Alert archive / Oklahoma / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 149, NWS Tulsa, OK

April 26, 1999Creek County, Oklahoma

NWS Tulsa, OK issued this severe thunderstorm warning at Apr 26, 1999, 9:21 AM CDT for Creek County, Oklahoma. It was in force for 24 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Apr 26, 1999, 9:21 AM CDT (14:21 UTC)
Expired
Apr 26, 1999, 9:45 AM CDT
In force
24 min
Issued by
NWS Tulsa, OK
Area
Whole counties; the outline is the Mesonet’s reconstruction

County Creek County, OK

The radar

The Tulsa radar (KINX), 79 km from the middle of the area, began a volume at 14:20 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

Norman, OK (KOUN), launched 12:00Z, 2.4 hours before the alert went out and 120 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, Norman, OK at 12:00Z on 1999-04-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 518 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, Norman, OK at 12:00Z on 1999-04-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 58 square meters per square second.19395878Sfc1 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
518 J/kg
Mixed-layer CIN
-59 J/kg
Mixed-layer LCL
644 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
58 m²/s²
0-3 km storm-relative helicity
54 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

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 Apr 26, 4:25 AM CDT, 4 hours 56 minutes earlier.

Area forecast discussion, Apr 26, 4:25 AM CDT, 4 hours 56 minutes before
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In the hours before

Special weather statement, Apr 26, 6:15 AM CDT, 3 hours 6 minutes before
ARZ001-002-010-011-019-020-029-OKZ049-053>076-271100-

EASTERN OKLAHOMA/NORTHWEST ARKANSAS HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TULSA OK
615 AM CDT MON APR 26 1999

...ISOLATED SEVERE THUNDERSTORMS WILL BE POSSIBLE FROM MID MORNING
THROUGH THIS EVENING ACROSS EASTERN OKLAHOMA AND NORTHWEST ARKANSAS...

.SYNOPSIS...
AN UPPER LOW OVER COLORADO/NEW MEXICO WILL MOVE EAST INTO KANSAS AND
OKLAHOMA DURING THE DAY.  STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED TO
DEVELOP AHEAD OF THIS UPPER LOW.  A WEAK SURFACE FRONT WILL ALSO MOVE
INTO EASTERN OKLAHOMA DURING THE AFTERNOON TO HELP INITIATE MORE
THUNDERSTORM DEVELOPMENT.

.DISCUSSION...
AN UPPER LEVEL IMPULSE HAS HELPED DEVELOP STRONG THUNDERSTORMS OVER
NORTH CENTRAL TEXAS AND SOUTHWEST OKLAHOMA.  THESE STORMS WILL MOVE INTO
EASTERN OKLAHOMA LATER THIS MORNING.  AND ALTHOUGH THE AIRMASS THIS
MORNING IS RELATIVELY STABLE...AN ISOLATED STORM COULD PRODUCE
MARGINALLY SEVERE WEATHER BEFORE NOON.  HOWEVER...THE MAIN THREAT FROM
THESE STORMS WILL BE HEAVY RAIN.

THE AIRMASS OVER EASTERN OKLAHOMA AND NORTHWEST ARKANSAS WILL BECOME
MORE UNSTABLE THIS AFTERNOON...AS SURFACE TEMPERATURES WARM INTO THE 70S
AND AS THE UPPER LOW BRINGS COOLER AIR ALOFT OVER THE AREA.  MODERATE
CONVERGENCE ALONG THE SURFACE FRONT SHOULD PROVIDE SUFFICIENT LIFT TO
DEVELOP THUNDERSTORMS...SOME OF WHICH MAY BECOME SEVERE.  LARGE HAIL
WILL BE THE MAIN THREAT...ALTHOUGH STRONG WINDS WILL ALSO BE POSSIBLE.

