General Weather Discussion - May 2015

[okatty]

KFOR just reported that wild animals are loose in the Tuttle area from a wildlife park. Have heard it ALL now.

[d-usa]

I wonder if today may make a case for sectioning off the storm sirens in Oklahoma City. I hope that nobody on the north side gets siren fatigue and gets hit by anything later tonight...

[rezman]

9:50 pm and the severe threat is over for Oklahoma County, and the sirens just went off again in northern Okla county.... What the hell?!! They've been going off all evening at about 10 - 15 minute intervals and nothing is going on up here....Enough already!.

[venture]

A 60% chance for thunderstorms in OKC for Thursday night.

Doesn't really answer what he was asking for.

I wonder if today may make a case for sectioning off the storm sirens in Oklahoma City. I hope that nobody on the north side gets siren fatigue and gets hit by anything later tonight...

Norman did that when they replaced all the sirens a few years back. OKC definitely should considering how large it is.

[Urban Pioneer]

They are actually capable of being sounded individually. It is a far more sophisticated system in capability in contrast to how it is used. Our company actually designed and installed a system for OUHSC that annunciates a recording "A tornado is in the area." "A tornado is not in the area."

The excuse that has been given is that OKC sounds it sirens anytime a warning encroaches anywhere in Oklahoma County as Emergency Management policy assumes that someone may commute into the storm. It's a liability issue created policy.

[venture]

The national weather service in norman has issued a


* tornado warning for...
Central seminole county in east central oklahoma...


* until 1145 pm cdt

* at 1120 pm cdt...a severe thunderstorm capable of producing a
tornado was located 3 miles southwest of seminole...moving east at
15 mph.


Hazard...tornado and tennis ball size hail.


Source...radar indicated rotation.

[venture]

SPC Outlooks...

Day 1 - SLIGHT RISK for Western and South Central OK, MARGINAL for everyone else.

Day 2 - ENHANCED RISK for Central into Southwest OK, SLIGHT RISK for all but extreme Southeast OK - MARGINAL for them.

[UnclePete]

People in Oklahoma City and the state of Oklahoma can't run anything right. How long will it be until the residents start ignoring the sirens?

[bandnerd]

Venture, what causes storms to stall out like that and just sit over an area? It happened two years ago with the El Reno tornado, too. We had flooding and so did the Paseo and other parts of OKC, much like last night. Both of those storms took hours to move on. Thanks!

[SoonerDave]

They are actually capable of being sounded individually. It is a far more sophisticated system in capability in contrast to how it is used. Our company actually designed and installed a system for OUHSC that annunciates a recording "A tornado is in the area." "A tornado is not in the area."

The excuse that has been given is that OKC sounds it sirens anytime a warning encroaches anywhere in Oklahoma County as Emergency Management policy assumes that someone may commute into the storm. It's a liability issue created policy.

That may be the public story, but I was told by someone with credentials I absolutely trust that, as you note, the system is absolutely addressable on an individual basis, but the main control system has, in effect, big "panic button" that fires all the sirens a once. I was told it is much easier to hit that, and then selectively turn off the ones not affected, than to do the reverse. It's a matter of convenience in a critical situation. I just don't know if I buy 100% into the liability issue considering the notion of sovereign immunity..

[jn1780]

Doesn't seem like it would be hard to divide the sirens in half and have north side sirens and Southside sirens.

[Jesseda]

what is the official rain total? I am curious about how much Moore got.

[Anonymous.]

OKC

Slight risk today.
Enhanced risk tomorrow.
Moderate risk Saturday.

Friday and Saturday could be big time. Saturday will likely be the first High Risk of the season (somewhere).

[Anonymous.]

You can gauge how much rain fell with this. This does include the overnight rain we got before the storms:





bchris, this was not one storm. This was identical to two years ago when storms keep riding up the same boundaries. Each passing storm lays down a type of boundary and the next storm kind of hugs and manipulates the boundary as it moves along. With supercells, they are so strong and self-sustained, that they actually move the boundary (usually laid down just south of passing storm) back to the north slightly. The result is a chain or linking of supercells riding along over the same areas.

[venture]

Just to reinforce what Anon has posted...Saturday is the big deal. We have a Day 3 Moderate Risk and these almost always translate to a High Risk day.



DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0255 AM CDT THU MAY 07 2015

VALID 091200Z - 101200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PORTIONS OF OKLAHOMA AND
KANSAS...

...THERE IS AN ENH RISK OF SVR TSTMS AROUND THE MDT RISK AREA FROM
NORTH TX TO KANSAS...

