Discussion Forums

I reviewed the NWS alerts for Saturday, and it appears that the tornado outbreak developed quickly. At 5:03 I received the first alert, but it seemed to play down tornado possibilities. At: 6:05 and 6:15, the world had changed.

Received at 5:03 PM
From: "nwsTulsa" <ldad@ls1-tsa.abrfc.noaa.gov>
Date: Saturday, May 10, 2008 5:03 PM
To: <ChasesStorms@live.com
Subject: Discussion_WeatherAlert_8
Page 1 of 2
5/12/2008
TO: PUBLIC SAFETY AGENCIES
FM: NWS TULSA OPERATIONS
RE: MESOSCALE UPDATE MESSAGE
RELEASED...456 PM CDT SAT MAY 10 2008
NEW CONVECTION IS DEVELOPING ACROSS EASTERN
OKLAHOMA NOW IN A ZONE OF LOW-LEVEL CONFLUENCE
THAT IS ACTING AS A WEAK DRY LINE. THE STORMS
ARE IN AN AXIS OF EXTREME INSTABILITY OF
SURFACE-BASED CAPE OF UP TO 4000 J/KG AND LIFTED
INDEX VALUES OF -13. DEEP-LAYER SHEAR IS STRONG
AND GIVEN THE WEAK L0W-LEVEL FORCING AND ORIENTATION
OF THE SHEAR...THE CELLS ARE EXPECTED TO BECOME
SUPERCELLS. HOWEVER WITH THEIR CURRENT MOTIONS...
STORM-RELATIVE HELICITES ARE ONLY NEAR 100 M2/S2.
ALSO HODOGRAPHS SHOW A WEAKNESS IN THE MID-LEVEL
STORM-RELATIVE FLOW...SO TORNADO POTENTIAL SEEMS
RATHER LIMITED AT THIS TIME...BUT CELLS THAT
CAN BECOME SUSTAINED WILL HAVE A VERY LARGE HAIL
POTENTIAL. THE CELLS ARE STILL FIGHTING SYNOPTIC
SCALE DOWNWARD MOTION IN THE WAKE OF THE EARLIER
ACTIVITY.
AT 4PM PRESSURE RISES AND SURFACE WIND GUSTS
INDICATE THE COLD FRONT IS BEGINNING ITS SURGE
AND AS IT REACHES THE BACK EDGE OF THE MOISTURE
A SQUALL LINE OF SOME EXTENT IS EXPECTED TO
FORM WITH ENHANCED WIND DAMAGE POTENTIAL.
...NOTE PREVIOUS MESOSCALE AFD WAS STUCK IN TRANSMISSION
AND WAS ACTUALLY WRITTEN AROUND 345 PM INSTEAD OF THE
INDICATED 443 PM...

The Picher tornado hit at 5:39PM

Received at 6:05 PM
From: "nwsTulsa" <ldad@ls1-tsa.abrfc.noaa.gov>
Date: Saturday, May 10, 2008 6:05 PM
To: <ChasesStorms@live.com
Subject: Discussion_WeatherAlert_9
Page 1 of 1
5/12/2008
TO: PUBLIC SAFETY AGENCIES
FM: NWS TULSA OPERATIONS
RE: MESOSCALE UPDATE MESSAGE
RELEASED...558 PM CDT SAT MAY 10 2008
DURING THE PAST HOUR A SIGNIFICANT TORNADO
OUTBREAK BEGAN ACROSS EASTERN OKLAHOMA.
THE EXTREME INSTABILITY HAS COMPENSATED
FOR THE LESS THAN IDEAL WIND PROFILES.
ALL OF THE ORGANIZED SUPERCELLS IN EASTERN
OKLAHOMA APPEARED TO HAVE PRODUCED TORNADOES
IN THE LAST HOUR...SOME REPORTS INDICATE
RATHER LARGE TORNADOES HAVE OCCURRED.
THE MOST FAVORABLE WIND FIELDS...WHICH
HAVE BEEN IN ARKANSAS AND EXTREME EASTERN
OKLAHOMA ARE BEGINNING TO OVERLAP THE
HIGHER INSTABILITY AS THE INSTABILITY
AXIS IS FORCED EAST AHEAD OF THE
WEAK DRY LINE. AS THIS PROCESS CONTINUES
AND WE MOVE TOWARD EVENING THE TORNADO
POTENTIAL WILL CONTINUE INTO ARKANSAS.
ALL INTERESTS AHEAD OF THESE SUPERCELLS
SHOULD SHOULD MOVE TO A HIGH STATE OF
READINESS.