.EMERGENCY MANAGEMENT AGENCY AND SPOTTER ACTIVATION...
SPOTTER ACTIVATION MAY BE NECESSARY LATER THIS MORNING IN EASTERN
OKLAHOMA. SPOTTER ACTIVATION SHOULD BE EXPECTED OVER EASTERN OKLAHOMA
LATER THIS AFTERNOON...AND IN NORTHWEST ARKANSAS THIS EVENING.
Special weather statement, Apr 26, 6:15 AM CDT, 3 hours 6 minutes before
ARZ001-002-010-011-019-020-029-OKZ049-053>076-271100-

EASTERN OKLAHOMA/NORTHWEST ARKANSAS HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TULSA OK
615 AM CDT MON APR 26 1999

...ISOLATED SEVERE THUNDERSTORMS WILL BE POSSIBLE FROM MID MORNING
THROUGH THIS EVENING ACROSS EASTERN OKLAHOMA AND NORTHWEST ARKANSAS...

.SYNOPSIS...
AN UPPER LOW OVER COLORADO/NEW MEXICO WILL MOVE EAST INTO KANSAS AND
OKLAHOMA DURING THE DAY.  STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED TO
DEVELOP AHEAD OF THIS UPPER LOW.  A WEAK SURFACE FRONT WILL ALSO MOVE
INTO EASTERN OKLAHOMA DURING THE AFTERNOON TO HELP INITIATE MORE
THUNDERSTORM DEVELOPMENT.

.DISCUSSION...
AN UPPER LEVEL IMPULSE HAS HELPED DEVELOP STRONG THUNDERSTORMS OVER
NORTH CENTRAL TEXAS AND SOUTHWEST OKLAHOMA.  THESE STORMS WILL MOVE INTO
EASTERN OKLAHOMA LATER THIS MORNING.  AND ALTHOUGH THE AIRMASS THIS
MORNING IS RELATIVELY STABLE...AN ISOLATED STORM COULD PRODUCE
MARGINALLY SEVERE WEATHER BEFORE NOON.  HOWEVER...THE MAIN THREAT FROM
THESE STORMS WILL BE HEAVY RAIN.

THE AIRMASS OVER EASTERN OKLAHOMA AND NORTHWEST ARKANSAS WILL BECOME
MORE UNSTABLE THIS AFTERNOON...AS SURFACE TEMPERATURES WARM INTO THE 70S
AND AS THE UPPER LOW BRINGS COOLER AIR ALOFT OVER THE AREA.  MODERATE
CONVERGENCE ALONG THE SURFACE FRONT SHOULD PROVIDE SUFFICIENT LIFT TO
DEVELOP THUNDERSTORMS...SOME OF WHICH MAY BECOME SEVERE.  LARGE HAIL
WILL BE THE MAIN THREAT...ALTHOUGH STRONG WINDS WILL ALSO BE POSSIBLE.

.EMERGENCY MANAGEMENT AGENCY AND SPOTTER ACTIVATION...
SPOTTER ACTIVATION MAY BE NECESSARY LATER THIS MORNING IN EASTERN
OKLAHOMA. SPOTTER ACTIVATION SHOULD BE EXPECTED OVER EASTERN OKLAHOMA
LATER THIS AFTERNOON...AND IN NORTHWEST ARKANSAS THIS EVENING.

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 26, 9:45 AM CDTFlash Flood WarningTSACreek, McIntosh, Okfuskee, Okmulgee, Tulsa4 hr
Apr 26, 9:45 AM CDTFlash Flood WarningTSAPittsburg4 hr
Apr 26, 11:27 AM CDTFlash Flood WarningTSACraig, Mayes, Nowata, Rogers, Wagoner, Washington3 hr
Apr 26, 11:27 AM CDTFlash Flood WarningTSAOsage3 hr
Apr 26, 11:27 AM CDTFlash Flood WarningTSAMuskogee3 hr
Apr 26, 11:57 AM CDTSevere Thunderstorm WarningTSALeFlore48 min
Apr 26, 12:33 PM CDTSevere Thunderstorm WarningTSASequoyah42 min
Apr 26, 1:49 PM CDTFlash Flood WarningTSACraig, Ottawa116 min
Apr 26, 6:34 PM CDTSevere Thunderstorm WarningTSAPittsburg41 min
Apr 26, 1:05 PM CDTSevere Thunderstorm WarningTSACrawford40 min
Apr 26, 1:15 PM CDTSevere Thunderstorm WarningTSAFranklin, Sebastian30 min
Apr 26, 1:44 PM CDTSevere Thunderstorm WarningTSAFranklin, Madison31 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 1999Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.