Alert archive / Oklahoma / Flash Flood Warnings in 1990
Flash Flood Warning 10, NWS Norman, OK
NWS Norman, OK issued this flash flood warning at Apr 21, 1990, 3:48 PM CDT for Johnston County, Oklahoma. It was in force for 117 min.
The area
The counties it named.
The facts
- Issued
- Apr 21, 1990, 3:48 PM CDT (20:48 UTC)
- Expired
- Apr 21, 1990, 5:45 PM CDT
- In force
- 117 min
- Issued by
- NWS Norman, OK
- Area
- Whole counties
County Johnston County, OK
The radar
The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.
The nearest sounding before it
Norman, OK (KOUN), launched 12:00Z, 8.8 hours before the alert went out and 121 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.
- Mixed-layer CAPE
- 369 J/kg
- Mixed-layer CIN
- -102 J/kg
- Mixed-layer LCL
- 789 m above ground
- 0-6 km bulk shear
- 24 kt
- 0-1 km storm-relative helicity
- 86 m²/s²
- 0-3 km storm-relative helicity
- 85 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
000 TTAA00 KOKC 212050 FFWOKC OKC069-212245- BULLETIN - EBS ACTIVATION REQUESTED FLASH FLOOD WARNING NATIONAL WEATHER SERVICE OKLAHOMA CITY OK 348 PM CDT SAT APR 21 1990 THE NATIONAL WEATHER SERVICE IN OKLAHOMA CITY HAS ISSUED A FLASH FLOOD WARNING EFFECTIVE UNTIL 545 PM CDT FOR THE FOLLOWING OKLAHOMA LOCATIONS... IN SOUTHEAST OKLAHOMA ...JOHNSTON COUNTY AT 348 PM RADAR INDICATED AN AREA OF STRONG THUNDERSTORMS OVER NORTHERN JOHNSTON COUNTY. RADAR INDICATED THAT RAINFALL AMOUNTS OVER TWO INCHES MAY HAVE FALLEN FROM THESE STORMS. AS A RESULT FLASH FLOODING IS LIKELY ESPECIALLY IN LOW LYING AREAS. THE THUNDERSTORMS WERE MOVING SLOWLY SOUTHEAST A 5 TO 10 MPH. A FLASH FLOOD WARNING MEANS THAT FLOODING IS OCCURRING OR IS IMMINENT. MOST FLASH FLOOD DEATHS OCCUR IN AUTOMOBILES. DO NOT ATTEMPT TO CROSS BRIDGES...DIPS...OR LOW SPOTS IF WATER COVERS THE ROADWAY. NEVER TRY TO CROSS A FLOWING STREAM...EVEN A SMALL ONE...ON FOOT. TO ESCAPtE RISING WATER MOVE UP TO HIGHER GROUND.
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.
In the hours before
Special weather statement, Apr 21, 12:53 PM CDT, 2 hours 55 minutes before
OKZALL-221200- OKLAHOMA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE OKLAHOMA CITY OK 100 PM CDT SAT APR 21 1990 NO SEVERE THUNDERSTORMS ARE FORECAST IN OKLAHOMA THIS AFTERNOON OR TONIGHT. WIDELY SCATTERED THUNDERSTORMS MAY DEVELOP THIS AFTER NOON DUE TO HEATING AND AN ABUNDANCE OF LOW LEVEL MOISTURE...BUT THEY ARE NOT EXPECTED TO BECOME SEVERE. LOW CLOUDS AND FOG WHICH BLANKETED MUCH OF THE STATE EARLY THIS MORNING WERE BURNING OFF BY MIDDAY. HOWEVER DEWPOINTS REMAIN FAIRLY HIGH AND IF AFTERNOON TEMPERATURES RISE INTO THE LOW AND MID 80S WIDELY SCATTETED THUNDERSTORMS MAY DEVELOP IN MOST ANY SECTION OF THE STATE. THE WIND PATTERNS IN THE MID LEVELS OF THE ATMOSPHERE ARE RATHER WEAK AND UNFAVORABLE FOR THE OCCURENCE OF ORGANIZED SEVERE THUNDERSTORMS...HOWEVER ANY THUNDERSTORMS THAT FORM THIS AFTERNOON COULD PRODUCE BRIEF GUSTY WIND.
The office that day
Everything else NWS Norman, OK issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 21, 1:58 PM CDT | Severe Thunderstorm Warning | OUN | Coal | 32 min |
| Apr 21, 2:28 PM CDT | Severe Thunderstorm Warning | OUN | Coal | 47 min |
| Apr 21, 2:33 PM CDT | Flash Flood Warning | OUN | Coal | 117 min |
| Apr 21, 3:18 PM CDT | Severe Thunderstorm Warning | OUN | Johnston | 42 min |
| Apr 21, 4:48 PM CDT | Severe Thunderstorm Warning | OUN | Carter, Johnston, Marshall | 57 min |
| Apr 21, 5:42 PM CDT | Flash Flood Warning | OUN | Carter, Johnston, Murray | 2 hr |
| Apr 21, 5:56 PM CDT | Severe Thunderstorm Warning | OUN | Bryan, Johnston | 49 min |
Nearby
Flash Flood Warnings in Oklahoma, 1990Every flash flood warning in 1990
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.