April 26th Severe Weather

[TheWeatherPimp]

[CUmet]

SPC is probably seeing the low spinning up over AR and moving NE over the 00-06z time frame in the RUC and HRRR, hence the reason for the high risk upgrade to the east.

We are probably witnessing history being made in the next 36 hours.

[VAwxman]

SPC is probably seeing the low spinning up over AR and moving NE over the 00-06z time frame in the RUC and HRRR, hence the reason for the high risk upgrade to the east.

We are probably witnessing history being made in the next 36 hours.

Coming from you, these are incredibly strong words. (I of course mean that out of respect )

Hard to argue with the potential though, no doubt.

[Powerball]

DTX issed a briefing for the severe weather threat this afternoon.

http://www.crh.noaa.gov/dtx/?n=multimediabriefing

[Powerball]

GRR, IWX and CLE included a severe wording in their point forecasts.

[OceanStWx]

SPC is probably seeing the low spinning up over AR and moving NE over the 00-06z time frame in the RUC and HRRR, hence the reason for the high risk upgrade to the east.

We are probably witnessing history being made in the next 36 hours.

Considering the GEFS forecasting a -3 sigma surface low tracking across the Red River into Arkansas, I would expected some near record weather to go with it.

[earthlight]

60% hatched wind extends east with the high as well

[Powerball]

Per IWX's update, they're banking on the mid-level dry slot over IL/MO to move NE and further destabilize the atmosphere, and while they're not impressed with the strength of the cold front they still believe it will be sufficient to trigger convection.

Per GRR's update, they're not overly impressed, but they can't discount the strength of the approaching vort max and the high shear values so they think hail will be the biggest threat, with the best time between 4 PM and 8 PM.

[Hoosier]

I just don't know if there's going to be enough directional shear in our area. Looks borderline and could go either way. I probably would've gone 5% like SPC.

[TheWeatherPimp]

Latest HWO from IND:

SCATTERED THUNDERSTORMS ARE EXPECTED THIS AFTERNOON ACROSS

CENTRAL INDIANA. SEVERE THUNDERSTORMS WILL BE POSSIBLE THIS

AFTERNOON WITH DAMAGING WINDS...LARGE HAIL AND ISOLATED TORNADOES.

[caviman2201]

Does anyone have any insight on why there's no Tornado Watch or at least Svr T-Storm Watch up for NE TX and SW AR?

[k***]

Does anyone have any insight on why there's no Tornado Watch or at least Svr T-Storm Watch up for NE TX and SW AR?

Because we still have a ways to go before the actual threat...you don't want to issue it too early and give the general public the impression that nothing is happening as you wait for initiation to occur hours later. Some may preemptively declare a bust and tune out before things get dangerous.

[Chinook]

They usually issue a watch when they see the first blip on radar they think will turn into a severe storm. I am seeing almost nothing on radar.

[Powerball]

Does anyone have any insight on why there's no Tornado Watch or at least Svr T-Storm Watch up for NE TX and SW AR?

Several reasons...

1. It's too early

2. Tbe rest of the reasons are because of number one.

-We still have to erode the cap

-We sitll have ot mix out the leftover cloud debris

-The main shortwave has yet to arrive

[caviman2201]

I'm just saying it seems you'd want to get a dangerous situation like this on the public's minds early... 15Z HRRR has SVR storms breaking out in the next 2-3 hours if I'm reading this correctly...

[Dunkman]

I'm just saying it seems you'd want to get a dangerous situation like this on the public's minds early... 15Z HRRR has SVR storms breaking out in the next 2-3 hours if I'm reading this correctly...

I generally agree and hope that more is done in the future to make the public aware of the differences between a tornado watch when they're expecting EF0 tornadoes and a high risk outlook and PDS TW. That said, the media coverage for this event has been massive and anyone who doesn't know there's a major severe threat the next few days isn't paying any attention and wouldn't notice a tornado watch anyway.

