Dryling retreating back to the west per AMA radar. Looks at the latest Vis with the nice low sun angle, the CU out there is very high based stuff. Nothing seems to really have much if any height to it overall. Looks like Cap o' Death wins again.

Oh well, now to look for discrete cells ahead of the main push tomorrow afternoon :)

Oh well, now to look for discrete cells ahead of the main push tomorrow afternoon :)

Indeed. Once it gets going I'll start paying attention to the chat room more. LOL

Potentially very busy severe weather day appears on tap for Central and Eastern Oklahoma. Looking at the way this day has trended of the last several runs and the new 00Z NAM this evening, appears likely we'll see an upgrade to Moderate Risk over parts of Central and Eastern OK. I've outlined the ideas I feel is most likely to see the higher end threat tomorrow.

The setup. Our always favorite friend, the Dryline, will finally get enough of the sites in the Texas PH and Western OK that it will want to visit Central OK. By 7PM the dryline is projected to be near or just east of US 183. The cap will be strong again tomorrow, but it will finally not be unbreakable. Forcing will be stronger along the dryline to allow for isolated supercell development. The most likely area of initiation appears to be over Southern/Southwest OK near Lawton. Storms will race NE 35 to 50 mph (unfortunately since this reduces lead times but is common for April), at least if the forecast sounding is correct tonight. This one of the main reasons for the orientation of my risk area. We will still see severe storms outside of this area, but this is the part where I feel all the conditions will be prime for the higher end severe threat. CAPE will be strongest here as well as the better environment for rotating supercells and tornadoes, some which could be strong (EF2-EF3). LCL forecast is a little difficult to gauge right now since the lower/better levels will be more in Central to Northern Oklahoma, but don't think it'll be a major issue. If this does come to realization, this could mean intense damaging hail storms moving up from the SW that will start to lower and tornado as they get into the better conditions. The other part of this is the hail. I'm not going to be shocked at all to see reports of baseballs tomorrow out of some of these initial supercells.

Now what could throw a curve ball in all of this? Wind profiles aren't ideal. Directional shear could be better, but rarely do we get ideal conditions. We also have to keep in mind if we get a right turning storm (which the profiles aren't all that in favor of) that can enhance SRH and allow for a localized favorable environment. We also have a cold front coming in as well (I'll deal with the winter precip stuff later). It'll start overtaking the dryline in Northern OK by evening and sweep through during the night. If this front comes in too fast it'll undercut any dryline convection that will move the threat to a more hail/wind mode. Expect a squall line to develop along the front that will race through. Finally the last curve ball will be the cap. If it is too strong for the dryline to break, then we wait for the front to come through and give us the squall line. We are going to have storms tomorrow as the cap can't hold back the front.

http://www.weatherspotlight.com/screencap/outlooks/20130409_Tuesday-4.png

http://beta.wxcaster.com/skewts/NAM-test/024/SKT_NAM__KOUN.png

http://www.spc.noaa.gov/products/outlook/day1otlk_1200.gif

http://www.spc.noaa.gov/products/outlook/day1probotlk_1200_torn.gif

Probability of a tornado within 25 miles of a point.
Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point. (More Info (http://www.spc.noaa.gov/products/outlook/probinfo.html))

http://www.spc.noaa.gov/products/outlook/day1probotlk_1200_hail.gif

Probability of one inch diameter hail or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of two inch diameter hail or larger within 25 miles of a point. (More Info (http://www.spc.noaa.gov/products/outlook/probinfo.html))

Pretty much exactly what I outlined earlier...

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0100 AM CDT TUE APR 09 2013

VALID 091200Z - 101200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF CNTRL OK...SRN
OK AND NORTH TX...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN
PLAINS...CNTRL PLAINS...NW AR...MO...SRN IA AND WRN IL...

