Hail size is back up on the storm east of Watonga. Radar estimate 2.09" where the triangle marker is.

http://www.weatherspotlight.com/screencap/ktlx_20130422-1.png

Local Extension for the Watch...

WATCH COUNTY NOTIFICATION FOR WATCH 136
NATIONAL WEATHER SERVICE NORMAN OK
1037 PM CDT MON APR 22 2013


OKC015-017-081-109-230600-
/O.EXB.KOUN.SV.A.0136.000000T0000Z-130423T0600Z/


THE NATIONAL WEATHER SERVICE HAS EXTENDED SEVERE THUNDERSTORM
WATCH 136 TO INCLUDE THE FOLLOWING AREAS UNTIL 1 AM CDT TUESDAY


IN OKLAHOMA THIS WATCH INCLUDES 4 COUNTIES


IN CENTRAL OKLAHOMA


CANADIAN LINCOLN OKLAHOMA


IN SOUTHWEST OKLAHOMA


CADDO


THIS INCLUDES THE CITIES OF...ANADARKO...CHANDLER...EL RENO...
MUSTANG...OKLAHOMA CITY AND YUKON.

Storms are moving into an area of higher CIN so they may start to weaken quite a bit, but the northern one is just plugging along. We'll see how this goes. If it keeps up and maintains its path, Oklahoma County and then along the Canadian River will need to watch out.

For those who are just waking up to their weather radios. :)

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE NORMAN OK
1046 PM CDT MON APR 22 2013


THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A


* SEVERE THUNDERSTORM WARNING FOR...
NORTHEASTERN CANADIAN COUNTY IN CENTRAL OKLAHOMA...
SOUTHWESTERN KINGFISHER COUNTY IN CENTRAL OKLAHOMA...
NORTHWESTERN OKLAHOMA COUNTY IN CENTRAL OKLAHOMA...


* UNTIL 1130 PM CDT


* AT 1041 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED
A SEVERE THUNDERSTORM LOCATED 9 MILES WEST OF OKARCHE...MOVING
SOUTHEAST AT 35 MPH.

HAZARDS IN THE WARNING INCLUDE...
DESTRUCTIVE WINDS IN EXCESS OF 70 MPH...
LARGE HAIL UP TO PING PONG BALL SIZE...

* LOCATIONS IMPACTED INCLUDE...
NORTHWESTERN OKLAHOMA CITY...EL RENO...CONCHO...PIEDMONT...
UNION CITY... OKARCHE... CALUMET AND RICHLAND.

Incoming hail cores...

http://www.weatherspotlight.com/screencap/ktlx_20130422-2.png

Southern Cell extended...looks like it is trying to recycle some, but still weaker than before.

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE NORMAN OK
1054 PM CDT MON APR 22 2013


THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A


* SEVERE THUNDERSTORM WARNING FOR...
NORTHEASTERN CADDO COUNTY IN SOUTHWEST OKLAHOMA...
SOUTHWESTERN CANADIAN COUNTY IN CENTRAL OKLAHOMA...
NORTHWESTERN GRADY COUNTY IN CENTRAL OKLAHOMA...


* UNTIL 1130 PM CDT


* AT 1051 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED
A SEVERE THUNDERSTORM LOCATED 4 MILES EAST OF LOOKEBA...MOVING
SOUTHEAST AT 40 MPH.

HAZARDS IN THE WARNING INCLUDE...
QUARTER SIZE HAIL...
DAMAGING WINDS IN EXCESS OF 60 MPH...

* LOCATIONS IMPACTED INCLUDE...
MINCO...UNION CITY...BINGER AND COGAR.

Southern storm is dead now...main storm is struggling with the less than favorable environment over Central OK.

Incoming hail core...

http://www.weatherspotlight.com/screencap/ktlx_20130422-3.png

New warning for Oklahoma and Canadian...

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE NORMAN OK
1127 PM CDT MON APR 22 2013


THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A


* SEVERE THUNDERSTORM WARNING FOR...
EASTERN CANADIAN COUNTY IN CENTRAL OKLAHOMA...
SOUTHWESTERN OKLAHOMA COUNTY IN CENTRAL OKLAHOMA...