...THERE IS A SLGT RISK OF SVR TSTMS AROUND THE ENH RISK AREA FROM
TX RIO GRANDE VALLEY TO WRN MO AND WEST TO A SMALL PART OF ERN CO...

...THERE IS A MRGL RISK OF SVR TSTMS FROM TX TO THE MIDWEST...

...SUMMARY...
A SEVERE WEATHER OUTBREAK APPEARS POSSIBLE ACROSS PARTS OF THE GREAT
PLAINS ON SATURDAY. WIDESPREAD INTENSE THUNDERSTORMS SHOULD DEVELOP
OVER PORTIONS OF OKLAHOMA...KANSAS...AND TEXAS DURING THE AFTERNOON.
TORNADOES...VERY LARGE HAIL...AND DAMAGING WINDS ARE LIKELY IN THESE
AREAS.

...SOUTHERN AND CENTRAL PLAINS...
THERE IS INCREASING CONFIDENCE IN THE LARGE SCALE PATTERN EVOLUTION
ACROSS THE SRN AND CENTRAL PLAINS THROUGH SATURDAY AS A POTENT AND
PROGRESSIVE MID/UPPER DISTURBANCE EMERGES FROM THE ROCKIES AND
SPREADS HEIGHT FALLS/ASCENT AND STRONG SHEAR ACROSS A WARM AND
UNSTABLE AIRMASS.

BY LATE SATURDAY AFTERNOON...THE INGREDIENTS SHOULD COME TOGETHER TO
SUPPORT A SEVERE WEATHER OUTBREAK ACROSS THE SRN/CENTRAL PLAINS.
ALTHOUGH THERE REMAIN UNKNOWN DETAILS WITH RESPECT TO MOST
SIGNIFICANT THREAT AND STORM EVOLUTION...GENERAL PATTERN RECOGNITION
AND REMARKABLE AGREEMENT IN LATEST GUIDANCE WITH RESPECT TO LARGE
SCALE FORCING FOR ASCENT ASSOCIATED WITH HEIGHT FALLS/UPPER TROUGH
AND JUXTAPOSITION OF INSTABILITY AXIS...AND CLIMATOLOGY...ALL
SUPPORT A RELATIVELY HIGH CONFIDENCE FORECAST OF NUMEROUS INTENSE
STORMS/SUPERCELLS CAPABLE OF PRODUCING VERY LARGE/DAMAGING HAIL AND
A FEW STRONG/LONGER-LIVED TORNADOES IN THE MODERATE RISK AREA.

THIS SCENARIO WILL UNFOLD AMIDST A VERY MOIST WARM SECTOR WHERE SFC
DEW POINTS AROUND 70F SHOULD RESIDE AHEAD OF A SHARPENING DRYLINE
EXTENDING SOUTH FROM DEEPENING LEE CYCLONE FROM SWRN KS SWD INTO W
TX. 50-60 KTS OF SWLY 500 MB FLOW WILL PIVOT AROUND MID/UPPER LOW
AND ACROSS OK/KS AS A SFC LOW CONTINUES TO STRENGTHEN THROUGH EARLY
EVENING. BACKED LOW LEVEL FLOW BENEATH THE STRONG SWLY 500MB FLOW
WILL RESULT IN HIGH SRH SUPPORTIVE OF POTENTIAL STRONG TORNADOES AS
WELL AS VERY LARGE HAIL. INITIAL DISCRETE CONVECTION SHOULD GROW
UPSCALE INTO CLUSTERS OR LINES THROUGH THE EVENING WITH SEVERE
WIND...HAIL...AND FLOODING THREATS CONTINUING INTO THE NIGHT EAST
ACROSS THE MISSOURI VALLEY AND SOUTH INTO TX.

..CARBIN.. 05/07/2015

[Anonymous.]

Storms developing now in TX PH. As our atmosphere here in C and W OK continues to destabilize with the sun being out, we could see a couple storms become rowdy by this afternoon.

NAM sort of brings the storms up as a cluster without much individual organization, but anything that tries to get isolated could become a pretty good hailer or more.

[Mike_M]

Agreed on the siren fatigue. I was downtown doing an event with some non-locals and they kept freaking out every time they heard the sirens. I had to pull out the weather map on my phone every time and explain that we weren't in danger.