...SRN AND CNTRL PLAINS...
AN UPPER-LEVEL LOW OVER THE FOUR CORNERS REGION WILL MOVE NEWD INTO
THE CNTRL ROCKIES ON TUESDAY. AT THE SFC...A COLD FRONT WILL ADVANCE
QUICKLY SEWD ACROSS THE SRN HIGH PLAINS AND CNTRL PLAINS. AHEAD OF
THE FRONT...SFC DEWPOINTS SHOULD REACH THE LOWER 60S F ACROSS ERN KS
WITH MID TO UPPER 60S F ACROSS CNTRL OK AND NORTH TX. MODERATE TO
STRONG INSTABILITY IS FORECAST TO DEVELOP ALONG THIS CORRIDOR WITH
CONVECTIVE INITIATION BEGINNING FIRST IN NRN KS DURING THE
MID-AFTERNOON. THUNDERSTORM DEVELOPMENT SHOULD TAKE PLACE ALONG THE
COLD FRONT...QUICKLY EXPANDING SSWWD ACROSS SRN KS AND CNTRL OK
DURING THE LATE AFTERNOON INTO NCNTRL TX BY EARLY EVENING. THE
STRONG INSTABILITY ALONG WITH COUPLED LOW AND MID-LEVEL JETS WILL BE
FAVORABLE FOR A SIGNIFICANT SEVERE WEATHER EVENT FROM LATE TUESDAY
AFTERNOON INTO TUESDAY EVENING.

FORECAST SOUNDINGS AT OKLAHOMA CITY AND WICHITA FALLS AT 00Z/WED
SHOW MLCAPE VALUES OF 2500 TO 3000 J/KG WITH AN IMPRESSIVE SHEAR
ENVIRONMENT. 0-6 KM SHEAR IS FORECAST TO INCREASE DURING THE LATE
AFTERNOON INTO THE 50 TO 60 KT RANGE AS A MID-LEVEL JET MOVES INTO
THE SRN PLAINS. THE SHEAR ALONG WITH MID-LEVEL LAPSE RATES AROUND
8.0 C/KM SHOULD BE FAVORABLE FOR SUPERCELL DEVELOPMENT WITH LARGE
HAIL. THE MORE DOMINANT SUPERCELLS SHOULD BE CAPABLE OF PRODUCING
HAIL GREATER THAN 2 INCHES IN DIAMETER. 0-1 KM SHEAR IS FORECAST TO
INCREASE INTO THE 25 TO 30 KT RANGE DURING THE EARLY EVENING AS THE
LOW-LEVEL JET STRENGTHENS MAKING CONDITIONS FAVORABLE FOR TORNADOES.
A FEW STRONG TORNADOES COULD OCCUR FROM THE OKLAHOMA CITY AREA SSWWD
TO AROUND WICHITA FALLS WHERE THE COMBINATION OF PARAMETERS APPEARS
TO BE MOST IDEAL. ALTHOUGH SOME CONCERN EXISTS ABOUT THE TIMING OF
INITIATION IN SRN OK AND NORTH TX...THE CURRENT THINKING IS THE
THREAT FOR SUPERCELL DEVELOPMENT WILL PERSIST WELL INTO THE EVENING
DUE TO THE STRONG INSTABILITY THAT IS FORECAST.

FURTHER TO THE NORTH FROM ECNTRL KS SWD INTO NERN OK...THE MODELS
APPEAR TO QUICKLY ORGANIZE A LINE OF THUNDERSTORMS ALONG THE FRONT.
THIS SUGGESTS THAT THE POTENTIAL FOR SIGNIFICANT SEVERE MAY BE
SOMEWHAT LESS THERE. HOWEVER...THE LINE SHOULD BE INTENSE WITH
ROTATING CELL ELEMENTS. SEVERE THREAT COVERAGE COULD BE EXTENSIVE
WITH A POTENTIAL FOR LARGE HAIL...WIND DAMAGE AND TORNADOES AS WELL.