* UNTIL 1200 AM CDT


* AT 1123 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED
A SEVERE THUNDERSTORM LOCATED 4 MILES NORTHWEST OF YUKON...MOVING
SOUTHEAST AT 35 MPH.

HAZARDS IN THE WARNING INCLUDE...
QUARTER SIZE HAIL...
DAMAGING WINDS IN EXCESS OF 60 MPH...

* LOCATIONS IMPACTED INCLUDE...
OKLAHOMA CITY...DEL CITY...YUKON...BETHANY...MUSTANG...THE
VILLAGE...WARR ACRES...NICHOLS HILLS...SPENCER...PIEDMONT...FOREST
PARK...VALLEY BROOK...LAKE ALUMA AND RICHLAND.

http://www.weatherspotlight.com/screencap/ktlx_20130422-4.png

Hail size increasing on the latest set of data...now up to 2.02"

http://www.weatherspotlight.com/screencap/ktlx_20130422-5.png

Watch Update...

WATCH COUNTY NOTIFICATION FOR WATCH 136
NATIONAL WEATHER SERVICE NORMAN OK
1135 PM CDT MON APR 22 2013


OKC027-125-230600-
/O.EXA.KOUN.SV.A.0136.000000T0000Z-130423T0600Z/


THE NATIONAL WEATHER SERVICE HAS EXTENDED SEVERE THUNDERSTORM
WATCH 136 TO INCLUDE THE FOLLOWING AREAS UNTIL 1 AM CDT TUESDAY


IN OKLAHOMA THIS WATCH INCLUDES 2 COUNTIES


IN CENTRAL OKLAHOMA


CLEVELAND POTTAWATOMIE


THIS INCLUDES THE CITIES OF...MOORE...NORMAN AND SHAWNEE.

Any hail cores between May and MacArthur on 122nd?

Warning for Northern half of Cleveland.

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE NORMAN OK
1139 PM CDT MON APR 22 2013


THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A


* SEVERE THUNDERSTORM WARNING FOR...
NORTHWESTERN CLEVELAND COUNTY IN CENTRAL OKLAHOMA...


* UNTIL 1230 AM CDT


* AT 1137 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED
A SEVERE THUNDERSTORM LOCATED NEAR YUKON...MOVING SOUTHEAST AT 35
MPH.

HAZARDS IN THE WARNING INCLUDE...
LARGE DAMAGING HAIL UP TO GOLF BALL SIZE...
DAMAGING WINDS IN EXCESS OF 60 MPH...

* LOCATIONS IMPACTED INCLUDE...
NORMAN...MOORE...STELLA AND STANLEY DRAPER LAKE.

http://www.weatherspotlight.com/screencap/ktlx_20130422-6.png

Any hail cores between May and MacArthur on 122nd?

All south of you.

I like it! Thanks!

Estimated max hail at the diamond marker is 2.17".

Hmm so is it getting stronger?

I am getting slammed at NW 22nd and Villa. Holy hail.

3rd roof in 3 years? Sounds like a possibility.

Sounded very loud here (near NW 23rd & Portland), but none of the hail was very big. Looking out my front window, I'd say dime size at best.

Small hail with heavy rain near 63rd and Meridian.

Lots of small hail at NW 16th and Gatewood

New warning for OK county...

THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A


* SEVERE THUNDERSTORM WARNING FOR...
SOUTHERN OKLAHOMA COUNTY IN CENTRAL OKLAHOMA...


* UNTIL 1230 AM CDT


* AT 1151 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED
A SEVERE THUNDERSTORM LOCATED NEAR OKLAHOMA CITY...MOVING
SOUTHEAST AT 40 MPH.

HAZARDS IN THE WARNING INCLUDE...
LARGE HAIL UP TO PING PONG BALL SIZE...
DAMAGING WINDS IN EXCESS OF 60 MPH...