[venture]

Slight Risk Expanded East






...OK/TX THROUGH TONIGHT...
AN OUTFLOW BOUNDARY IS LOCATED ACROSS N CENTRAL/NW TX THIS MORNING.
THE ONGOING CONVECTION OVER THE RED RIVER VALLEY WILL HELP MAINTAIN
THE COLD POOL THIS MORNING...BUT IT IS LIKELY TO MODIFY AND RETREAT
NWD LATER TODAY ACROSS NW TX/SW OK/SE TX PANHANDLE. THE PROBABLE
SCENARIO FOR TODAY IS TO SEE THE BOUNDARY RETREAT AND SOME
ADDITIONAL CONVECTION FORM BY LATE MORNING-EARLY AFTERNOON TO THE
W...WITH THE STORMS EXPECTED TO SPREAD EWD THROUGH THE
AFTERNOON/EVENING ALONG THE RESIDUAL OUTFLOW BOUNDARY. BOUNDARY
LAYER DEWPOINTS IN THE MID-UPPER 60S IMMEDIATELY S OF THE
OUTFLOW...COMBINED WITH DAYTIME HEATING AND A RE-ESTABLISHED
ELEVATED MIXED LAYER PER 12Z MAF SOUNDING...WILL RESULT IN MLCAPE
VALUES AOA 2500 J/KG. DEEP-LAYER VERTICAL SHEAR AND BUOYANCY WILL
AGAIN FAVOR SUPERCELLS CAPABLE OF PRODUCING ISOLATED VERY LARGE
HAIL. A FEW TORNADOES WILL ALSO BE POSSIBLE GIVEN THE SUFFICIENTLY
MOIST BOUNDARY LAYER...AND SOME MODEST ENHANCEMENT TO LOW-LEVEL
SHEAR BY THIS EVENING ACROSS N/NW TX AND SW OK WITH THE BELT OF
STRONGER LOW-LEVEL FLOW...AND IN CONJUNCTION WITH ANY RESIDUAL
BACKED LOW-LEVEL FLOW ALONG THE REMNANT OUTFLOW BOUNDARY. STORMS
MAY EVOLVE INTO ANOTHER MCS ACROSS CENTRAL/SRN OK THIS EVENING INTO
EARLY TONIGHT.

[Anonymous.]

Not to alarm anyone, but some of the short-range models are painting another 3-6 inches of rain over much of C OK through tonight with the storms that will be evolving out of NW TX and into SW and W OK.

[venture]

HRRR going super widespread today with convection, storms could be into the Metro by 4PM, but should...hopefully, be out of here by 9 to 10PM. Greatest tornado threat should be over Southwest and South Central OK...but just keep an eye out.

[HangryHippo]

Venture, what is Saturday morning looking like? I've got a loved one flying to Indianapolis early that morning and am having some anxiety over them making the flight.

Edit: The itinerary is DFW - CLT - IND for Saturday morning.

[LocoAko]

As a meteorologist, that was one of the most ridiculous evolutions of a storm that I've ever seen. It did remind me a bit of 5/31/13 (sans that large/strong of a tornado), but I was back home dealing with a family situation at the time and didn't watch the radar in real-time for most of that event. Still trying to wrap my head around it. Later on in the evening, seemingly random couplets were forming and just being slingshot around the main mesocyclone and dissipating just as quickly as they formed (particularly in the southern half of OKC). I'm confident a lot of investigating and research will be done on this as a case study... pretty incredible stuff. Myself and a bunch of friends couldn't get home last night and wound up sleeping at friends' houses or in our offices... and saw some pretty bad damage around I35/SE44th while driving back home today.

Between all of the rain two nights ago and the insane rains last night, I shudder to think what would happen with more widespread rain over the area today. And I'll be the first to admit that the models did not forecast this well at all. I think the local mets (and SPC) did a pretty good job (sans a few comments on-air that made me cringe) considering the strange evolution of the storm and being on air for 8 hours straight... pretty noble work IMO. But from what I can recall none of the models really forecast anything close to what wound up transpiring last night.

[bchris02]

Does tonight look like a repeat, with supercells going up in SW OK and moving up the H.E. Bailey into OKC?

[Dessert Fox]

Does tonight look like a repeat, with supercells going up in SW OK and moving up the H.E. Bailey into OKC?

No, It'll be storms moving in a line from the Texas panhandle through Oklahoma. It should just be mainly heavy rain and some hail/wind.

[LakeEffect]

Not to alarm anyone, but some of the short-range models are painting another 3-6 inches of rain over much of C OK through tonight with the storms that will be evolving out of NW TX and into SW and W OK.

Yikes. Listening to the scanner last night, OKCFD was being worked very hard. Hope tonight isn't as bad.