There was a slight risk of storms from the Gulf Coast of Texas/Lousiana to Southern Minnesota. I didnt have a definative target area but i was sure we would end up in south central or central oklahoma.   We left at 10:30am from Ft. Smith, AR heading West on I-40. Skies were partly cloudy when we left but soon the clouds began to increase as we continued further into Oklahoma.   By the time we got to Henryetta, OK it actually started to drizzle.   This worried us a little but looking at the visible satellite imagery we could see that there was clearing behing the clouds and ahead of the dryline so i figured there was still an oppurtunity for storms to get going. 

The clouds did push us to head a bit further west.   We exited off of I-40 on Hwy 99 heading south into Seminole, OK.  From there we headed west on hwy 9 through Tecumseh and over to Norman.  In norman the low clouds and drizzle started to clear.  From Norman we did decide to head further southwest to Chickasha.  We got to Chickasha around 2pm and with the great road options in all directions we decided to sit tight there.

When we first got into Chickasha the cumulus wasnt all that impressive but slowly over the next hour and a half the clouds began to be somewhat better organized although we could tell that storm initiation was not imminent.   By about 330pm we had to move a little bit further east to stay ahead of dryline.  We headed southeast on HWY 19 but stopped just outside of Chickasha.   At 351pm a mesoscale discussion was issued for our area and by this time we definately were happy with what the spc was thinking. 

MESOSCALE DISCUSSION 0542
NWS STORM PREDICTION CENTER NORMAN OK
0351 PM CDT SUN APR 10 2005

AREAS AFFECTED...AREA NEAR I-35 ACROSS OK
CONCERNING...SEVERE THUNDERSTORM POTENTIAL
VALID 102051Z - 102145Z

SEVERE TSTM POTENTIAL -- SLOWER TO DEVELOP IN THIS AREA BECAUSE OF LINGERING/STABILIZING EFFECTS OF EARLIER STRATIFORM CLOUD DECK -- APPEARS TO BE INCREASING ENOUGH THAT WW MAY BE NEEDED SOON. DAMAGING GUSTS AND HAIL WILL BE MAIN CONSIDERATIONS BECAUSE OF STRONGLY LINEAR FORCING...THOUGH BRIEF/ISOLATED TORNADO CANNOT BE RULED OUT VERY EARLY IN STORM EVOLUTIONS BEFORE CELLS BEGIN TO BLEND TOGETHER.

2040Z SFC MESOANALYSIS SHOWS DRYLINE FROM WOODS COUNTY SSEWD TO WRN CANADIAN COUNTY THEN GENERALLY SWD ACROSS WRN COTTON COUNTY. DRYLINE APPEARS TO BE DECELERATING AS ISALLOBARIC FORCING -- ASSOCIATED WITH PROGRESSIVE MID/UPPER LEVEL LOW OVER SERN CO -- BACKS FLOW SOMEWHAT W OF DRYLINE. DESPITE THAT BACKING...EXPECT CONVERGENCE TO REMAIN STRONG ENOUGH...IN COMBINATION WITH HEATING...TO INITIATE TSTMS ALONG DRYLINE NEXT 1-2 HOURS. VIS IMAGERY INDICATES 30-40 NM WIDE GAP OF CLEARING W OF LINE FROM WRN MARSHALL COUNTY OK NNWWD ACROSS OKC METRO AREA...AND TCU ALONG DRYLINE. INSOLATION AND LOW 60S F SFC DEW POINTS WILL CONTRIBUTE TO MLCAPES INCREASING TO 500-1000 J/KG RANGE IN VERY NARROW CORRIDOR. INITIAL STORM DEVELOPMENT MAY BE AS DISCRETE CELLS AND/OR SHORT LINE SEGMENTS. HOWEVER...VWP/PROFILER TRENDS AND SHORT-TERM MODELS INDICATE TENDENCY WILL CONTINUE TOWARD INCREASINGLY MERIDIONAL DEEP-LAYER FLOW COMPONENT...ORIENTED NEARLY PARALLEL TO DRYLINE THAT IS PRIMARY FORCING BOUNDARY. THIS SHOULD COMPEL MORE PURELY LINEAR MODE WITHIN 1-2 HOURS AFTER DEEP INITIATION.

..EDWARDS.. 04/10/2005

  We continued to slowly head southeast over the next hour to stay ahead of the dryline.   It seemed like every new cumulus that went up seemed better than the one before but still nothing impressive.   Finally, a little before 5pm we started to notice a shower off to our south.   We were still on HWY 19 near Bradley and although we couldnt see the top of the storm because of another cloud between us we could see the rain curtain building.   Although we were happy that finally a shower was developing it really wasnt impressive at all.   I had been in touch with the weekend meteorologists at home and he let us know that while it didnt look that impressive it was continuing to strengthen each scan.   We headed further southeast to Lindsey with the storm to our south in southeastern Grady County.   We took 59B north from Lindsey to stay in front of the storm which was moving more North-Northeast.  