* LOCATIONS IMPACTED INCLUDE...
OKLAHOMA CITY...MIDWEST CITY...DEL CITY...BETHANY...THE VILLAGE...
WARR ACRES...CHOCTAW...HARRAH...NICHOLS HILLS...SPENCER...NICOMA
PARK...TINKER AIR FORCE BASE...FOREST PARK...VALLEY BROOK AND LAKE
ALUMA.

If anyone is getting hail that is over 1" in diameter, please submit a storm report so they have a record of it:

Submit a Storm Report (http://www.srh.noaa.gov/StormReport/SubmitReport.php?site=oun)

Do you see anything coming out of the storm over by Concho? Looks like its moving more straight east.

http://www.weatherspotlight.com/screencap/ktlx_20130422-7.png

Do you see anything coming out of the storm over by Concho? Looks like its moving more straight east.

Maybe some pea sized hail, nothing major.

Nw 10th and Meridian got slammed pretty good.

Im at a family members house and have my car in her garage but if I go home...its all open to elements parking.

Hail core is coming way down, but its almost moving closer to the radar which can cause issues.

Near the OUHSC campus, hail was about pea sized.

http://www.spc.noaa.gov/products/md/mcd0552.gif

MESOSCALE DISCUSSION 0552
NWS STORM PREDICTION CENTER NORMAN OK
1115 PM CDT MON APR 22 2013

AREAS AFFECTED...CENTRAL OKLAHOMA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 230415Z - 230515Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...SVR THUNDERSTORMS ARE ONGOING IN CENTRAL OKLAHOMA...AND
WILL APPROACH THE OKLAHOMA CITY AREA FROM THE NW. THE SEVERE
THUNDERSTORM WATCH 136 WAS EXTENDED IN TIME/SPACE...BUT ADDITIONAL
WW ISSUANCE WILL BE UNLIKELY.

DISCUSSION...ONGOING SUPERCELL STRUCTURE IS MOVING SEWD AT 30-35 KT
IN CANADIAN COUNTY. KTLX DATA INDICATE STRONG LOW-LEVEL OUTFLOW
WINDS ASSOCIATED WITH AN ATTENDANT REAR-INFLOW JET AT THE 0.5-DEGREE
TILT. QUARTER TO HALF-DOLLAR SIZE HAIL AND DAMAGING WIND GUSTS WILL
LIKELY ACCOMPANY THIS STORM DURING THE NEXT HOUR OR SO AS IT TRACKS
ACROSS PARTS OF CENTRAL OKLAHOMA...MAINTAINED BY MASS CONVERGENCE
ACCOMPANYING A 45 KT SLY NOCTURNAL BOUNDARY-LAYER WIND MAX AROUND 1
KM AGL PER KTLX VWP DATA. CURRENT EXTRAPOLATION TAKES THIS STORM
INTO THE OKC AREA IN THE 0445-0530Z TIME FRAME. THIS STORM MAY
INTERACT/MERGE WITH THE A RELATIVELY LESS INTENSE STORM OVER NRN
CADDO/SWRN CANADIAN COUNTIES...THOUGH THE LATTER ENTITY SHOULD
CONTINUE WEAKENING. ALL OF THIS ACTIVITY WILL CONTINUE TRACKING
ESEWD/SEWD...AND THE SEVERE THUNDERSTORM WATCH WAS LOCALLY EXTENDED
IN TIME/SPACE IN COORDINATION WITH THE NORMAN WFO. AFTER
06Z...STORMS WILL LIKELY HAVE WEAKENED BELOW SEVERE LIMITS OWING TO
LIMITED LOW-LEVEL MOISTURE...AND SUBSTANTIAL NOCTURNAL CINH...THOUGH
A FEW STRONG STORMS MAY DEVELOP/PERSIST INTO THE OVERNIGHT HOURS.

..COHEN/DIAL.. 04/23/2013

Things appear to be settling down mostly now. A couple storms will keep going for probably the next hour or so, but I think we are done with the very large hail threat.

https://sphotos-b.xx.fbcdn.net/hphotos-ash3/488136_440029662753575_1256119495_n.jpg
Photo from KFOR facebook posted a few minutes ago, taken near fairgrounds.

