Oklahoma Severe Weather Discussion - May 2012

[jn1780]

I went through a derecho in 2006 in St Louis. They are every bit as scary as a tornado. This occurred during the same weekend as the opening of the new Busch Stadium, and several people were hurt very badly during a Cardinals game. The best way I would describe it is 3-5 minutes of howling 70-80 mph winds (no gusts just straight unrelenting winds). Since they are huge geographically there is no escape. I just got my power back on at my house this morning and I definitely will be preparing for this tonight. During the height of the storm, something like 70% of St Louis City/County was without power.

Venture, maybe I heard wrong but I always understood that derechos were summer events that usually occurred in the Midwest and Northeast?

Derecho's are what causes power to be out for several days. That and icestorms.

[bandnerd]

How do you say Derecho? Is it Derecho, like Jericho, or Der-Echo? If I ever have a reason to say it out loud, I don't want to sound like an idiot

[venture]

Venture, maybe I heard wrong but I always understood that derechos were summer events that usually occurred in the Midwest and Northeast?

Growing up in the Great Lakes we definitely seemed to experience them quite a bit it seemed, more so than down here. However, in the 2nd link above it had an image to show just how common they are here and the typical time frame for them...



As you can see we are pretty much right in the thick of it and also in the peak season for them. Normally we do tend to see them more in the summer here because we are often in a NW flow pattern then where they develop over SE CO and W KS and race southeast.

[venture]

How do you say Derecho? Is it Derecho, like Jericho, or Der-Echo? If I ever have a reason to say it out loud, I don't want to sound like an idiot

I'm so glad Wiki has this already typed out. LOL

derecho (Spanish: derecho "straight", pronounced [de̞ˈɾe̞tʃo̞])

[Kaye]

Sure...so the main page is: http://ruc.noaa.gov/hrrr/
Step 2) Click on 3km HRRR-CONUS hourly
Step 3) Under Domain select SC for South Central US
Step 4) Look at the time frames available. Usually if it isn't through Hour 06 yet, I'll just go up to Date and select the previous time.
Step 5) Depending on what you want to see you can click on the specific time or to loop all the times available you'll see a Check Mark under loop. You can click that to loop them all.

So for the simulated radar image you will go under the 3rd product called Composite Reflectivity and click the check mark under loop. That will provide the image I normally put. There are a ton of other products available for this model so enjoy.

Thanks very much! I'm off to have a look.

[bandnerd]

I'm so glad Wiki has this already typed out. LOL

derecho (Spanish: derecho "straight", pronounced [de̞ˈɾe̞tʃo̞])

I'm glad you didn't have to type that out lol.

[venture]

I'm glad you didn't have to type that out lol.

I would still be trying to figure it out. LOL

Couple updates...

- Moderate Risk has been expanded in size. The Western Edge is now from the Beaver/Harper County line south to Arnett to Sayre to Altus. The Eastern edge is now from Bartlesville to Tulsa to Okmulgee to Coalgate to Durant.
- 10% Tornado Risk area is roughly from Medford to Guthrie to NW OKC to El Reno to Arapaho to Arnett and back to the north...so north of that line is the great tornado risk.
- 45% Hail Risk with Significant Hail Risk (2"+) is in the Moderate Risk area.
- 45% Damaging Wind Risk with Significant Wind (75 mph +) is in the same Moderate Risk area.

[PennyQuilts]

Sure...so the main page is: http://ruc.noaa.gov/hrrr/
Step 2) Click on 3km HRRR-CONUS hourly
Step 3) Under Domain select SC for South Central US
Step 4) Look at the time frames available. Usually if it isn't through Hour 06 yet, I'll just go up to Date and select the previous time.
Step 5) Depending on what you want to see you can click on the specific time or to loop all the times available you'll see a Check Mark under loop. You can click that to loop them all.

So for the simulated radar image you will go under the 3rd product called Composite Reflectivity and click the check mark under loop. That will provide the image I normally put. There are a ton of other products available for this model so enjoy.

So neat, Venture. Thanks for the link and instructions. I am not sure I am making proper heads or tails of them but am having fun exploring.

[venture]

2PM Update...

CU development is well underway in many areas west of I-35. Best CU fields right now are over SW KS, NC OK, and also along the dryline in the southern TX PH. We also still show good evidence of outflow boundaries remaining. Most prominent one is from around Lawton southeast into the DFW Metroplex. Looking at visible satellite also shows a good amount of difference in wind direction with height.

Instability is increase rapidly as well. We are now highly unstable here in Central sections. CIN values are still relatively high right now to keep a lid on things for a bit longer. CIN values are gone in the TX PH and instability is very high to extreme out there.