Just a few minutes later the SPC issued a severe thunderstorm watch for our area.

  URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 145
NWS STORM PREDICTION CENTER NORMAN OK
525 PM CDT SUN APR 10 2005

THE NWS STORM PREDICTION CENTER HAS ISSUED A SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

CENTRAL AND EASTERN OKLAHOMA

EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 525 PM UNTIL 1100 PM CDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 70 STATUTE MILES EAST AND WEST OF A LINE FROM 10 MILES WEST OF DURANT OKLAHOMA TO 55 MILES NORTH NORTHEAST OF OKLAHOMA CITY OKLAHOMA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU5).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION...CONTINUE...WW 141...WW 142...WW 143...WW 144....

DISCUSSION...DRY LINE FROM NWRN OK SSEWD TO S CENTRAL OK MOVING VERY SLOW EWD. WITH AIRMASS NOW E OF DRYLINE MDTLY UNSTABLE AND WEAKLY CAPPED...THE ONGOING MID LEVEL COOLING AND LARGE SCALE VERTICAL MOTION WITH APPROACHING UPPER TROUGH SHOULD INITIATE THUNDERSTORMS ALONG/E OF DRY LINE DURING EVENING. SHEAR PROFILES SUFFICIENT FOR ROTATING STORMS...WITH PRIMARY THREAT LARGE HAIL/DAMAGING WINDS..

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM MOTION VECTOR 23030.

As we made our way up 59b to the intersection with Hwy 39 the storm finally developed a very heavy rain core.  We were also finally seeing some lightning but still the storm wasnt very impressive.  With no other activity except into north texas and kansas we didnt have much choice but to continue on this storm.  We took Hwy 39 east to 24 North.  When 24 intersected into 77 the storm started to look a little better organized.  We were finally able to see a somewhat organized updraft but as had been the case already before the storm again became disorganized.   After 6pm we made it onto I-35 and headed north into Norman and exited off onto Hwy 9 east.  I was looking for a quick bite to eat.   But before we could do that the NWS in Norman issued a severe thunderstorm warning for eastern Grady county and McClain county.

WUUS54 KOUN 102328
SVROUN
OKC051-087-110015-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE NORMAN OK
628 PM CDT SUN APR 10 2005

THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
FAR EASTERN GRADY COUNTY IN CENTRAL OKLAHOMA
MCCLAIN COUNTY IN CENTRAL OKLAHOMA

* UNTIL 715 PM CDT

* AT 628 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
A SEVERE THUNDERSTORM 7 MILES SOUTH-SOUTHWEST OF
BLANCHARD...MOVING NORTH AT 15 MPH.

* LOCATIONS IN THE WARNING INCLUDE BLANCHARD...COLE AND NEWCASTLE

HAIL UP TO THE SIZE OF QUARTERS IS LIKELY.

SEVERE THUNDERSTORMS CAN PRODUCE TORNADOES WITH NO ADVANCE WARNING.
MOVE IMMEDIATELY TO A STORM SHELTER... BASEMENT OR STURDY BUILDING IF
A TORNADO IS SIGHTED.

The storm still didnt look impressive but we headed back west on Hwy 9 across I-35 and soon we saw that the storm had intensified and that there was a large area of heavy rain.  We made it a few miles east of Norman on Hwy 9 before we started to get some very heavy rain and then it started hailing.   The biggest was about quarter size but it didnt last long.  


Video can be found under video section of website
After the hail and heavy rain ended we could see to our south a bit of a lowering.   We headed back East to Jct I-35 and 9 west.   I wanted to head further east but since we had a good viewing location we decided to stay at the Jct.   Soon we were joined by other chasers and tv stations.   The lowering moved closer and we were finally able to see some rotation.   It was very weak and just like the storm itself all afternoon the wall cloud and rotation went through several cycles of organization.   At 7:29 PM the rotation intensified dramatically.   You could see clouds below the wall cloud extending more than halfway to the ground rotating quickly.   Although there definately was the possiblity that it could put down a tornado the circulation was probably a little too broad still even with the strong rotation.  

Norman, OK Storm Rotation Video

Soon the intense rotation slowed but rotation did persist for several minutes until about 7:40 PM when that whole circulation weakened away.   I had been watching the last of the previous circulation when my partner told me to look the other way.   The storm had already redevloped new circulation on the other side of us to our northeast...we took off heading east on Hwy 9.

At 7:52 PM we made it through Norman and just east a couple miles when we had a nice viewing location.