Got dime-sized hail last night in N OKC. No big deal.

The OKC metro picked up anywhere from .4" to over .6" of rain last night.

http://www.srh.noaa.gov/images/fxc/oun/graphicast/image7.jpg (http://www.srh.noaa.gov/graphicast.php?site=oun&gc=7)

If we are lucky maybe we can keep our cloud cover and keep our lows from dropping below freezing?

So does this look like the end of winter finally? Will it be okay to start planting after this cold snap or do the long-range models show more freezing temperatures coming?

This is just about like living in western Kansas all over again in a normal year. No wonder I didn’t like living there.

I planted 5 tomatoes and 5 bell peppers on the 13th…. they have grown some but for the second time this spring I have them covered with 5 gallon buckets with a brick on top.

So does this look like the end of winter finally? Will it be okay to start planting after this cold snap or do the long-range models show more freezing temperatures coming?

Eh...hard to say. Still looks like a couple possibilities for lows to drop into 30s overnight through the first week of May.

Personally I'm not really minding this. Kill as many bugs as we can. LOL


This is just about like living in western Kansas all over again in a normal year. No wonder I didn’t like living there.

I planted 5 tomatoes and 5 bell peppers on the 13th…. they have grown some but for the second time this spring have them covered with 5 gallon buckets with a brick on top.

Mover farther south. :-P

Eh...hard to say. Still looks like a couple possibilities for lows to drop into 30s overnight through the first week of May.

Personally I'm not really minding this. Kill as many bugs as we can. LOL



Mover farther south. :-P

This year is exceedingly rare. Usually in April and May, cold fronts out of the rockies are more common than the arctic blasts we are seeing this year. I wonder if we will break the all-time record for latest freeze which is May 3rd?

With temperatures heading into the 80s this weekend, what type of severe threat are we looking at when the next arctic front comes south? Was this last round tamed by cooler temperatures prior to the front?

It seems that the stronger cold fronts tend to keep the severe threat down a bit. The cold air is heavier and moves in faster so it undercuts a lot of the quality conditions we normally would have. However, this moisture has been what we needed and I'll take that if it means keep the stinking hot summer at bay.

I'll definitely take this over the last couple of scorchers we've had.

I picked a hell of a year to try my hand at gardening, though. :\

I'll definitely take this over the last couple of scorchers we've had.

I picked a hell of a year to try my hand at gardening, though. :\

Exactly... I'm still holding off planting my maters for another week.

Exactly... I'm still holding off planting my maters for another week. I going to try and get them in the ground this weekend then cross my fingers.

Looks like a chance at showers and a few thunderstorms Friday night into Saturday.

Better chances showing up next week for more moisture - looks like chances almost every day.

I've had all of my stuff planted and my tropical plants moved outside since mid(ish) March and they've been okay. A few have been burned but nothing serious

Frost advisory in effect from 2 am to 8 am cdt thursday...

The national weather service in norman has issued a frost
advisory...which is in effect from 2 am to 8 am cdt thursday.

* temperature: 33 to 37 degrees

* impacts: The clear skies...light winds and cool temperatures
will create areas of frost... Especially in low-lying areas.

Winter isn't over yet.

Another round of arctic air for late next week bringing more freezing temperatures and highs in the 30s and 40s. We are looking at starting May with temperatures that are near our averages for January.

The all time record low for May is 32* If this plays out right we could be in the upper 20s with this next system. I am beginning to wonder if true spring is going to come this year.

CH 5 David Lane feels that much of May will be colder than normal.
That probably means above average precipitation which we still need.

Damon Lane said this cold weather pattern with arctic blasts looks to continue through most of the month of May.

Theoretically, how late are freezing temperatures are possible? I am pretty sure we will set a new record this year. In 2001 we saw lower 40s the third week of May so it's not that unthinkable to prepare for lower 30s/upper 20s even that late this year. In 1947 we saw 39*F on May 29th. Maybe we will break that this year.

