Oklahoma Severe Weather Discussion - May 2011

[TulsaRobert]

I have family in Joplin; both my aunt & uncle's house and my grandmother's house are destroyed. I tried to drive up there taking 66 (since I knew I-44 was shut down), but hit the storm in Vinita and had to turn back. I hear that the city is effectively closed off now to traffic anyway.

Given my familiarity with the city, looking at the pictures is incredibly difficult. In some pictures, I can't even recognize the area. In those pictures I can recognize, the Home Depot serves as my landmark and is only 2 blocks from my grandmother's house and about a mile from my cousin's. They said Duquesne (the Joplin suburb in which they live) is absolutely demolished. Very anxious for them to open the city back up so I can help them out...

[venture]

They do have at least 1 other hospital that took most of the intensive care patients.

Robert I feel for your and your family. You'll be in all of our thoughts here.

[adaniel]

http://www.radioreference.com/apps/a...=cwp&ctid=1527

Live Police, Fire and EMS scanners in the Joplin Area.. Very interesting to listen to.

I actually clicked on this and in the span of 5 minutes I'm pretty sure I heard two emergercy workers discover 2 bodies a piece, with a third saying he was "running low on body bags."

I had to turn it off...just a bit too chilling to listen to.

[venture]

Still working on the forecast for tomorrow and Tuesday. There is a reason why it is taking longer. I'm spending more time sitting at the screen looking at the models going ... "really?"

First thoughts...100% moderate risk next two days. No question. Just getting a handle on the specifics is the big thing right now and I don't want to over-hype anything that I would have to apologize for later.

[TulsaRobert]

My family is all safe, but having to sit on my hands, knowing that there isn't anything I can do until they open the city back up, is driving me crazy.

[Dustin]

Venture, when will the storms here in the metro start up? Early morning?

[venture]

Short term models are indicating that we'll have two batches. One north that will form very late tonight or tomorrow after day break. Those storms will stay north.

Another is the batch in Texas, but those will stay south of the Red.

[Thunder]

Eh, I don't think we want to know what is in store for us tomorrow and/or Tuesday, since the latest trends with tornadoes hitting major cities across the country. :-(

[venture]

Discussion thread for tomorrow on Storm-Scope: http://www.storm-scope.com/forum/vie....php?f=11&t=15

I'll be keeping that thread over there updated with more specifics, but here is my full outlook and ramblings for Monday only.
-----

Okay here we go. SPC outlook should be rolling soon, so it will be interesting to see how this compares. There is some disagreement between the short term models and the traditional medium range-type models (NAM and GFS or NAM isn't that medium range, but yeah).

Experimental NSSL WRF and HRRR keep OK mostly dry tonight, except for some activity in far northern OK/southern KS and in North Texas. They also keep the main body of OK dry for most of tomorrow, except for maybe a stray shower/storm.

NAM is pretty close to the above, but has precip a bit more widespread. It also blows up supercells from the OKC area and back to the SW and W.

GFS is the outsider here (but could be right) and has precip forming early tomorrow morning moving through Central and Northern OK. It also has activity in Western OK by early afternoon again and moves it east to cover Western & Central OK north of I-40. Considering how dry nearly every model want to keep today, I'm not buying it.

A wave will eject out into Oklahoma by mid to late afternoon. We'll have a surface low develop near NW OK. We will also have a quasi warm front develop and lay across northern OK. Then we will have our good ol' dryline in western OK. It won't get as far east today that it did on Sunday. So those are our boundaries. There might be a few weaker ones laying around from Sunday's activity or will be around after any morning activity. Any unique boundary intersection is going to enhance any turning of the atmosphere in that area, not to mention additional lift to kick off storms.

So let's look at the forecast sounds. Wow. I have a spreadsheet where I plug in the values and help provide guidance based on the values. However, I really don't need it for something as loaded as this. The sounding for tomorrow is flat our stupid (don't get me started on Tuesday). Now, I want to point on that the highest instabilities will be just east of the dryline, so they'll be set off to the west of I-35 a bit. However, I've never seen so many very high/extreme indices get triggered on my spreadsheet before.

