOR SATURDAY.  THEN WILL COOL
THINGS OFF SLIGHTLY FOR SUNDAY.

FCSTID = 17
TUL   70  85  58  85 /  50  30   0   0
FSM   70  88  58  85 /  50  50   0   0
MLC   70  87  60  86 /  50  50   0   0
BVO   66  83  56  85 /  50  20   0   0
FYV   63  83  53  82 /  50  30   0   0
BYV   62  84  52  83 /  50  30   0   0
MIO   65  83  55  83 /  50  30   0   0
MKO   69  85  57  85 /  50  30   0   0
F10   70  86  58  86 /  50  30   0   0
HHW   70  92  63  88 /  50  50  20   0

.TUL...
AR...NONE.
OK...NONE.

--------------------
EXPERIMENTAL OUTPUT:

HAZARDOUS WEATHER EXPECTED NEXT 24 HOURS: CHANCE SEVERE
THUNDERSTO@RMS
NGM CONFIDENCE:  7 ON A SCALE OF 0 TO 10
ETA CONFIDENCE:  8 ON A SCALE OF 0 TO 10
AVN CONFIDENCE:  7 ON A SCALE OF 0 TO 10
FCST CONFIDENCE: 8 ON A SCALE OF 0 TO 10

In the hours before

Local storm report, Sep 7, 6:33 PM CDT, 53 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TULSA OK
633 PM CDT TUE SEP 07 1999

TIME(CDT)  .....CITY LOCATION..... STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0615 PM    NELAGONEY                 OK    2 INCH HAIL
09/07/99   OSAGE

Local storm report, Sep 7, 6:33 PM CDT, 53 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TULSA OK
633 PM CDT TUE SEP 07 1999

TIME(CDT)  .....CITY LOCATION..... STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0615 PM    NELAGONEY                 OK    2 INCH HAIL
09/07/99   OSAGE

Local storm report, Sep 7, 6:41 PM CDT, 45 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TULSA OK
641 PM CDT TUE SEP 07 1999

TIME(CDT)  .....CITY LOCATION..... STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0637 PM    5 W SKIATOOK              OK    65 MPH TSTM GUST
09/07/99   OSAGE

Local storm report, Sep 7, 6:59 PM CDT, 27 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TULSA OK
659 PM CDT TUE SEP 07 1999

TIME(CDT)  .....CITY LOCATION..... STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0655 PM    VERA                      OK    60 MPH TSTM GUST
09/07/99   WASHINGTON

Local storm report, Sep 7, 6:59 PM CDT, 27 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TULSA OK
659 PM CDT TUE SEP 07 1999

TIME(CDT)  .....CITY LOCATION..... STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0655 PM    VERA                      OK    60 MPH TSTM GUST
09/07/99   WASHINGTON

Local storm report, Sep 7, 7:10 PM CDT, 16 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TULSA OK
710 PM CDT TUE SEP 07 1999

TIME(CDT)  .....CITY LOCATION..... STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0700 PM    WELLING                   OK    1 INCH HAIL
09/07/99   CHEROKEE

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 7, 7:18 PM CDT	Severe Thunderstorm Warning	TSA	Osage, Pawnee	42 min
Sep 7, 7:34 PM CDT	Severe Thunderstorm Warning	TSA	Rogers	41 min
Sep 7, 7:54 PM CDT	Severe Thunderstorm Warning	TSA	Adair, Cherokee	51 min
Sep 7, 7:57 PM CDT	Severe Thunderstorm Warning	TSA	Craig, Delaware, Mayes, Ottawa	48 min
Sep 7, 8:01 PM CDT	Flash Flood Warning	TSA	Adair, Cherokee	119 min
Sep 7, 8:03 PM CDT	Severe Thunderstorm Warning	TSA	Creek, Pawnee	42 min
Sep 7, 8:13 PM CDT	Tornado Warning	TSA	Creek	32 min
Sep 7, 8:32 PM CDT	Severe Thunderstorm Warning	TSA	Delaware	43 min
Sep 7, 8:41 PM CDT	Severe Thunderstorm Warning	TSA	Mayes	34 min
Sep 7, 8:45 PM CDT	Severe Thunderstorm Warning	TSA	Creek, Okmulgee, Tulsa	45 min
Sep 7, 8:45 PM CDT	Severe Thunderstorm Warning	TSA	Okfuskee	45 min
Sep 7, 9:57 PM CDT	Severe Thunderstorm Warning	TSA	McIntosh, Muskogee	48 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 1999 Every severe thunderstorm warning in 1999

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.