...MID-MO VALLEY/MO/SRN IA/WRN IL...
A SHORTWAVE UPPER-LEVEL RIDGE IS FORECAST TO MOVE NNEWD ACROSS THE
UPPER MIDWEST AS AN UPPER-LEVEL LOW MOVES INTO THE CNTRL ROCKIES. A
MID-LEVEL JET TO THE EAST OF THE UPPER-LEVEL SYSTEM IS FORECAST TO
NOSE INTO THE MID-MO VALLEY LATE TUESDAY AFTERNOON. AT THE SFC...A
COLD FRONT WILL ADVANCE SEWD ACROSS SERN NEB WITH A WARM FRONT
EXTENDING EWD NEAR THE IA-MO STATE LINE INTO NCNTRL IL. ALONG AND
SOUTH OF THE WARM FRONT...SFC DEWPOINTS ARE FORECAST TO BE IN THE
LOWER 60S F WITH MODERATE INSTABILITY DEVELOPING BY MID-AFTERNOON. A
LACK OF A CAPPING INVERSION COULD ENABLE THUNDERSTORMS TO DEVELOP
ALONG AND SOUTH OF THE BOUNDARY AROUND MID-DAY WITH A GRADUAL
INCREASE IN CONVECTIVE COVERAGE TAKING PLACE DURING THE AFTERNOON
AND EARLY EVENING.

FORECAST SOUNDINGS AT 00Z/WED FROM NEAR KANSAS CITY EWD TO NEAR
SPRINGFIELD IL SHOW MLCAPE VALUES AROUND 1500 J/KG WITH 40 KT OF 0-6
KM SHEAR. THIS ENVIRONMENT SHOULD SUPPORT SEVERE STORM DEVELOPMENT.
THE MORE DISCRETE CELLS ALONG AND TO THE SOUTH OF THE BOUNDARY WHERE
MODERATE INSTABILITY IS FORECAST...MAY OBTAIN BETTER ORGANIZATION.
ROTATING STORMS AND/OR BOWING LINE-SEGMENTS SHOULD BE CAPABLE OF
PRODUCING ISOLATED LARGE HAIL AND WIND DAMAGE. A FEW TORNADOES COULD
OCCUR WITH THE GREATEST POTENTIAL EXISTING WITH CELLS THAT CROSS THE
WARM FRONT DURING THE EARLY EVENING WHEN LOW-LEVEL FLOW SHOULD
BECOME ENHANCED.

..BROYLES/GARNER.. 04/09/2013

Quick side note look ahead according to the 00Z GFS run...

Next block of severe chances are next this coming weekend into next week.

Sunday 14th - Moderate instability from Lawton to Enid and east. Strong cap though.
Monday 15th - High to very high instability south of I-44. Cap weaker, storms firing along and south of I-44 spreading north.
Tuesday 16th - Very high instability Central and Western OK, weak cap, storms firing along dryline moving ENE.

For giggles, here is the forecast sounding for Tuesday the 16th. This is going to change a lot until we get there, but I just wanted to post this. There is almost as text book of a tornado favorable environment as you can get.

http://www.stormchaser.niu.edu/chaser/tempgif/19049.GIF

Venture sorry to sound dense, but could you possibly offer a Readers Digest summary of what that sounding chart is showing?

What's up with the weather charts showing 28 degrees on Wednesday???? That straight up pisses me off! >_< lol

If we get another big hail storm the insurance companies are going to pack up and leave Oklahoma.

What's up with the weather charts showing 28 degrees on Wednesday???? That straight up pisses me off! >_< lol

We've had a freeze as late as May 3rd, so its not out of the question to have a freeze this late.

The short term models this morning are keep much of the initial development limited to the frontal boundary in Western OK (mainly SW OK) starting around 1PM today. Current indications show the front overtaking the dryline early since it is all the way back into the TX PH right now. This could help to reduce the tornado threat some today.

The cold front is surging way too quickly, it will undercut any discrete cells that fire off the dryline bfore they get to churning.

Low tornado, but higher straight-line wind threats. Also hail will be a threat, but mostly with the individual cells early, then it moves to heavy rain/wind and freezing temperatures behind it.


It is already in the 20s in the panhandle.

Wind is sustained around 30mph behind the front, pushing windchill values into the teens.

The cold front is surging way too quickly, it will undercut any discrete cells that fire off the dryline bfore they get to churning.

