Oklahoma Severe Weather Discussion - April 2011

[bandnerd]

I could see the edge of the clouds driving home. Made me miss the rumble of thunder. Wish the rain was closer.

[venture]

Slight risk has officially been put out for Saturday (as expected based on latest model runs).

FARTHER SOUTH ALONG THE DRYLINE...STRONG BOUNDARY LAYER HEATING
ACROSS THE SRN PLAINS SHOULD EASILY REMOVE CONVECTIVE INHIBITION
ACROSS WRN OK INTO NWRN TX. SCATTERED THUNDERSTORMS ARE EXPECTED TO
DEVELOP ACROSS THIS REGION AS TEMPERATURES SOAR INTO THE 90S WHERE
SFC DEW POINTS HOLD IN THE UPPER 50S/LOWER-MID 60S. SHEAR PROFILES
WILL SUPPORT SUPERCELLS AND LARGE HAIL...ALTHOUGH AN ISOLATED
TORNADO CAN NOT BE RULED OUT NEAR DUSK AS LOW LEVEL WINDS BACK AND
BEFORE CONVECTION DECOUPLES FROM BOUNDARY LAYER.

Slight risk is also in effect on Sunday for Eastern OK mainly from Tulsa to Ada and to the east.

...OZARKS/SRN PLAINS...
AN IMPRESSIVE UPPER-LEVEL TROUGH WILL MOVE INTO THE GREAT PLAINS
SUNDAY AS A WELL-DEVELOPED 90 TO 110 KT MID-LEVEL JET EJECTS NEWD
ACROSS THE SRN PLAINS AND OZARKS. THE JET WILL CREATE STRONG DEEP
LAYER SHEAR PROFILES ACROSS MUCH OF THE REGION AS A COLD FRONT
ADVANCES SEWD. THUNDERSTORM DEVELOPMENT SHOULD OCCUR LATE SUNDAY
AFTERNOON FROM NCNTRL MO SWWD ACROSS NW AR INTO ERN OK AND ECNTRL TX
ALONG AN AXIS OF MODERATE INSTABILITY. THE SHEAR ENVIRONMENT SHOULD
SUPPORT SUPERCELL DEVELOPMENT BUT THE FAVORED MODE COULD BE
LINEAR...FORCED BY CONVERGENCE ALONG THE COLD FRONT. STORMS THAT
REMAIN DISCRETE COULD BECOME SUPERCELLS WITH A THREAT FOR ISOLATED
LARGE HAIL. WIND DAMAGE MAY BE THE FAVORED THREAT WITH LINE-SEGMENTS
THAT PERSIST THROUGH THE EVENING WITH THE THREAT GREATEST FROM NW AR
NEWD INTO WCNTRL IL WHERE A 30 PERCENT PROBABILITY IS LOCATED. IF A
SQUALL-LINE DEVELOPS ON THE SERN SIDE OF THE MID-LEVEL JET THEN AN
ENHANCED WIND DAMAGE THREAT COULD EXIST ACROSS ERN AND SRN MO.

[venture]

Today looks pretty close to a carbon copy of yesterday, just relocating the storms a bit further west. Based on the HRRR model (which was pretty accurate yesterday except for firing storms about 50 miles too far south) initiation should take place again between 4 and 6PM in NW OK. Between 5 and 7 PM we are looking at additional developing in Western & SW OK between Clinton and Altus. Storms will move generally NE and will remain West and North of the metro area...at least according to this last run. Considering how close it was yesterday, we can probably expect something to pop later but the exact position won't be known until it does (I know, duh. LOL).

Fire Weather outlook for Sunday. At 7 AM most of the state will have RH (relative humidity) levels at 50% or higher simply because it is morning. By 10AM the dryline is forecast to really mix east fast to just west of I-35. By 1PM it will be west of I-35 running from near Tulsa to Ardmore. It will slowly keep pushing to the east making it almost through the state by stopping short of clearing SE OK. RH values behind the dryline will drop to 10-20% and winds will be 20-40mph with gusts 50 to 60. Winds should slack off some by evening, but will still remain high.