Instability. It's there. Severe indices are all in like to support tornadic, and strong tornadoes at that, tomorrow in Oklahoma. Monster hail will be probable again. Storm motions will be on the side of early warnings where storms only moving 15-25 mph. Cap strength, is very breakable - with values right around 1.

Are we going to have a major tornado outbreak tomorrow? I can't answer that yet. There will be severe weather. There will be large hail. There will be tornadoes. It is May.

I'm going with a high end Moderate Risk for Monday for nearly all of Central and Western Oklahoma. Far west may be in the clear if the dryline passes and far SE OK should be mostly in the slight risk area. Northeast OK will probably be in the moderate as well, but it really depends on morning convection...but it might not even matter at that point.

SPC will be rolling their outlook out here soon, but these are my thoughts. If they are wrong, they are wrong. I will always defer to the people that get the healthy government pay checks. To me, it just looks ugly.

[venture]

Day 2 outlook is out (Tuesday) from SPC...they have upgraded to Moderate Risk with the headline "...AN OUTBREAK OF SEVERE THUNDERSTORMS AND TORNADOES IS POSSIBLE LATE TUESDAY AFTERNOON AND EVENING..."

The moderate risk is for Central & Eastern OK...exact placement isn't available yet, but I wouldn't get too hung up on it yet.

Adding the map for the Day 2...generally along I-35 and east is the Moderate Risk.

[blangtang]

which is likely to be worse, mon or tuesday?

[venture]

Monday's activity will have a direct impact on Tuesday, so let's get through Monday first.

[venture]

Well didn't expect this at all, but it makes sense if they are biting on the potential for convection to fire overnight and last. They have downgraded to slight for the entire area due to uncertainty with any complications of ongoing convection.

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0100 AM CDT MON MAY 23 2011

VALID 231200Z - 241200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE SRN KS/OK/NRN TX AREA ENEWD INTO THE LOWER GREAT LAKES AND MID ATLANTIC REGIONS...

...SYNOPSIS...
AN UPPER TROUGH OVER THE WRN U.S. WILL MAKE SLOW EWD PROGRESS TODAY...WHILE MORE COMPLICATED FLOW FIELD -- COMPRISED OF SEVERAL SMALLER-SCALE DISTURBANCES WITHIN GENERAL WSWLY FLOW -- AFFECTS THE CENTRAL AND ERN CONUS.

AT THE SURFACE...A COLD FRONT IS FORECAST TO MOVE SLOWLY EWD ACROSS THE UPPER MIDWEST AND INTO THE OH VALLEY...WHILE A DRYLINE ADVANCES EWD ACROSS THE SRN PLAINS DURING THE AFTERNOON. THE WRN UPPER TROUGH -- AND THE ERN FRONT/DRYLINE -- WILL ALL CONTRIBUTE TO WIDESPREAD CONVECTION THIS PERIOD.

...S CENTRAL AND SERN KS/OK/N TX...
VERY COMPLEX SCENARIO IS EVIDENT ACROSS THE SRN KS/OK/N TX VICINITY TODAY...AS MODELS CONTINUE TO HINT AT ONGOING STORM DEVELOPMENT AT THE START OF THE PERIOD...LINGERING THROUGH THE DAY ALONG WITH ASSOCIATED CLOUD COVER AS SEVERAL WEAK UPPER WAVES EMERGE INTO THE PLAINS DURING THE DAY. LOCATIONS OF ANY RESULTING CONVECTIVE BOUNDARIES...AND AREAS WHICH MAY EVENTUALLY RECOVER AND DESTABILIZE...REMAIN DIFFICULT TO DETERMINE ATTM. HAVING SAID THAT...STEEP LAPSE RATES ALOFT IN AREAS AWAY FROM ONGOING STORMS COULD DESTABILIZE RAPIDLY WITH SUFFICIENT HEATING. THUS...EXPECT AREAS OF AFTERNOON STORM DEVELOPMENT TO OCCUR -- AND GROW RAPIDLY WITH THE AID OF MODERATE SHEAR EXPECTED ACROSS THE AREA. AS SEVERE/SUPERCELL STORMS EVOLVE...ACCOMPANYING THREAT FOR LARGE HAIL AND DAMAGING WINDS ALONG WITH A COUPLE OF TORNADOES IS EXPECTED.
STORMS SHOULD DIMINISH SLOWLY WITH TIME THROUGH THE EVENING...WITH SOME CONVECTION LIKELY TO SHIFT EWD INTO AR AND VICINITY...AS LOW-LEVEL JET DEVELOPS AND VEERS OVERNIGHT.