CH 5 David Lane feels that much of May will be colder than normal.
That probably means above average precipitation which we still need.

And fronts from the north rather than the west hopefully mean less chances for really severe tornado outbreaks.

Slight Risk today has been expanded from the Day 2. It now covers all over Oklahoma south of I-40, and NW Oklahoma mainly along and south of Highway 3. Main hazard today is hail and it could be over 2" in areas west of I-35 in the risk area.

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1232 AM CDT FRI APR 26 2013

VALID 261200Z - 271200Z

...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS WRN TX/OK BORDER
REGION TO EXTREME WRN AR AND EXTREME NRN TX...

...SYNOPSIS...
SPLIT-FLOW PATTERN FCST ACROSS CONUS...WITH NRN STREAM JET CORE
REMAINING OVER OR EVEN N OF CANADIAN BORDER...EXCEPT OVER PAC NW.
MEANWHILE...PRIMARY PERTURBATION FOR CONVECTIVE POTENTIAL IS APCHG
CENTRAL/SRN ROCKIES ATTM. THIS FEATURE WILL MAINTAIN DECIDEDLY
POSITIVE TILT AS IT MOVES TO NERN/CENTRAL KS...SRN TX PANHANDLE AND
SERN NM BY 27/00Z. ASSOCIATED HEIGHT GRADIENTS...250-500 MB FLOW
MAXIMA AND 500-MB VORTICITY FIELD EACH WILL CONTINUE TO WEAKEN IN
SYSTEM-RELATIVE SENSE THROUGHOUT REMAINDER PERIOD. DESPITE
THAT...HEIGHT RISES AND FLATTENING OF PATTERN TO ITS N COULD RESULT
IN THIS PERTURBATION DEVELOPING WEAK/NEARLY CLOSED 500-MB LOW BY
DEFAULT OVER NRN MO/SRN IA BY 24/12Z...WITH TROUGH TRAILING SWWD
ACROSS OK AND NW TX.

AT SFC...RESIDUAL/QUASISTATIONARY FRONTAL ZONE WAS ANALYZED AT 04Z
FROM OFFSHORE CAROLINAS SWWD ACROSS SRN GA TO NERN/N-CENTRAL
GULF...BECOMING WARM FRONT OVER NWRN GULF OFFSHORE TX.
WRN/WARM-FRONTAL SEGMENT WILL PROGRESS INLAND DURING DAY...BECOMING
MORE ILL-DEFINED WITH WWD EXTENT AMIDST STG LOW-LEVEL WAA AND
DIABATICALLY DRIVEN VERTICAL MIXING ON BOTH SIDES OF BOUNDARY. WARM
FRONT SHOULD REACH SERN OK AND SRN AR BY
27/00Z...DECLERATING/STALLING AS IT ENCOUNTERS SWATH OF PERSISTENT
CLOUD COVER/PRECIP-ALTERED BOUNDARY LAYER OVER ERN OK. INCREASING
BOUNDARY-LAYER MOISTURE TO ITS S WILL RESULT IN PROGRESSIVELY
BETTER-DEFINED DRYLINE THROUGHOUT DAY...EXTENDING AT 27/00Z ROUGHLY
FROM CDS AREA SWD TO SSWWD ACROSS EDWARDS PLATEAU INTO COAHUILA.
FRONT/DRYLINE INTERSECTION...IF ANY...SHOULD BE POORLY DEFINED NEAR
SFC LOW LOCATED AROUND CDS/LTS AREA...WITH INVERTED TROUGH EXTENDING
NNEWD OVER WRN OK. LOW SHOULD MOVE/REDEVELOP NEWD THROUGH REMAINDER
PERIOD...REACHING ERN OK/WRN AR BY 27/12Z WITH COLD FRONT SWWD
ACROSS N-CENTRAL/W-CENTRAL TX.