Low tornado, but higher straight-line wind threats. Also hail will be a threat, but mostly with the individual cells early, then it moves to heavy rain/wind and freezing temperatures behind it.

It is already in the 20s in the panhandle.

The cold front is about 50 miles further east/south than the 00Z forecasts. The big kicker is that the dryline pulled well west of AMA this morning which none of the guidance caught on to. Latest RAP output has the dryline moving somewhat east by early afternoon through extreme SW OK. So conditions might just be right there for a few spin ups before the front undercuts any surface based storms.

For those that want a visual, this is the current surface map right now...

http://www.weatherspotlight.com/screencap/outlooks/20130409_Tuesday-amsurf.png

Here is the probability we get more than a quarter inch of ice Tuesday night into Wednesday:

http://www.hpc.ncep.noaa.gov/pwpf_48hr/prb_48hicez_ge.25_2013040912f048.gif

Yeah if NAM is to be believed, we are going to head below freezing around Midnight tonight and stay there until mid morning tomorrow. If it happens could definitely see elevated surfaces get a good glaze on them tonight. We'll have to see how things work out. The other models keep us a few degrees above freezing and out of any icing issues here in the Metro area specifically.

Latest Update from Norman


AREA FORECAST DISCUSSION...UPDATEDNATIONAL WEATHER SERVICE NORMAN OK
1045 AM CDT TUE APR 9 2013


.UPDATE...
WITH THE CHANGE IN THE WINTER WX FORECAST AND THE POSSIBLE
IMPACTS... WILL BE ISSUING A WINTER WX ADVISORY IN THE NEXT HOUR
OR SO.


COLD FRONT IS MOVING ACROSS THE REGION MUCH FASTER THAN PREVIOUSLY
FORECASTED. THE FRONT HAS ALREADY MOVED INTO PARTS OF NORTHWEST OK
WITH TEMPERATURES FALLING FROM THE UPPER 60S TO THE 40S AND 50S IN
A SHORT PERIOD OF TIME. MODIFIED TEMPS TO SHOW FALLING TEMPS
THROUGHOUT THE DAY AND ADJUSTED WINDS TO BETTER REPRESENT THE
FRONT. ADDED SOME LOW POPS TO NW PARTS OF FA FOR THIS MORNING.
SOME ACTIVITY HAS BEEN DEVELOPING WITH THE FRONT THIS MORNING. IT
STILL LOOKS LIKE SEVERE STORMS THIS AFTERNOON/EVENING ALONG AND
AHEAD OF THE FRONT AND POSSIBLY THE DRYLINE... WITH RAIN/STORMS
TONIGHT INTO WEDNESDAY BEHIND THE FRONT. HOWEVER... THE MORE
WIDESPREAD IMPACT MAY BE WINTER WX TONIGHT. WITH THE COLD AIR
MOVING INTO THE REGION BEHIND THE COLD FRONT AND RAIN EXPECTED
BEHIND THE FRONT... FREEZING RAIN AND SLEET WILL BE LIKELY. THE
SLEET AND FREEZING RAIN COULD HAVE A SIGNIFICANT IMPACT. WITH THE
FREEZING RAIN... ROADWAYS MAY REMAIN RELATIVELY CLEAR DUE TO THE
WARM GROUND TEMPERATURES BUT A GOOD BUILD-UP ON TREES AND
POWERLINES COULD BE POSSIBLE. THIS ALONG WITH FAIRLY WINDY
CONDITIONS COULD CAUSE POWER OUTAGES IN SOME LOCATIONS. SO WILL
ISSUE A WINTER WX ADVISORY IN THE NEXT HOUR OR SO. WILL SEND
UPDATES SHORTLY.

What is the latest in the year OKC has seen a significant winter weather event?

Some forecasters are saying this will be am event that will down trees and power lines.

Cold front? :)

http://www.mesonet.org/data/public/mesonet/maps/realtime/current.TAIR.grad.png

Winds...

http://www.mesonet.org/data/public/mesonet/maps/realtime/current.gustarrows.gif?1365523298815

THe main reason this event could be bad is due to the wind. The wind behind this front is 20mph sustained, with gusts approaching 40mph.