...AR/MO NEWD TO THE LOWER GREAT LAKES AND MID ATLANTIC REGIONS...
MULTIPLE ROUNDS OF CONVECTION ARE FORECAST THIS PERIOD...WITHIN A BROAD/MOIST LOW-LEVEL AIRMASS THAT WILL DESTABILIZE THROUGH THE AFTERNOON. AN INITIAL ROUND OF STORMS MOVING ACROSS THE OH VALLEY EARLY SHOULD WEAKEN THROUGH THE DAY...AND THEN SHOULD RE-FIRE E OF THE APPALACHIANS DURING THE AFTERNOON. MEANWHILE...NEW DEVELOPMENT IS FORECAST INVOF THE FRONT MOVING ACROSS THE MIDWEST...WHILE A THIRD AREA OF MORE CONCENTRATED STORMS IS FORECAST ACROSS THE OZARKS REGION AND INTO THE MID MS/LOWER OH VALLEYS BY LATE AFTERNOON.

WITH A BELT OF FASTER SWLY FLOW THROUGH THE LOWER AND MIDDLE TROPOSPHERE ACROSS THIS REGION...STRONGER/SEVERE STORMS WILL LIKELY ORGANIZE -- ALONG WITH ACCOMPANYING THREATS FOR HAIL AND DAMAGING WINDS...AND POSSIBLY AN ISOLATED TORNADO. STORMS WILL BEGIN DIMINISHING AFTER DARK...BUT NOT BEFORE WIDESPREAD SEVERE CONVECTION AFFECTS A LARGE PORTION OF THE MID MS/TN/OH VALLEYS AND INTO THE LOWER GREAT LAKES AND MID-ATLANTIC REGION.

...UT AND VICINITY...
PRONOUNCED UPPER SHORT-WAVE TROUGH -- WITHIN THE LARGER-SCALE CYCLONIC FLOW OVER THE WEST -- IS PROGGED TO SHIFT ACROSS UT AND VICINITY DURING THE AFTERNOON. RESULTING STEEPENING OF LAPSE RATES ATOP A HEATING BOUNDARY LAYER WILL RESULT IN MODEST DESTABILIZATION ACROSS THIS AREA -- EVENTUALLY FUELING THE DEVELOPMENT OF WIDESPREAD AFTERNOON STORMS FROM THE GREAT BASIN EWD INTO WY/CO.

MID-LEVEL FLOW SHOULD REMAIN MODEST /20 TO 30 KT/...BUT POSSIBLY SUFFICIENT GIVEN DEGREE OF DESTABILIZATION TO SUPPORT A FEW STRONGER/SUSTAINED CELLS. THEREFORE...WILL EXTEND LOW SEVERE PROBABILITIES WWD ACROSS PARTS OF CO AND WY INTO UT/SERN ID/ERN NV TO COVER ISOLATED THREAT THROUGH EARLY EVENING.

..GOSS.. 05/23/2011

[venture]

Some short term model guidance is showing initiation of activity by late morning/early afternoon which would throw things off for today. As of right now, it is all quiet out there with a shower or two scattered around. We'll have to wait and see what the morning brings.

[SkyWestOKC]

What's the timing do you think. I'm flying into OKC this morning at 10am.

[BG918]

Morning convection was (as of right now) much less than expected. I think they upgrade back to Moderate Risk especially if we have the daytime heating we did yesterday.