[venture]

Just in case you were wondering if it was unusually warm this morning (and yesterday)...

RECORD EVENT REPORT
NATIONAL WEATHER SERVICE NORMAN OK
1040 AM CDT SAT APR 9 2011

...NEW RECORD WARMEST LOW TEMPERATURE BROKEN AT OKLAHOMA CITY...

THE LOW TEMPERATURE THIS MORNING AT WILL ROGERS WORLD AIRPORT WAS 67
DEGREES... WHICH HAS BROKEN THE RECORD WARMEST LOW TEMPERATURE FOR
THIS DATE. THE PREVIOUS RECORD WAS 66 DEGREES... WHICH OCCURRED
BACK ON THIS DATE IN 1927. THE RECORD WILL OFFICIALLY BE SET AT
MIDNIGHT CST... AND TEMPERATURES ARE NOT EXPECTED TO FALL BELOW 67
DEGREES BY THAT TIME.

...NEW RECORD WARMEST HIGH TEMPERATURE SET AT OKLAHOMA CITY...

THE HIGH TEMPERATURE YESTERDAY AT WILL ROGERS WORLD AIRPORT WAS 89
DEGREES... WHICH HAS SET THE RECORD WARMEST HIGH TEMPERATURE FOR
APRIL 8. THE PREVIOUS RECORD WAS 88 DEGREES... WHICH OCCURRED ON
THAT DATE IN 1905

TEMPERATURE RECORDS FOR OKLAHOMA CITY DATE BACK TO 1890.

[BG918]

Today looks pretty close to a carbon copy of yesterday, just relocating the storms a bit further west. Based on the HRRR model (which was pretty accurate yesterday except for firing storms about 50 miles too far south) initiation should take place again between 4 and 6PM in NW OK. Between 5 and 7 PM we are looking at additional developing in Western & SW OK between Clinton and Altus. Storms will move generally NE and will remain West and North of the metro area...at least according to this last run. Considering how close it was yesterday, we can probably expect something to pop later but the exact position won't be known until it does (I know, duh. LOL).

Fire Weather outlook for Sunday. At 7 AM most of the state will have RH (relative humidity) levels at 50% or higher simply because it is morning. By 10AM the dryline is forecast to really mix east fast to just west of I-35. By 1PM it will be west of I-35 running from near Tulsa to Ardmore. It will slowly keep pushing to the east making it almost through the state by stopping short of clearing SE OK. RH values behind the dryline will drop to 10-20% and winds will be 20-40mph with gusts 50 to 60. Winds should slack off some by evening, but will still remain high.

The outlook for Sunday looks like storms will fire in eastern OK. Any chance that moves further west? It looks like it was now I'm not sure.

[venture]

Red Flag Warning for Tomorrow is now posted...

URGENT - FIRE WEATHER MESSAGE
NATIONAL WEATHER SERVICE NORMAN OK
318 PM CDT SAT APR 9 2011

OKZ006>008-011>013-017>020-023>030-038>041-044>046-050-TXZ086-089-
090-100430-
/O.UPG.KOUN.FW.A.0018.110410T1600Z-110411T0300Z/
/O.NEW.KOUN.FW.W.0016.110410T1500Z-110411T0300Z/
ALFALFA-GRANT-KAY-MAJOR-GARFIELD-NOBLE-BLAINE-KINGFISHER-LOGAN-
PAYNE-CADDO-CANADIAN-OKLAHOMA-LINCOLN-GRADY-MCCLAIN-CLEVELAND-
POTTAWATOMIE-COMANCHE-STEPHENS-GARVIN-MURRAY-COTTON-JEFFERSON-
CARTER-LOVE-WICHITA-ARCHER-CLAY-
318 PM CDT SAT APR 9 2011

...RED FLAG WARNING IN EFFECT FROM 10 AM TO 10 PM CDT SUNDAY FOR
MOST OF CENTRAL OKLAHOMA AND NORTH CENTRAL TEXAS.

THE NATIONAL WEATHER SERVICE IN NORMAN HAS UPGRADED THE FIRE
WEATHER WATCH TO A RED FLAG WARNING... EFFECTIVE FROM 10 AM TO 10
PM CDT SUNDAY.