Those winds combined with temps in the 20s is a recipe for significant icing on elevated objects. The wind helps to provide an air conditioning effect on exposed surfaces by moving the radiating heat off of them, think of it as blowing on hot soup. Now add you blowing on your hot soup in a below 30F environment.


It is going to be hard to call until the front moves through and we see how the precip. shield sets up. Forecasting ice storms is extremely difficult.

If we get another big hail storm the insurance companies are going to pack up and leave Oklahoma.

LOL, I know, right? We've had two roofs put on in the last four years.

Here is the Advisory. Includes the NW half of the Metro area.

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE NORMAN OK
1108 AM CDT TUE APR 9 2013


OKZ006>008-011>013-015>025-027-033>038-TXZ083>085-087-100015-
/O.NEW.KOUN.WW.Y.0009.130410T0500Z-130410T1800Z/
ALFALFA-GRANT-KAY-MAJOR-GARFIELD-NOBLE-DEWEY-CUSTER-BLAINE-
KINGFISHER-LOGAN-PAYNE-BECKHAM-WA****A-CADDO-CANADIAN-OKLAHOMA-
GRADY-HARMON-GREER-KIOWA-JACKSON-TILLMAN-COMANCHE-HARDEMAN-FOARD-
WILBARGER-KNOX-
INCLUDING THE CITIES OF...CHEROKEE...MEDFORD...PONCA CITY...
FAIRVIEW...ENID...PERRY...TALOGA...WEATHERFORD...C LINTON...
WATONGA...KINGFISHER...GUTHRIE...STILLWATER...ELK CITY...SAYRE...
CORDELL...ANADARKO...YUKON...EL RENO...MUSTANG...OKLAHOMA CITY...
CHICKASHA...HOLLIS...MANGUM...HOBART...ALTUS...FRE DERICK...
LAWTON...QUANAH...CHILLICOTHE...CROWELL...VERNON.. .MUNDAY...
KNOX CITY
1108 AM CDT TUE APR 9 2013


...WINTER WEATHER ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO
1 PM CDT WEDNESDAY...


THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A WINTER
WEATHER ADVISORY FOR FREEZING RAIN AND SLEET...WHICH IS IN EFFECT
FROM MIDNIGHT TONIGHT TO 1 PM CDT WEDNESDAY.


* TIMING: AROUND MIDNIGHT THROUGH MIDDAY WEDNESDAY.


* MAIN IMPACT: FREEZING RAIN AND SLEET ARE LIKELY TO ACCUMULATE ON
ELEVATED SURFACES. POWER LINES AND TREE LIMBS MAY BREAK UNDER
THE WEIGHT OF ICE...AND THE FORCE OF STRONG NORTHWEST WINDS.


* OTHER IMPACTS: POWER OUTAGES WILL BE POSSIBLE THROUGHOUT THE
ADVISORY AREA...BUT WILL BE MOST LIKELY FROM WESTERN NORTH TEXAS
INTO CENTRAL AND NORTH-CENTRAL OKLAHOMA. SLEET MAY BE MORE
DOMINANT IN WESTERN OKLAHOMA...RESULTING IN SLIPPERY CONDITIONS
ON ROADS...ESPECIALLY BRIDGES AND OVERPASSES.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

LOL, I know, right? We've had two roofs put on in the last four years.

I've had a roof and all my windows on the south side replaced in the past couple years.

Moderate risk pulled down due to the reduced widespread large hail threat.

Storm Prediction Center Apr 9, 2013 1630 UTC Day 1 Convective Outlook (http://www.spc.noaa.gov/products/outlook/archive/2013/day1otlk_20130409_1630.html)

...CENTRAL/SRN PLAINS THIS AFTERNOON INTO TONIGHT...
A FEED OF LOW-MID 60S BOUNDARY LAYER DEWPOINTS PERSISTS FROM TX INTO
OK/KS...BENEATH STEEP MIDLEVEL LAPSE RATES PER 12Z SOUNDINGS. A
STRONG CAP ALSO CONTINUES IN ASSOCIATION WITH THE WARM ELEVATED
MIXED LAYER...AND SURFACE HEATING FROM NRN OK INTO KS WILL LIKELY BE
SLOWED BY LINGERING STRATUS. THUS...THE STRONGEST INSTABILITY
/MLCAPE OF 2000-3000 J PER KG/ IS EXPECTED FROM CENTRAL OK INTO N
TX...WITH VALUES DIMINISHING TO ABOUT 1000 J/KG FARTHER NE ACROSS
KS.