Video can be found under video section of website
There wasnt as much rotation as before but it did seem to be continuing to reogranize.   While we didnt see much increase in rotation the updraft itself did seem to strengthen.   At 8:00 PM we were realizing we needing to get in better postion so we headed further east on Hwy 9 looking for a north/south road to take north back near the storm.

We were looking for the road that on our map (one of the laminated flip maps) went from Hwy 9 north to I-40 just on the otherside of Lake Thunderbird.   We missed that road but got on another road heading north at Pink.   Unfortunately the flip map was WRONGGG and we ended on a dead end a half mile north of the interstate somewhere south of I-40 and north of hwy 9. and of course there was no on ramp to the Interstate!   And then to top it all off NWS in Norman finally issued a Tornado Warning.

WFUS54 KOUN 110130
TOROUN
OKC109-110200-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE NORMAN OK
830 PM CDT SUN APR 10 2005

THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A

* TORNADO WARNING FOR...
SOUTHEAST OKLAHOMA COUNTY IN CENTRAL OKLAHOMA

* UNTIL 900 PM CDT

* AT 830 PM CDT...A TORNADO WAS DETECTED BY DOPPLER RADAR 8 MILES
SOUTHWEST OF HARRAH...MOVING NORTHEAST AT 20 MPH.
* LOCATIONS IN THE WARNING INCLUDE HARRAH

TORNADOES ARE ESPECIALLY DANGEROUS AT NIGHT BECAUSE THEY ARE HARD TO
SEE. TAKE COVER NOW. IF A BASEMENT IS NOT AVAILABLE...MOVE TO AN
INTERIOR ROOM OR HALLWAY ON THE LOWEST FLOOR. LEAVE MOBILE HOMES AND
VEHICLES FOR REINFORCED SHELTER. STAY AWAY FROM WINDOWS.

Luckily we were able to stop a vehicle and ask for directions to the interstate and fortunately we were only a mile away from the a onramp at Jct 177/I-40.   We made it onto Hwy 177 heading north and soon we were back in on the storm.   We soon were hearing reports of a possible tornado near Harrah with damage already being reported.   At 9:00pm we made it to Jacktown, which is about 10 miles east of Harrah.   We firgued the circulation would pass just to our north but unfortunately there wasnt a tremendous ammount of lightning so that made spotting the possible tornado pretty dificult.   The only real way we would be able to tell would be from power flashes and we didnt see anything that was for sure a power flash.   About 10 minutes later we decided to head further north as the storm seemed to be moving more northeast.   We had several tense moments going from Jacktown north toward Hwy 66/I-44 as there was possibility a tornado could develop suddenly very near our location or maybe even right on us.   We made it through unscathed and at 9:25pm made it to jct 66 and we headed east toward Chandler.

Moments later our Weather Radio alerted us to the latest tornado warning.

WFUS54 KOUN 110227
TOROUN

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE NORMAN OK
926 PM CDT SUN APR 10 2005

THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A

* TORNADO WARNING FOR...
LINCOLN COUNTY IN CENTRAL OKLAHOMA

* UNTIL 1000 PM CDT

* AT 926 PM CDT...A TORNADO CONTINUED TO BE DETECTED BY DOPPLER
RADAR 3 MILES SOUTHWEST OF WARWICK...MOVING NORTHEAST AT 25 MPH.
NUMEROUS REPORTS OF POWER FLASHES HAVE BEEN REPORTED...WHICH CAN
INDICATE THE PRESENCE OF A TORNADO. IF YOU ARE IN THE PATH OF THIS
STORM...TAKE IMMEDIATE TORNADO PRECAUTIONS.

* LOCATIONS IN THE WARNING INCLUDE WARWICK

TAKE COVER NOW. IF A BASEMENT IS NOT AVAILABLE...MOVE TO AN INTERIOR
ROOM OR HALLWAY ON THE LOWEST FLOOR. LEAVE MOBILE HOMES AND VEHICLES
FOR REINFORCED SHELTER. STAY AWAY FROM WINDOWS.

I looked on our map and while i knew we were probably pretty close i was a little nervous to see that Warwick was about a mile up the road so that put the tornado somewhere very near us probably just to our southeast.   We never had any great viewing locations so we did not see anything indicative of a tornado.   We continued east into Chandler and then to Stroud.   At Stroud we decided to take off toward home which was a few hours away from being nailed by some storms as well.   I guess the best thing about this chase was the few moments of near tornadic intensity rotation near Norman.   And while chasing at night certainly provided for some andrenalicious (word? :) moments i am slowly learning that night chasing isnt much fun, isnt very productive in terms of pictures and video, and is to dangerous! &nsbp but will i do it again? you betcha i probably will!