[SoonerDave]

Man, seeing what happened in Joplin and knowing what's happened here over the years, makes the next 48 hours pretty sobering.

[venture]

Well I hate being the one that was right in this. We are watching a wave approach that was over Northern Mexico early this morning. As this moves over, more widespread severe storms will start to develop across the body of Oklahoma. Tornado threat is going to be higher near any left over boundaries from yesterday and this morning's activity.

We are back under a moderate risk for nearly all of OK except for extreme western, southern and southeast OK.

[venture]

Here is the Norman AFD from this morning...probably one of the most strongly worded ones you'll ever see.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
457 AM CDT MON MAY 23 2011

.DISCUSSION...
MAIN FOCUS IS ON SEVERE WEATHER POTENTIAL NEXT 2 DAYS.

THERE IS GROWING CONCERN THIS MORNING THAT A MORE WIDESPREAD SEVERE EVENT MAY OCCUR LATER TODAY. THE AREA IS UNDISTURBED BY OVERNIGHT CONVECTION... AND SKIES ARE MOSTLY CLEAR AT THE MOMENT. DIURNAL HEATING SHOULD LEAD TO MODERATE TO EXTREME INSTABILITY AGAIN BY AFTERNOON WITH SBCAPES 3000-5000 J/KG. DEEP-LAYER SHEAR /0-6KM/ IS FORECAST TO BE STRONGER TODAY OVER THE MOIST SECTOR WITH MAGNITUDES 45-60KT OR SO BY 00Z THIS EVENING... VS 35-45KT SUNDAY EVENING. SATELLITE LOOP INDICATES AN OMINOUS-LOOKING IMPULSE OVER N MEXICO MOVING RAPIDLY ENE. THIS FEATURE EXTRAPOLATES TO N TX AREA THIS AFTERNOON WITH A PROBABLE STEEPENING OF MID-LEVEL LAPSE RATES WITHIN THE AREA OF DRYING ALOFT. BASED ON 06Z NAM WE WILL NOT HAVE THE DRYLINE IN THE AREA AS A FOCUS... IT REMAINS NEAR OUR W BORDER... BUT NAM INDICATES WIDESPREAD CONVECTION BLOWING UP ACROSS THE ENTIRE MAIN BODY OF OKLAHOMA 18-21Z. THIS MAY BE CONNECTED TO THE APPROACHING SYSTEM NOW NEAR EL PASO. UNLIKE THE LAST 2 DAYS WHEN LIMITED AREAL COVERAGE PRECLUDED MORE THAN A
SLIGHT RISK... WE MAY HAVE THE OPPOSITE PROBLEM TODAY WITH STORMS BECOMING TOO NUMEROUS AND UPDRAFT COMPETITION LIMITING THE CHANCES OF ANY ONE STORM TO MAINTAIN DOMINANCE. BUT WITH ALL ELSE SUPPORTING MORE WIDESPREAD SEVERE STORMS TODAY... WE ARE DISCUSSING THE SITUATION FURTHER WITH SPC AND WILL GO TO A MODERATE RISK IN THE UPCOMING HWO. WE PLAN TO DO ANOTHER 18Z SOUNDING TODAY.

TUESDAY HAS THE POTENTIAL TO BE EVEN WORSE IN TERMS OF WIDESPREAD AND POSSIBLY SIGNIFICANT SEVERE WEATHER. MUCH WILL DEPEND ON HOW STORMS EVOLVE TODAY AND TONIGHT. AXIS OF VERY POTENT NEGATIVE-TILT UPPER TROUGH IS FORECAST TO MOVE INTO NM EARLY TUE AND DRIVE E INTO W TX BY 18Z. EFFECTS OF THIS SYSTEM MAY ARRIVE RELATIVELY EARLY IN OK ON TUE AND LEAD TO AN EARLY START TO THE CONVECTION. IF CAP HOLDS OFF INITIATION UNTIL LATER IN THE DAY WHEN INSTABILITY WILL LIKELY GO FROM STRONG TO EXTREME.. WE COULD BE LOOKING AT A SIGNIFICANT SEVERE WEATHER OUTBREAK PER SWODY2.