THE PRESENCE OF THE CAP IN THE WARM SECTOR...LARGELY FRONT-PARALLEL
DEEP-LAYER FLOW/SHEAR ACROSS KS/OK...AND ANAFRONTAL FLOW WILL
PROMOTE LINE SEGMENTS NEAR AND IMMEDIATELY BEHIND THE SURFACE COLD
FRONT THIS AFTERNOON INTO TONIGHT. STILL...SOMEWHAT DISCRETE
SUPERCELLS WILL STILL BE POSSIBLE WITH THE INITIAL CONVECTION NEAR
THE DRYLINE-COLD FRONT INTERSECTION THIS AFTERNOON FROM EXTREME NW
TX INTO SW OK BEFORE THE FRONT UNDERCUTS THE STORMS...AND IN KS
WHERE THE FRONT IS ORIENTED A LITTLE MORE N-S AND THE CAP COULD BE A
LITTLE WEAKER ACROSS CENTRAL KS THIS AFTERNOON PER THE 12Z DDC
SOUNDING. LARGE HAIL WILL BE THE PRIMARY CONCERN WITH THE STORMS
THIS AFTERNOON INTO TONIGHT WITH STORMS ALONG AND ON THE COOL SIDE
OF THE FRONT. THE DAMAGING WIND RISK IS MORE QUESTIONABLE GIVEN THE
LIKELY ELEVATED/POST-FRONTAL NATURE OF MOST OF THE
STORMS...ESPECIALLY TONIGHT. LIKEWISE...THE TORNADO RISK WILL
DEPEND LARGELY ON MAINTAINING DISCRETE STORMS ALONG THE FRONT.

http://www.youtube.com/watch?v=PSkpN09g0rY

Starting to see more activity attempt to get going along the cold front now, so I'll be watching the chat room for the rest of the afternoon...

Live Chat | Weather Spotlight (http://www.weatherspotlight.com/?page_id=40)

Pretty impressive satellite image showing the front...

http://climate.cod.edu/data/satellite/1km/Oklahoma/current/Oklahoma.vis.gif

http://www.weatherspotlight.com/radar/ktlx_br1.png

NWS Norman just launched a balloon to do a special midday sounding to see how things look upstairs. Should have details soon.

Current radar has a bunch of crap from Arapaho north to Alva. The more interesting stuff is down around Childress. Norman Updated their afternoon graphic...

http://www.srh.noaa.gov/images/fxc/oun/graphicast/image3.jpg

Current radar has a bunch of crap from Arapaho north to Alva. The more interesting stuff is down around Childress. Norman Updated their afternoon graphic...

http://www.srh.noaa.gov/images/fxc/oun/graphicast/image3.jpg

So are they expecting most of the hail to be gone by the time it reaches OK county? Or will that just be after 7pm but the storms will be the same?

So are they expecting most of the hail to be gone by the time it reaches OK county? Or will that just be after 7pm but the storms will be the same?

They are thinking mostly after 7PM. So the eastern edge of this is where they think things will line up at that time, there is another graphic for after 7PM.

http://www.srh.noaa.gov/images/fxc/oun/graphicast/image1.jpg

Here is the 18Z Sounding

http://climate.cod.edu/data/raob/KOUN/skewt/KOUN.skewt.20130409.18.gif

Haha it's going to take a major effort to bust that cap pre-fropa. Good luck.

Yeah the cap it just a monster still. Cap is stout down toward Fort Worth as well, but not as strong.

We have one cell right now going up right along the front in Foard County, TX. A few other cells behind the front that are still trying.