...SRN PLAINS TO ARKLATEX/OZARKS...
ISOLATED TO WIDELY SCATTERED TSTMS ARE POSSIBLE LATE AFTN INVOF
DRYLINE...WARM FRONT AND SFC TROUGH. COVERAGE INITIALLY WILL BE
LIMITED BY CAP...BUT A FEW SUPERCELLS ARE POSSIBLE WITH LARGE
HAIL...DAMAGING GUSTS AND LOW/CONDITIONAL TORNADO RISK. EVENTUAL
CLUSTERED TO LINEAR EVOLUTION IS POSSIBLE WITH CONVECTIVE UPSCALE
GROWTH SHIFTING EWD ACROSS OK AND AR DURING EVENING AND OVERNIGHT.

MOST PROBABLE AREA FOR AFTN DEVELOPMENT MAY BE INVOF DRYLINE AND SFC
TROUGH OVER WRN OK AND PERHAPS SMALL PART OF NW TX...DESPITE GREATER
LOW-LEVEL THETAE BEING FARTHER S AND SE. BY THAT TIME...SFC
DIABATIC HEATING SHOULD BE MOST PERSISTENT S AND W OF CLOUD COVER IN
ACTING TO ERODE MLCINH. THIS AREA SHOULD RESIDE JUST WITHIN NRN
FRINGES OF STRONGEST DIURNAL HEATING...NARROW NWRN TONGUE OF
FAVORABLE LOW-LEVEL MOISTURE...AND SERN RIM OF LARGE-SCALE
ASCENT/DCVA PRECEDING MID-UPPER TROUGH. BACKED FLOW N OF
WARM-FRONTAL REMNANTS WILL AID IN LOW-LEVEL AND DEEP-LAYER
SHEAR...RESULTING IN WIND PROFILES FAVORABLE FOR SUPERCELLS WITH
LARGE HAIL AND SVR GUSTS. GEOMETRY OF WIND PROFILES INFLUENCED BY
POSITIVE TILT OF MID-UPPER TROUGH SHOULD LEAD TO SOME PRONOUNCED
WEAKNESSES IN 1-4 KM AGL HODOGRAPHS...WHICH COULD LEAD TO
STORM-SCALE PROCESSES MAKING TORNADO RISK CONDITIONAL BUT NOT
PRECLUDING IT.

ANY ACTIVITY DEVELOPING OR QUICKLY MOVING INTO LARGER-HODOGRAPH
ENVIRONMENT OF NE TX OR SE OK DURING LATE AFTERNOON...ESPECIALLY
ALONG WARM FRONT...MAY RESIDE IN BAROCLINIC ZONE LONG ENOUGH TO POSE
TORNADO RISK...GIVEN FRONTAL ENHANCEMENT TO LOW-LEVEL VORTICITY AND
STORM-RELATIVE INFLOW...AS WELL AS FORECAST SOUNDINGS SHOWING
300-400 J/KG EFFECTIVE SRH. HOWEVER...COVERAGE OF SFC-BASED TSTMS
ALONG/S OF FRONT IS IN QUESTION...MAKING THIS POTENTIAL IS TOO
CONDITIONAL FOR MORE THAN MRGL TORNADO OUTLOOK ATTM.

..EDWARDS/ROGERS.. 04/26/2013

What will tonight be like? There's a baseball game downtown OKC.

Looks pretty wet. If clearing/destabalization occurrs this afternoon over W and SW OK, there could be some decent storms.


It will not rain the entire time, so the game may be in a window to be played. But keep an eye on the radars.

OKC is bullseyed for 1" + over the next 24 hours.

http://www.hpc.ncep.noaa.gov/qpf/fill_9eewbg.gif

I'll take the rain

http://www.spc.noaa.gov/products/outlook/archive/2013/day1otlk_20130426_1630_prt.gif

..there is a slgt risk of svr tstms late this afternoon through
tonight across much of ok...