HRRR is wanting to get things going pretty quickly now, but seems it is off by a couple of hours. It has storms popping up initially in SW KS (where an MCD is now posted by SPC) and then along the dryline in the TX PH. It keeps Oklahoma activity relatively low right now until 5PM with some storms moving into far northern and far SW OK. It then also develops some isolated storms over Central OK by 6PM. Damaging MCS is well advertised now to enter NW OK by 7PM and race SE. It is shown to impact OKC Metro by 10PM.

We'll need to see how things progress. I think timing is off by a bit and it is underplaying some chances for earlier development in Oklahoma. Of course if we don't see anything in Oklahoma before hand, that is going to provide a lot of energy for this MCS/MCC to feed off of through Oklahoma. It isn't out of the realm of possibility we could see a rare PDS SVR box.

I'll be in the chat later this afternoon. Have some things to tend to right before dinner time. I'll hurry - promise!

[RadicalModerate]

If we get a rerun of last night's storm, I think that all of the local TV Weatherpersons need to be replaced.

(that was a veiled compliment to what you, Sir (venture79) do right here in this forum.
please do not confuse that statement with anything other than what it is.)

Where I grew up (on the eastern slope o' the Rockies) we didn't have "Der-Ah-Chose" . . .
We had "Chinooks".

I worked with a guy from Chicago (back then) who thought that "Schnook Winds" were the funniest thing he ever heard of.
He also never ended sentences in prepositions.
In addition to that, he never had all of the windows of every vehicle at the house broken out by flying gravelrocks and all of the windows on the west side of the house blown out by the 110 mph peak gusts--that interrupted the 60 mph straight winds.

(You could see NCAR On The Mesa from our front yard.
The Chinooks once broke their Wind Gauge so they could only estimate the actual speed . . . )

[venture]

Starting to get some elevated development along the dryline. Appears to be several tower CU / "turkey towers" going up. On radar nothing is showing on the surface scan, but on the ones as a higher angle do pick them up. Would not be shocked to see the panhandle and western OK boxed here soon to accommodate this.

[venture]

No major changes to the SPC outlook except reducing tornado risk due to expected MCS mode...pretty much the main point we've been pushing the last couple of days.

[Kaye]

Venture, do you think that by the time storms reach the metro the hail threat and size will have diminished? I'm asking because it seems when the storms came through last night they were split for a good while. I honestly don't remember ever hearing of such a large coverage of large hail in other storms when they're congealed.

[venture]

Tornadoes

Probability of 2 or more tornadoes	Mod (40%)
Probability of 1 or more strong (F2-F5) tornadoes	Low (20%)

Wind

Probability of 10 or more severe wind events	Mod (40%)
Probability of 1 or more wind events > 65 knots	Low (20%)

Hail

Probability of 10 or more severe hail events	Mod (40%)
Probability of 1 or more hailstones > 2 inches	Mod (30%)

Combined Severe Hail/Wind

Probability of 6 or more combined severe hail/wind events

Mod (60%)

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 322
NWS STORM PREDICTION CENTER NORMAN OK
340 PM CDT WED MAY 30 2012

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

EXTREME SOUTHWEST OKLAHOMA
PARTS OF THE EASTERN TEXAS PANHANDLE AND NORTHWEST TEXAS

EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 340 PM UNTIL
900 PM CDT.

SEVERAL TORNADOES
SCATTERED DAMAGING WINDS TO 80 MPH
SCATTERED LARGE HAIL
ISOLATED HAIL TO 3.0 INCHES IN DIAMETER POSSIBLE

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 30 STATUTE
MILES EAST AND WEST OF A LINE FROM 120 MILES NORTH OF CHILDRESS
TEXAS TO 100 MILES SOUTH OF CHILDRESS TEXAS. FOR A COMPLETE
DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE
(WOUS64 KWNS WOU2).

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 321...

DISCUSSION...STORMS ARE DEVELOPING ON THE DRY LINE OVER THE ERN TX
PANHANDLE WITHIN A VERY UNSTABLE AND FAVORABLY SHEARED ENVIRONMENT.
SUPERCELL STORMS ARE LIKELY TO DEVELOP WITH POTENTIAL TO PRODUCE
VERY LARGE HAIL...DAMAGING WIND GUSTS...AND POSSIBLY A TORNADO OR
TWO. ERN EXTENT OF THE THREAT AREA IS LIMITED BY LOW LEVEL
STABILITY AS INDICATED BY WAVE CLOUDS ON VISIBLE IMAGERY...RESULTING
IN A RATHER NARROW ZONE OF SEVERE WEATHER THREAT.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
600. MEAN STORM MOTION VECTOR 27015.

[venture]

Venture, do you think that by the time storms reach the metro the hail threat and size will have diminished? I'm asking because it seems when the storms came through last night they were split for a good while. I honestly don't remember ever hearing of such a large coverage of large hail in other storms when they're congealed.