* WINDS... SOUTHWEST 25 TO 35 MPH WITH HIGHER GUSTS.

* HUMIDITY...10 TO 20 PERCENT.

* TEMPERATURE...UPPER 70S TO MID 80S.

* IMPACTS...ANY FIRES THAT DEVELOP WILL LIKELY SPREAD RAPIDLY.
OUTDOOR BURNING IS NOT RECOMMENDED.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

FIRES MAY START EASILY AND SPREAD RAPIDLY. REPORT SMOKE OR FIRE
TO YOUR LOCAL FIRE DEPARTMENT.

[venture]

The outlook for Sunday looks like storms will fire in eastern OK. Any chance that moves further west? It looks like it was now I'm not sure.

It all depends on how fast the dryline mixes east. If it doesn't kick out fast enough, then storms could form closer to I-35.

Quick comment on today, short term rapid refresh model has pulled back most storm chances now and not nearly as definitive as earlier today. SPC has removed the slight risk but does retain at least low probabilities for tornadoes, hail, and damaging winds if a storm should fire.

[Thunder]

There some clouds trying to grow way out there.

[venture]

There some clouds trying to grow way out there.

There are some, but the CU field is definitely no where close to the quality we had yesterday.

[venture]

Been a couple hours since the last update. CU field continues to look rather pathetic, especially for being at peak heating. Water vapor out in that area and back towards TX doesn't give much hope, a ton of dry air is moving in right now. The best CU along the whole dry line is way up into NE where initiation of explosive development is now taking place. CU is falling apart over much of KS and the next decent area is in NW OK, but it is pretty sparse.

[venture]

It appears initial storm development is starting in NW OK. Indications on radar of a new cell developing 8 mi to the NE of Buffalo. It will be crossing into Kansas shortly however.

[venture]

Initial cell is struggling to really get established, it is already in KS though. Now watching additional CU development south through Roger Mills County.

[venture]

MESOSCALE DISCUSSION 0391
NWS STORM PREDICTION CENTER NORMAN OK
0728 PM CDT SAT APR 09 2011

AREAS AFFECTED...SWRN KS/NWRN OK

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 100028Z - 100200Z

DIURNALLY ENHANCED CONVERGENCE ALONG THE DRYLINE HAS AIDED RECENT
CONVECTION AND ISOLATED HIGH-BASED THUNDERSTORMS OVER SWRN KS. THIS
ACTIVITY HAS DEVELOPED WITHIN A VERY STEEP LAPSE RATE
ENVIRONMENT...BUT PWAT VALUES ARE NOT PARTICULARLY IMPRESSIVE WITH
ROUGHLY .75 INCHES NOTED ACROSS THIS REGION. WITH LLJ EXPECTED TO
INCREASE ACROSS THE SRN PLAINS THESE UPDRAFTS MAY LINGER FOR THE
NEXT FEW HOURS BUT OVERALL COVERAGE/INTENSITY DO NOT SUGGEST A WATCH
WILL BE NEEDED AT THIS TIME.

..DARROW.. 04/10/2011


ATTN...WFO...ICT...OUN...DDC...

[venture]

Bringing the chat room up, we have new development in SW Oklahoma now moving into Wash ita County.

[Dustin]

I've forgotten what rain smells like!!!

[Thunder]

Well, its morning and I wonder just how toasted Oklahoma will be today.

[venture]

Dryline is racing east this morning and fire danger will start climbing (rapidly) once it passes.

[Thunder]

Good morning, Humidity, sorry to see you go so quickly. Come back soon!

[venture]

Really lucked out on the winds not transporting to the surface today. New Tornado Watch out for the east though...



URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 124
NWS STORM PREDICTION CENTER NORMAN OK
730 PM CDT SUN APR 10 2011

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

WESTERN AND NORTHERN ARKANSAS
SOUTHWEST AND SOUTH CENTRAL MISSOURI
EASTERN AND SOUTHERN OKLAHOMA

EFFECTIVE THIS SUNDAY NIGHT AND MONDAY MORNING FROM 730 PM UNTIL
300 AM CDT.