[OceanStWx]

I generally agree and hope that more is done in the future to make the public aware of the differences between a tornado watch when they're expecting EF0 tornadoes and a high risk outlook and PDS TW. That said, the media coverage for this event has been massive and anyone who doesn't know there's a major severe threat the next few days isn't paying any attention and wouldn't notice a tornado watch anyway.

Another consideration is that if you issue too early and nothing happens within the first few hours some of the public will then write off the threat. A lot of research is currently being done on public response, and we may find in the future that longer lead times can lead to a more prudent response. For the time being the thought is that there is such a thing as too early for a watch.

[caviman2201]

I guess since I live in MD, I wouldn't know how the local media is handling this. I'm glad the local news agencies are doing their jobs...

[Thundersnow12]

dryline will really start to tighten as we go through the afternoon and end up around I-35 with backed sfc winds and dew points in the low 70's heading up towards the metroplex..

84/71 at CRS

[Stevo6899]

Probably not the place to be asking this but where are all these low pressures coming from and why is their such a slow movement east. Just glanced at the next 48 hours on the gfs and low after low keep tracking along the stationary boundary/cold front. So used to one cold front blasting through and that's it.

[Jonbo]

I generally agree and hope that more is done in the future to make the public aware of the differences between a tornado watch when they're expecting EF0 tornadoes and a high risk outlook and PDS TW. That said, the media coverage for this event has been massive and anyone who doesn't know there's a major severe threat the next few days isn't paying any attention and wouldn't notice a tornado watch anyway.

Definitely agree there. After the past couple of days between the STL tornado, Vilonia and other towns in AR, I think the general public will be much more aware today so hopefully it limits the potential for fatalities. Plus the fact that spotter activity will likely be enormous, it'll give people much more time to prepare.

[tornadojay]

Probably not the place to be asking this but where are all these low pressures coming from and why is their such a slow movement east. Just glanced at the next 48 hours on the gfs and low after low keep tracking along the stationary boundary/cold front. So used to one cold front blasting through and that's it.

if you look at the upper levels a bit.. you can get an idea of how the surface features will evolve. You've got a trof that is continually digging itself in that particular area with a continual stream of vorticity advection, which is basically lowering surface pressure across the same area for a long period of time. By about hour 30, the vorticity maximum has finally made it around the base of the trof and then begins to eject northeastward, and the low begins moving a bit faster.... but it's that digging phase early on that keeps things on the slower side, initially.

[weathergy]

From me, just so you folks know.

[Stevo6899]

if you look at the upper levels a bit.. you can get an idea of how the surface features will evolve. You've got a trof that is continually digging itself in that particular area with a continual stream of vorticity advection, which is basically lowering surface pressure across the same area for a long period of time. By about hour 30, the vorticity maximum has finally made it around the base of the trof and then begins to eject northeastward, and the low begins moving a bit faster.... but it's that digging phase early on that keeps things on the slower side, initially.

Makes sense. Thanks for the input. Feel for those down south. Hope mother nature shows some mercy today and takes it easy on the flood/ tornado prone areas the past few days. 14 inches of rain in Ark and were not even close to being in the clear. Ridiculous

[psualum95]

MESOSCALE DISCUSSION 0589

NWS STORM PREDICTION CENTER NORMAN OK

0111 PM CDT TUE APR 26 2011

AREAS AFFECTED...NORTHEAST TX AND FAR SOUTHEAST OK/NORTHERN

LA/SOUTHERN AR

CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY

VALID 261811Z - 262015Z

THE SEVERE THREAT IS EXPECTED TO STEADILY INCREASE THROUGH MID/LATE

AFTERNOON...INITIALLY ACROSS PORTIONS OF NORTHEAST TX AND INTO

SOUTHEAST OK/NORTHERN LA/SOUTHERN AR. A RELATIVELY LONG LEAD

TIME/DURATION PARTICULARLY DANGEROUS SITUATION /PDS/ TORNADO WATCH

WILL LIKELY BE ISSUED BY MID AFTERNOON.