As it looks right now hail around 2" is still going to be possible with the MCS, though typically these are more wind machines than hail producers.

[Kaye]

Thank you. And I know the wind threat is nothing to sneeze at. I remember years ago, maybe 1994 or so, when we had a straight line wind event. No power for several days, downed limbs, trees across streets, etc. I'd just prefer not to have the hail blowing in that kind of wind.

[venture]

Thank you. And I know the wind threat is nothing to sneeze at. I remember years ago, maybe 1994 or so, when we had a straight line wind event. No power for several days, downed limbs, trees across streets, etc. I'd just prefer not to have the hail blowing in that kind of wind.

Yup I'm with you there.

Just an FYI...Kansas is now boxed in with a severe tstorm watch.

[OkieHornet]

"god-awful" mike morgan last night.
http://www.youtube.com/watch?v=TNNc20qKJiY

[Achilleslastand]

Will we be getting heavy rainfall in the metro again?

[jmpokc1957]

Watching Amarillo radar light up while enjoying 70 deg in Portland Oregon. 2200Z HRRR got it pretty good although a bit to the east.

Say venture79, your avatar sure looks like landing at pdx( portland, Or ) with Mt. Hood in the background. My second guess would be landing at SeaTac.

Miss the thunderstorms... Very quiet in Oregon.

Mike

[OKCMallen]

About what time will it hit the metro?

[venture]

Tornadoes

Probability of 2 or more tornadoes	Low (20%)
Probability of 1 or more strong (F2-F5) tornadoes	Low (5%)

Wind

Probability of 10 or more severe wind events	Mod (60%)
Probability of 1 or more wind events > 65 knots	Mod (30%)

Hail

Probability of 10 or more severe hail events	Mod (30%)
Probability of 1 or more hailstones > 2 inches	Low (20%)

Combined Severe Hail/Wind

Probability of 6 or more combined severe hail/wind events

High (90%)

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 325
NWS STORM PREDICTION CENTER NORMAN OK
615 PM CDT WED MAY 30 2012

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

WESTERN AND CENTRAL OKLAHOMA
A SMALL PART OF NORTH TEXAS

EFFECTIVE THIS WEDNESDAY NIGHT AND THURSDAY MORNING FROM 615 PM
UNTIL 200 AM CDT.

SCATTERED DAMAGING WINDS
ISOLATED WIND GUSTS TO 65 MPH POSSIBLE
WIDELY SCATTERED LARGE HAIL TO 2.5 INCHES IN DIAMETER
ISOLATED TORNADOES

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 85
STATUTE MILES EAST AND WEST OF A LINE FROM 20 MILES NORTHEAST OF
ALVA OKLAHOMA TO 40 MILES SOUTH OF WICHITA FALLS TEXAS. FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU5).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION...CONTINUE...WW 321...WW 322...WW
323...WW 324...

DISCUSSION...TSTMS ARE STARTING TO FORM OVER W CNTRL AND SW OK.
CURRENT CHARACTER/MOVEMENT OF THIS ACTIVITY SUGGEST THAT STORMS ARE
ROOTED ABOVE THE BOUNDARY LAYER. THE TSTMS MAY CONTINUE TO INCREASE
IN COVERAGE/STRENGTH AS FORCING FOR ASCENT INCREASES WITH CONTINUED
ESE MOTION OF UPR LVL IMPULSES...AND WITH NOCTURNAL INCREASE IN LLJ.
SETUP APPEARS AT LEAST CONDITIONALLY FAVORABLE FOR LOCALLY DMGG WIND
GUSTS / HEAT BURSTS...AND POSSIBLY SVR HAIL. ADDITIONAL STORMS...OR
A COMPLEX OF STORMS...MAY MOVE SSE INTO NRN OK FROM KS LATER THIS
EVE...POSING A FURTHER THREAT FOR HIGH WIND...SVR HAIL ...AND
POSSIBLY ISOLD TORNADOES.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 65
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM
MOTION VECTOR 30025.

[venture]

Watching Amarillo radar light up while enjoying 70 deg in Portland Oregon. 2200Z HRRR got it pretty good although a bit to the east.

Say venture79, your avatar sure looks like landing at pdx( portland, Or ) with Mt. Hood in the background. My second guess would be landing at SeaTac.

Miss the thunderstorms... Very quiet in Oregon.

Mike

Yeah HRRR is doing alright as usual. That is SeaTac with Rainier in the background.

[venture]

Chat room is going at http://www.weatherspotlight.com/chat.html

If anyone has an issue getting in let me know via PM here. CoverItLive changed their system overnight and they are now wanting to charge like $45 a month instead of allow people to use it free with ads. So needless to say, I need to find a new software suite to use. LOL

[OKCisOK4me]

The way it looks on radar, other than the lone storm west of the metro, it looks as if the majority of it will come through late tonight.