SEVERAL TORNADOES
SCATTERED DAMAGING WINDS
ISOLATED WIND GUSTS TO 70 MPH POSSIBLE
SCATTERED LARGE HAIL TO 2.0 INCHES IN DIAMETER

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 75 STATUTE
MILES EAST AND WEST OF A LINE FROM 15 MILES NORTH OF VICHY
MISSOURI TO 40 MILES EAST SOUTHEAST OF ARDMORE OKLAHOMA. FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU4).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND 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.

OTHER WATCH INFORMATION...CONTINUE...WW 120...WW 121...WW
122...WW 123...

DISCUSSION...TSTMS EXPECTED TO FORM IN THE NEXT HOUR OR SO ALONG DRY
LINE FROM SW MO SSW INTO S CNTRL OK...AS UVV BEGINS TO INCREASE WITH
APPROACH OF W TX UPR IMPULSE. AMPLE SHEAR SHOULD PERSIST FOR
SUPERCELLS. SETUP APPEARS FAVORABLE FOR EVENTUAL EVOLUTION INTO
BROKEN LINE SEGMENTS/LEWPS WITH AN ATTENDANT THREAT FOR POSSIBLE
TORNADOES IN ADDITION TO SVR WIND/HAIL GIVEN 40+ KT 850-700 MB FLOW
BENEATH 70+ KT 500 MB WIND IN ENTRANCE REGION OF DEVELOPING UPR LVL
JET STREAK.

AVIATION...TORNADOES AND 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
550. MEAN STORM MOTION VECTOR 24045.

[Bostonfan]

How can they be so wrong about the winds? Glad we didn't get them, but come on. The forecast of 50-60 mph gusts was ridiculous!

[venture]

How can they be so wrong about the winds? Glad we didn't get them, but come on. The forecast of 50-60 mph gusts was ridiculous!

Its only wind right? How hard can they be to forecast, I know. Anywho...the strong winds did develop, but we didn't see any gusts in Oklahoma up to 60 mph. To make it as plain to understand as possible, winds just behind the dryline were very light at the surface but near 40 mph or more just above the surface. However you need to have proper mixing take place to transport those winds to the surface, that didn't happen here in Central OK as much as what was expected. Wind gusts here were mainly 30 to 40 mph, whereas NW OK was 40 to 51 mph. Had things turned over in the atmosphere as expected behind the passing dryline and pacific front, the winds would have been transported to the surface and the 50-60mph forecast verified. Fortunately that didn't occur and the high winds remained above the surface, but still there based on profiler reports and soundings.

[venture]

Continuing to see additional high based development behind the dryline and ahead of the incoming cold front (which is just NW of the Metro at this time). Activity is moving generally to the NE and there is now a chance for some storms to pass over the southern sections of the Metro area. Currently Purcell is having a storm move over that developed in the last 20 minutes. More rain and storms are just to the South and SE of Lawton. I would expect once the cold front passes, most of the precip will be pushed off with it...but hopefully at least some areas will get some rain.

[Thunder]

The weather will always be unpredictable. I'd say the best term that I can think of when forecasting is by "estimating" of what is to come. I can't think of another word right now. We're humans and computers are not as perfect as we think they are. A lot of factors within the weather are always constantly changing hour by hour.

[venture]

Significant severe weather possible in Eastern OK Thursday.



DAY 3 CONVECTIVE OUTLOOK CORR 1
NWS STORM PREDICTION CENTER NORMAN OK
0336 AM CDT TUE APR 12 2011

VALID 141200Z - 151200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN
PLAINS...CNTRL PLAINS...OZARKS AND MID-MO VALLEY...