Watch Soon...

http://www.spc.noaa.gov/products/md/mcd0411.gif

MESOSCALE DISCUSSION 0411
NWS STORM PREDICTION CENTER NORMAN OK
0214 PM CDT TUE APR 09 2013

AREAS AFFECTED...NWRN TX INTO MUCH OF CNTRL OK

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 091914Z - 092115Z

PROBABILITY OF WATCH ISSUANCE...80 PERCENT

SUMMARY...SCATTERED STORMS WILL EVENTUALLY FORM AND LARGE HAIL WILL
BE POSSIBLE. A WATCH MAY BE REQUIRED BEFORE 21Z.

DISCUSSION...AN ARCTIC FRONT CONTINUES TO SURGE SWD ACROSS TX INTO
WRN OK. ALONG THIS FRONT...OCCASIONAL CU HAVE RAPIDLY DEVELOPED AND
DISSIPATED AS SOURCE AIR GETS UNDERCUT. AHEAD OF THE FRONT...THE AIR
MASS HAS BEEN CAPPED.

HOWEVER...LATEST VISIBLE IMAGERY INDICATES CHANGING CHARACTER TO THE
CU FIELDS FROM NWRN TX INTO WRN OK NEAR THE FRONT. A DEEPER GROUPING
OF TCU HAS FORMED ON THE NOSE OF THE HOTTER AIR ACROSS NWRN
TX...NEAR A WEAK SURFACE LOW AND DRYLINE/COLD FRONT INTERSECTION
WHERE CAPPING IS NEGLIGIBLE. MORE RECENTLY...STABLE WAVE CLOUDS HAVE
MIXED ACROSS W CNTRL AND SWRN OK...SUGGESTING THE CAP IS BEING
LIFTED THERE AS WELL. WITH ADDITIONAL SURFACE HEATING AHEAD OF THE
FRONT...AND COOLING IN THE CAPPING LAYER...STORM INITIATION WILL
BECOME INCREASINGLY LIKELY OVER THE NEXT COUPLE HOURS.

ONE POTENTIAL PROBLEM IN REGARD TO LONG LIVED SEVERE CONVECTION IS
THE TENDENCY FOR THE FRONT TO UNDERCUT DEVELOPMENT OCCURRING ALONG
IT...ORPHANING THE INCIPIENT UPDRAFTS. THEREFORE...MUCH OF THE
CONVECTION MAY END UP BEING ELEVATED BEHIND THE FRONT.

..JEWELL/THOMPSON.. 04/09/2013

Looks like some action may be getting started around Lawton.

This will be the first SVR Thunderstorm Watch issued for OKC this year. (We have had 1 tornado watch)

Even behind the front, storms are just have a tough time getting established. Heating is still on going down to the SW though so every little bit helps.

Wow...
3630

(credit: kfor.com)

I wonder how much pressure the techs working on the FDR radar are feeling right now. LOL

Cell in NE Foard Co showing signs are getting stronger.

Even behind the front, storms are just have a tough time getting established. Heating is still on going down to the SW though so every little bit helps.

From Oklahomaskies.net:

SEVERE WEATHER UPDATE: Special sounding out of Norman still showing a decent CAP in place which is inhibiting thunderstorm development for now. A strong cold front is racing south through western Oklahoma and will begin to overtake a dryline situated from southwest Oklahoma into west Texas. As this occurs, strong forcing along the front will result in a line of storms(squall line) with severe hail and wind possible. If we can get any storm to isolate itself, more significant severe weather including tornadoes will be probable. The most likely area for this to occur would be across southwest Oklahoma into western north Texas.

The Frederick Radar actually came back on around an hour ago.

SSEiYah, not sure what you are saing 'wow' to, but that large circle is ground clutter near the radar - not convection.

SSEiYah, not sure what you are saing 'wow' to, but that large circle is ground clutter near the radar - not convection.

ahh ok.