UNSEASONABLY STRONG WINDS FOR LATE MAY COULD DEVELOP TUESDAY AND WEDNESDAY IN ASSOCIATION WITH THE INTENSE 992-ISH SURFACE LOW - ALSO UNSEASONABLY STRONG FOR LATE MAY. STRONGEST WINDS LIKELY TO BE SOUTHWESTERLY OUT W TUESDAY AFTERNOON BEHIND THE DRY LINE... AND FROM THE NW ON WEDNESDAY ON THE BACK SIDE OF THE LOW. GFS-MOS GUIDANCE GIVES US 30-35 KT OVER W OK... AND 35-45 KT OVER W KS AND NW TX. THIS IS VERY REMARKABLE FOR THIS LATE IN THE SPRING. WE WILL NOT GO QUITE THAT STRONG... BUT VERY WELL MAY BE LOOKING AT WIND ADVISORIES ON EITHER OR BOTH DAYS.

COOLER ALL AREAS WED AS SYSTEM WINDS UP AND BECOMES VERTICALLY STACKED OVER E KS. MAY BE SOME WRAPAROUND SHOWERS OR SOME RELATIVELY WEAK COLD-POOL CONVECTION ON WEDNESDAY ACROSS MAINLY N OK.

EXTENDED GRIDS BASED ON STANDARD INITIALIZATION WITH MINOR RETOOLING TO MATCH UP BETTER WITH NEIGHBORS. KEEPING IT DRY FOR NOW... BUT THERE ARE INCREASING INDICATIONS THAT THE RIDGING UPSTREAM OF THE TUE-WED SYSTEM WILL BREAK DOWN BY THE END OF THE WEEK. THIS COULD PLACE US BACK INTO AN ACTIVE PATTERN BY MEMORIAL DAY WEEKEND. POPS ALMOST CERTAINLY WILL NEED TO BE RAISED AT SOME POINT... BUT THERE IS PRESENTLY TOO MUCH VARIANCE BETWEEN THE GFS AND THE ECMWF TO EVEN BEGIN TO SAY WHEN AND WHERE THE HIGHER CHANCES WILL BE.

[venture]

We are in the chat room already this morning. I reset everything. Please, if you are a reg - send me an email at info@chatokc.com and I'll send you an invite to where you won't have to get unmoderated every time you enter the room.

[BG918]

Two main things to watch today which will affect tomorrow:

1. Coverage of storms. If there are lots of storms that develop, especially several clusters, the tornado threat won't be as high but there will still be the possibility of hail, high winds and very heavy rain/flash flooding.

2. Lingering storms tomorrow. If the first wave goes through and then there is another, or just morning convection due to the moist unstable airmass, that will limit the severe potential tomorrow. It doesn't appear that will be an issue today though as even where there were morning storms/clouds in NE Oklahoma it is expected to clear later this morning. Central OK is clear with temps. and dewpoints already in the 70's.

Isolated storms on the dryline this afternoon could be tornado producers. We will just have to watch and see what happens.

[Thunder]

Well I hate being the one that was right in this. We are watching a wave approach that was over Northern Mexico early this morning. As this moves over, more widespread severe storms will start to develop across the body of Oklahoma. Tornado threat is going to be higher near any left over boundaries from yesterday and this morning's activity.

We are back under a moderate risk for nearly all of OK except for extreme western, southern and southeast OK.

What do you mean by "wave" ... storms or what?

[BrettL]

Rather than repeat the forecast - here's our thoughts. Plan on chasing today and tomorrow. Tomorrow could be particularly dangerous. Stay weather aware!

Hook-Echo.com Severe Weather Blog

[bandnerd]

All I can say is that humidity is staggering. Wow.

[Thunder]

All I can say is that humidity is staggering. Wow.

The dryline will be the yellow and westward. Anything east of that will be where the areas will be critical for a disaster repeat.