Recevied at 6:16 PM
From: "nwsTulsa" <ldad@ls1-tsa.abrfc.noaa.gov>
Date: Saturday, May 10, 2008 6:16 PM
To: <ChasesStorms@live.com
Subject: NWS_TUL_HazardousWeather_Alert_9
Page 1 of 2
5/12/2008
TO: PUBLIC SAFETY AGENCIES
FM: NWS TULSA OPERATIONS
RE: WEATHER THREAT POTENTIAL
RELEASED...608 PM CDT SAT MAY 10 2008
ALERT LEVEL...9
SPOTTER ACTIVATION IS ONGOING. EMERGENCY MANAGERS SHOULD
ENSURE ALL COMMUNICATION MODES FOR SEVERE WEATHER OPERATIONS ARE
READY AND VISIT THE DECISION SUPPORT PAGE FOR UPDATES THROUGHOUT THE
EVENING.
.DAY ONE...REMAINDER OF THIS EVENING AND TONIGHT.
TORNADO.
RISK...SIGNIFICANT.
AREA...EAST OF A MIAMI...STIGLER...ATOKA LINE
ONSET...ONGOING.
AREA AT GREATEST RISK...FAR EASTERN OKLAHOMA AND WESTERN ARKANSAS.
SEVERE THUNDERSTORM.
RISK...SIGNIFICANT.
AREA...EAST OF A MIAMI...STIGLER...ATOKA LINE
ONSET...ONGOING.
FLASH FLOOD.
RISK...LIMITED.
AREA...NORTHWEST ARKANSAS.
ONSET...THIS EVENING.
SIGNIFICANT WINDS.
RISK...LIMITED.
AREA...EASTERN OKLAHOMA AND NORTHWEST ARKANSAS.
ONSET...ONGOING.
DISCUSSION...
A LINE OF TORNADIC THUNDERSTORMS WERE ONGOING ACROSS FAR EASTERN
OKLAHOMA AND MOVING INTO WESTERN ARKANSAS. THUNDERSTORMS WILL
CONTINUE TO DEVELOP AND RAPIDLY INTENSIFY THROUGH THE EARLY EVENING
HOURS AS THE ATMOSPHERE REMAINS VERY UNSTABLE. WITH STRONG DEEP
LAYER SHEAR PRESENT...SUPERCELL THUNDERSTORMS WILL CONTINUE WITH
THE THREAT FOR LONG LIVE LARGE TORNADOES AND VERY LARGE HAIL TO THE
SIZE OF BASEBALLS. THE SEVERE WEATHER THREAT IS EXPECTED TO END BY
LATE EVENING AS THE COLD FRONT SWEEPS ACROSS THE REMAINDER OF
EASTERN OKLAHOMA AND NORTHWEST ARKANSAS.
.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.
SUNDAY...HIGH WIND POTENTIAL.
MONDAY...HIGH WIND POTENTIAL.
TUESDAY...THUNDERSTORM POTENTIAL...HIGH WIND POTENTIAL.
WEDNESDAY...THUNDERSTORM POTENTIAL.
THURSDAY...THUNDERSTORM POTENTIAL.
FRIDAY...THUNDERSTORM POTENTIAL.
EXTENDED DISCUSSION...
STRONG AND GUSTY WINDS WILL DEVELOP IN THE AREA BEHIND THE CURRENT
STORM SYSTEM AS IT DEEPENS RAPIDLY ONCE IT MOVES EAST OF THE
REGION.
THERE WILL BE THUNDERSTORM POTENTIAL AGAIN IN THE AREA IN THE
MIDDLE OF NEXT WEEK AS THE NEXT WEATHER SYSTEM DEVELOPS IN THE
PLAINS.