WITH SURFACE CYCLOGENESIS UNDERWAY ACROSS THE SOUTHERN HIGH

PLAINS...THE WARM SECTOR AIRMASS...EAST OF A NEAR I-35 CENTRAL TX

DRYLINE...AND ALONG/SOUTH OF A SLOW NORTHWARD-RETURNING

SOUTHWEST-NORTHEAST ORIENTED FRONTAL BOUNDARY FROM THE SOUTH DFW

METRO INTO SOUTHERN AR...HAS ALREADY BECOME MODERATE TO STRONGLY

UNSTABLE IN THE PRESENCE OF LITTLE CINH. AFTER A BRIEF BOUT OF

SHORTWAVE RIDGING AT MIDDAY...THE LEADING EDGE OF AN UPPER JET

STREAK APPEARS TO HAVE REACHED THE SOUTHERN HIGH PLAINS...WITH

LIKELY-ASSOCIATED DEEP MIXED CUMULIFORM DEVELOPMENT NOW EVIDENT

ACROSS EASTERN NM/NORTHWEST TX PER VISIBLE SATELLITE IMAGERY.

INCREASING DEEP LAYER WIND FIELD ATOP THE MOIST/UNSTABLE WARM SECTOR

WILL BE HIGHLY FAVORABLE FOR SUPERCELLS WITH AN INCREASING LARGE

HAIL/TORNADO THREAT INTO THIS EVENING. STRENGTHENING LOWER

TROPOSPHERIC WINDS THIS EVENING WILL ACCENTUATE THE RISK OF STRONG

TORNADOES ESPECIALLY ACROSS THE ARKLATEX VICINITY/ADJACENT FAR

SOUTHEAST OK.

..GUYER.. 04/26/2011

[tornadotony]

Nice rotating low-topped sup in Kankakee County, IL.

[OceanStWx]

Impressive cloud field, as stated by the SPC

[psualum95]

URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 215

NWS STORM PREDICTION CENTER NORMAN OK

145 PM CDT TUE APR 26 2011

THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF

SOUTHERN AND CENTRAL ARKANSAS

NORTHERN LOUISIANA

EXTREME SOUTHEAST OKLAHOMA

NORTHEAST AND NORTH CENTRAL TEXAS

EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 145 PM UNTIL

1000 PM CDT.

..THIS IS A PARTICULARLY DANGEROUS SITUATION

DESTRUCTIVE TORNADOES...LARGE HAIL TO 4 INCHES IN DIAMETER...

THUNDERSTORM WIND GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE

POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 80 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 45 MILES NORTHWEST OF WACO

TEXAS TO 60 MILES NORTHEAST OF EL DORADO ARKANSAS. FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU5).

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 213...WW 214...

DISCUSSION...SEVERE THUNDERSTORMS ARE EXPECTED TO RAPIDLY DEVELOP

THIS AFTERNOON OVER NORTHEAST TX...SPREADING ACROSS THE WATCH AREA

THROUGH EARLY EVENING. OTHER INTENSE STORMS WILL DEVELOP BY EARLY

EVENING OVER NORTHEAST TX AND ALSO SPREAD EASTWARD. BOTH AREAS OF

SEVERE STORMS WILL LIKELY INCLUDE DISCRETE SUPERCELLS CAPABLE OF

VERY LARGE HAIL...DAMAGING WINDS...AND TORNADOES. WIND FIELDS WILL

BE STRENGTHENING THROUGH THE EVENING...AND STORMS TRACKING NEAR THE

EXISTING BOUNDARY FROM TX INTO AR WILL HAVE ENHANCED SHEAR AND THE

RISK OF STRONG/LONG-LIVED TORNADOES.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL

SURFACE AND ALOFT TO 4 INCHES. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

600. MEAN STORM MOTION VECTOR 25035.

...HART

[OceanStWx]

The hazard probabilities for this PDS watch are as high as I've ever seen.

[huronicane]

I'm not sure I've ever seen probabilities on a watch like that:

P(2+Tor): >95%

P(>EF2): 90%

P(10+AnyHail): >95%

P(2"+Hail): >95%

P(10+AnyWind): 90%

P(>65knotWind): 80%