Current Radar with front, wind, and dewpoint

http://www.weatherspotlight.com/screencap/outlooks/20130409_Tuesday-current240p.png

From Oklahomaskies.net:

SEVERE WEATHER UPDATE: Special sounding out of Norman still showing a decent CAP in place which is inhibiting thunderstorm development for now. A strong cold front is racing south through western Oklahoma and will begin to overtake a dryline situated from southwest Oklahoma into west Texas. As this occurs, strong forcing along the front will result in a line of storms(squall line) with severe hail and wind possible. If we can get any storm to isolate itself, more significant severe weather including tornadoes will be probable. The most likely area for this to occur would be across southwest Oklahoma into western north Texas.

Pretty much repeats everything we've been saying so far today.


The Frederick Radar actually came back on around an hour ago.

It went down again just after 2PM. OUN advised it was going to be on and off all afternoon as they work on it.

If someone is going to be away from their pc/tv this evening what radio station is recommended to get the best info?

What's the speed of that front? Doesn't look like its going to take two hours to cross greater OKC..?

Moving around 18 mph to the east. It is about 40 miles from downtown so it looks like 5pm there.

Tornado threat pretty much done for today, could be a spin up ahead of the front if any storms happen there. Large hail the main story. Convective wind won't be a major deal either.

http://www.spc.noaa.gov/products/outlook/archive/2013/day1probotlk_20130409_2000_hail_prt.gif

...SRN PLAINS...
CONVECTIVE POTENTIAL IS INCREASING ACROSS PORTIONS OK AND NW TX
WHERE MLCINH IS ERODING AHEAD OF SFC COLD FRONT...AMIDST FAVORABLY
STEEP MIDLEVEL LAPSE RATES AND DEEP SHEAR. REF SPC MESOSCALE
DISCUSSION 411 FOR MORE DETAILED NEAR-TERM ASSESSMENT.
ALSO...THOUGH POTENTIAL STILL EXISTS FOR SVR TSTMS WITH LARGE HAIL
AND DAMAGING GUSTS TO DEVELOP OVERNIGHT INVOF COLD FRONT...CORRIDOR
OF MAX HAIL COVERAGE AND SIGNIFICANT-HAIL PROBABILITIES HAS BEEN
TRIMMED NWD TOWARD RED RIVER. GEOMETRY OF KINEMATIC FIELDS SUGGESTS
MORE LINEAR EVOLUTION WITH TIME THAT WOULD DISFAVOR THE SORT OF
PERSISTENT SUPERCELLULAR MORPHOLOGIES OPTIMALLY SUITABLE FOR MORE
THAN ISOLATED SIGNIFICANT-HAIL THREAT OVER MOST AREAS. STILL..ANY
RELATIVELY DISCRETE CONVECTION THAT CAN DEVELOP AHEAD OF
FRONT...ESPECIALLY OVER NW TX/SRN-CENTRAL OK REGION...MAY PRODUCE
DAMAGING HAIL.

Moving around 18 mph to the east. It is about 40 miles from downtown so it looks like 5pm there.

Ahhh, okay. I was under the impression it was moving much faster than that.

Clouds are reaaallly thickening up here in E. OK County....

18Z NAM ramping up precip amounts between 10pm tonight and 10am tomorrow. OKC metro is right around the freezing mark. A 1-2 degree shift one way or the other could make things very interesting.

18Z NAM ramping up precip amounts between 10pm tonight and 10am tomorrow. OKC metro is right around the freezing mark. A 1-2 degree shift one way or the other could make things very interesting.

Looks like it keeps most of Central OK above freezing until 4AM, but still a quarter inch of precip after that. So who knows what may happen. RAP keeps it above freezing and most precip out west - similar to the GFS runs earlier.

This has to be the most exciting severe weather day ever. :rolleyes:

This front can't even get sustained convection going. RAP keeps saying there should be something by now, but NAM does hold things off for a couple more hours. So we'll see.

Did I mention I hate cold weather?

http://wxcaster4.com/nam/CONUS1_MESO-NAM212_SFC_ACCUM-FZRN_30HR.gif

Did I mention I hate cold weather?

Have you considered Mexico or Arizona? :-P

I will wager a large pizza that convection fires just east of the metro. Any takers?