...ok...
Morning water vapor loops show a well-defined shortwave trough over
eastern nm and the tx panhandle. This feature will track eastward
and across the southern plains today into tonight. Ahead of the
trough...southerly low level winds are transporting moisture
northward across tx/ok with dewpoints rising through the 50s. Low
clouds are slowly eroding over western ok and western north tx...but
are likely to persist most of the day over the bulk of ok. This
will limit daytime heating and keep a substantial capping inversion
in place through 00z.

By early evening...lift associated with the nm/tx trough will
overspread the moist axis over ok. Large scale ascent will likely
result in a rapid weakening of the cap and scattered thunderstorm
development over northwest and central ok. Forecast soundings show
steep mid level lapse rates and elevated mucape values of 1500+
j/kg. Favorable effective shear values will promote supercell storm
structures capable of hail. While damaging winds and tornadoes are
not out of the question...it appears that large hail will be the
main threat today.

The suite of storm-scale model solutions this morning /nam
nests...nmm...nssl...hrrr/ show strong agreement in a narrow
corridor of greatest risk of supercell storms this evening after
00z. This area of western/central ok have been included in a 30
percent hail risk.

http://www.spc.noaa.gov/products/md/mcd0558.gif



MESOSCALE DISCUSSION 0558
NWS STORM PREDICTION CENTER NORMAN OK
0256 PM CDT FRI APR 26 2013

AREAS AFFECTED...WRN/CNTRL OK...FAR ERN TX PANHANDLE

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 261956Z - 262230Z

PROBABILITY OF WATCH ISSUANCE...80 PERCENT

SUMMARY...A FEW DISCRETE SUPERCELLS APPEAR LIKELY TO FORM BY 22-23Z
ALONG THE TX/OK BORDER AND DEVELOP SEWD INTO CNTRL OK THIS EVENING.
LARGE HAIL WILL BE THE PRIMARY HAZARD...BUT ISOLATED SEVERE WINDS
AND PERHAPS A TORNADO OR TWO WILL ALSO BE POSSIBLE.

DISCUSSION...19Z SURFACE ANALYSIS PLACED A 1011 MB CYCLONE IN THE
NRN TX PANHANDLE WITH AN ATTENDANT DRYLINE EXTENDING S/SWWD TOWARDS
THE PECOS VALLEY. A WARM FRONT THAT IS BECOMING QUASI-STATIONARY
EXTENDED E/SEWD INTO CNTRL OK TO THE ARKLATEX. CONVERGENCE ALONG
BOTH BOUNDARIES APPEARS TO BE STRENGTHENING IN RESPONSE TO THE
LOW-AMPLITUDE SHORTWAVE IMPULSE THAT WILL TRACK EWD ALONG THE KS/OK
BORDER...AS SURFACE PRESSURE FALLS HAVE INCREASED ACROSS SWRN
OK/NWRN TX. HERE...NEARLY FULL INSOLATION IS OCCURRING WITH SURFACE
TEMPERATURES WARMING THROUGH THE 70S INTO 80S AMIDST DEW POINTS
STILL RISING THROUGH 50S. THIS IS PROMOTING RAPID DESTABILIZATION
AND WILL YIELD WEAK TO EVENTUALLY MODERATE MIXED-LAYER BUOYANCY BY
EARLY EVENING.

12Z CONVECTION-ALLOWING WRF GUIDANCE ALONG WITH LATER MORNING HRRR
RUNS HAVE BEEN HIGHLY CONSISTENT WITH SIMULATING A BLOSSOMING OF
CONVECTIVE INTENSITY BY ABOUT 22Z. BASED ON CURRENT POSITION OF THE
SMALL CLUSTER OF TSTMS ATTENDANT TO THE SHORTWAVE IMPULSE...AND
INCREASING CU S ALONG THE DRYLINE...THIS SCENARIO APPEARS QUITE
REASONABLE. INITIAL DEVELOPMENT SHOULD BE RELATIVELY HIGH-BASED WITH
ELONGATED/NEARLY STRAIGHT-LINE HODOGRAPHS FAVORING SPLITTING
SUPERCELL STRUCTURES WITH MAIN THREATS OF LARGE HAIL AND ISOLATED
SEVERE WINDS.