CORRECTED TO CHANGE WEDNESDAY TO THURSDAY IN 1ST PARAGRAPH

...SRN AND CNTRL PLAINS/OZARKS AND MID-MO VALLEY...
AN IMPRESSIVE UPPER-LEVEL TROUGH WITH A NEGATIVE TILT IS FORECAST TO
MOVE INTO THE SRN HIGH PLAINS THURSDAY. A WELL-DEFINED 70 TO 90 KT
MID-LEVEL JET IS FORECAST TO MOVE THROUGH THE BASE OF THE TROUGH
WITH THE EXIT REGION SPREADING EWD ACROSS THE SRN PLAINS. THIS
FEATURE WILL CREATE STRONG DEEP LAYER SHEAR PROFILES CREATING A
FAVORABLE SHEAR ENVIRONMENT FOR SEVERE STORMS. AHEAD OF THE
SYSTEM...A STRENGTHENING LOW-LEVEL JET SHOULD TRANSPORT MOISTURE NWD
WITH THE MODELS DEVELOPING AN AXIS OF MODERATE INSTABILITY ACROSS
ERN OK AND ERN KS THURSDAY AFTERNOON. FORECAST SOUNDINGS DIMINISH A
STRONG CAPPING INVERSION AROUND 21Z WITH STORMS INITIATING JUST TO
THE EAST OF A DRYLINE ORIENTED NORTH TO SOUTH ALONG THE I-35
CORRIDOR. AS STORM COVERAGE INCREASES DURING THE LATE AFTERNOON AND
EARLY EVENING...THE ENVIRONMENT SHOULD SUPPORT SUPERCELL DEVELOPMENT
ESPECIALLY BENEATH THE EXIT REGION OF THE MID-LEVEL JET WHERE 0-6 KM
SHEAR VALUES ARE FORECAST TO BE IN THE 50 TO 60 KT RANGE.

FORECAST SOUNDINGS BY EARLY EVENING ACROSS ERN OK...WRN AR AND SERN
KS SHOW LOOPED HODOGRAPHS WITH 0-3 KM STORM RELATIVE HELICITIES IN
THE 400 TO 450 M2/S2 RANGE. THE LOW-LEVEL SHEAR SHOULD INCREASE BY
EARLY EVENING AS THE LOW-LEVEL JET STRENGTHENS...SUPPORTING A
TORNADO THREAT WITH THE MORE DOMINANT SUPERCELL STORMS. IN
ADDITION...MODERATE INSTABILITY...STEEP MID-LEVEL LAPSE RATES AND
500 MB TEMPS OF -14 TO -16 C SHOULD BE FAVORABLE FOR LARGE HAIL. A
THREAT FOR VERY LARGE HAIL...>= 2 INCHES IN DIAMETER...WILL ALSO BE
POSSIBLE WITH THE BETTER ORGANIZED SUPERCELLS. THE SEVERE THREAT
SHOULD EXTEND AS FAR NORTH AS KANSAS CITY WHERE THE NAM SHOWS A 995
MB SFC LOW JUST TO THE EAST OF THE UPPER-LEVEL LOW. BACKED SELY
WINDS AHEAD OF THE SFC LOW AND STRONG LOW-LEVEL SHEAR SHOULD ALSO BE
SUFFICIENT FOR A TORNADO THREAT IN NE KS AND WRN MO WHERE COLD TEMPS
ALOFT WILL ALSO MAKE LARGE HAIL POSSIBLE AS WELL.

ON THE SRN EDGE OF THE SLIGHT RISK AREA ABOUT 100 STATUTE MILES
SOUTH OF THE RED RIVER...FORECAST SOUNDINGS MAINTAIN A STRONG
CAPPING INVERSION THROUGH THE AFTERNOON AND EVENING. THIS SUGGESTS
THE THREAT FOR SEVERE STORMS SHOULD DROP OFF QUICKLY FROM NORTH TO
SOUTH ACROSS THE ARKLATEX. THE SEVERE THREAT IN THE OZARKS IS
EXPECTED TO WEAKEN DURING THE LATE EVENING BUT A MARGINAL SEVERE
THREAT COULD CONTINUE INTO THE OVERNIGHT PERIOD AS AN MCS OR
CONVECTIVE CLUSTER MOVES EWD INTO THE LOWER TO MID-MS VALLEY.

..BROYLES.. 04/12/2011

[Thunder]

David, has the OKC Zoo ever been ravaged by a tornado in the past?